Prevent NaN values in sampled functions with a degenerate Domain - #21891
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Some documents use a DeviceN colour space that includes a `/None` colorant, and their tint transform declares a zero-width Domain such as `[0 0]` for that input because it never contributes to the output. The interpolation then divides by zero, every output of the function becomes NaN, and all content painted with that colour space ends up black. Handle it the same way the stitching function already guards against a zero-width interval, which also matches what PDFium does. Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
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From: Bot.io (Linux m4)ReceivedCommand cmd_makeref from @calixteman received. Current queue size: 0 Live output at: http://54.241.84.105:8877/c66a3fe9f95187d/output.txt |
From: Bot.io (Windows)ReceivedCommand cmd_makeref from @calixteman received. Current queue size: 0 Live output at: http://54.193.163.58:8877/3713f6649d94bcb/output.txt |
From: Bot.io (Linux m4)SuccessFull output at http://54.241.84.105:8877/c66a3fe9f95187d/output.txt Total script time: 18.99 mins
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From: Bot.io (Windows)SuccessFull output at http://54.193.163.58:8877/3713f6649d94bcb/output.txt Total script time: 23.66 mins
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5 participants
Overview
Type 0 (sampled) function evaluation divides by zero when a
Domainentry has identical bounds, causing every output to become NaN and the affected content to render as black. This occurs in real-world documents that use a DeviceN color space containing a/Nonecolorant, where the tint transform specifies[0 0]as theDomainfor that input. No warning or error is logged, so the issue is not visible in the console.The fix mirrors the existing guard used for stitching functions and matches PDFium's behavior.
Reproduction
The reduced test file
test/pdfs/devicen-none-zero-domain.pdf(added in this PR) paints two rectangles using such a color space: the left one with a 50% tint of the spot color, and the right one with 100% black. Without this patch, both rectangles are rendered as solid black in the currentpdfjs-distrelease (6.3.289) as well as onmaster.The behavior is browser-independent, since the issue arises entirely from function evaluation.
Before:
After:
The original document that exposed this issue is a commercial ebook and therefore cannot be shared. The reduced file reproduces the same color-space and function structure.