plug-in, libgimp: Fixes #6753: redesign of WebP Export dialog
Added an option for exporting thumbnail in WebP Export dialogbox.
Additionally, introduced a function gimp_procedure_dialog_fill_expander. The function is similar to gimp_procedure_dialog_fill_frame but allows adding GtkExpander instead of GtkFrame.
However, the commit has one issue: If animated WebP is being saved then scale for image quality and alpha quality become very small, as shown in the attached screenshot.
The size of these scale slider is fine in case of un-animated (having single layer) WebP.
As a first time hacker of GIMP codebase, I was not able to solve this issue. Any suggestion is welcome on this issue.
Fix #6753 (closed)