pdfcraft/vendor/README.md

Vendored crates

Permissively licensed crates we carry small patches for. Each directory keeps the upstream licence files unchanged. Every patch is marked PdfCraft patch: in the source, is covered by a PdfCraft test, and should be proposed upstream. Remove the vendored copy once upstream releases the fix. Vendoring copyleft code is never allowed (plan/adr/0001).

Crate	Version	Licence	Patches	Test
hayro-interpret	0.7.0	Apache-2.0 OR MIT	(1) select /AP /N appearance states via /AS (checkboxes, radios, stateful icons) and honour the NoView flag; (2) Type3 Unicode fallback to /Encoding glyph names, then printable ASCII; (3) Type3Glyph::advance_width; (4) InterpreterSettings::ocg_overrides for viewer layer toggles; (5) soft masks whose group lacks /CS were dropped (Chrome gradient text); (6) paint nesting cap MAX_PAINT_NESTING for tiling patterns and Type 3 glyphs (self-referencing content overflowed the stack); (7) CID width ranges in /W and /W2 clamped to MAX_CID (a 0 4294967295 w range hung); (8) InterpreterSettings::hide_comments skips markup annotations but keeps widgets and links (View ▸ Hide all comments); (9) image_size_ok: images and masks over 2^28 pixels are not decoded (a fuzzed /W 4294967295 stencil mask allocated 4 GiB); (10) MAX_NESTED_PAINTS: nested paints (forms, Type 3 glyphs and tiling patterns inside one another) share a per-page budget of 50,000 (a glyph showing eight glyphs of its own font, sixteen deep, hung); (11) depends on skrifa 0.47 instead of 0.42 (upstream read-fonts fixed a Type 1 tokenizer that recursed through runs of numbers: a fuzzed font hung or overflowed the stack), with the one API change (Charset::glyph_id returns Option); (12) annotation appearances whose /BBox or /Matrix collapses to a line or a point are skipped (mapping them onto /Rect divided by zero and handed the device infinite or NaN matrices); (13) a Highlight annotation without a usable normal appearance is drawn from its /QuadPoints, /C and /CA with Multiply blending, as pdfcraft-annot draws highlights (it was not drawn at all); (14) simple-font /Widths (read_widths): entries only for codes 0–255 (one entry per code below /FirstChar was allocated: 4294967295 asked for 34 GB), an entry that isn't a number leaves its code missing instead of ending the array, and a /LastChar below /FirstChar gives no widths instead of discarding the font for a standard one; (15) the appearance box is mapped onto /Rect corner to corner: the translation now accounts for the scale (an appearance whose box didn't start at the origin and differed in size from /Rect was drawn shifted); (16) a clip set by W/W* takes effect after whichever path-painting operator ends the path (S, f, B, … as well as n; ISO 32000-2 §8.5.4): it was applied only on n, so re W* S clipped nothing and the clip stayed pending for a later, unrelated n; (17) InterpreterSettings::cancelled: once set, interpretation stops before the next content operator (a render pool sets it for every worker when dropped, after an edit or on closing, and for one worker when the watchdog gives up on its render, so renders whose answers nobody can receive stop instead of running to the end); (18) MAX_PAGE_CONTENT: the content a page holds at once (its contents, and the forms, tiling patterns and Type 3 glyph procedures being painted) stays within 512 MiB (decode_content; once it runs out, InterpreterWarning::ContentTruncated is reported (once per page by pdfcraft-render) so a truncated page is not a clean render; each level gives its bytes back when it finishes): forms nest fifty deep and each level kept its content while the next ran, so a form painting itself around a stream inflating to 256 MiB would have held over 12 GB; and Type 0 sampled functions take at most MAX_SAMPLE_ENTRIES (2^21) table points and MAX_SAMPLE_VALUES (2^23) samples, read no further than /Size asks (256 MiB of 1-bit samples asked for over 8 GB); (19) mesh shadings (types 4–7) are sampled only inside the area being drawn (ShadingPattern::encode_within, which the vendored hayro renderer calls with that area plus a pixel), within 8 visits per pixel of it plus 4 per triangle (TriangleSampler), and patches are triangulated one at a time: points far off the page were sampled over their whole bounding box, up to 65536 × 65536 entries (a fuzzed 147-byte patch stream; a synthetic page passed 6 GB in six seconds), ten thousand overlapping triangles ran for minutes, and every patch became 722 triangles before any limit; meshes hold at most MAX_MESH_PATCHES (2^16) patches and MAX_MESH_TRIANGLES (2^20) triangles, a lattice needs two to 2^19 vertices per row (/VerticesPerRow 0 pushed empty rows for ever; one huge row read the whole stream), and a page samples at most MAX_PAGE_MESH_TRIANGLES (2^25) mesh triangles in all (a mesh painted a thousand times was triangulated a thousand times); each cut logs a warning; (20) PDF function construction is limited to 64 levels and 10,000 total nodes with cycle detection; calculator parsing and evaluation share procedure depth/work budgets, integer division/bitshift/rotation/index are panic-free, and fixed-size stack errors propagate; (21) a Type 0 font drawn with a substitute that isn't CID-keyed (it isn't embedded, or its program doesn't load) draws .notdef for a CID of an Adobe character collection (Japan1, GB1, CNS1, Korea1) that it can't find by Unicode: hayro took the CID for a glyph index of the substitute, which numbers its glyphs its own way, so the character was drawn as an unrelated one (𠮷 as "Ｑ" in BIZ UDPGothic); (22) a Type 0 font drawn with a substitute finds a character given with a variation selector (/ToUnicode, or Adobe-Japan1-UCS2, which maps the JIS X 0208 forms of the kanji JIS X 0213:2004 redrew that way: CID 1247 is 噂 U+E0100) through the substitute's variation sequences, else as the character alone: such a CID found no glyph and was drawn as an unrelated one	(1) raster::tests::widget_appearance_states; (2, 3) xtask text-oracle on corpus/pdfjs issue918; (4) raster::tests::layer_override_hides_content; (5) raster::tests::soft_mask_without_group_colour_space_is_applied; (6) raster::tests::self_referencing_tiling_pattern_terminates, raster::tests::self_referencing_type3_glyph_terminates; (7) raster::tests::huge_cid_width_ranges_terminate; (8) raster::tests::hiding_comments_keeps_fields; (9) raster::tests::absurd_mask_and_fax_sizes_are_refused_before_decoding; (10) raster::tests::type3_glyphs_that_fan_out_into_themselves_finish; (11) raster::tests::type1_font_programs_with_long_runs_of_numbers_load_quickly; (12) raster::tests::degenerate_annotation_appearances_are_skipped; (13) raster::tests::highlights_without_an_appearance_are_drawn; (14) raster::tests::malformed_simple_font_widths_keep_later_widths_and_the_font, raster::tests::huge_simple_font_first_char_terminates; (15) raster::tests::annotation_appearance_box_maps_onto_rect; (16) raster::tests::clipping_path_applies_after_any_painting_operator; (17) raster::tests::dropping_the_pool_cancels_its_renders, raster::tests::the_watchdog_stops_the_render_it_gives_up_on; (18) raster::tests::page_contents_and_nested_forms_share_one_budget, raster::tests::content_painted_again_and_again_keeps_drawing, raster::tests::sampled_functions_with_billions_of_samples_are_refused; (19) raster::tests::mesh_shadings_far_off_the_page_render, raster::tests::many_overlapping_mesh_triangles_finish, raster::tests::mesh_shadings_with_many_patches_or_no_rows_finish; (20) raster::tests::function_limits_calculator_arithmetic_and_depth, raster::tests::function_limits_public_construction_work_and_depth, raster::tests::function_limits_stitching_cycles_are_refused_and_shared_children_work, raster::tests::function_limits_invalid_calculator_keeps_the_page_renderable; (21) raster::tests::cids_a_substitute_lacks_are_not_drawn_as_other_glyphs

| hayro | 0.7.1 | Apache-2.0 OR MIT | (1) RenderSettings::{x_offset, y_offset} to render one tile of a large page; (2) images over MAX_IMAGE_PIXELS (2^28) are skipped (a fuzzed /W 4294967295 hung in resampling); (3) tiling_cell_scale keeps a tiling pattern's cell pixmap within 3000 px a side whatever its /XStep//YStep (a fuzzed step far beyond /BBox allocated 2 GB); (4) stroke widths clamped to 4 × (canvas width + height) device pixels (a fuzzed /LW 9223372036854775807 allocated 10 GB in stroke expansion); (5) usable_dash_pattern: a stroke whose dash pattern could cut it into more than MAX_DASHES_PER_STROKE (250,000) pieces, counting kurbo's restart of the pattern at every subpath and ClosePath, is drawn solid (a fuzzed /D [[11] 0] on a line from