Fix #502: no startup crash on dual-GPU Linux desktops under Wayland

0.5.0 asked wgpu for the low-power adapter everywhere (#306). On a Linux
desktop whose KDE Wayland compositor runs on an NVIDIA GPU, wgpu sorted the
Ryzen's integrated RADV GPU first: it reports that it can present to the
window, but KWin can't import the buffers it allocates ("importing the
supplied dmabufs failed"), which is a fatal Wayland protocol error. The next
surface configuration then got ERROR_SURFACE_LOST_KHR and egui-wgpu panicked
("The surface isn't supported by this adapter", winit.rs:129).

- Preferences > Performance > Graphics Processor gains Automatic, the new
  default: power saving on Windows and macOS as #306 wanted, and on Linux the
  system's order, where Mesa's device-select layer puts the GPU the desktop
  runs on first. Values are now automatic / lowPower / highPerformance; 0.5.0
  saved powerSaving for everyone, which reads as automatic.
- The app picks the window's adapter itself (apps/vectorcraft/src/gpu.rs,
  eframe's native_adapter_selector): only adapters that present to the
  surface, WGPU_ADAPTER_NAME first, hardware before software, native backends
  before OpenGL, then the power preference. Every adapter and the pick are
  logged.
- run_native runs under the engine guard. When the graphics fail during the
  first frames (a wgpu error, or a panic in wgpu, egui-wgpu or naga), the app
  starts again without that adapter (exec on Unix, so an AppImage stays
  mounted; a new process on Windows), passing the failed adapters in
  VECTORCRAFT_GPU_SKIP, and says so in the status bar. When none is left it
  logs why and exits with an error, never a panic.
- docs/development.md, README and ROADMAP: the new default, the restart and
  the escape hatches (WGPU_POWER_PREF, WGPU_ADAPTER_NAME, WGPU_BACKEND,
  MESA_VK_DEVICE_SELECT, DRI_PRIME).

Co-Authored-By: Claude Opus 5.5 <[email protected]>

AGENTS.md

@@ -6,13 +6,19 @@ Formerly **DrawCraft** (renamed 2026-10-01): old `.drawcraft` files and `"format
 
 ## Start every session here
 1. Read the [honest assessment in `ROADMAP.md`](ROADMAP.md#honest-assessment-2026-10-05): where we stand by dimension, **where we're lacking** (the prioritized gap list) and **where we're going**. Unless the user gives you a task, pick work from that list.
-2. Read `plan/STATUS.md` (local session notes, may lag the ROADMAP), then the task in `plan/execution-plan.md` §3 and the relevant `plan/architecture.md` section. Behaviour reference: `plan/illustrator/*.md`.
+2. Read `plan/STATUS.md` (local session notes, may lag the ROADMAP), then the task in `plan/execution-plan.md` §3 and the relevant `plan/architecture.md` section. Behaviour reference: public documentation only (see Clean-room below); `plan/illustrator/*.md` holds notes from it.
 3. Follow the autonomous operation protocol (`plan/execution-plan.md` §7): orient → plan → implement + test → verify → record → commit. Don't stop to ask unless §7 lists the decision as the user's.
 
 `plan/` is gitignored (local only).
 
 ## Non-negotiables
-- **Clean-room.** Never read, disassemble or copy anything inside the Illustrator bundle (names/listings only). Never copy Adobe icons, artwork, presets or wording beyond feature names. Behaviour comes from public docs and black-box observation of the running app with synthetic documents only (screenshots by window id, stored under `plan/illustrator/screenshots/`, never committed). Never copy GPL/AGPL code (Inkscape, lib2geom…).
+- **Clean-room: never use Adobe software (absolute rule, from the project owner).** Adobe's Terms of Use forbid reverse engineering, including observing a program's inputs and outputs to recreate it. So:
+  - Never launch, run, script, automate (COM, AppleScript, ExtendScript, UI automation), screenshot or measure Illustrator or any other Adobe application, and never compare our output against one. Don't make test files with them, not even "synthetic" ones.
+  - Never read, disassemble or copy anything inside an Adobe install (binaries, plug-ins, presets, procsets, resources, help files, fonts, ICC profiles).
+  - Never copy Adobe-authored code or text into this repo, tests included: no PostScript procsets or prologs (AGM, CoolType, the Illustrator prologs), no sample files. Write test inputs from scratch from the public specifications (PostScript Language Reference, PDF / ISO 32000, TIFF, EPSF/DCS).
+  - Behaviour comes only from public documentation (helpx, published specs, public forum posts), cited by URL, and from files users send us that they own (used locally, never committed). Never copy Adobe icons, artwork, presets or wording beyond feature names.
+  - If a task seems to need any of this, stop and say so instead. `cargo xtask cleanroom` (run by `cargo xtask ci`) fails on Adobe copyright notices and on fixtures made with Adobe applications.
+  - Never copy GPL/AGPL code (Inkscape, lib2geom…).
 - **Assets: no Adobe iconography or images — ever (absolute rule, from the project owner).**
   - Never add, copy, trace, redraw-from, embed or ship any icon, image, artwork, cursor, preset, swatch/brush/symbol/pattern/style library, ICC profile or screenshot from Adobe products or from any other source whose licence doesn't allow it.
   - Every image, icon, font or other asset must be one of:
@@ -44,7 +50,7 @@ Formerly **DrawCraft** (renamed 2026-10-01): old `.drawcraft` files and `"format
 ## Running and looking at the app
 - `cargo run --release -p vectorcraft -- --control 7979 [file.svg|file.vectorcraft]` (sibling apps' agents use the same default port: if the log says it failed to bind, pick another port — otherwise your requests reach a different app).
 - Drive it: JSON lines on `127.0.0.1:7979`, e.g. `{"id":1,"method":"engine.execute","params":{"command":"shape.rectangle","params":{"x":10,"y":10,"width":100,"height":50}}}` then `{"id":2,"method":"ui.screenshot","params":{"path":"/tmp/shot.png"}}`. Methods: `crates/ui-egui/src/control.rs`.
-- **For UI work, look at the result** (take `ui.screenshot`, read the PNG) and compare with `plan/illustrator/02-ui-ux.md` / `10-observed-ui.md`. `ui.screenshot` needs a presented frame: if it errors (screen locked), check the art with `ui.render` / `vectorcraft-cli run … --export x.png`, and cover panels with a headless egui frame test (see `panels/transparency.rs` tests).
+- **For UI work, look at the result** (take `ui.screenshot`, read the PNG) and compare with the public documentation (`plan/illustrator/02-ui-ux.md` notes). `ui.screenshot` needs a presented frame: if it errors (screen locked), check the art with `ui.render` / `vectorcraft-cli run … --export x.png`, and cover panels with a headless egui frame test (see `panels/transparency.rs` tests).
 - **Performance:** `vectorcraft-cli perf` checks the budgets (render/pan/zoom, hit test, save/open, SVG, Pathfinder) on a synthetic 50k-path document; `vectorcraft-cli bench FILE` times one file. Run them before and after renderer, format or geometry changes, on an idle machine (the report warns when the load average makes timings noise).
 - MCP: `vectorcraft-cli mcp` (see `docs/mcp.md`).
 - Shell gotcha: `mv`/`cp` are aliased interactive here — use `/bin/mv -f` / `/bin/cp -f`.
@@ -53,7 +59,7 @@ Formerly **DrawCraft** (renamed 2026-10-01): old `.drawcraft` files and `"format
 ## Roadmap
 `ROADMAP.md` (committed) is the shared picture of where VectorCraft stands. It holds status, the honest assessment (by dimension, the gap list, the direction), milestones, the parity table and time-to-parity estimates.
 - When a task lands, update it in the same PR: the milestone row, the parity-table row (score, missing items, hours), "Shipped so far", and the gap list if the gap closed or shrank.
-- Grade by behaviour against `plan/illustrator/`, not by whether a menu item exists. Scores are self-assessed, so err low.
+- Grade by behaviour against the public documentation (`plan/illustrator/` notes), not by whether a menu item exists. Scores are self-assessed, so err low.
 - Keep the README's Status section in step with the ROADMAP headline.
 
 ## Contributor credits (About window)

CLAUDE.md

@@ -6,13 +6,19 @@ Formerly **DrawCraft** (renamed 2026-10-01): old `.drawcraft` files and `"format
 
 ## Start every session here
 1. Read the [honest assessment in `ROADMAP.md`](ROADMAP.md#honest-assessment-2026-10-05): where we stand by dimension, **where we're lacking** (the prioritized gap list) and **where we're going**. Unless the user gives you a task, pick work from that list.
-2. Read `plan/STATUS.md` (local session notes, may lag the ROADMAP), then the task in `plan/execution-plan.md` §3 and the relevant `plan/architecture.md` section. Behaviour reference: `plan/illustrator/*.md`.
+2. Read `plan/STATUS.md` (local session notes, may lag the ROADMAP), then the task in `plan/execution-plan.md` §3 and the relevant `plan/architecture.md` section. Behaviour reference: public documentation only (see Clean-room below); `plan/illustrator/*.md` holds notes from it.
 3. Follow the autonomous operation protocol (`plan/execution-plan.md` §7): orient → plan → implement + test → verify → record → commit. Don't stop to ask unless §7 lists the decision as the user's.
 
 `plan/` is gitignored (local only).
 
