Alpha fill check action list

[JavierLFPC]

Hi,

I need to create an action list in PitStop pro that detects any object with an alpha fill and show me an error message if there is not an alpha fill.
Typically the jobs will include jpeg objets with transparency.
In attachment you can find 2 pdf files, with and without transparency.

NoTransparency.jpeg (137.01 KiB) Viewed 5582 times

Transparency.jpeg (217.05 KiB) Viewed 5582 times

[freddyp]

The JPEG format does not support transparency, so a method that is based on the properties of the image will not work. What you are referring to is undoubtedly the fact that there are white pixels.

Here is a conceptual way of detecting those. Run a PitStop Server Action List on the image (make sure to enable image input on the app):
Trace path (you can play a bit with the resolution and the white threshold; white holes can be ignored)
Select last added objects
Log selection

If the size of the created trace path is smaller than that of the image, there were "transparent" pixels. All other jobs do not have them.