x = 92234775807 allocated over 5 GB, [0.000001] 0 d on a 20 pt line over 10 GB); (6) a dash pattern with a negative or non-finite entry, or a period that isn't positive, is drawn solid ([-1 -1] 0 d looped for ever in kurbo); (7) render_size and render_into: render into a buffer the caller allocates (PdfCraft renders into pixel-aligned memory that the GUI takes over as texture data); render is render_into on a new pixmap; (8) checked image source/target/RGBA, alpha-premultiplication scratch and intermediate sizes before resampling, finite transforms and exact source/mask buffers; sources wider than u16 may shrink before backend limits, with a 2^20 source-axis cap and conservative 128 MiB filter-planning estimate; an over-limit or failed resize keeps the original image resolution and geometry when the source fits the backend, otherwise skips it, with a logged warning; staging, resampling output/scratch, RGBA conversion and padding buffers use fallible reserves; (9) may_paint_canvas: a fill or stroke whose control-point box, grown by how far its paint reaches past the path (half the stroke width times the larger of the miter limit and √2) plus 0.5 user units and 2 pixels, misses the canvas is not drawn, so a tile no longer strokes and fills every path of its page (item 5 of #623); set_skip_offscreen_paths turns this off for the regression test | (1) raster::tests::tiles_match_full_render; (2) raster::tests::absurd_image_dimensions_are_skipped; (3) raster::tests::tiling_cells_stay_small_whatever_the_step; (4) raster::tests::absurd_predictor_columns_and_line_widths_render; (5) raster::tests::dash_patterns_that_cut_a_stroke_into_billions_of_pieces_render; (6) raster::tests::invalid_dash_patterns_terminate_and_are_drawn_solid; (7) raster::tests::pixels_are_a_plain_renders_bytes_in_a_buffer_a_gui_can_take_over; (8) raster::tests::image_resampling_rejects_anisotropic_target_growth, raster::tests::image_resampling_bounds_intermediate_before_planning, raster::tests::image_resampling_rejects_invalid_sources_and_scales, raster::tests::image_resampling_keeps_valid_sizes_and_exact_limits, raster::tests::resampling_fallback_preserves_original_geometry_and_pixels, raster::tests::image_resampling_wide_sources_shrink_before_backend_side_limits, raster::tests::image_resampling_wide_transparent_sources_still_shrink, raster::tests::image_resampling_padded_backend_dimensions_stay_checked, raster::tests::image_resampling_mismatched_alpha_mask_keeps_pixels_and_placement; (9) raster::tests::skipping_paths_off_the_canvas_changes_no_pixel | | hayro-jbig2 | 0.3.0 | Apache-2.0 OR MIT | (1) at most 2^28 pixels per bitmap, page bitmap, halftone grid and grayscale image (each side could be 65535: 4.3 billion pixels decoded one by one); (2) at most 2^26 symbol pixels per symbol dictionary (a fuzzed dictionary decoded for minutes); (3) a symbol dictionary's height classes are capped at one per new symbol and its export runs at 2 × symbols + 1, each plus EXTRA_EMPTY_STEPS (1024): an empty height class or a zero-length export run doesn't advance, and past the end of its data the arithmetic decoder can decode them for ever (one changed byte hung the renderer) | (1) raster::tests::jbig2_regions_of_billions_of_pixels_are_refused; (2) the nightly cargo xtask fuzz finding, which now finishes in about a second; (3) raster::tests::jbig2_symbol_dictionaries_that_never_advance_terminate | | lopdf | 0.45.0 | MIT | (1) PNG predictor rows longer than the data are refused before their buffers are allocated (a fuzzed /Columns 4294967295 allocated two 4 GiB rows), and empty frames return without row buffers; (2) predictor row widths use saturating arithmetic or reject overflow; (3) sub-byte TIFF Predictor 2 scratch is bounded by the samples present in the input instead of the declared /Colors, aligned with lopdf#589 | (1) inspect::tests::png_predictor_rows_longer_than_the_data_are_refused_before_allocating, inspect::tests::empty_png_predictor_frames_do_not_allocate_rows; (2) inspect::tests::tiff_subbyte_predictor_row_width_overflow_is_refused; (3) inspect::tests::tiff_subbyte_predictor_scratch_is_bounded_by_available_samples, inspect::tests::tiff_subbyte_predictors_keep_components_rows_and_padding | | hayro-syntax | 0.7.2 | Apache-2.0 OR MIT | (1) Page-tree cycle guard in resolve_pages (visited set + depth cap): a /Kids loop among compressed objects overflowed the stack and aborted the process; (2) ccitt_size_ok: CCITT images wider than 2^20 columns or over 2^28 pixels are not decoded (a fuzzed /Columns 4294967295 allocated 4 GiB); (3) Flate/LZW predictor row widths are saturating usize, a zero width is refused and a row longer than the data is not allocated (a fuzzed /Columns 9223372036854775807 wrapped to a 2^61-byte allocation and aborted); (4) the inline-image end-of-data check (EI) doesn't nest inside its own look-ahead and examines at most 256 candidates and steps (50 images with "EI" in their data ran for over ten minutes); (5) a stream whose /Length is wrong is recovered only when stream is the next token — scanning ahead to a later object's stream made an indirect appearance-state dictionary (Quartz checkboxes: /AP /N → << /Yes … /Off … >>) render as a non-form, so the widget was skipped; (6) JPX rescaling uses an exact integer sample range for 1–32-bit components (32 shifted past u32, and floating-point maxima at 25–31 bits wrapped to zero), and refuses zero-sized rows; (7) decode_limit: Flate (through flate2 and the fallback inflater), LZW and RunLength never write past MAX_DECODED_STREAM (256 MiB), or, for the last filter of an image of known size, past twice its pixel bytes (a predictor tag byte per byte), at most 1 GiB; Stream::decoded_within for budgeted callers; a page's /Contents array shares one MAX_DECODED_STREAM (a 2 MB page whose content stream or 8 × 8 image inflated to 2 GB took the renderer past 3 GB in under a second; naming the stream twenty times in /Contents, 5 GB); (8) high-precision numbers (jsPDF MediaBox coordinates with over 19 digits) parse without overflowing the u64 mantissa: fractional digits past it are dropped, integer digits past it scale the value (a real, kept finite); (9) large dictionary indexes are built on first use and shared across repeated reads within each PDF (#307); the validated-byte cache is bounded, reader contexts remain separate, repairs and inline/content dictionaries bypass sharing, and small dictionaries stay eager; (10) decoded object-stream slots publish once under contention, cold loading rejects recursive dependencies, and xref repair serializes without holding recursive read guards; this permits one parser per native render pool with private worker caches; (11) sync.rs: a poisoned lock is recovered instead of unwrapped (a worker panic no longer cascades into every reader of the same PDF), and xref repair takes a blocking write lock instead of asserting a non-blocking one; (12) SegmentList (util.rs) returns None for an out-of-range index instead of panicking; (13) a page's /UserUnit scales render_dimensions and initial_transform, so the page and everything on it are sized in points, as Acrobat shows them; it is read as Acrobat reads it (the page's own entry, not inherited; a number from 1 up, at most 75,000; anything else counts as 1), and a page without it keeps exactly the transform it had | (1) cos/tests/writer.rs::page_tree_loops_in_object_streams_do_not_crash_readers; (2) raster::tests::absurd_mask_and_fax_sizes_are_refused_before_decoding; (3) raster::tests::absurd_predictor_columns_and_line_widths_render; (4) raster::tests::inline_images_with_ei_in_their_data_parse_in_linear_time; (5) raster::tests::indirect_appearance_state_dict_is_not_another_stream; (6) raster::tests::jpx_stream_bit_depth_boundaries_do_not_panic, raster::tests::jpx_32_bit_image_does_not_prevent_other_page_content_from_rendering, raster::tests::jpx_gray_rgb_and_alpha_keep_eight_bit_samples, raster::tests::jpx_streams_reject_out_of_range_bit_depths; (7) raster::tests::decompression_bombs_stop_at_the_stream_limit, raster::tests::page_contents_and_nested_forms_share_one_budget; (8) inspect::tests::jspdf_high_precision_mediabox_does_not_overflow_dimensions, object::number::tests::high_precision_float_does_not_overflow_mantissa (hayro-syntax); (9) object::dict::lazy_index_tests, raster::tests::large_resource_indexes_preserve_pixels_and_text; (10) data::tests, xref::tests::concurrent_cold_object_stream_reads_all_succeed, raster::tests::shared_parser_is_lazy_and_initializes_once_under_contention; (11) data::tests::panicking_initializer_wakes_waiters_and_prevents_retries, xref::tests::concurrent_cold_object_stream_reads_all_succeed; (12) util::tests::segment_list_rejects_out_of_range_indices; (13) raster::tests::user_unit_scales_the_page_and_everything_on_it | | winit | 0.30.13 | Apache-2.0 | (1) on Windows 11 (build 22000 and later), WM_DPICHANGED applies the rect Windows suggests. It used to nudge the window onto the monitor MonitorFromWindow names, which during a drag is still the monitor being left; the nudge sent another WM_DPICHANGED, so a window dragged to a monitor with another scale factor grew and stayed on the wrong monitor at the wrong scale (#324). Backport of winit master 488c036a (winit#4341), which no 0.30 release has; Windows 10 keeps the old adjustment, as on winit master. (2) on Wayland, a seat's text input is destroyed when the seat goes away, not whenever it loses a capability: losing any capability (a touch screen or tablet unplugged, a remote-desktop session ending) destroyed it, and only an added capability recreated it, so IME stopped working until restart. Port of winit#4747; (3) on Windows, an IME composition reports its cursor from GCS_CURSORPOS only when WM_IME_COMPOSITION says it is set, and at the end of the composition otherwise: the Microsoft Korean IME never sets it, so the cursor read as 0 (egui then drew no caret while composing; it now draws it after the syllable). Port of winit#4746; (4) on Windows, a hidden window is not maximized until it is shown, and a hidden window shown while maximized gets one ShowWindow(SW_MAXIMIZE): SW_MAXIMIZE shows a hidden window, so PdfCraft, which eframe keeps hidden until its first frame is drawn, appeared unpainted (white) when it restored a maximized window, and could lose its focus. Port of winit#4587 (the later, focus-safe form of winit#4575); (5) on X11, when allowing or disallowing IME replaces the focused window's input context (egui does it each time a text field gains or loses focus), the new context is focused: no focus event follows, so it stayed unfocused until the window lost and regained focus. Port of winit#4727; (6) on macOS, insertText commits through IME when a composition was started (pending_commit, set by setMarkedText) rather than when marked text is left: input methods that end a composition with unmarkText before insertText lost the text, and Apple Korean dropped the key typed after a syllable (한 then 5 or ;); other insertText calls stay KeyboardInput; a commit outside a key press (a candidate clicked with the mouse, dictation) clears the marked text and leaves no key to swallow, as in winit#4748 (without it the next key, such as Backspace, was lost). validAttributesForMarkedText lists the underline and marked-clause attributes, without which some input methods don't compose. Port of winit#4650, the 0.30 backport of winit#4651 (merged on winit master), with the underline attribute spelled as AppKit's NSUnderlineStyleAttributeName (NSUnderline); (7) on macOS, disallowing IME with a composition in progress (focus leaving a text field) tells the input method to discard its marked text (discardMarkedText): it kept composing it once IME was allowed again, so the abandoned syllable came back (하, then 가 typed in the next field, became 학, then 하 + 가; Japanese か then さ became 傘). Port of winit#4745; (8) on macOS, text inserted outside a key press without a composition (the emoji picker) is reported as Ime::Commit; it was dropped. Port of the emoji-picker part of winit#4749 (0.30 backport of winit#4748); its selectedRange change for dictation is left out because it switches on press-and-hold for every held key (an accent menu instead of key repeat, and the chosen accent added after the repeated letters); (9) on macOS, a key whose text was committed through IME isn't also sent as KeyboardInput unless AppKit forwards it as a command (Enter): Apple Korean answers Space with no syllable in progress with setMarkedText(" "), insertText(" "), setMarkedText(""), and the last call reset winit's state, so the space arrived twice. Same goal as winit#4478, whose changes don't reach this call order (macOS 14); to be proposed upstream there; (10) on macOS, when the first key in a fresh app reaches Apple Korean's insertText as a raw compatibility jamo instead of starting a composition, that key is interpreted once more, synchronously, before it is sent