 ## Non-negotiables
-- **Clean-room.** Never read, disassemble or copy anything inside the Illustrator bundle (names/listings only). Never copy Adobe icons, artwork, presets or wording beyond feature names. Behaviour comes from public docs and black-box observation of the running app with synthetic documents only (screenshots by window id, stored under `plan/illustrator/screenshots/`, never committed). Never copy GPL/AGPL code (Inkscape, lib2geom…).
+- **Clean-room: never use Adobe software (absolute rule, from the project owner).** Adobe's Terms of Use forbid reverse engineering, including observing a program's inputs and outputs to recreate it. So:
+  - Never launch, run, script, automate (COM, AppleScript, ExtendScript, UI automation), screenshot or measure Illustrator or any other Adobe application, and never compare our output against one. Don't make test files with them, not even "synthetic" ones.
+  - Never read, disassemble or copy anything inside an Adobe install (binaries, plug-ins, presets, procsets, resources, help files, fonts, ICC profiles).
+  - Never copy Adobe-authored code or text into this repo, tests included: no PostScript procsets or prologs (AGM, CoolType, the Illustrator prologs), no sample files. Write test inputs from scratch from the public specifications (PostScript Language Reference, PDF / ISO 32000, TIFF, EPSF/DCS).
+  - Behaviour comes only from public documentation (helpx, published specs, public forum posts), cited by URL, and from files users send us that they own (used locally, never committed). Never copy Adobe icons, artwork, presets or wording beyond feature names.
+  - If a task seems to need any of this, stop and say so instead. `cargo xtask cleanroom` (run by `cargo xtask ci`) fails on Adobe copyright notices and on fixtures made with Adobe applications.
+  - Never copy GPL/AGPL code (Inkscape, lib2geom…).
 - **Assets: no Adobe iconography or images — ever (absolute rule, from the project owner).**
   - Never add, copy, trace, redraw-from, embed or ship any icon, image, artwork, cursor, preset, swatch/brush/symbol/pattern/style library, ICC profile or screenshot from Adobe products or from any other source whose licence doesn't allow it.
   - Every image, icon, font or other asset must be one of:
@@ -44,7 +50,7 @@ Formerly **DrawCraft** (renamed 2026-10-01): old `.drawcraft` files and `"format
 ## Running and looking at the app
 - `cargo run --release -p vectorcraft -- --control 7979 [file.svg|file.vectorcraft]` (sibling apps' agents use the same default port: if the log says it failed to bind, pick another port — otherwise your requests reach a different app).
 - Drive it: JSON lines on `127.0.0.1:7979`, e.g. `{"id":1,"method":"engine.execute","params":{"command":"shape.rectangle","params":{"x":10,"y":10,"width":100,"height":50}}}` then `{"id":2,"method":"ui.screenshot","params":{"path":"/tmp/shot.png"}}`. Methods: `crates/ui-egui/src/control.rs`.
-- **For UI work, look at the result** (take `ui.screenshot`, read the PNG) and compare with `plan/illustrator/02-ui-ux.md` / `10-observed-ui.md`. `ui.screenshot` needs a presented frame: if it errors (screen locked), check the art with `ui.render` / `vectorcraft-cli run … --export x.png`, and cover panels with a headless egui frame test (see `panels/transparency.rs` tests).
+- **For UI work, look at the result** (take `ui.screenshot`, read the PNG) and compare with the public documentation (`plan/illustrator/02-ui-ux.md` notes). `ui.screenshot` needs a presented frame: if it errors (screen locked), check the art with `ui.render` / `vectorcraft-cli run … --export x.png`, and cover panels with a headless egui frame test (see `panels/transparency.rs` tests).
 - **Performance:** `vectorcraft-cli perf` checks the budgets (render/pan/zoom, hit test, save/open, SVG, Pathfinder) on a synthetic 50k-path document; `vectorcraft-cli bench FILE` times one file. Run them before and after renderer, format or geometry changes, on an idle machine (the report warns when the load average makes timings noise).
 - MCP: `vectorcraft-cli mcp` (see `docs/mcp.md`).
 - Shell gotcha: `mv`/`cp` are aliased interactive here — use `/bin/mv -f` / `/bin/cp -f`.
@@ -53,5 +59,5 @@ Formerly **DrawCraft** (renamed 2026-10-01): old `.drawcraft` files and `"format
 ## Roadmap
 `ROADMAP.md` (committed) is the shared picture of where VectorCraft stands. It holds status, the honest assessment (by dimension, the gap list, the direction), milestones, the parity table and time-to-parity estimates.
 - When a task lands, update it in the same PR: the milestone row, the parity-table row (score, missing items, hours), "Shipped so far", and the gap list if the gap closed or shrank.
-- Grade by behaviour against `plan/illustrator/`, not by whether a menu item exists. Scores are self-assessed, so err low.
+- Grade by behaviour against the public documentation (`plan/illustrator/` notes), not by whether a menu item exists. Scores are self-assessed, so err low.
 - Keep the README's Status section in step with the ROADMAP headline.

README.md

@@ -163,9 +163,11 @@ Japanese fonts come from [storytold/craft-fonts](https://github.com/storytold/cr
 build input (releases always use it): `CRAFT_FONTS_DIR="$PWD/../craft-fonts" cargo run --release -p vectorcraft` (an absolute path).
 Without it, Japanese text uses the installed system fonts. See [`docs/development.md`](docs/development.md#fonts-craft-fonts-optional-build-input).
 
-On laptops with two graphics processors, VectorCraft uses the power-saving (integrated) one by default.
-To use the discrete one, choose **Preferences › Performance › Graphics Processor › High Performance**
-and restart, or start the app with `WGPU_POWER_PREF=high` (see [`docs/development.md`](docs/development.md#desktop-graphics-processor)).
+On machines with two graphics processors, VectorCraft renders on the power-saving (integrated) one by default on
+Windows and macOS, and on the one the desktop runs on under Linux. To choose, use **Preferences › Performance ›
+Graphics Processor** and restart. If a graphics processor can't show the window, VectorCraft starts again on the
+next one. To pick one when starting the app, set `WGPU_POWER_PREF=high` (or `low`), or `WGPU_ADAPTER_NAME` to part of
+its name, such as `WGPU_ADAPTER_NAME=nvidia` (see [`docs/development.md`](docs/development.md#desktop-graphics-processor)).
 
 On Linux under KDE Plasma 6.3 or later with Wayland, a drawing tablet's pen moves the cursor but VectorCraft doesn't
 respond to it yet (#491). Start the app under XWayland instead: `WAYLAND_DISPLAY= vectorcraft` (see

ROADMAP.md

@@ -4,7 +4,7 @@ VectorCraft is a clean-room, open-source, pure-Rust reimplementation of the Adob
 
 This file tracks **how far we are and what's left**. Time estimates are wall-clock hours of continuous Claude Opus 5.5 agent work (including builds and the CI gate), given both for **one agent** and for **4–6 parallel agents** on disjoint crates. They are counted from the remaining work (see [Parity estimate](#parity-estimate)), calibrated against measured throughput, and updated as work lands.
 
-_Last updated: 2026-10-08 (after M4.14–M4.98, M8.1–M8.20, M14.4–M14.7, the MCP prompts, resource templates, completions and logging, the 2026-10-07 issue fixes, the Layers panel rework and the 2026-10-08 community contributions: Pen and shape-tool modifiers, path editing, Layers, Artboards, Swatches/Brushes and dialogs, Japanese composition and PDF text, Hebrew/Arabic type, interface languages (Spanish among them), the font menu, saved selections, MCP and EPS, the missing-font export warning (#319), open paths in the Shape Builder (#374), PDF/`.ai` import keeping strokes live and hidden and nested layers (#372), per-corner Live Corners (#381), SVG type opening at the size it draws at (#396), the Wayland clipboard with copied-file paste (#398), ruler guides that can be selected, moved and deleted (#414), two batches of Preferences options that were stored but unused (#394), skeleton reads with `document.find` for large documents over MCP (#416) and anchors dragged with Direct Selection snapping to points, segments and smart guides, clipped SVG layers opening as clipping layers (#420), PDF/`.ai` layers read on pages of tens of millions of operators (#419), Document Color Mode putting RGB greys on the black plate on request and converting pattern tiles (#421) and movable dialogs with Offset Path's Joins dropdown (#423) and numeric fields scrubbed by dragging their label (#400), stroke weight presets in the stroke unit (#426), the Appearance panel's Opacity popup (#430), type on a path brackets, flip and Type on a Path Options that keep the type in place (#429), Layers rows dragged with a ghost and dropped on the trash or New Layer (#435), tool flyouts opening on a right or corner press (#436), tool flyouts torn off into floating toolbars (#437), the Shape Builder's erase mode deleting edges too (#439), installed fonts registered outside the font folders and fonts installed while the app runs listed in the font menus (#443), alike circular corners on rectangles that aren't square (#442), tool cursors as OS cursors so the pointer no longer trails over the canvas (#444), artboards copied and pasted with their art (#446), guides dragged out of the rulers snapping to the art's side midpoints and the artboards, artboard guides (#451), the toolbar's double arrow and Window › Toolbars › Double Column switching between one and two columns in any window height (#455), the Smart Guides display options and Snapping Tolerance (#394), Font Size and Leading combo boxes with preset lists in the Character and Properties panels and the Control bar (#458), screenshots pasted from the clipboard on macOS, Windows and the web (#457), the Properties panel's Fill and Stroke matching the Control bar's, Illustrator's Window menu panel keys (Shift+F7 for Align…) and Alt-wheel zoom whatever the wheel preference (Discord feedback), the point/area type widget (Discord feedback), groups in legacy Illustrator .ai files (Discord feedback), a rotating desktop log file (#465), image controls in the Control bar and Properties panel: Image Trace with its presets, Mask, Crop Image, Embed/Unembed, and an Image Trace object's preset, Expand and Release (Discord feedback), the Pen working as the Anchor Point tool with Alt held over a selected path's handles and anchors, and anchor buttons that convert, connect and cut paths at the selected anchors (Discord feedback), Japanese hanging punctuation (burasagari, #463), Escape leaving Presentation Mode with no screen mode saved across restarts, documents dropped on the desktop app opening as tabs of their own and a note that an `.ai` file's art off its artboards isn't in the part read (#472), Add/Delete Anchor Point tool icons drawn from the Pen tool's (#479), EPS files from Illustrator 2026, Inkscape/cairo, matplotlib, CorelDRAW, Affinity, LibreOffice and Ghostscript opening as vectors, and a preview that stands in saying why (Discord feedback, #466, #469, #474), chords with modifiers recorded in Edit › Keyboard Shortcuts (#487), Type Object Selection by Path Only (#394), Anti-aliased Artwork (#394), Show Pixel Grid (#394), pen and touch taps pressed and lifted within one frame clicking where they tapped and the Linux/Wayland pen-tablet workaround (#491), bounding-box resizes landing on the other objects' anchors and centres with labels, and the Rotate, Scale, Shear and Reflect tools snapping their drags (#482), Shift-drag marquees that toggle the objects or anchors they reach and a Lasso whose Alt subtraction keeps the rest of the selection (#483), the mouse wheel stepping the focused numeric field, the dialogs' and preferences' drag values made such fields (#485), Show The Home Screen When No Documents Are Open (#394), Numbers Without Units Are Points (#394), Auto-Collapse Iconic Panels (#394), the Contextual Task Bar moved by its handle and its More Options menu pinning and resetting its position, a designed macOS DMG window (#493), panels, panel groups and the Tools panel undocking intLine truncated
+_Last updated: 2026-10-08 (after M4.14–M4.98, M8.1–M8.20, M14.4–M14.7, the MCP prompts, resource templates, completions and logging, the 2026-10-07 issue fixes, the Layers panel rework and the 2026-10-08 community contributions: Pen and shape-tool modifiers, path editing, Layers, Artboards, Swatches/Brushes and dialogs, Japanese composition and PDF text, Hebrew/Arabic type, interface languages (Spanish among them), the font menu, saved selections, MCP and EPS, the missing-font export warning (#319), open paths in the Shape Builder (#374), PDF/`.ai` import keeping strokes live and hidden and nested layers (#372), per-corner Live Corners (#381), SVG type opening at the size it draws at (#396), the Wayland clipboard with copied-file paste (#398), ruler guides that can be selected, moved and deleted (#414), two batches of Preferences options that were stored but unused (#394), skeleton reads with `document.find` for large documents over MCP (#416) and anchors dragged with Direct Selection snapping to points, segments and smart guides, clipped SVG layers opening as clipping layers (#420), PDF/`.ai` layers read on pages of tens of millions of operators (#419), Document Color Mode putting RGB greys on the black plate on request and converting pattern tiles (#421) and movable dialogs with Offset Path's Joins dropdown (#423) and numeric fields scrubbed by dragging their label (#400), stroke weight presets in the stroke unit (#426), the Appearance panel's Opacity popup (#430), type on a path brackets, flip and Type on a Path Options that keep the type in place (#429), Layers rows dragged with a ghost and dropped on the trash or New Layer (#435), tool flyouts opening on a right or corner press (#436), tool flyouts torn off into floating toolbars (#437), the Shape Builder's erase mode deleting edges too (#439), installed fonts registered outside the font folders and fonts installed while the app runs listed in the font menus (#443), alike circular corners on rectangles that aren't square (#442), tool cursors as OS cursors so the pointer no longer trails over the canvas (#444), artboards copied and pasted with their art (#446), guides dragged out of the rulers snapping to the art's side midpoints and the artboards, artboard guides (#451), the toolbar's double arrow and Window › Toolbars › Double Column switching between one and two columns in any window height (#455), the Smart Guides display options and Snapping Tolerance (#394), Font Size and Leading combo boxes with preset lists in the Character and Properties panels and the Control bar (#458), screenshots pasted from the clipboard on macOS, Windows and the web (#457), the Properties panel's Fill and Stroke matching the Control bar's, Illustrator's Window menu panel keys (Shift+F7 for Align…) and Alt-wheel zoom whatever the wheel preference (Discord feedback), the point/area type widget (Discord feedback), groups in legacy Illustrator .ai files (Discord feedback), a rotating desktop log file (#465), image controls in the Control bar and Properties panel: Image Trace with its presets, Mask, Crop Image, Embed/Unembed, and an Image Trace object's preset, Expand and Release (Discord feedback), the Pen working as the Anchor Point tool with Alt held over a selected path's handles and anchors, and anchor buttons that convert, connect and cut paths at the selected anchors (Discord feedback), Japanese hanging punctuation (burasagari, #463), Escape leaving Presentation Mode with no screen mode saved across restarts, documents dropped on the desktop app opening as tabs of their own and a note that an `.ai` file's art off its artboards isn't in the part read (#472), Add/Delete Anchor Point tool icons drawn from the Pen tool's (#479), EPS files from Illustrator 2026, Inkscape/cairo, matplotlib, CorelDRAW, Affinity, LibreOffice and Ghostscript opening as vectors, and a preview that stands in saying why (Discord feedback, #466, #469, #474), chords with modifiers recorded in Edit › Keyboard Shortcuts (#487), Type Object Selection by Path Only (#394), Anti-aliased Artwork (#394), Show Pixel Grid (#394), pen and touch taps pressed and lifted within one frame clicking where they tapped and the Linux/Wayland pen-tablet workaround (#491), bounding-box resizes landing on the other objects' anchors and centres with labels, and the Rotate, Scale, Shear and Reflect tools snapping their drags (#482), Shift-drag marquees that toggle the objects or anchors they reach and a Lasso whose Alt subtraction keeps the rest of the selection (#483), the mouse wheel stepping the focused numeric field, the dialogs' and preferences' drag values made such fields (#485), Show The Home Screen When No Documents Are Open (#394), Numbers Without Units Are Points (#394), Auto-Collapse Iconic Panels (#394), the Contextual Task Bar moved by its handle and its More Options menu pinning and resetting its position, a designed macOS DMG window (#493), panels, panel groups and the Tools panel undocking intLine truncated
 
