Bug 6948

Summary:	Pen is not being transformed by cm operator
Product:	poppler	Reporter:	Carl Worth <cworth>
Component:	cairo backend	Assignee:	Jeff Muizelaar <jmuizelaar>
Status:	RESOLVED FIXED	QA Contact:
Severity:	normal
Priority:	high	CC:	nshmyrev
Version:	unspecified
Hardware:	x86 (IA32)
OS:	Linux (All)
Whiteboard:
i915 platform:		i915 features:
Attachments:	Test case showing buggy rendering use cairo's affine transformation support instead of ignoring it new patch that fixes dashing problems

Description Carl Worth 2006-05-17 08:12:00 UTC

It appears that the cm operator affects the coordinates of a path, but is not
properly tranforming the pen itself used for the stroke.

I know this affects the cairo backend at least, (haven't checked the others),
and I also happen to know that it's fairly easy to get cairo to do the right
thing here. So I'd be happy to provide any guidance needed on this.

Comment 1 Carl Worth 2006-05-17 08:19:27 UTC

Created attachment 5650 [details]
Test case showing buggy rendering

Here's a PDF file that demonstrates the bug. Acroread appears to render this
file as I expect, but poppler renders the top two strokes with a pen that is
too wide, (apparently unaffected by the transformation matrix).

The cairo code that generated this image can be found here:

http://gitweb.cairographics.org/?p=cairo;a=blob;h=HEAD:test/line-width-scale.c

which also shows how to get the desired result with cairo, (which is simply to
set the transform before calling cairo_set_line_width).

-Carl

Comment 2 Jeff Muizelaar 2006-05-17 09:51:51 UTC

Created attachment 5651 [details] [review]
use cairo's affine transformation support instead of ignoring it

rough patch that fixes this problem. I'll clean it up when I get the chance.

Comment 3 Carl Worth 2006-05-24 07:50:28 UTC

The patch solved my original problem, but it may have introduced another. See
what I describe in bug #7014 here:

https://bugs.freedesktop.org/show_bug.cgi?id=7014

-Carl

Comment 4 Jeff Muizelaar 2006-05-28 08:56:32 UTC

Created attachment 5751 [details] [review]
new patch that fixes dashing problems

Comment 5 Jeff Muizelaar 2006-05-31 10:33:03 UTC

Fixed in cvs.

Comment 6 Nickolay V. Shmyrev 2006-07-09 14:08:08 UTC

This patch broke selection with zoom not equal to 100%, although I failed to
find the reason. Can you please test it once again?

Comment 7 Jeff Muizelaar 2006-07-16 15:55:44 UTC

Does adding:
  out->setDefaultCTM(state->getCTM());
below:
  out->startPage (0, state); on line 3315 of TextOutputDev.cc
help?

Comment 8 Nickolay V. Shmyrev 2006-07-17 08:05:17 UTC

Yes, it does. 

That's great, please, commit the change.

Comment 9 Jeff Muizelaar 2006-07-18 17:25:41 UTC

Commited.

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