alloc_id bumped next_id with saturating_add: a presentation whose
next_id reached u32::MAX (a hostile file can arrive that way;
fix_next_id imports it) handed out that same id to every new slide,
shape, layout and media - duplicate ids, ambiguous references, silent
corruption on every later insert.
alloc_id now returns Option<u32> via checked_add, and every caller
refuses: the engine's insert/duplicate/media/layout commands answer
with a clear error naming the command, paste and duplicate re-id
helpers propagate it, media addition is fallible, and a fresh slide is
Option. The pptx export's synthesized blank layout is guarded the same
way. Loading keeps such a deck viewable: repair re-ids duplicate
slides while it can, and a duplicate it cannot re-id stays as it is -
growth is refused, and only that duplicate keeps its ambiguous id.
Renumbering the loaded graph was rejected: it needs the
cross-document reference remapping that issue #406 tracks.
Tests: model exhaustion (alloc_id None, fresh media refused, a new
slide refused), engine (slide.new, shape.insert, slide.duplicate and
edit.duplicate all refuse; the document holds no duplicate ids),
format repair (an unre-id-able duplicate stays visible).
A shape's picture fill marked not to rotate with the shape turned and
flipped with it (rotWithShape was neither kept nor written: always 1).
PowerPoint keeps such a picture upright, stretched (or tiled) over the
box the rotated shape covers on the slide and clipped to the shape. Now
read, written (PictureFill::upright) and drawn so.
Wild synthetic set: picture fills on rotated/flipped shapes 12.89 ->
3.87.
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
- a:biLevel (Color > Black and White) was ignored. It is now read, written
and drawn: white where the luminance reaches the threshold, else black
(observed thresholds at 30/50/70% on colour swatches).
- a:alphaInv was ignored; an opaque picture with it is invisible in
PowerPoint. Now read, written and drawn.
- Grayscale, duotone and saturation weighed channels 0.299/0.587/0.114;
PowerPoint's export greys pure red to 54 and green to 182: Rec. 709
weights (0.2126/0.7152/0.0722).
Wild synthetic set: recolour slide 7.60 -> 1.15, picture corrections
13.36 -> 7.36.
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
A table whose tblPr names no tableStyleId drew without any lines.
PowerPoint draws such a table with thin dark grid lines (as its "No Style,
Table Grid"); observed on a synthetic deck with and without the explicit
"No Style, No Grid" GUID. Such tables now read as the grid style.
Wild synthetic set: tables with cell margins/fills/styles 4.80 -> 2.82,
11.28 -> 10.15, 6.86 -> 3.16.
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Gradient tile rectangles were dropped on import. PowerPoint's "from
corner" radial presets depend on them: fillToRect puts the focus on a
corner and tileRect stretches the gradient's box a whole size past it, so
the circle is centred on that corner and reaches the far one. Without it
(after the two-point radial change) such fills washed out. A linear
gradient now spans its tile rectangle; a radial one ends on the circle
around it, with the focus still placed in the shape's own box (fitted to
PowerPoint's export of the corpus deck tdf114848: mean diff over the
filled box 0.77). Round-trips through pptx.
Wild synthetic set: tile-rect gradients 16.74 -> 2.48.
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
A shape or background blipFill with neither a:stretch nor a:tile (as some
tools write it, tdf#128596) was stretched across the shape; PowerPoint
tiles the picture at its own size.
Co-authored-by: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Sazid Al Bayazid