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Add notes on reporting bugs to BUGS file and move bugs listed there to ROADMAP instead.
This commit is contained in:
Carl Worth
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2 changed files with 116 additions and 36 deletions
101
BUGS
101
BUGS
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@ -1,56 +1,85 @@
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The place to find a current list of known bugs for cairo is:
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If you find a bug in cairo we would love to hear about it. We're also
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trying to make cairo better, and learning about the bugs that users
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encounter is an essential part of that. So we really appreciate the
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extra effort users put in to providing high-quality bug reports.
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There are two acceptable ways to report cairo bugs, and you can choose
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which you prefer:
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1) Bugzilla bug tracking database:
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You can use the following web interface to report new bugs, follow
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up on previous bug reports, and search for existing, known
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bugs. Just use the "cairo" product:
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http://bugs.freedesktop.org
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under either the cairo or libpixman products. New bugs should be
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reported there as well.
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It is necessary to go through a quick account creation process,
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(with email address verification), in order to be able to report
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new bugs in bugzilla. We apologize for any inconvenience that might
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cause, and hope it won't prevent you from reporting bugs.
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[A few old bugs have not been moved to bugs.freedesktop.org and are
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instead listed below:]
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2) Cairo mailing list:
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--
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For people who cannot stand the bugzilla interface, you can just
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send an email to cairo mailing list (cairo@cairographics.org). The
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mailing list only allows posting from subscribers, so use the
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following page for subscription instructions:
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The caches need to be invalidated at font destruction time.
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http://cairographics.org/lists
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--
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Again, we apologize for any inconvenience this subscription step
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might cause, but we've found it necessary to require this in order
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to enjoy spam-free discussions on the list.
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The polygon tessellation routine has problems. It appears that the
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following paper has the right answers:
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If you don't actually _want_ to be a subscriber to the mailing
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list, but just want to be able to send a message, the easiest thing
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to do is to go through the subscription process, and then use the
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preferences page to disable message delivery to your address.
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http://cm.bell-labs.com/cm/cs/doc/93/2-27.ps.gz
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Which of the above you use to report bugs depends on your own
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preferences. Some people find just typing an email message much easier
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than using the web-based forms on bugzilla. Others greatly prefer the
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ability to check back on a specific bug entry in bugzilla without
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having to ask on the mailing list if an issue has been resolved.
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[Hobby93c] John D. Hobby, Practical Segment Intersection with
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Finite Precision Output, Computation Geometry Theory and
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Applications, 13(4), 1999.
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Regardless of which method you use, here are some general tips that
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will help you improve the quality of your bug report, (which will help
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in getting the bug fixed sooner):
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Recent improvements to make the intersection code more robust (using
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128-bit arithmetic where needed), have exposed some of the weakness in
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the current tessellation implementation. So, for now, filling some
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polygons will cause "leaking" until we implement Hobby's algorithm.
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1) Check to see if the bug has been reported already. It's pretty easy
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to run a search or two against the cairo product in the
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http://bugs.freedesktop.org bugzilla database. Another place to
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look for known bugs is the cairo ROADMAP:
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--
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http://cairographics.org/ROADMAP
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Stroke extents might not work for degenerate cases, (e.g. single
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vertical or horizontal line).
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which shows a planned schedule of releases and which bug fixes are
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being planned for each release.
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--
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2) Provide an accurate description of the bug with detailed steps for
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how we can reproduce the problem.
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Stroke width of 0 might do bad things.
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3) If possible provide a minimal test case demonstrating the bug. A
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great test case would be a minimal self-contained function in C or
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python or whatever language you are using for cairo. The function
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might accept nothing more than a cairo context, (cairo_t* in C).
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--
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4) If you feel like being particularly helpful, you could craft this
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minimal test case in the form necessary for cairo's test
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suite. This isn't much more work than writing a minimal
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function. Just look at the cairo/test/README file and imitate the
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style of existing test cases.
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Could there be a bug in PS backend exposed by?:
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If you do submit a test case, be sure to include Copyright
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information, (with the standard MIT licensing blurb if you want us
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to include your test in the test case). Also, including a reference
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image showing the expected result will be extremely useful.
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cairo_save
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cairo_clip
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cairo_restore
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...
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5) Finally, the best bug report also comes attached with a patch to
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cairo to fix the bug. So send this too if you have it! Otherwise,
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don't worry about it and we'll try to fix cairo when we can.
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This needs a new testcase.
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Thanks, and have fun with cairo!
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--
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Text drawn with vertical metrics cannot currently use TrueType
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subsetting for PDF/PS output as the code doesn't write out the necessary
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VHEA or VMTX entries to the TrueType font objects. As a result, cairo uses
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Type3 fonts which generates slightly different outlines.
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-Carl
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51
ROADMAP
51
ROADMAP
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@ -136,3 +136,54 @@ Unscheduled stuff we'd like to get to at some point
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Misc
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1. xlib backend requires xrender to compile, while it can perform without
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xrender at run time. Make it compile without it.
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[Here's some stuff that was sitting in the BUGS file. Some of these
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are likely not existing bugs anymore. We should invesitgate each and
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either move it up into the ROADMAP above or else just delete it.]
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--
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The caches need to be invalidated at font destruction time.
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--
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The polygon tessellation routine has problems. It appears that the
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following paper has the right answers:
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http://cm.bell-labs.com/cm/cs/doc/93/2-27.ps.gz
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[Hobby93c] John D. Hobby, Practical Segment Intersection with
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Finite Precision Output, Computation Geometry Theory and
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Applications, 13(4), 1999.
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Recent improvements to make the intersection code more robust (using
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128-bit arithmetic where needed), have exposed some of the weakness in
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the current tessellation implementation. So, for now, filling some
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polygons will cause "leaking" until we implement Hobby's algorithm.
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--
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Stroke extents might not work for degenerate cases, (e.g. single
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vertical or horizontal line).
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--
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Stroke width of 0 might do bad things.
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--
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Could there be a bug in PS backend exposed by?:
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cairo_save
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cairo_clip
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cairo_restore
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...
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This needs a new testcase.
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--
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Text drawn with vertical metrics cannot currently use TrueType
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subsetting for PDF/PS output as the code doesn't write out the necessary
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VHEA or VMTX entries to the TrueType font objects. As a result, cairo uses
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Type3 fonts which generates slightly different outlines.
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|
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