Preview can't resize wide images properly

[oparoz]

This seems to happen whenever one of the asked dimension is larger than the actual dimension of the picture

Environment

oC 7.0.4 and 8.0
PHP 5.5

Configuration settings

'preview_max_scale_factor' => 1,

Step to reproduce

• Upload a panoramic picture of 1280x300
• Use the browser debugger to retrieve the URL used to generate the thumbnail
• Paste that URL in another tab and change x=36&y=36 to x=360&y=360. Note the 360 which is larger than the image's 300.

Actual result

You will get a 1280x300 picture

Expected result

A picture of max 360x360 dimension

cc @georgehrke

[oparoz]

The fix is in #16382