Closed Bug 305091 Opened 19 years ago Closed 19 years ago

png images do not display colours correctly

Categories

(Core :: Graphics: ImageLib, defect)

defect
Not set
normal

Tracking

()

RESOLVED INVALID

People

(Reporter: magicfool, Assigned: pavlov)

References

()

Details

Attachments

(1 file)

User-Agent: Mozilla/5.0 (Macintosh; U; PPC Mac OS X Mach-O; en-US; rv:1.7.7) Gecko/20050416 Build Identifier: Mozilla/5.0 (Macintosh; U; PPC Mac OS X Mach-O; en-US; rv:1.7.7) Gecko/20050416 when png images are displyed on mozilla browser their colour is lighter than the actual one. Reproducible: Always Steps to Reproduce: 1.create image (i.e. on photoshop/imageready) 2.save image as PNG 3.open it on mozilla or simply include it in an html page Actual Results: the colours have a lighter hue Expected Results: display the image with it's saved colour no other browser seems to have the same problem
Alias: PNG
Could we have a testcase? You are also using a very old build - please retest with a current nightly.
BTW: It might be that photoshop uses some color management which so leads to different colors. Also did you open the PNG file in photoshop/imageready directly and looked if the colors are still different?
(In reply to comment #2) > BTW: It might be that photoshop uses some color management which so leads to > different colors. Also did you open the PNG file in photoshop/imageready > directly and looked if the colors are still different? nope, it's just a mozilla display problem. the images are shown correctly on photoshop and on the other browsers as well
i've also tested 1.7.11
This is WFM with a variety of pngs on Windows. Please can you supply a test image showing the problem.
To see the full test case, go to http://paxdot.com/testcases/pngcolor/. The image is used as a non-repeating background and is filled in by background-color: #72C5E3; everywhere else. As a result, you shouldn't see where the image ends (if it was working properly).
I tested this on Linux, Mac and Windows and it was present in all (using Firefox 1.06). I also tested using Deer Park 2 on Mac and it still failed there.
> http://paxdot.com/testcases/pngcolor/ This times out. But the attached image does show the problem...
Assignee: general → pavlov
Status: UNCONFIRMED → NEW
Component: General → ImageLib
Ever confirmed: true
OS: MacOS X → All
Product: Mozilla Application Suite → Core
QA Contact: general
Hardware: Macintosh → All
Version: unspecified → Trunk
OK, vlad says that png has a gamma of 0.550 set, which is what causes the issue. So this is invalid.
Status: NEW → RESOLVED
Closed: 19 years ago
Resolution: --- → INVALID
The image has an embedded PNG gAMA chunk of 0.55; per http://lxr.mozilla.org/mozilla/source/modules/libpr0n/decoders/png/nsPNGDecoder.cpp#258 we tell libpng to use that gamma, instead of the default gamma of 0.45455. We're not as smart about gamma as we should be; however, the fix here is to use a tool like TweakPNG (http://entropymine.com/jason/tweakpng/) and simply delete the gAMA chunk from the PNG (or tell the image creating tool to not output gamma data).
Summary: png images do not dispaly colours correctly → png images do not display colours correctly
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