 ## Where we are
 
@@ -42,7 +42,7 @@ since 2026-10-01.
 | **Bundled content:** brush, symbol, style and swatch libraries | ~30% | Ours are original and generated in code, and far fewer than Illustrator ships; brush and symbol libraries are still missing |
 | **Performance** | unverified | Multithreaded, off-thread rendering and caches are in place. The last budget run (2026-10-01, loaded machine) measured 290 ms for a 50k-path fit against a 16 ms budget. Re-run `vectorcraft-cli perf` on an idle machine |
 | **Robustness** | good, new | ~2,840 tests, property tests, no panics in shipped code (lints, the `guard` safety net, import fuzzing), Data Recovery. Missing: a corpus of real-world files, Windows/Linux/browser QA |
-| **Platforms and 1.0 polish** | ~60% | The macOS app and the web build work, and Finder opens every readable format with the macOS app (#295, #354); hybrid-graphics laptops render on the power-saving GPU by default (#306); web drops land in the document they were dropped on (#359); desktop drops carry no pointer position (winit 0.30), so a dropped document opens as a tab of its own and a picture or text is placed in the middle of the view, while the web places anything dropped on the canvas and opens what is dropped off it, as Illustrator does (#472); a web page that loses its WebGPU device or WebGL context restarts its graphics with the same documents (#369); on Linux/Wayland the clipboard reads the compositor's own (data-control) and copied image files paste, but files can't be dropped on the window under Wayland until eframe moves to winit 0.31 (#398; the Wayland side is verified by compilation only); on KDE Plasma 6.3+ under Wayland, pens and pen displays reach the app only under XWayland (`WAYLAND_DISPLAY=`) or with KWin's `KWIN_WAYLAND_EMULATE_TABLET=1`, since winit 0.30 has no Wayland tablet input (#491, not verified on hardware); Windows/Linux packaging and accessibility are pending; an experimental, unsupported Windows 7 x64 OpenGL build exists (community-contributed, not verified by maintainers) |
+| **Platforms and 1.0 polish** | ~60% | The macOS app and the web build work, and Finder opens every readable format with the macOS app (#295, #354); hybrid-graphics laptops render on the power-saving GPU by default on Windows and macOS (#306), and Linux on the GPU the desktop runs on, since a Wayland compositor may refuse frames from the other one; a window that fails on its GPU while starting up starts again on the next one instead of crashing (#502; the dual-GPU Wayland case is verified by unit tests and cross-compilation, not on such hardware); web drops land in the document they were dropped on (#359); desktop drops carry no pointer position (winit 0.30), so a dropped document opens as a tab of its own and a picture or text is placed in the middle of the view, while the web places anything dropped on the canvas and opens what is dropped off it, as Illustrator does (#472); a web page that loses its WebGPU device or WebGL context restarts its graphics with the same documents (#369); on Linux/Wayland the clipboard reads the compositor's own (data-control) and copied image files paste, but files can't be dropped on the window under Wayland until eframe moves to winit 0.31 (#398; the Wayland side is verified by compilation only); on KDE Plasma 6.3+ under Wayland, pens and pen displays reach the app only under XWayland (`WAYLAND_DISPLAY=`) or with KWin's `KWIN_WAYLAND_EMULATE_TABLET=1`, since winit 0.30 has no Wayland tablet input (#491, not verified on hardware); Windows/Linux packaging and accessibility are pending; an experimental, unsupported Windows 7 x64 OpenGL build exists (community-contributed, not verified by maintainers) |
 | **Agent automation** | beyond Illustrator | Every command, gesture and dialog is drivable over MCP, the CLI and the control channel |
 | **Scrubby numeric fields** | beyond Illustrator | As in Photoshop, dragging a numeric field's label (`W:`, `Opacity:`, the Character panel's icons) left or right steps its value live; one undo step per drag, Escape cancels (#400) |
 
@@ -157,7 +157,7 @@ grade by behaviour against `plan/illustrator/`, not by whether a menu item exist
   - EPS and DXF in and out, EMF/WMF in and out; PNG (with PNG-8), JPEG, WebP, GIF, TIFF, BMP, Targa and layered PSD export. EPS import runs Illustrator's AGM/CoolType prologs (resource categories, `resourceforall`, `clipsave`/`cliprestore`, subarrays and substrings that share storage, the standard dictionaries in `systemdict`, `dictstack`, `internaldict`, executable filters, `cshow`, metadata skipped with `flushfile`), so Illustrator 30 EPS files open as vectors. It also runs what other generators write (Discord feedback, #466, #469): Illustrator 2026's procsets (`gcheck`, `rootfont`, `currentcolorrendering`: every Illustrator 2026 EPS fell back to its preview before), cairo/Inkscape (`status`/`flushfile`, images with a mask, `ImageType 3`, reusable streams), matplotlib's Type 3 fonts, Illustrator 8 EPS (stock art's usual format: executable strings such as its gradients' `ed`, `load` by integer keys, #474), Ghostscript's `//name` immediate names, `pdfmark`, `token`, `execform` and user paths. Tiling patterns come in as pattern swatches, uncoloured ones too; Type 3 fonts' glyphs as their outlines, spaced by `ashow`/`widthshow`/`xshow`/`kshow`; mesh and function-based shadings (types 1, 4–7) as gradient meshes; sampled functions (type 0) and Flate/LZW predictors are read. When a file's PostScript still can't be read, it opens as its TIFF preview, its Windows metafile preview (as vectors) or its EPSI preview, and the warning (in the status bar, `document.open`/`app.open`/MCP `open_file` replies and `vectorcraft-cli info`) names the error, the operator that raised it and the procedures it ran in. Legacy PostScript `.ai` files (Illustrator 3–8, written with the prolog that defines their operators) keep their groups and nested groups (`u` … `U`), between and inside clipping groups; EPS and EMF/WMF import nest clips (and groups) at most 128 deep, so a hostile file can't exhaust the stack. DXF TEXT justified Fit or Aligned spans its two points (stretched, or scaled as a whole).
   - Place and the Links panel, Package, File Info, Print with print presets, PostScript output and print tiling, slices and Save for Web, Export for Screens and Asset Export, CSS Properties, PNG/PDF/SVG/text clipboard flavours; files copied in a file manager paste as art (SVG, PDF, EMF/WMF, bitmaps) on every desktop platform, and Linux/Wayland reads the compositor's clipboard (#398); screenshots and other copied pictures paste as embedded images at the view centre everywhere, the web included (#457).
 - **Performance:** 20k shapes + 1k texts render in 27 ms per full-retina frame (7.8 ms zoomed), 7× faster than the first version. The UI thread never blocks. The web build is 7.1 MB gzipped.
-- **Graphics processor:** the canvas is rasterized on the CPU and the GPU only composites it, so the desktop app asks for the power-saving GPU by default (the integrated one on hybrid-graphics laptops, where presenting from the discrete GPU made the window flicker, #306). Preferences › Performance › Graphics Processor (`gpuPreference`) or `WGPU_POWER_PREF` picks the discrete one; Help › About and `ui.inspect` name the adapter in use. When the browser drops the page's WebGPU device or WebGL context, the web build writes recovery copies, starts again on new graphics with the same app and uploads its textures again; if it can't, it removes the stale canvas and says to reload, which offers the copies back. The desktop app writes the copies and says to restart (#369). On Windows and Linux the tools' cursors are OS cursors (bitmaps rasterized once per display scale), which the system moves itself: painted into the window, they trailed the pointer by the frames waiting to be shown, and the window now queues one frame instead of two (#444). macOS and the web still paint them (macOS sizes cursor bitmaps in points, eframe has no bitmap cursors on the web). Pens and touch drive the tools as the mouse does, and a tap pressed and lifted within one frame clicks where it tapped (#491); pen pressure reaches the Liquify tools' Use Pressure Pen on Windows, while winit 0.30 reports none on macOS or Linux and egui none on the web. On Linux, see `docs/development.md` for pens under Wayland.
+- **Graphics processor:** the canvas is rasterized on the CPU and the GPU only composites it, so any GPU that can show the window will do. Preferences › Performance › Graphics Processor (`gpuPreference`) is Automatic by default: the power-saving GPU on Windows and macOS (the integrated one on hybrid-graphics laptops, where presenting from the discrete GPU made the window flicker, #306), and the GPU the desktop runs on under Linux, where KWin on an NVIDIA GPU refused frames from a Ryzen's integrated GPU and 0.5.0 crashed at startup (#502). Power Saving and High Performance pick a kind of GPU; `WGPU_POWER_PREF`, `WGPU_ADAPTER_NAME` and `WGPU_BACKEND` override them. The app picks among the adapters that can present to the window (native backends before OpenGL, hardware before software), and if the window fails on one while starting up it starts again without it instead of crashing; Help › About, `ui.inspect` and the log name the adapter in use. When the browser drops the page's WebGPU device or WebGL context, the web build writes recovery copies, starts again on new graphics with the same app and uploads its textures again; if it can't, it removes the stale canvas and says to reload, which offers the copies back. The desktop app writes the copies and says to restart (#369). On Windows and Linux the tools' cursors are OS cursors (bitmaps rasterized once per display scale), which the system moves itself: painted into the window, they trailed the pointer by the frames waiting to be shown, and the window now queues one frame instead of two (#444). macOS and the web still paint them (macOS sizes cursor bitmaps in points, eframe has no bitmap cursors on the web). Pens and touch drive the tools as the mouse does, and a tap pressed and lifted within one frame clicks where it tapped (#491); pen pressure reaches the Liquify tools' Use Pressure Pen on Windows, while winit 0.30 reports none on macOS or Linux and egui none on the web. On Linux, see `docs/development.md` for pens under Wayland.
 - **Tests and robustness:** ~2,840 automated tests: model-based property tests, a junk-parameter sweep over every command, import fuzzing (SVG, PDF, libraries), golden renders, and MCP end-to-end tests over stdio. Shipped code never panics (workspace lints and a rollback safety net; see `docs/development.md`).
 
