Use PDF TrimBox when generating previews

[ausi]

AFAIK the TrimBox is the bounding box that most programs use for PDF previews.

See https://community.contao.org/de/showthread.php?85566

[fritzmg]

Looks correct to me (but I am unable to verify at the moment).

[ausi]

AFAIK the TrimBox is the bounding box that most programs use for PDF previews.

Looks like this info was not accurate, Apple Preview uses the CropBox for example.

But I still think for our preview, the trimbox usually makes more sense, as we probably do not want to show crop marks and bleed.

[kroerig]

I adopted the changes to my demo installation, but it does not work. No preview is created anymore with the changes.

[ausi]

@kroerig can you please post a screeshot of your changed source code?

Are you using ImageMagick or GraphicsMagick?
Did you clear the preview cache after your changes?

[kroerig]

Yes, i cleared all caches.

GraphicsMagick 6.9.10.23

[kroerig]

Yeah, got it working. Had to switch to ImageMagick and now I get nice previews. Thx a lot.

[ausi]

Does anyone know how to set pdf:use-trimbox=true in GraphicsMagick, or if this is even supported at all?

A similar option should be available according to http://www.graphicsmagick.org/NEWS.html#december-24-2011:

Support application of the PDF crop box via '-define pdf:use-cropbox=true'.

But I don’t know how to do a -define via GMagick in PHP.

[ausi]

@kroerig can you please check if the latest version of this pull request works for GraphicsMagick too?

[kroerig]

Unfortunately, I don't have Gmagick in PHP. That's why I had to switch to ImageMagick to make it work.

[fritzmg]

I tested the changes of this PR with the PDF from https://community.contao.org/de/showthread.php?85566 on a shared hosting from Hostingwerk, which uses Gmagick. However, it does not appear to work. The preview image stays the same.

[fritzmg]

Never mind, the changes work - I always only cleared the image cache instead of the preview cache 🙈

[leofeyer]

Thank you @ausi.