Commit Graph
4 Commits
Author SHA1 Message Date
Dylan M. Taylor c55a9f771e security(metafile): harden EMF+ parsing, clipping complexity, and memory accounting (#1280)
* fix(metafile): harden EMF+ parsing, clipping complexity, and memory accounting

- Row 72: Use checked tail slicing in comment header offset calculations
- Row 78: Break FillRects and DrawRects loops early when canvas is full
- Row 75: Pre-check dimensions in decode_compressed before RGBA pixel allocation
- Row 85: Account for EMF+ object table image/path memory against MAX_BYTES
- Row 42: Replace O(N^2) prefix copying in wrap_line with linear measurement
- Row 43 & 54: Share immutable clip regions Arc across placed items and charge canvas regions
- Row 48: Bound text transformation scale and glyph curve geometry in Picture::place and draw_text
- Row 52 & 68: Impose work budget bounds on Sutherland-Hodgman polygon clipping and bitmap masking

* fix(metafile): collapse nested if statement per clippy
2026-10-24 05:06:04 -04:00
NikitaandCursor 4fee02636a Metafile: clip EMF and WMF drawing to rectangle regions
INTERSECTCLIPRECT, EXCLUDECLIPRECT and EXTSELECTCLIPRGN limit what later records paint, including a region made of several rectangles. A rotated map stores the bounds of the clip rectangle.

Co-authored-by: Cursor <cursoragent@cursor.com>
2026-10-13 17:57:34 +03:00
Brandon ThomasandClaude Opus 5.5 e28851d2f1 Pictures: WMF/EMF text, pattern and hatch brushes draw; ActiveX previews show (#336)
* ActiveX controls show their pictures

A slide's p:controls are read: each control with a p:pic (the image PowerPoint shows for it,
often a WMF) becomes a picture above the slide's shapes.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

* Metafiles draw their text, pattern and hatch brushes

deckcraft-metafile (still kurbo + thiserror only, so it builds for wasm):
- Text: WMF EXTTEXTOUT/TEXTOUT and EMF EXTTEXTOUTW/EXTTEXTOUTA/SMALLTEXTOUT with the
  selected font (CREATEFONTINDIRECT, EXTCREATEFONTINDIRECTW: face, signed LOGFONT height,
  width, weight, italic, underline, strike-out, escapement, charset), text and background
  colour, background mode, TA_* alignment and TA_UPDATECP, the dx array (ETO_PDY pairs too),
  ETO_OPAQUE fills and ETO_CLIPPED clips. 8-bit strings decode through their charset
  (Windows-1252/1250/1251; symbol fonts keep their codes at U+F000; double-byte sets keep
  their advances). The neutral Item::Text carries a text-space-to-picture transform, so the
  mapping and escapement are folded in and glyphs are never mirrored.
- Brushes: WMF DIBCREATEPATTERNBRUSH, EMF CREATEDIBPATTERNBRUSHPT and CREATEMONOBRUSH, and
  BS_HATCHED, as Item::Pattern tiles in 96-dpi pixels; WMF PATBLT. The XOR / AND-pattern /
  XOR see-through shadow of old PowerPoint WMFs draws its pattern in the XOR colour.
- MFCOMMENT escapes with an embedded EMF are ignored: PowerPoint draws the WMF's records.
- Pattern pixels and text count against the byte budget; strings are capped.

deckcraft-render draws text through deckcraft-fonts with the face slide text would use
(document_face), symbol fonts mapped as bullets map them (deckcraft_text::symbol_char, now
public, with Webdings), per-character fallback, the file's advances, GDI cell metrics for
top/bottom alignment, underline/strike-out and synthetic bold/italic. Tiles below 1.5 output
pixels per cell are drawn as their average colour.

On the 24 corpus slides that show a metafile, mean abs diff against PowerPoint goes from
28.31 to 5.06 (with the OLE/ActiveX preview commits).

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
2026-10-12 22:40:56 -04:00
Brandon ThomasandClaude Opus 5.5 f8d54d7af4 Pictures: WMF and EMF draw, with the metafile reader ported from WordCraft (#317)
Co-authored-by: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
2026-10-12 18:27:19 -04:00