Png/Jpg images rendered on linux are stretched on windows

[sergiuiscoding]

Tested with phantomjs 1.8.2 on ubuntu 11.04/12.04

phantomjs ../examples/rasterize.js http://google.com google.png

The rendered image looks good on the same linux machine, but seems to have wrong pixel aspect ratio on a windows machine.
If I open the image in an image editor (paint.net, photoshop) the image looks good. So I'm guessing there's some kind of metadata messed-up.

Original image fixed on upload as attachment (or by viewing it in the browser):

Print screen with the issue:

[sergiuiscoding]

Uploading the image as an attachment seems to have corrected the issue.

[sergiuiscoding]

ImageMagick:

identify -verbose image.png

[...] Properties: date:create: 2013-03-22T11:24:34+02:00 date:modify: 2013-03-22T11:14:45+02:00 png:IHDR.bit-depth-orig : 8 png:IHDR.bit_depth : 8 png:IHDR.color-type-orig : 6 png:IHDR.color_type : 6 (RGBA) png:IHDR.interlace_method: 0 (Not interlaced) png:IHDR.width,height : 652, 600 png:pHYs : x_res=4055, y_res=4331, units=1 png:sRGB : intent=0 (Perceptual Intent)

[JamesMGreene]

I'm assuming those details are from the "stretchy" image. What are the details for it when it isn't stretchy?

[sergiuiscoding]

Details of image rendered with my fix in place (Attn at x_res / y_res):

[...] Properties: date:create: 2013-03-22T15:00:35+02:00 date:modify: 2013-03-22T15:00:33+02:00 png:IHDR.bit-depth-orig : 8 png:IHDR.bit_depth : 8 png:IHDR.color-type-orig : 6 png:IHDR.color_type : 6 (RGBA) png:IHDR.interlace_method: 0 (Not interlaced) png:IHDR.width,height : 604, 600 png:pHYs : x_res=2834, y_res=2834, units=1 png:sRGB : intent=0 (Perceptual Intent)

[ariya]

I finally found out a possible lead.

PNG image writer needs to get horizontal and vertical resolutions. Qt's default horizontal and vertical dpi values are obtained via qt_defaultDpiX() and qt_defaultDpiY() (see src/gui/text/qfont.cpp). For our headless implementation on Linux, apparently some QPlatformScreen settings are either incomplete or incorrect, thus giving a wrong dpi.

[ariya]

@sudosu- Can you try this with 1.9? I think I fixed this already in 3f42fb230f (see issue #10659).

[sergiuiscoding]

@ariya thank you for looking into this. I've just tested with 1.9 and cannot reproduce the issue anymore. The PNG looks good.
So I guess my workaround is not necessary anymore, will switch to the official release.

[stale]

Due to our very limited maintenance capacity, we need to prioritize our development focus on other tasks. Therefore, this issue will be automatically closed (see #15395 for more details). In the future, if we see the need to attend to this issue again, then it will be reopened. Thank you for your contribution!