From: Tim M. <or...@le...> - 2013-04-12 11:53:25
Attachments:
fix_colored_notes_patch
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I've noticed on my system (64-bit Qt 4.7) the rendering of colored note heads is pretty rough in the raster-graphics mode. No problem in the native mode, though. The issue involves the alpha channel. The image of a colored note head is carved out of a solid, filled-in rectangle of color pixels by the action of an alpha channel that has been retrieved from an original black image. But in this context the alpha channel seems to be inverting color hues rather than simply adjusting pixel transparency. The result is ragged, multicolored halos of pixel debris surrounding the note heads. 1. In the raster (fast) graphics mode, open a piece using the notation editor. 2. If no colored notes are present, create some by selecting ordinary black notes. 3. Use the zoom wheel in the lower-right corner to zoom in on a colored note. 4. Any problem should be obvious. I've come up with a workaround that solves the problem, at least on my platform. It appears compatible with both native and raster graphics. I suspect I'm hacking around some Qt4 bugginess here, so I don't know how this will play out on different setups using different revisions. Tim Munro |
From: D. M. M. <ros...@gm...> - 2013-04-12 12:21:37
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On 04/12/2013 07:53 AM, Tim Munro wrote: > I've noticed on my system (64-bit Qt 4.7) the rendering of colored note > heads is pretty rough in the raster-graphics mode. No problem in the > native mode, though. The issue involves the alpha channel. I remember futzing around trying to fix this irritating problem myself. > I've come up with a workaround that solves the problem, at least on my > platform. It appears compatible with both native and raster graphics. > > I suspect I'm hacking around some Qt4 bugginess here, so I don't know how > this will play out on different setups using different revisions. I haven't tried it yet, and might not for a couple of days, but it's an approach I never thought of, and it definitely looks like it could work. I look forward to seeing this in action. I think what Qt is doing here probably is something different from what it ought to be doing, but I don't actually expect there to be problems with different setups and different revisions. This weird aberration you're trying to correct has been present ever since the port, in 32-bit and 64-bit versions from Qt 4.4 or something all the way to present. I'm optimistic that your hack will "just work" everywhere if it works for you. Hopefully that optimism will prove well-founded. Let me know if you ever change your mind about having commit access. I'm extremely comfortable extending it to you at this point. Reviewing your code is starting to feel like checking over Albert Einstein's math homework. -- D. Michael McIntyre |
From: D. M. M. <ros...@gm...> - 2013-04-15 02:20:33
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Sweet. Night and day difference. The funky off-hue pixels magically go away. I approve. Great work! -- D. Michael McIntyre |