Summary: | "Inverted" page devices have the wrong ctm | ||
---|---|---|---|
Product: | Ghostscript | Reporter: | Robin Watts <robin> |
Component: | Graphics Library | Assignee: | Robin Watts <robin.watts> |
Status: | CONFIRMED --- | ||
Severity: | normal | CC: | christinedelight.top85 |
Priority: | P4 | ||
Version: | master | ||
Hardware: | PC | ||
OS: | Windows XP | ||
Customer: | Word Size: | --- |
Description
Robin Watts
2009-12-31 06:02:20 UTC
Can I demonstrate this is really causing problems with the current code? Not yet. I will try and find a concrete example where it can be shown to render differently in a bit. This is hampered a bit by the inablity to do an automated comparison of bitmap and windows display device. It certainly *does* cause problems when combined with Rays "FILL_ZERO_WIDTH" code, but I'd like to demonstrate that it's wrong at the moment without throwing that into the mix too. A local cluster regression test yesterday shows that changing this will change 16000 of our 24000 test cases. I'm running a test to show the bitmap diffs for these, but that's clearly going to take a VERY long time to complete. Preliminary results show that mostly these are very small changes. Any thoughts on this (both on the correctness of my logic and on ways to test it) would be gratefully received. This was discussed between myself, Henry and Michael on irc yesterday. The log can be found at: http://ghostscript.com/irclogs/20091230.html.bz2 By 1/256 I assume you really mean to adjust the y-offset down by the minimum "fixed_epsilon" in device coordinates == 1 which is 1>>fixed_shift pixels (in case someone is using other than fixed_shift 8). Most people run the default, but one or two customers have used different values with the warning from us that we don't do testing at other values. Regarding the testing, the main concern is missing elements, not shifted graphics, so I recommend comparing the two bitmaps with 'fuzzy -w 3 ___ ___' to see if anything pops out. (fuzzy.c is in toolbin/tests) Reassigning to new email address. |