tree 78de6492f6d125491c26029274050d18fb5e629b
parent 997e797922ae2f6db23d036493899b02c87cff10
author Shikha Walia <shwali@microsoft.com> 1579085748 +0000
committer Chromium commit bot <commit-bot@chromium.org> 1579085748 +0000

Add support in FPDFAnnot_SetAP() for transparent appearance streams

Annotation's appearance stream data only supports RGB and CMYK color
schemes and not RGBA. This makes it impossible to support transparency
through color values in the appearance stream. Transparency in
annotation is supported through modifying Graphics State (/GS) for the
entire object.

This CL adds support for specifying transparency in FPDFAnnot_SetAP()
for annotations by populating appropriate entries (e.g., /CA) in the
Graphics State dictionary.

This CL also includes test cases to validate creation of graphics state
dictionary in case alpha value specified in annotation's color is not
opaque and vice versa.

Bug: pdfium:1434
Change-Id: I2f14f6d14e49f1397e14bf6c57d56b7e49a6b473
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/63610
Commit-Queue: Shikha Walia <shwali@microsoft.com>
Reviewed-by: Lei Zhang <thestig@chromium.org>