Bug 74872 – [Qt] QtWebKit scales compressed SVG (SVGZ) files as if they were raster images

• Status: RESOLVED
• Resolution: INVALID
• Component: WebKit Qt

[Bartosz Brachaczek]

Created attachment 119885 [details]
testcase.zip

QtWebkit (tried with 2.0 and 2.2) scales compressed SVG (SVGZ) files as if they were raster images, while it does nicely scale uncompressed SVG files. You can see it easily when setting zoom factor to 2.0 for example. Attaching a simple testcase and screenshot from it.

Originally I experienced this problem in a bit different way: it looked like a compressed SVG filed was rendered in its native size and it was then scaled like a raster image, leading to jagged image even with zoom factor 1.0. You can see it here: http://www.kadu.im/redmine/issues/2281. Unfortunately it's in Polish but I translated the most relevant comments to English there.

[Bartosz Brachaczek]

Created attachment 119887 [details]
testcase-screenshot.png

[Bartosz Brachaczek]

Forgot to say that it might be related to bug 5246. My totally wild guess is that maybe WebKit fails to load that compressed SVG, passes it to Qt which returns a raster image with that SVG file rendered.

[Allan Sandfeld Jensen]

(In reply to comment #2)
> Forgot to say that it might be related to bug 5246. My totally wild guess is that maybe WebKit fails to load that compressed SVG, passes it to Qt which returns a raster image with that SVG file rendered.

Good guess. Qt supports SVGZ but WebKit really doesn't, bug #5246 . The only reason svgz works over the internet is due a common hack where the server lies about the content-type and encoding so it looks like a normal SVG that was only  gzip encoded for transport.

We have two separate issues here. 
1. We do not handle the SVG in WebKit like we could
2. We seem to support scaling in QImageIO plugins.

[Allan Sandfeld Jensen]

(In reply to comment #3)
> 2. We seem to support scaling in QImageIO plugins.

We do NOT seem to support scaling in QImageIO plugins.

[Jocelyn Turcotte]

=== Bulk closing of Qt bugs ===

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