as KeyboardInput (g k s typed ㅎㅏㄴ instead of 한); only an unmodified, non-repeated first key whose one callback inserts that same jamo, with IME enabled and nothing composed, focus and input source unchanged, is retried (ime_startup.rs). Port of winit#4744, with its policy tests. The published crate's asset files (docs/res/*.svg, examples/data/*.png) are left out, so its window example doesn't build | (1) pdfcraft tests::winit_carries_the_windows_11_monitor_scale_fix keeps the patch in the build; the drag itself needs two monitors with different scale factors on Windows 11; (2) pdfcraft tests/winit_wayland_text_input.rs; the capability change itself needs a Wayland session and an input method; (3) pdfcraft tests/winit_windows_ime_cursor.rs; composing itself needs the Microsoft Korean IME; (4) pdfcraft tests/winit_windows_hidden_maximized.rs; the start-up itself needs Windows and a window that was closed maximized; (5) pdfcraft tests/winit_x11_ime_focus.rs; switching fields itself needs an X11 session and an input method (IBus, fcitx5); (6) pdfcraft tests/winit_macos_ime_commit.rs; composing itself needs macOS and an input method; (7) pdfcraft tests/winit_macos_ime_discard.rs; composing itself needs macOS and an input method; (8) pdfcraft tests/winit_macos_emoji_picker.rs; the picker itself needs macOS; (9) pdfcraft tests/winit_macos_korean_space.rs; composing itself needs macOS and Apple Korean; (10) pdfcraft tests/winit_macos_korean_first_key.rs and ime_startup.rs's own tests (run them with rustc --test); typing itself needs macOS and Apple Korean | | egui-wgpu | 0.36.2 | MIT OR Apache-2.0 | (1) winit::surface_fit: a window's surface is configured within the device's max_texture_dimension_2d, both sides shrunk by one factor that egui then draws at (pixels_per_point × render_scale), so the whole window is drawn into the surface (on DX12 it is stretched over the window and lines up with the pointer; wgpu's GL backend copies it unscaled into a corner); the longer side becomes exactly the limit; the depth and MSAA textures follow, and a recreated surface starts again from the window's own size. egui-wgpu configured the window's size as is, and Surface::configure panics beyond the limit: a window restored at another monitor's scale (opening an Outlook attachment on a mixed-DPI laptop asked an 8192-pixel device for 8600 × 3423, #577) or stretched across monitors closed PdfCraft, before its window appeared when it happened at start-up (emilk/egui#8361). The published crate leaves out egui's licence files; LICENSE-APACHE and LICENSE-MIT are from the 0.36.2 tag; (2) winit::catch_errors: a new window's surface is configured inside wgpu error scopes (validation, out of memory, internal), and a failure is returned as WgpuError::ConfigureSurface (for the root window at start-up eframe returns it as Error::Wgpu, which PdfCraft retries with OpenGL); nothing is kept for the window. wgpu's default handler panicked instead, and eframe configures the root surface before the app is created, so a driver that can't configure one closed PdfCraft at launch (a 2015 Intel GPU through wgpu's GL backend timed out waiting for the GPU to go idle, GpuWaitTimeout, #519). Unchanged, so still a panic: an error in a later reconfigure (resize, a lost surface), a device lost during the first configure (wgpu reports it only to a callback), and a window shown at zero size (first configured on resize) | (1) pdfcraft tests::a_window_larger_than_the_gpu_limit_gets_a_surface_within_it, tests::surface_fit_never_empties_or_overflows_a_surface, and tests::egui_wgpu_carries_the_surface_size_fit, which keeps the patch in the build and in the paths that size a surface; (2) pdfcraft tests::a_gpu_error_while_a_window_is_set_up_is_returned_not_a_panic (a real device: an error inside catch_errors is returned, not a panic) and tests::egui_wgpu_returns_a_surface_it_cannot_configure_as_an_error, which keeps it around add_surface's configure |

Temporary: hayro is the bootstrap renderer and lopdf the bootstrap inspector (ADR-0004); M2.6 replaces them with our own devices and cos/model.

Text extraction: hayro-interpret exposes OutlineGlyph::is_vertical from a Type0 font’s CMap writing mode. PdfCraft follows negative glyph-space y for WMode 1 so upright vertical columns can be searched (#126).