Issue 557 in pdfium: Corrupt rendering of certain pdf-pages

[carsten.… via monorail]

Status: New
Owner: ----
Labels: Type-Defect Priority-Medium

New issue 557 by carsten....@gmail.com: Corrupt rendering of certain pdf-pages
https://bugs.chromium.org/p/pdfium/issues/detail?id=557

Rendering the attached pdf with pdfium_test renders first page correctly but changes the background color for page 2. The text on page 2 gets completely unreadable.

What steps will reproduce the problem?
1. Build pdfium_test.exe on Windows 7 plattform
2. starting pdfium_text --bmp 003_Test.pdf

What is the expected output?
2 correctly rendered pages

What do you see instead?
1 correctly rendered page, one unreadable page - see second image in zip.

What version of the product are you using? On what operating system?
pdfium as of 11.08.2016, built on Windows 7




Attachments:
003_Test.pdf 595 KB
003_Test_Output.zip 337 KB

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[dsincl… via monorail]

Updates:
Cc: the...@chromium.org cary...@chromium.org
Owner: dsin...@chromium.org
Status: Accepted

Comment #1 on issue 557 by dsin...@chromium.org: Corrupt rendering of certain pdf-pages
https://bugs.chromium.org/p/pdfium/issues/detail?id=557#c1

Looking at the PNG generated, the background of the second page is being generated as transparent. Not sure if this is how the PDF is written or something PDFium is doing wrong, needs to be investigated further.

[carycl… via monorail]

Comment #2 on issue 557 by cary...@google.com: Corrupt rendering of certain pdf-pages
https://bugs.chromium.org/p/pdfium/issues/detail?id=557#c2

The PDF page two uses multiple layers with transparency and non-standard color spaces to draw the graphic in the top right corner. Skia draws it incorrectly; I'll investigate further.

[carycl… via monorail]

Comment #3 on issue 557 by cary...@google.com: Corrupt rendering of certain pdf-pages
https://bugs.chromium.org/p/pdfium/issues/detail?id=557#c3

Attached is a reduced version of the page that demonstrates the problem.

I don't understand why this is considered a bug. As far as I can tell, when drawn on a white background, this pdf is correct.

Is this bug a request to clear the output to white before creating a PNG in pdfium_test?

Attachments:
003_Test_2.pdf 59.5 KB

[dsincl… via monorail]

Comment #4 on issue 557 by dsin...@chromium.org: Corrupt rendering of certain pdf-pages
https://bugs.chromium.org/p/pdfium/issues/detail?id=557#c4

If we're correctly drawing what's in the PDF, and the PDF is set to have a transparent 2nd page, then it sounds like this isn't a bug.

[Carsten Keltsch]

In addition:

The pdfium version as of 12/2016 renders both pages as expected!

[dsincl… via monorail]

Updates:
Status: Invalid

Comment #5 on issue 557 by dsin...@chromium.org: Corrupt rendering of certain pdf-pages
https://bugs.chromium.org/p/pdfium/issues/detail?id=557#c5

(No comment was entered for this change.)

[carsten.… via monorail]

Comment #6 on issue 557 by carsten....@gmail.com: Corrupt rendering of certain pdf-pages
https://bugs.chromium.org/p/pdfium/issues/detail?id=557#c6

Why was the status set to: Invalid?

See my comment from Aug 12th:
"In addition:
The pdfium_test version as of 12/2016 renders both pages as expected!"

[dsincl… via monorail]

Comment #7 on issue 557 by dsin...@chromium.org: Corrupt rendering of certain pdf-pages
https://bugs.chromium.org/p/pdfium/issues/detail?id=557#c7

I was going by comment #3 when marking invalid.

I don't see any comments from the 12th on the bug? Do you mean that it is now working correctly, or what does 12/2016 mean? If it's now working, then it sounds like the bug is now invalid?

[carsten.… via monorail]

Comment #8 on issue 557 by carsten....@gmail.com: Corrupt rendering of certain pdf-pages
https://bugs.chromium.org/p/pdfium/issues/detail?id=557#c8

Sorry for that, I commented through the forum group which is obviously not reflected here.

The last Test before this one I made with the pdfium_test version checked out in December 2015 (not 2016!). Using that version renders both pages as expected!
The actual one doesn't.

Hopefully a little more clearly ...

[dsincl… via monorail]

Updates:
Status: Accepted

Comment #9 on issue 557 by dsin...@chromium.org: Corrupt rendering of certain pdf-pages
https://bugs.chromium.org/p/pdfium/issues/detail?id=557#c9

Thanks for the clarification. Sounds like we've changed something that is effecting the rendering.

[thes… via monorail]

Updates:
Cc: -cary...@chromium.org

Comment #11 on issue 557 by the...@chromium.org: Corrupt rendering of certain pdf-pages
https://bugs.chromium.org/p/pdfium/issues/detail?id=557#c11

https://pdfium.googlesource.com/pdfium/+/84f6a5616be0a1988d361a4b54eb83fff8b8c59f for bug 336 changed the background rendered by pdfium_test from white to transparent. I think this is ok. Depending on how a PNG viewer draws the transparent background, it could look ok, slightly bad, or very bad.

Attached is a sample with modern pdfium_test.

Attachments:
b557.pdf.1.png 94.7 KB

[n… via monorail]

Comment #12 on issue 557 by ni...@chromium.org: Corrupt rendering of certain pdf-pages
https://bugs.chromium.org/p/pdfium/issues/detail?id=557#c12

the...@chromium.org
Since the both AGG and SkiaPaths are rendering the second page as a transparent page, should we close this ticket?

[km… via monorail]

Updates:
Status: WontFix

Comment #13 on issue 557 by km...@chromium.org: Corrupt rendering of certain pdf-pages
https://bugs.chromium.org/p/pdfium/issues/detail?id=557#c13

I think we're happy with the transparent rendering behavior as is.