 ## Milestones and estimates

apps/vectorcraft/src/gpu.rs

@@ -0,0 +1,470 @@
+//! Which graphics adapter the window renders with (#306, #502), and what happens when it can't
+//! show the window.
+//!
+//! The canvas is rasterized on the CPU; the GPU only composites it and draws the UI, so any
+//! adapter that can present to the window will do. [`adapter_order`] ranks the adapters: those that
+//! can't present to the window's surface never, then the one `WGPU_ADAPTER_NAME` names, hardware
+//! before software, the native backends (Vulkan, Metal, DX12) before OpenGL, and the power
+//! preference ([`power_preference`]) among the rest. eframe is handed [`selector`], which takes
+//! the first of that order.
+//!
+//! An adapter can report that it presents to the window and still fail once it does: on a hybrid
+//! Linux desktop under Wayland, the compositor runs on one GPU and may refuse the frame buffers
+//! another GPU allocates, which kills the window's Wayland connection; egui-wgpu then panics while
+//! configuring the surface (#502). Nothing in the process can show a window after that, so when
+//! the graphics fail while the window is starting up, [`finish`] starts the app again without
+//! that adapter, as the next one in the order would be tried. Each restart leaves out one more
+//! adapter, so it ends when none is left.
+
+use std::sync::atomic::{AtomicBool, Ordering};
+use std::sync::{Arc, OnceLock};
+
+use eframe::egui_wgpu::NativeAdapterSelectorMethod;
+use eframe::wgpu::{self, Backend, DeviceType, PowerPreference};
+
+/// The adapters a restart leaves out, those the window failed on, as comma-separated
+/// `backend:vendor:device` keys (`Vulkan:1002:164e`). Set by the app itself when it starts again.
+pub const SKIP_ENV: &str = "VECTORCRAFT_GPU_SKIP";
+
+/// wgpu's variable for choosing an adapter by (part of) its name, any case.
+const NAME_ENV: &str = "WGPU_ADAPTER_NAME";
+
+/// Where to read how to choose another adapter, for the error that ends the app.
+const HELP: &str =
+    "to choose a graphics adapter, see https://github.com/storytold/vectorcraft/blob/main/docs/development.md#desktop-graphics-processor";
+
+/// Frames the UI ran before the failure, below which it was still starting up. The failure in
+/// #502 came on the first or second frame; later, the adapter has proved itself, and a lost
+/// window is something else (such as the compositor restarting).
+const STARTUP_FRAMES: u64 = 10;
+
+/// The preference used when Preferences say Automatic. Windows and macOS show frames from any GPU
+/// (the integrated one avoids the flicker of #306). Elsewhere, the system's own order: Mesa's
+/// device-select layer puts the GPU the desktop runs on first (the integrated one on hybrid
+/// laptops), and a Wayland compositor may not show frames from another GPU (#502).
+pub const AUTOMATIC: PowerPreference = if cfg!(any(windows, target_os = "macos")) { PowerPreference::LowPower } else { PowerPreference::None };
+
+/// The power preference that orders the adapters: the `WGPU_POWER_PREF` environment variable
+/// (`low`, `high`, `none`) when set, otherwise Preferences › Performance › Graphics Processor
+/// (`gpuPreference`). Automatic, and any value this version doesn't know (0.5.0's default
+/// `powerSaving`, a newer or damaged preference file), is [`AUTOMATIC`].
+pub fn power_preference(pref: Option<&str>, env: Option<PowerPreference>) -> PowerPreference {
+    match (env, pref) {
+        (Some(p), _) => p,
+        (None, Some("highPerformance")) => PowerPreference::HighPerformance,
+        (None, Some("lowPower")) => PowerPreference::LowPower,
+        (None, _) => AUTOMATIC,
+    }
+}
+
+/// One adapter, as [`adapter_order`] sees it.
+#[derive(Clone, Debug)]
+pub struct Candidate {
+    /// Identifies the adapter across a restart: `backend:vendor:device` ([`key`]).
+    pub key: String,
+    pub name: String,
+    pub backend: Backend,
+    pub device_type: DeviceType,
+    /// Reports that it can present to the window's surface.
+    pub presents: bool,
+}
+
+impl Candidate {
+    fn new(adapter: &wgpu::Adapter, surface: Option<&wgpu::Surface<'_>>) -> Self {
+        let info = adapter.get_info();
+        Self {
+            key: key(info.backend, info.vendor, info.device),
+            presents: surface.is_none_or(|s| adapter.is_surface_supported(s)),
+            name: info.name,
+            backend: info.backend,
+            device_type: info.device_type,
+        }
+    }
+}
+
+/// `backend:vendor:device`, e.g. `Vulkan:1002:164e` (PCI ids, as `MESA_VK_DEVICE_SELECT` takes them).
+fn key(backend: Backend, vendor: u32, device: u32) -> String {
+    format!("{backend:?}:{vendor:04x}:{device:04x}")
+}
+
+/// The order to try `candidates` in (their indices): only those that present to the window and
+/// aren't in `skip`; the one whose name contains `named` (any case) first; hardware before
+/// software; native backends before OpenGL; then by `power`, keeping the system's order among
+/// equals (all of it for [`PowerPreference::None`]).
+pub fn adapter_order(candidates: &[Candidate], power: PowerPreference, named: Option<&str>, skip: &[String]) -> Vec<usize> {
+    let named = named.map(str::to_lowercase).filter(|n| !n.is_empty());
+    let mut order: Vec<(usize, &Candidate)> = candidates.iter().enumerate().filter(|(_, c)| c.presents && !skip.contains(&c.key)).collect();
+    // Stable, so equals keep the system's order.
+    order.sort_by_key(|(_, c)| {
+        let unnamed = named.as_ref().is_some_and(|n| !c.name.to_lowercase().contains(n));
+        (unnamed, c.device_type == DeviceType::Cpu, c.backend == Backend::Gl, power_rank(c.device_type, power))
+    });
+    order.into_iter().map(|(i, _)| i).collect()
+}
+
+/// wgpu's own ranking for a power preference: the preferred kind of GPU, the other kind, unknown,
+/// virtual, software.
+fn power_rank(t: DeviceType, power: PowerPreference) -> u8 {
+    match (power, t) {
+        (PowerPreference::None, _) => 0,
+        (PowerPreference::LowPower, DeviceType::IntegratedGpu) | (PowerPreference::HighPerformance, DeviceType::DiscreteGpu) => 0,
+        (_, DeviceType::IntegratedGpu | DeviceType::DiscreteGpu) => 1,
+        (_, DeviceType::Other) => 2,
+        (_, DeviceType::VirtualGpu) => 3,
+        (_, DeviceType::Cpu) => 4,
+    }
+}
+
+/// The adapters [`SKIP_ENV`] lists.
+pub fn skipped() -> Vec<String> {
+    std::env::var(SKIP_ENV).map(|v| parse_skip(&v)).unwrap_or_default()
+}
+
+fn parse_skip(v: &str) -> Vec<String> {
+    v.split(',').map(str::trim).filter(|k| !k.is_empty()).map(String::from).collect()
+}
+
+/// What the window's start-up leaves for [`finish`].
+#[derive(Default)]
+pub struct Startup {
+    /// The key of the adapter [`selector`] picked.
+    adapter: OnceLock<String>,
+    /// The UI's context, which counts the frames run.
+    ui: OnceLock<egui::Context>,
+}
+
+impl Startup {
+    /// The app was created on `ctx`.
+    pub fn created(&self, ctx: &egui::Context) {
+        // Set once; the window is created once.
+        let _ = self.ui.set(ctx.clone());
+    }
+}
+
+/// eframe's adapter choice: the first of [`adapter_order`] for `power`, `WGPU_ADAPTER_NAME` and the
+/// adapters a restart left out. Every adapter and the choice are logged, for bug reports.
+pub fn selector(power: PowerPreference, startup: Arc<Startup>) -> NativeAdapterSelectorMethod {
+    let named = std::env::var(NAME_ENV).ok();
+    let skip = skipped();
+    Arc::new(move |adapters, surface| {
+        let candidates: Vec<Candidate> = adapters.iter().map(|a| Candidate::new(a, surface)).collect();
+        let order = adapter_order(&candidates, power, named.as_deref(), &skip);
+        let listed: Vec<String> = candidates
+            .iter()
+            .map(|c| {
+                let note = if !c.presents {
+                    ", can't show the window"
+                } else if skip.contains(&c.key) {
+                    ", failed before"
+                } else {
+                    ""
+                };
+                format!("{} ({:?}, {:?}, {}{note})", c.name.trim(), c.backend, c.device_type, c.key)
+            })
+            .collect();
+        log::info!("graphics adapters: {}", listed.join("; "));
+        let first = order.first().and_then(|&i| adapters.get(i).zip(candidates.get(i)));
+        let Some((adapter, chosen)) = first else {
+            return Err(format!("no graphics adapter can show the window (power preference {power:?}, {} adapters)", adapters.len()));
+        };
+        // Set once; eframe picks the adapter once.
+        let _ = startup.adapter.set(chosen.key.clone());
+        Ok(adapter.clone())
+    })
+}
+
+/// The last panic came from the graphics stack (see [`watch_panics`]).
+static GRAPHICS_PANIC: AtomicBool = AtomicBool::new(false);
+
+/// Note whether each panic comes from the graphics stack, so [`finish`] can tell a failing adapter
+/// from a bug. The default hook still prints it.
+pub fn watch_panics() {
+    let default = std::panic::take_hook();
+    std::panic::set_hook(Box::new(move |info| {
+        GRAPHICS_PANIC.store(info.location().is_some_and(|l| in_graphics_stack(l.file())), Ordering::Relaxed);
+        default(info);
+    }));
+}
+
+/// A source file of wgpu (`wgpu-core-30.0.1/src/…`, `wgpu-hal-…`), egui-wgpu or naga.
+fn in_graphics_stack(file: &str) -> bool {
+    file.split(['/', '\\']).any(|dir| ["wgpu-", "egui-wgpu-", "naga-"].iter().any(|p| dir.starts_with(p)))
+}
+
+/// The adapter to start again without: the one picked, when the graphics failed while the window
+/// was starting up and it wasn't already left out.
+fn restart_without<'a>(graphics_failed: bool, frames: u64, picked: Option<&'a str>, skip: &[String]) -> Option<&'a str> {
+    picked.filter(|p| graphics_failed && frames < STARTUP_FRAMES && !skip.iter().any(|s| s == p))
+}
+
+/// After the window's run: `Ok` when it closed normally or the app started again (see the module
+/// docs), otherwise why it failed. `outcome` is eframe's result, or the message of a panic that
+/// ended it.
+pub fn finish(outcome: Result<eframe::Result, String>, startup: &Startup) -> Result<(), String> {
+    let (why, graphics_failed) = match outcome {
+        Ok(Ok(())) => return Ok(()),
+        Ok(Err(e @ eframe::Error::Wgpu(_))) => (e.to_string(), true),
+        Ok(Err(e)) => (e.to_string(), false),
+        Err(panic) => (panic, GRAPHICS_PANIC.load(Ordering::Relaxed)),
+    };
+    let frames = startup.ui.get().map_or(0, egui::Context::cumulative_frame_nr);
+    let mut skip = skipped();
+    let Some(failed) = restart_without(graphics_failed, frames, startup.adapter.get().map(String::as_str), &skip) else {
+        return Err(if graphics_failed { format!("{why} ({HELP})") } else { why });
+    };
+    log::error!("the window failed on graphics adapter {failed} ({why}): starting again without it");
+    skip.push(failed.to_string());
+    restart(&skip.join(",")).map_err(|e| format!("{why}; starting again failed: {e}"))
+}
+
+/// Start the app again with the same arguments, leaving out the adapters in `skip`. On Unix the
+/// new app replaces this process (same process id, so an AppImage keeps its files mounted), and
+/// this returns only on failure; on Windows it starts beside this one, which then exits.
+fn restart(skip: &str) -> std::io::Result<()> {
+    log::logger().flush();
+    let mut c = std::process::Command::new(std::env::current_exe()?);
+    c.args(std::env::args_os().skip(1)).env(SKIP_ENV, skip);
+    #[cfg(unix)]
+    {
+        use std::os::unix::process::CommandExt as _;
+        Err(c.exec())
+    }
