fix(pdf): apply color filters when exporting to PDF on android - #718
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farfromrefug merged 1 commit intoSep 10, 2026
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loadImage() applied the page's colorMatrix (grayscale, b/w, ...) by
building a Canvas backed by the same bitmap it then drew onto:
val canvas = android.graphics.Canvas(bmp)
canvas.drawBitmap(bmp, 0F, 0F, paint)
Source and destination bitmap being identical is undefined behavior
on Android and effectively drops the color filter, so exported PDFs
kept the original colors even when a page had grayscale/b&w applied
in the app (other adjustments like "improve" go through a different
path and were unaffected). Render into a separate bitmap instead.
Refs ossappscollective#695
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Summary
Exported PDFs kept the original page colors even when a color adjustment (grayscale, b&w, sepia, invert, polaroid, or a brightness/contrast tweak — anything that produces a non-null
colorMatrix) was applied in the app before exporting. Other adjustments like "improve" go through a different path and were unaffected. The linked issue reports it for grayscale/b&w specifically, but the bug is in the sharedcolorMatrixapplication, so it affects any filter/adjustment.loadImage()inPDFUtils.ktapplies the page's colorMatrix by building aCanvasbacked by the same bitmap it then draws onto:Source and destination bitmap being identical is undefined behavior on Android, so the color filter never reliably made it into the encoded output. Render into a separate bitmap instead and swap references.
Testing
Refs #695