Don't repeat background images when it's not needed

[diethardsteiner]

I just tested my stylesheet on Fedora and Mac OS X and the rendering is different. For the top left margin box I have a background image and background color defined. The preview via weasyprint.navigator is the same on both OSes, however the actual PDF output not: On Fedora, the background color is applied to the whole box, whereas on Mac OS X I see the background color only behind the background image. This seems to be related to the css property background-size.

Here is the CSS I apply:

@top-left {
        width: 70%;
        content: "";
        background-color: rgba(42, 201, 80, 0.220);
        background-image: url('images/logo_v4.png');
        background-size: contain;
        background-repeat: no-repeat;
        background-position: left;
        border-bottom: solid green;
    } 

[SimonSapin]

Do you use the same PDF viewer on both systems? If not, try view each PDF file on the other system to see if the files are actually different or just rendered differently.

[diethardsteiner]

Thanks a lot for your reply! Yes, you are correct, it is actually a problem related to the PDF viewer. On Fedora I use 'Document Viewer' and on Mac OS X 'Preview'. So which one is correct then? Is Preview at fault here?

I also tried to read up a bit more on the CSS definitions and adjusted the CSS a bit:

        background: url('images/logo_v4.png'), rgba(42, 201, 80, 0.220);
        background-repeat: no-repeat, repeat;
        background-position: left center, left;
        background-size: contain

however that didn't really help.

Based on your experience, what is the best cross platform PDF viewer?

[diethardsteiner]

Closing the issue as this seems to be Mac OS X 'Preview' related - although I cannot confirm it with 100% certainty.

[SimonSapin]

The same PDF file is rendered differently by different PDF viewers, so there is a PDF interoperability issue here independently of WeasyPrint.

That said, the way WeasyPrint paints background images (using a repeating pattern even for background-repeat: no-repeat) is a bit unusual and has likely caused other issues before. (See #232 and #222 for example.) WeasyPrint could potentially be changed to generate a more straightforward PDF file, which would likely work around this issue.

[diethardsteiner]

Ok, thanks for your feedback. Reopened ticket in hope WeayPrint's background image logic will be optimised.

[SimonSapin]

“Optimized” is a strong word. It’s more like “do something kinda differently at seemingly random in the hope that maybe something different will happen” :)

[diethardsteiner]

Ok :)