+    #[cfg(not(unix))]
+    c.spawn().map(|_| ())
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn gpu(name: &str, backend: Backend, device_type: DeviceType) -> Candidate {
+        Candidate { key: format!("{backend:?}:{name}"), name: name.into(), backend, device_type, presents: true }
+    }
+
+    fn names(c: &[Candidate], order: &[usize]) -> Vec<String> {
+        order.iter().map(|&i| c[i].name.clone()).collect()
+    }
+
+    /// The machine of #502 as Vulkan lists it with Mesa's device-select layer: the GPU KDE's
+    /// compositor runs on (NVIDIA) first, then the Ryzen's integrated GPU, Mesa's software
+    /// renderer, and OpenGL.
+    fn issue_502() -> Vec<Candidate> {
+        vec![
+            gpu("NVIDIA GeForce RTX 5070", Backend::Vulkan, DeviceType::DiscreteGpu),
+            gpu("AMD Ryzen 9 7900X (RADV RAPHAEL_MENDOCINO)", Backend::Vulkan, DeviceType::IntegratedGpu),
+            gpu("llvmpipe (LLVM 20.1.8, 256 bits)", Backend::Vulkan, DeviceType::Cpu),
+            gpu("NVIDIA GeForce RTX 5070/PCIe/SSE2", Backend::Gl, DeviceType::Other),
+        ]
+    }
+
+    #[test]
+    fn automatic_keeps_the_systems_order_on_linux_and_saves_power_elsewhere() {
+        let c = issue_502();
+        let order = adapter_order(&c, power_preference(None, None), None, &[]);
+        let first = &c[order[0]].name;
+        if cfg!(any(windows, target_os = "macos")) {
+            assert_eq!(first, "AMD Ryzen 9 7900X (RADV RAPHAEL_MENDOCINO)");
+        } else {
+            // #502: the integrated GPU couldn't show frames to a compositor on the NVIDIA GPU.
+            assert_eq!(first, "NVIDIA GeForce RTX 5070");
+        }
+    }
+
+    #[test]
+    fn each_preference_orders_the_adapters_then_falls_back_to_opengl_and_software() {
+        let c = issue_502();
+        let order = |power| names(&c, &adapter_order(&c, power, None, &[]));
+        assert_eq!(
+            order(PowerPreference::None),
+            [
+                "NVIDIA GeForce RTX 5070",
+                "AMD Ryzen 9 7900X (RADV RAPHAEL_MENDOCINO)",
+                "NVIDIA GeForce RTX 5070/PCIe/SSE2",
+                "llvmpipe (LLVM 20.1.8, 256 bits)"
+            ]
+        );
+        assert_eq!(
+            order(PowerPreference::LowPower),
+            [
+                "AMD Ryzen 9 7900X (RADV RAPHAEL_MENDOCINO)",
+                "NVIDIA GeForce RTX 5070",
+                "NVIDIA GeForce RTX 5070/PCIe/SSE2",
+                "llvmpipe (LLVM 20.1.8, 256 bits)"
+            ]
+        );
+        assert_eq!(
+            order(PowerPreference::HighPerformance),
+            [
+                "NVIDIA GeForce RTX 5070",
+                "AMD Ryzen 9 7900X (RADV RAPHAEL_MENDOCINO)",
+                "NVIDIA GeForce RTX 5070/PCIe/SSE2",
+                "llvmpipe (LLVM 20.1.8, 256 bits)"
+            ]
+        );
+    }
+
+    /// A restart leaves out the adapter the window failed on, so Power Saving on the machine of
+    /// #502 ends up on the NVIDIA GPU, and once every adapter failed there is nothing to try.
+    #[test]
+    fn a_restart_tries_the_next_adapter() {
+        let c = issue_502();
+        let mut skip = vec![];
+        let mut tried = vec![];
+        while let Some(&i) = adapter_order(&c, PowerPreference::LowPower, None, &skip).first() {
+            tried.push(c[i].name.clone());
+            skip.push(c[i].key.clone());
+        }
+        assert_eq!(
+            tried,
+            [
+                "AMD Ryzen 9 7900X (RADV RAPHAEL_MENDOCINO)",
+                "NVIDIA GeForce RTX 5070",
+                "NVIDIA GeForce RTX 5070/PCIe/SSE2",
+                "llvmpipe (LLVM 20.1.8, 256 bits)"
+            ]
+        );
+    }
+
+    #[test]
+    fn adapters_that_cannot_present_to_the_window_are_never_tried() {
+        let mut c = issue_502();
+        c[0].presents = false;
+        c[3].presents = false;
+        for power in [PowerPreference::None, PowerPreference::LowPower, PowerPreference::HighPerformance] {
+            let order = adapter_order(&c, power, None, &[]);
+            assert!(!order.contains(&0) && !order.contains(&3), "{power:?}: {order:?}");
+            assert_eq!(order.len(), 2);
+        }
+        for p in &mut c {
+            p.presents = false;
+        }
+        assert!(adapter_order(&c, PowerPreference::None, None, &[]).is_empty());
+        assert!(adapter_order(&[], PowerPreference::HighPerformance, None, &[]).is_empty());
+    }
+
+    #[test]
+    fn wgpu_adapter_name_picks_an_adapter_first_and_the_rest_stay_as_fallbacks() {
+        let c = issue_502();
+        let order = adapter_order(&c, PowerPreference::HighPerformance, Some("radv"), &[]);
+        assert_eq!(c[order[0]].name, "AMD Ryzen 9 7900X (RADV RAPHAEL_MENDOCINO)");
+        assert_eq!(order.len(), 4);
+        // Any case; every match comes before the rest, natively first.
+        let order = adapter_order(&c, PowerPreference::LowPower, Some("GeForce"), &[]);
+        assert_eq!(names(&c, &order[..2]), ["NVIDIA GeForce RTX 5070", "NVIDIA GeForce RTX 5070/PCIe/SSE2"]);
+        // An empty name or one nothing matches changes nothing.
+        for named in ["", "no such gpu"] {
+            assert_eq!(adapter_order(&c, PowerPreference::LowPower, Some(named), &[]), adapter_order(&c, PowerPreference::LowPower, None, &[]));
+        }
+        // A named adapter that failed is left out like any other.
+        let skip = vec![c[1].key.clone()];
+        assert_eq!(adapter_order(&c, PowerPreference::None, Some("radv"), &skip)[0], 0);
+    }
+
+    /// A Windows machine lists every GPU twice (Vulkan and DX12): power saving still takes the
+    /// integrated GPU first, as wgpu's own choice did (#306).
+    #[test]
+    fn hybrid_laptop_on_windows_renders_on_the_integrated_gpu_with_power_saving() {
+        let c = vec![
+            gpu("Intel(R) Arc(TM) A370M", Backend::Vulkan, DeviceType::DiscreteGpu),
+            gpu("Intel(R) Iris(R) Xe Graphics", Backend::Vulkan, DeviceType::IntegratedGpu),
+            gpu("Intel(R) Arc(TM) A370M", Backend::Dx12, DeviceType::DiscreteGpu),
+            gpu("Intel(R) Iris(R) Xe Graphics", Backend::Dx12, DeviceType::IntegratedGpu),
+            gpu("Microsoft Basic Render Driver", Backend::Dx12, DeviceType::Cpu),
+        ];
+        let order = adapter_order(&c, PowerPreference::LowPower, None, &[]);
+        assert_eq!(order, [1, 3, 0, 2, 4]);
+        assert_eq!(adapter_order(&c, PowerPreference::HighPerformance, None, &[]), [0, 2, 1, 3, 4]);
+    }
+
+    #[test]
+    fn power_preference_follows_the_environment_then_the_preference() {
+        assert_eq!(power_preference(None, None), AUTOMATIC);
+        assert_eq!(power_preference(Some("automatic"), None), AUTOMATIC);
+        assert_eq!(power_preference(Some("lowPower"), None), PowerPreference::LowPower);
+        assert_eq!(power_preference(Some("highPerformance"), None), PowerPreference::HighPerformance);
+        // 0.5.0's default, and values this version doesn't know (a newer or damaged file).
+        for old in ["powerSaving", "turbo", ""] {
+            assert_eq!(power_preference(Some(old), None), AUTOMATIC, "{old}");
+        }
+        // WGPU_POWER_PREF wins over the preference, either way.
+        assert_eq!(power_preference(Some("lowPower"), Some(PowerPreference::HighPerformance)), PowerPreference::HighPerformance);
+        assert_eq!(power_preference(Some("highPerformance"), Some(PowerPreference::LowPower)), PowerPreference::LowPower);
+        assert_eq!(power_preference(Some("lowPower"), Some(PowerPreference::None)), PowerPreference::None);
+        assert_eq!(AUTOMATIC, if cfg!(any(windows, target_os = "macos")) { PowerPreference::LowPower } else { PowerPreference::None });
+    }
+
+    /// The preference the engine saves is the one the app reads back before the window opens.
+    #[test]
+    fn the_saved_engine_preference_is_found() {
+        let mut prefs = vectorcraft_engine::Prefs::default();
+        let saved = prefs.to_json();
+        assert_eq!(saved.get("gpuPreference").and_then(serde_json::Value::as_str), Some("automatic"));
+        for (value, power) in [("lowPower", PowerPreference::LowPower), ("highPerformance", PowerPreference::HighPerformance)] {
+            prefs.gpu_preference = value.into();
+            let saved = prefs.to_json();
+            assert_eq!(power_preference(saved.get("gpuPreference").and_then(serde_json::Value::as_str), None), power);
+        }
+        // Every choice Preferences offer means something here.
+        for (value, _) in vectorcraft_engine::cmd::prefscmds::GPU_PREFERENCES {
+            assert!(["automatic", "lowPower", "highPerformance"].contains(value), "{value}");
+        }
+    }
+
+    #[test]
+    fn skipped_adapters_parse_from_a_comma_separated_list() {
+        assert_eq!(parse_skip("Vulkan:1002:164e, Gl:10de:2f04,,"), ["Vulkan:1002:164e", "Gl:10de:2f04"]);
+        assert!(parse_skip("").is_empty());
+        assert_eq!(key(Backend::Vulkan, 0x1002, 0x164e), "Vulkan:1002:164e");
+        assert_eq!(key(Backend::Gl, 0x10de, 0x2f04), "Gl:10de:2f04");
+    }
+
+    #[test]
+    fn panics_in_wgpu_egui_wgpu_and_naga_are_graphics_failures() {
+        for file in [
+            "/home/u/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/egui-wgpu-0.36.2/src/winit.rs",
+            r"C:\Users\u\.cargo\registry\src\index.crates.io-1949cf8c6b5b557f\wgpu-core-30.0.1\src\device\mod.rs",
+            "/rustc/deps/wgpu-hal-30.0.1/src/vulkan/adapter.rs",
+            "naga-30.0.0/src/back/spv/writer.rs",
+        ] {
+            assert!(in_graphics_stack(file), "{file}");
+        }
+        for file in [
+            "apps/vectorcraft/src/main.rs",
+            "/home/wgpu/vectorcraft/crates/ui-egui/src/lib.rs",
+            "egui-0.36.2/src/context.rs",
+            "winit-0.30.12/src/x.rs",
+        ] {
+            assert!(!in_graphics_stack(file), "{file}");
+        }
+    }
+
+    #[test]
+    fn only_a_graphics_failure_while_starting_up_restarts_without_the_adapter() {
+        let amd = Some("Vulkan:1002:164e");
+        assert_eq!(restart_without(true, 0, amd, &[]), amd);
+        assert_eq!(restart_without(true, STARTUP_FRAMES - 1, amd, &[]), amd);
+        // After start-up the adapter has shown frames; a lost window is something else.
+        assert_eq!(restart_without(true, STARTUP_FRAMES, amd, &[]), None);
+        // A bug outside the graphics, or no adapter picked: nothing another adapter would change.
+        assert_eq!(restart_without(false, 0, amd, &[]), None);
+        assert_eq!(restart_without(true, 0, None, &[]), None);
+        // Never the same adapter twice, so restarts end.
+        assert_eq!(restart_without(true, 0, amd, &["Vulkan:1002:164e".into()]), None);
+    }
+
+    #[test]
+    fn a_normal_exit_or_another_failure_does_not_restart() {
+        let startup = Startup::default();
+        assert_eq!(finish(Ok(Ok(())), &startup), Ok(()));
+        // No adapter was picked (none can show the window): the error is returned, nothing restarts.
+        let none =
+            eframe::Error::Wgpu(eframe::egui_wgpu::WgpuError::CustomNativeAdapterSelectionError("no graphics adapter can show the window".into()));
+        assert_eq!(
+            finish(Ok(Err(none)), &startup),
+            Err(format!("WGPU error: Adapter selection failed: no graphics adapter can show the window ({HELP})"))
+        );
+        let _ = startup.adapter.set("Vulkan:1002:164e".into());
+        GRAPHICS_PANIC.store(false, Ordering::Relaxed);
+        assert_eq!(finish(Err("a bug".into()), &startup), Err("a bug".into()));
+    }
+}

