Closed
Bug 58264
Opened 24 years ago
Closed 23 years ago
RFE - PNG alpha with 100% transparency is not rendered 100% transparent. [gfx][png]
Categories
(Core Graveyard :: GFX, defect, P3)
Tracking
(Not tracked)
RESOLVED
WORKSFORME
Future
People
(Reporter: mgalli, Assigned: dcone)
References
()
Details
Attachments
(2 files)
Some help is needed here to certify.
Tested with older versions and Gecko/20001023, win98.
From long time I saw PNG images with portions 100% transparent (in the alpha
channel) that over some background colors is possible to note that these images
are not rendered completelly 100% transparent (in the 100% transp areas).
http://www.libpng.org/pub/png/pngs-img.html
Note the toucan images. If you have a notebook TFT display, look from the bottom
- is easy to note :-). When background are light colors or very dark it's
difficult to see. With this test that is a green background I can see. In a lot
of other pages with PNG just change the background for something like #aaaaaa
and you will note.
Comment 1•24 years ago
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Maybe a Windows thing? They look pretty damn transparent on Linux 2000-10-27
nightly trunk build, XFree86 DRI CVS snapshot, 16-bit color.
Summary: RFE - PNG alpha with 100% transparency is not rendered 100% transparent. → RFE - PNG alpha with 100% transparency is not rendered 100% transparent.
Reporter | ||
Comment 2•24 years ago
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Tested with Linux, 2000-09-29 Netscape 6 Build just to verify behavior with
Linux. Agreed - pretty and 100% transparent (for the eyes).
Comment 3•24 years ago
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Tested the actual transparency with a graphics application. All of the toucan
images transparencies are correct here on Windows 2000 (2000102905) trunk bits.
Comment 4•24 years ago
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Aha! Note the user mentions a TFT screen. And what's different about a TFT
screen compared with most decent hardware these days? 16bpp frame buffer!
This could very well be a different rendering path for images (no matter whether
transparent) and page backgrounds. On 24bpp it all comes out in the wash, but on
16bpp or 8bpp you might see tiny but perceptible differences.
Owner/ testers - tell your OS or Windowing system to use 16bpp, and repeat the
experiments you tried earlier. The differences may need VERY GOOD eye sight, but
they are probably there.
Since this behaviour won't be seen on decent display hardware it is only a minor
niggle and shouldn't be corrected while engineer resources are needed elsewhere.
Note that WinIE and NS4x won't display the transparency anyway so we're already
ahead.
Reporter | ||
Comment 5•24 years ago
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Agreed, this may be a behavior in the 65K color mode. Tests welcome to help
confirming this bug. If this is a bug in the nightly build I agreed that this is
minor. Also that is an easy fix.
Comment 6•24 years ago
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Please check 51179 for another possible cause of the symptoms in Marcio's
original bug report. Here I cannot _see_ the problem, but a screenshot and an
image editor's "eyedropper" tool makes it obvious in short order.
The TFT 16bpp thing would exacerbate the problem in 51179 if I'm right.
Comment 7•24 years ago
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umm.. Win98 desktop. pIII 550MHz Moz Build: 2000121508
16bit colour - Toucans background not 100% transparent.
24/32bit colour - Toucans background transparent.
If it will help I can throw in some screen shots of the difference?
However my display was set to 16bit by default.. would be nice if 16bit would
show transparency.. is this possible, or imporrible due to the capabilites of
16bit display?
Anyway.. I can see what the reporter saw, so I am confirming. However I think
this could be a duplicate of bug 19283 - that is marked fixed, so I'm not too
sure what's going on.
Status: UNCONFIRMED → NEW
Ever confirmed: true
Updated•24 years ago
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QA Contact: petersen → tpreston
Comment 9•24 years ago
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Using Mozilla 0.7 on Linux, you can see transparent PNG images aren't 100%
transparent when you stack them. The more you stack, the more apparent it
becomes. Will attach a screen snapshot of this behavior.
Comment 10•24 years ago
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Comment 11•24 years ago
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The images in the attached example havea visual depth of 16.
Reporter | ||
Comment 12•24 years ago
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staked transp png was a great idea!!
Assignee | ||
Updated•24 years ago
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Status: NEW → ASSIGNED
Summary: RFE - PNG alpha with 100% transparency is not rendered 100% transparent. → RFE - PNG alpha with 100% transparency is not rendered 100% transparent. [gfx][png]
Target Milestone: --- → Future
Comment 13•24 years ago
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http://Games.GadgetScope.com/ - View in 16 bit color
Transparent areas are not being rendered properly - instead there almost seems
to be an ordered dither occuring that isn't necessary. Looks OK in 32 bit color.
Build: 2001062004 Win98 + 3dfx Voodoo3 3000 800x600x16
Comment 14•24 years ago
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Comment 15•23 years ago
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WFM 2002022103/WinXP@16bbp
neither do the parrots look wrong (tested by enhancing a screenshots contrast
with the GIMP) nor does http://games.gadgetscope.com/ show the errors displayed
by the screenshot.
anyone still seeing thist? otherwise WFM?
Assignee | ||
Comment 16•23 years ago
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Marking works for me.. if anyone see's the problem.. reopen. and describe exact
symptoms.
Status: ASSIGNED → RESOLVED
Closed: 23 years ago
Resolution: --- → WORKSFORME
Comment 17•23 years ago
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Mass removing self from CC list.
Comment 18•23 years ago
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Now I feel sumb because I have to add back. Sorry for the spam.
Updated•16 years ago
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Product: Core → Core Graveyard
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Description
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