An unedited raw's face tile is cut from its largest embedded preview, read
the planned way (header and JPEG, never the sensor data), when the preview
holds at least 3/4 of the tile's pixels across the face; otherwise, and for
edited photos and other files, it is developed as before. Tiles keep going
to the memory + on-disk thumbnail cache, now at 16 px size steps so the
thumbnail slider reuses them. The planned preview path carries an Adobe RGB
preview colour space and applies it instead of declining to the whole-file
read (Sony alpha 1 previews).
Jason Baldwin
6477d031fc