apps/vectorcraft/src/main.rs

@@ -16,6 +16,8 @@ compile_error!("the win7 target requires --no-default-features --features window
 
 mod clipboard;
 mod control_server;
+#[cfg(feature = "wgpu")]
+mod gpu;
 mod logging;
 #[cfg(target_os = "macos")]
 mod native_menu;
@@ -297,23 +299,6 @@ fn app_icon() -> egui::IconData {
     eframe::icon_data::from_png_bytes(png).unwrap_or_default()
 }
 
-/// The power preference wgpu picks the window's graphics adapter with (#306): the
-/// `WGPU_POWER_PREF` environment variable (`low`, `high`, `none`) when set, otherwise Preferences ›
-/// Performance › Graphics Processor (`gpuPreference`). Power saving unless the preference asks for
-/// high performance: the canvas is rasterized on the CPU and the GPU only composites it, which the
-/// integrated GPU of a hybrid-graphics laptop does easily, while presenting frames rendered on the
-/// discrete GPU through the integrated one made the window flicker on some laptops. With a single
-/// GPU both preferences pick it.
-#[cfg(feature = "wgpu")]
-fn power_preference(pref: Option<&str>, env: Option<eframe::wgpu::PowerPreference>) -> eframe::wgpu::PowerPreference {
-    use eframe::wgpu::PowerPreference;
-    match (env, pref) {
-        (Some(p), _) => p,
-        (None, Some("highPerformance")) => PowerPreference::HighPerformance,
-        (None, _) => PowerPreference::LowPower,
-    }
-}
-
 /// "name (backend, kind)" of the adapter the window renders with, for Help › About and bug reports.
 #[cfg(feature = "wgpu")]
 fn adapter_summary(info: &eframe::wgpu::AdapterInfo) -> String {
@@ -324,7 +309,7 @@ fn adapter_summary(info: &eframe::wgpu::AdapterInfo) -> String {
 /// macOS keeps its traffic lights over the integrated title strip.
 const CUSTOM_TITLEBAR: bool = !cfg!(target_os = "macos");
 
-fn main() -> eframe::Result {
+fn main() -> std::process::ExitCode {
     // First, so every start-up warning is recorded (`logging`).
     let logger = logging::install();
     vectorcraft_ui_egui::i18n::detect_system_lang_in_background();
@@ -336,7 +321,7 @@ fn main() -> eframe::Result {
             "--control" => control_port = args.next().and_then(|p| p.parse().ok()),
             "--version" => {
                 println!("vectorcraft {}", env!("CARGO_PKG_VERSION"));
-                return Ok(());
+                return std::process::ExitCode::SUCCESS;
             }
             _ => files.push(a),
         }
@@ -360,7 +345,9 @@ fn main() -> eframe::Result {
     #[cfg(feature = "wgpu")]
     let gpu_pref = saved.as_ref().and_then(|ui| ui.engine_prefs.get("gpuPreference")).and_then(serde_json::Value::as_str);
     #[cfg(feature = "wgpu")]
-    let power = power_preference(gpu_pref, eframe::wgpu::PowerPreference::from_env());
+    let power = gpu::power_preference(gpu_pref, eframe::wgpu::PowerPreference::from_env());
+    #[cfg(feature = "wgpu")]
+    let startup = std::sync::Arc::new(gpu::Startup::default());
     let options = eframe::NativeOptions {
         viewport: egui::ViewportBuilder::default()
             .with_title("VectorCraft")
@@ -383,86 +370,94 @@ fn main() -> eframe::Result {
         // One frame queued, not two: the canvas is rasterized on the CPU and the GPU only
         // composites it, so the window answers the pointer a frame sooner (#444).
         options.wgpu_options.surface = eframe::egui_wgpu::SurfaceConfig::LOW_LATENCY;
+        // Only adapters that can show the window, in the order `gpu` gives (#306, #502).
         if let eframe::egui_wgpu::WgpuSetup::CreateNew(create) = &mut options.wgpu_options.wgpu_setup {
-            create.power_preference = power;
+            create.native_adapter_selector = Some(gpu::selector(power, startup.clone()));
         }
         options
     };
+    #[cfg(feature = "wgpu")]
+    gpu::watch_panics();
     // Files opened from Finder and the Dock arrive as events, not arguments.
     #[cfg(target_os = "macos")]
     open_documents::install();
-    eframe::run_native(
-        "VectorCraft",
-        options,
-        Box::new(move |cc| {
-            let mut app = VectorcraftApp::new(Session::new(), services());
-            load_prefs(&mut app, saved);
-            // Fit the window to its monitor, or put it back where it was (still hidden).
-            if let Some(w) = cc.winit_window() {
-                app.ui.window = Some(window::restore(w, saved_window));
-            }
-            // User Defined swatch and graphic style libraries live next to the preferences.
-            let swatches = prefs_path().and_then(|p| Some(p.parent()?.join("Swatches").to_string_lossy().to_string()));
-            app.session.swatch_libraries.set_user_dir(swatches);
-            let styles = prefs_path().and_then(|p| Some(p.parent()?.join("Graphic Styles").to_string_lossy().to_string()));
-            app.session.style_libraries.set_user_dir(styles);
-            // Data Recovery copies live next to the preferences too (none for runs without
-            // preferences, such as agents' test runs, unless the recoveryFolder preference is set).
-            if std::env::var_os("VECTORCRAFT_NO_PREFS").is_none() {
-                let recovery = prefs_path().and_then(|p| Some(p.parent()?.join("Data Recovery").to_string_lossy().to_string()));
-                app.session.recovery.set_default_folder(recovery);
-            }
-            let graphics_loss = GraphicsLoss::default();
-            #[cfg(feature = "wgpu")]
-            if let Some(rs) = &cc.wgpu_render_state {
-                let summary = adapter_summary(&rs.adapter.get_info());
-                log::info!("rendering with {summary} (power preference {power:?})");
-                app.graphics_adapter = Some(summary);
-                let (loss, ctx) = (graphics_loss.clone(), cc.egui_ctx.clone());
-                rs.device.set_device_lost_callback(move |reason, msg| loss.report(&ctx, format!("{reason:?}: {msg}")));
-            }
-            #[cfg(feature = "windows7")]
-            {
-                app.graphics_adapter = Some("OpenGL (Windows 7 compatibility)".into());
-            }
-            app.integrated_titlebar = cfg!(target_os = "macos");
-            app.custom_titlebar = CUSTOM_TITLEBAR;
-            if let Some(port) = control_port {
-                let rx = control_server::start(port, cc.egui_ctx.clone());
-                app = app.with_control(rx);
-            }
-            #[cfg(target_os = "macos")]
-            open_documents::set_ui(&cc.egui_ctx);
-            open_files(&mut app, files);
-            Ok(Box::new(App {
-                app,
-                graphics_loss,
-                graphics_lost: false,
+    #[cfg(feature = "wgpu")]
+    let created = startup.clone();
+    // A panic that ends the window (egui-wgpu's own, #502) is caught here: never a crash.
+    let outcome = vectorcraft_engine::guard::catch_panic(|| {
+        eframe::run_native(
+            "VectorCraft",
+            options,
+            Box::new(move |cc| {
+                let mut app = VectorcraftApp::new(Session::new(), services());
+                load_prefs(&mut app, saved);
+                // Fit the window to its monitor, or put it back where it was (still hidden).
+                if let Some(w) = cc.winit_window() {
+                    app.ui.window = Some(window::restore(w, saved_window));
+                }
+                // User Defined swatch and graphic style libraries live next to the preferences.
+                let swatches = prefs_path().and_then(|p| Some(p.parent()?.join("Swatches").to_string_lossy().to_string()));
+                app.session.swatch_libraries.set_user_dir(swatches);
+                let styles = prefs_path().and_then(|p| Some(p.parent()?.join("Graphic Styles").to_string_lossy().to_string()));
+                app.session.style_libraries.set_user_dir(styles);
+                // Data Recovery copies live next to the preferences too (none for runs without
+                // preferences, such as agents' test runs, unless the recoveryFolder preference is set).
+                if std::env::var_os("VECTORCRAFT_NO_PREFS").is_none() {
+                    let recovery = prefs_path().and_then(|p| Some(p.parent()?.join("Data Recovery").to_string_lossy().to_string()));
+                    app.session.recovery.set_default_folder(recovery);
+                }
+                let graphics_loss = GraphicsLoss::default();
+                #[cfg(feature = "wgpu")]
+                if let Some(rs) = &cc.wgpu_render_state {
+                    let summary = adapter_summary(&rs.adapter.get_info());
+                    log::info!("rendering with {summary} (power preference {power:?})");
+                    created.created(&cc.egui_ctx);
+                    if !gpu::skipped().is_empty() {
+                        app.status(format!("The graphics processor tried first couldn't show the window, so VectorCraft started again on {summary}"));
+                    }
+                    app.graphics_adapter = Some(summary);
+                    let (loss, ctx) = (graphics_loss.clone(), cc.egui_ctx.clone());
+                    rs.device.set_device_lost_callback(move |reason, msg| loss.report(&ctx, format!("{reason:?}: {msg}")));
+                }
+                #[cfg(feature = "windows7")]
+                {
+                    app.graphics_adapter = Some("OpenGL (Windows 7 compatibility)".into());
+                }
+                app.integrated_titlebar = cfg!(target_os = "macos");
+                app.custom_titlebar = CUSTOM_TITLEBAR;
+                if let Some(port) = control_port {
+                    let rx = control_server::start(port, cc.egui_ctx.clone());
+                    app = app.with_control(rx);
+                }
                 #[cfg(target_os = "macos")]
-                menu: None,
-            }))
-        }),
-    )
+                open_documents::set_ui(&cc.egui_ctx);
+                open_files(&mut app, files);
+                Ok(Box::new(App {
+                    app,
+                    graphics_loss,
+                    graphics_lost: false,
+                    #[cfg(target_os = "macos")]
+                    menu: None,
+                }))
+            }),
+        )
+    });
+    #[cfg(feature = "wgpu")]
+    let outcome = gpu::finish(outcome, &startup);
+    #[cfg(not(feature = "wgpu"))]
+    let outcome = outcome.and_then(|r| r.map_err(|e| e.to_string()));
+    match outcome {
+        Ok(()) => std::process::ExitCode::SUCCESS,
+        Err(e) => {
+            log::error!("VectorCraft stopped: {e}");
+            std::process::ExitCode::FAILURE
+        }
+    }
 }
 
 #[cfg(all(test, feature = "wgpu"))]
 mod tests {
     use super::*;
-    use eframe::wgpu::PowerPreference;
-
-    #[test]
-    fn power_saving_unless_the_preference_or_the_environment_says_otherwise() {
-        assert_eq!(power_preference(None, None), PowerPreference::LowPower);
-        assert_eq!(power_preference(Some("powerSaving"), None), PowerPreference::LowPower);
-        assert_eq!(power_preference(Some("highPerformance"), None), PowerPreference::HighPerformance);
-        // A value this version doesn't know (a newer or damaged preference file) is the default.
-        assert_eq!(power_preference(Some("turbo"), None), PowerPreference::LowPower);
-        assert_eq!(power_preference(Some(""), None), PowerPreference::LowPower);
-        // WGPU_POWER_PREF wins over the preference, either way.
-        assert_eq!(power_preference(Some("powerSaving"), Some(PowerPreference::HighPerformance)), PowerPreference::HighPerformance);
-        assert_eq!(power_preference(Some("highPerformance"), Some(PowerPreference::LowPower)), PowerPreference::LowPower);
-        assert_eq!(power_preference(None, Some(PowerPreference::None)), PowerPreference::None);
-    }
 
     /// The file extensions the macOS bundle declares: its document types and its own exported type.
     fn plist_extensions(plist: &str) -> Vec<&str> {
@@ -492,16 +487,4 @@ mod tests {
         assert!(types > 1 && plist.matches("<key>LSHandlerRank</key>").count() == types, "every document type has a rank");
         assert_eq!(plist.matches("<string>Owner</string>").count(), 2, "only VectorCraft documents and templates are owned");
     }
-
-    /// The preference the engine saves is the one the app reads back before the window opens.
-    #[test]
-    fn the_saved_engine_preference_is_found() {
-        let mut prefs = vectorcraft_engine::Prefs::default();
-        let saved = prefs.to_json();
-        assert_eq!(saved.get("gpuPreference").and_then(serde_json::Value::as_str), Some("powerSaving"));
-        prefs.gpu_preference = "highPerformance".into();
-        let saved = prefs.to_json();
-        let pref = saved.get("gpuPreference").and_then(serde_json::Value::as_str);
-        assert_eq!(power_preference(pref, None), PowerPreference::HighPerformance);
-    }
 }

crates/engine/src/cmd/prefscmds.rs

@@ -82,8 +82,11 @@ pub const UNITS: &[(&str, &str)] = &[
     ("feet", "Feet"),
 ];
 const LINE_STYLE: &[(&str, &str)] = &[("lines", "Lines"), ("dots", "Dots")];
-/// Performance › Graphics Processor (`gpuPreference`), read by the desktop app at startup.
-pub const GPU_PREFERENCES: &[(&str, &str)] = &[("powerSaving", "Power Saving (integrated)"), ("highPerformance", "High Performance (discrete)")];
+/// Performance › Graphics Processor (`gpuPreference`), read by the desktop app at startup. The
+/// values are WebGPU's power preferences plus `automatic`; 0.5.0's default, `powerSaving`, reads as
+/// `automatic` (#502).
+pub const GPU_PREFERENCES: &[(&str, &str)] =
+    &[("automatic", "Automatic"), ("lowPower", "Power Saving (integrated)"), ("highPerformance", "High Performance (discrete)")];
 const BLACK: &[(&str, &str)] = &[("accurate", "Display All Blacks Accurately"), ("rich", "Display All Blacks as Rich Black")];
 const BLACK_OUT: &[(&str, &str)] = &[("accurate", "Output All Blacks Accurately"), ("rich", "Output All Blacks as Rich Black")];
 

crates/engine/src/lib.rs

@@ -446,10 +446,13 @@ pub struct Prefs {
     pub gpu_performance: bool,
     pub animated_zoom: bool,
     /// Which graphics processor the desktop app asks for at startup (it takes effect after a
-    /// restart): `powerSaving` (the integrated GPU on hybrid-graphics laptops) or `highPerformance`
-    /// (the discrete one). The canvas is rasterized on the CPU and only composited on the GPU, so
-    /// the integrated GPU is plenty; presenting from the discrete GPU through the integrated one
-    /// made some hybrid laptops flicker (#306). Single-GPU machines are unaffected.
+    /// restart): `automatic`, `lowPower` (the integrated GPU on hybrid-graphics machines) or
+    /// `highPerformance` (the discrete one). The canvas is rasterized on the CPU and only
+    /// composited on the GPU, so the integrated GPU is plenty; presenting from the discrete GPU
+    /// through the integrated one made some hybrid laptops flicker (#306). Automatic is power
+    /// saving on Windows and macOS and the system's default GPU elsewhere, the one the desktop
+    /// runs on: a Wayland compositor may not show frames from another GPU (#502). Single-GPU
+    /// machines are unaffected.
     pub gpu_preference: String,
     pub history_states: u32,
     pub real_time_drawing: bool,
@@ -653,7 +656,7 @@ impl Default for Prefs {
             interface_language: s("auto"),
             gpu_performance: true,
             animated_zoom: true,
-            gpu_preference: s("powerSaving"),
+            gpu_preference: s("automatic"),
             history_states: 500,
             real_time_drawing: true,
             render_threads: -1,

crates/engine/src/tests_prefs.rs

@@ -123,34 +123,37 @@ fn prefs_serde_round_trip_and_tolerates_missing_fields() {
     assert_eq!(partial.corner_radius, 12.0);
 }
 
-/// Performance › Graphics Processor (#306): power saving by default, set by value or label, kept
-/// through a save/load round trip, and a bad value is an error that changes nothing.
+/// Performance › Graphics Processor (#306, #502): automatic by default, set by value or label,
+/// kept through a save/load round trip, and a bad value (0.5.0's `powerSaving` among them) is an
+/// error that changes nothing.
 #[test]
-fn gpu_preference_defaults_to_power_saving_and_validates() {
+fn gpu_preference_defaults_to_automatic_and_validates() {
     let mut s = Session::new();
-    assert_eq!(s.prefs.gpu_preference, "powerSaving");
-    assert_eq!(s.execute("prefs.get", &json!({"key": "gpuPreference"})).unwrap(), json!("powerSaving"));
+    assert_eq!(s.prefs.gpu_preference, "automatic");
+    assert_eq!(s.execute("prefs.get", &json!({"key": "gpuPreference"})).unwrap(), json!("automatic"));
     s.execute("prefs.set", &json!({"key": "gpuPreference", "value": "highPerformance"})).unwrap();
     assert_eq!(s.prefs.gpu_preference, "highPerformance");
     s.execute("prefs.set", &json!({"key": "gpuPreference", "value": "Power Saving (integrated)"})).unwrap();
-    assert_eq!(s.prefs.gpu_preference, "powerSaving");
-    for bad in [json!("turbo"), json!(""), json!(1), json!(null), json!(["highPerformance"])] {
+    assert_eq!(s.prefs.gpu_preference, "lowPower");
+    s.execute("prefs.set", &json!({"key": "gpuPreference", "value": "automatic"})).unwrap();
+    assert_eq!(s.prefs.gpu_preference, "automatic");
+    for bad in [json!("powerSaving"), json!("turbo"), json!(""), json!(1), json!(null), json!(["highPerformance"])] {
         assert!(s.execute("prefs.set", &json!({"key": "gpuPreference", "value": bad})).is_err(), "{bad}");
-        assert_eq!(s.prefs.gpu_preference, "powerSaving");
+        assert_eq!(s.prefs.gpu_preference, "automatic");
     }
-    let p = Prefs { gpu_preference: "highPerformance".into(), ..Default::default() };
+    let p = Prefs { gpu_preference: "lowPower".into(), ..Default::default() };
     let back: Prefs = serde_json::from_value(p.to_json()).unwrap();
-    assert_eq!(back.gpu_preference, "highPerformance");
+    assert_eq!(back.gpu_preference, "lowPower");
     // Preference files written before the preference existed get the default.
     let old: Prefs = serde_json::from_value(json!({"gpuPerformance": true})).unwrap();
-    assert_eq!(old.gpu_preference, "powerSaving");
+    assert_eq!(old.gpu_preference, "automatic");
     let l = s.execute("prefs.list", &json!({})).unwrap();
     let row = l.as_array().unwrap().iter().find(|e| e["key"] == "gpuPreference").unwrap().clone();
     assert_eq!(row["category"], "Performance");
-    assert_eq!(row["options"], json!(["powerSaving", "highPerformance"]));
+    assert_eq!(row["options"], json!(["automatic", "lowPower", "highPerformance"]));
     s.execute("prefs.set", &json!({"key": "gpuPreference", "value": "highPerformance"})).unwrap();
     s.execute("prefs.reset", &json!({"category": "Performance"})).unwrap();
-    assert_eq!(s.prefs.gpu_preference, "powerSaving");
+    assert_eq!(s.prefs.gpu_preference, "automatic");
 }
 
 /// Selection & Anchor Display › Tolerance, Object Selection by Path Only and Command Click to

crates/ui-egui/src/i18n/es.tsv

@@ -3571,6 +3571,7 @@ axis	Both	Ambos
 @msg	Sent to {_1}	Se envió a {_1}
 @msg	{_1} files	{_1} archivos
 @msg	The graphics were lost and have been restarted	Se perdieron los gráficos y se reiniciaron
+@msg	The graphics processor tried first couldn't show the window, so VectorCraft started again on {summary}	El procesador gráfico probado primero no pudo mostrar la ventana, así que VectorCraft se inició de nuevo con {summary}
 @msg	Loading VectorCraft…	Cargando VectorCraft…
 @msg	VectorCraft failed to start: {e}	VectorCraft no pudo iniciarse: {e}
 @msg	A browser with WebGPU or WebGL2 is required.	Se necesita un navegador con WebGPU o WebGL2.

crates/ui-egui/src/prefs_dialog.rs

@@ -6,7 +6,7 @@
 
 use serde_json::{Map, Value, json};
 use vectorcraft_engine::Prefs;
-use vectorcraft_engine::cmd::prefscmds::{PREF_CATEGORIES, PREF_GROUPS, PREF_SPECS, PrefKind};
+use vectorcraft_engine::cmd::prefscmds::{GPU_PREFERENCES, PREF_CATEGORIES, PREF_GROUPS, PREF_SPECS, PrefKind};
 
 use crate::state::Dialog;
 use crate::theme::{self, Brightness, Tokens};
@@ -69,6 +69,11 @@ pub fn restore(app: &mut VectorcraftApp) {
     {
         p.interface_language = code;
     }
+    // 0.5.0 saved its default, `powerSaving`, which Automatic replaced (#502): any value this
+    // version doesn't offer reads as the default, as the desktop app reads it at startup.
+    if !GPU_PREFERENCES.iter().any(|(v, _)| *v == p.gpu_preference) {
+        p.gpu_preference = Prefs::default().gpu_preference;
+    }
     app.session.apply_prefs(p);
 }
 
@@ -454,8 +459,8 @@ mod tests {
         assert_eq!(a.session.prefs.ui_brightness, "light");
     }
 
-    /// Performance › Graphics Processor (#306): shown with its restart note, applied by OK and
-    /// saved with the UI state under the key the desktop app reads before the window opens.
+    /// Performance › Graphics Processor (#306, #502): shown with its restart note, applied by OK
+    /// and saved with the UI state under the key the desktop app reads before the window opens.
     #[test]
     fn graphics_processor_preference_shows_and_persists() {
         fn texts(s: &egui::Shape, out: &mut Vec<String>) {
@@ -477,7 +482,7 @@ mod tests {
         let mut shown = vec![];
         out.shapes.iter().for_each(|c| texts(&c.shape, &mut shown));
         assert!(shown.iter().any(|t| t.starts_with("Graphics Processor")), "{shown:?}");
-        assert!(shown.iter().any(|t| t == "Power Saving (integrated)"), "{shown:?}");
+        assert!(shown.iter().any(|t| t == "Automatic"), "{shown:?}");
         assert!(shown.iter().any(|t| t == "Applies the next time VectorCraft starts."), "{shown:?}");
         a.ui.dialog.as_mut().unwrap().fields.insert("gpuPreference".into(), json!("highPerformance"));
         confirm(&mut a).unwrap();
@@ -514,6 +519,19 @@ mod tests {
         assert!(picas_in_use(d), "enabled with a unit in picas");
     }
 
+    /// 0.5.0 saved `powerSaving` for everyone (its default): it reads as Automatic, while the
+    /// choices this version offers are kept (#502).
+    #[test]
+    fn a_graphics_processor_this_version_does_not_offer_reads_as_automatic() {
+        for (saved, read) in [("powerSaving", "automatic"), ("turbo", "automatic"), ("lowPower", "lowPower"), ("highPerformance", "highPerformance")]
+        {
+            let mut a = app();
+            a.ui.engine_prefs = json!({"gpuPreference": saved});
+            restore(&mut a);
+            assert_eq!(a.session.prefs.gpu_preference, read, "{saved}");
+        }
+    }
+
     #[test]
     fn every_category_renders_fields() {
         for c in PREF_CATEGORIES {

docs/development.md

@@ -36,10 +36,19 @@ How the web shell (`apps/vectorcraft-web/src/web.rs`) differs from desktop:
 
 ## Desktop graphics processor
 
-The canvas is rasterized on the CPU (`vectorcraft-render`, vello_cpu); the GPU (wgpu, through eframe) only composites the canvas texture and draws the UI. The desktop app (`apps/vectorcraft/src/main.rs`) therefore asks wgpu for the **power-saving** adapter by default, which is the integrated GPU on hybrid-graphics laptops. Presenting frames rendered on a discrete GPU through the integrated one made the window flicker on some laptops (#306). A machine with one GPU gets that GPU either way.
+The canvas is rasterized on the CPU (`vectorcraft-render`, vello_cpu); the GPU (wgpu, through eframe) only composites the canvas texture and draws the UI, so any GPU that can show the window will do. The desktop app picks the window's adapter itself (`apps/vectorcraft/src/gpu.rs`, eframe's `native_adapter_selector`) and logs every adapter it found and the one it uses.
 
-- **Preferences › Performance › Graphics Processor** (`gpuPreference`: `powerSaving` or `highPerformance`) picks the other one. The adapter is chosen when the window opens, so a change applies after a restart.
-- The `WGPU_POWER_PREF` environment variable (`low`, `high` or `none`) overrides the preference.
+- **Order:** adapters that report they can't present to the window are never tried; then the one `WGPU_ADAPTER_NAME` names; hardware before software (llvmpipe, WARP); the native backends (Vulkan, Metal, DX12) before OpenGL; then the power preference, keeping the system's order among equals.
+- **Preferences › Performance › Graphics Processor** (`gpuPreference`): `automatic` (the default), `lowPower` (Power Saving, the integrated GPU) or `highPerformance` (the discrete GPU). The adapter is chosen when the window opens, so a change applies after a restart.
+  - **Automatic on Windows and macOS** is power saving: the system shows frames from any GPU, and presenting frames rendered on a discrete GPU through the integrated one made the window flicker on some hybrid laptops (#306).
+  - **Automatic on Linux and the BSDs** keeps the system's order: Mesa's Vulkan device-select layer puts the GPU the desktop runs on first (the integrated one on hybrid laptops; `DRI_PRIME` and `MESA_VK_DEVICE_SELECT` steer it). A Wayland compositor may not accept frames from another GPU: on a desktop whose compositor ran on an NVIDIA GPU, rendering on the Ryzen's integrated GPU made KWin end the window's connection ("importing the supplied dmabufs failed") and 0.5.0 crashed at startup (#502).
+  - 0.5.0 saved `powerSaving`, its default, for everyone; it reads as `automatic`.
+- **If the window fails on its adapter while starting up** (an error from wgpu, or a panic inside wgpu or egui-wgpu during the first frames), the app starts again without that adapter and tries the next one, telling which in the status bar; the run that failed keeps its log as `vectorcraft.1.log`. On Unix the new app replaces the process (an AppImage stays mounted); on Windows it starts beside it. The adapters left out travel in `VECTORCRAFT_GPU_SKIP` (`backend:vendor:device`, such as `Vulkan:1002:164e`), one more on each restart, so the restarts end. When no adapter is left, the app logs why and exits with an error instead of panicking.
+- **Environment variables** for when the choice still goes wrong, all read at startup and stronger than the preference:
+  - `WGPU_POWER_PREF`: `low`, `high` or `none` (the system's order).
+  - `WGPU_ADAPTER_NAME`: part of an adapter's name, any case (`WGPU_ADAPTER_NAME=nvidia`, `=radv`, `=intel`); the names are in the log.
+  - `WGPU_BACKEND`: the backends to use, such as `vulkan`, `dx12`, `metal` or `gl`.
+  - On Linux with Mesa, `MESA_VK_DEVICE_SELECT=10de:2f04!` (vendor:device as `vulkaninfo --summary` or `lspci -nn` show it) leaves only that GPU to Vulkan, and `DRI_PRIME=1` picks the other GPU.
 - Help › About and the control channel's `ui.inspect` (`graphicsAdapter`) show the adapter in use, and the app logs it at startup.
 
 ## Logs
@@ -55,11 +64,14 @@ By default VectorCraft's own crates log at `info` and everything else at `warn`.
 | `VECTORCRAFT_CONTROL_PORT` | Same as `--control <port>` |
 | `VECTORCRAFT_NO_PREFS` | No preferences read or written, no default Data Recovery folder and no log file (agents' test runs) |
 | `WGPU_POWER_PREF` | Graphics adapter: `low`, `high` or `none` (see [Desktop graphics processor](#desktop-graphics-processor)) |
+| `WGPU_ADAPTER_NAME` | Graphics adapter by (part of) its name, any case (see [Desktop graphics processor](#desktop-graphics-processor)) |
+| `WGPU_BACKEND` | Graphics backends: `vulkan`, `dx12`, `metal`, `gl` |
+| `VECTORCRAFT_GPU_SKIP` | Set by the app when it starts again without a graphics adapter that failed (see [Desktop graphics processor](#desktop-graphics-processor)) |
 | `RUST_LOG` | Log levels for standard error and the log file (see [Logs](#logs)) |
 
 ## Linux: Wayland and X11
 
-The window runs natively on Wayland (eframe's `wayland` feature) and on X11. The system clipboard (`apps/vectorcraft/src/clipboard.rs`) is arboard with its `wayland-data-control` feature:
+The window runs natively on Wayland (eframe's `wayland` feature) and on X11. On machines with two GPUs it renders on the one the desktop runs on unless Preferences say otherwise; see [Desktop graphics processor](#desktop-graphics-processor) (#502). The system clipboard (`apps/vectorcraft/src/clipboard.rs`) is arboard with its `wayland-data-control` feature:
 
 - **Clipboard:** under Wayland arboard talks to the compositor through the data-control protocol (wlroots compositors such as Sway and Hyprland, KDE Plasma), so bitmaps (`image/png`), SVG markup and text copied in any app paste (#398). Where the compositor lacks the protocol (GNOME's Mutter, [arboard#223](https://github.com/1Password/arboard/issues/223)), arboard falls back to the X11 clipboard through XWayland, which only holds what X11 apps copied. egui's own text paste into fields goes through smithay-clipboard and works either way.
 - **Copied files:** files copied in a file manager (`text/uri-list`; `CF_HDROP` on Windows, file URLs on macOS) paste as the first one that is art (SVG, PDF, EMF/WMF or a bitmap), before the clipboard's other formats (which include the files' paths as text).