New image plugins control panel dialog zooming features in 0.9.0

Since a long time, i have talking with Unai Garo (the Image Editor Hot Pixels plugin author) about to add zooming features into control panel dialog of all Image Editor plugins. It's done now in svn 'trunk' and will be available to 0.9.0 release.

Current zoom factor are :

- x1.0 (no zoom)
- x1.5
- x2.0
- x2.5
- x3.0

For any memory performance reasons, i have limited zoom factor to 3.0. It's will be enough to see fine details of large image like 10Mpx photograph.

There is a screenshot of "Restoration" plugin in action using 2.5 zoom factor to check JPEG correction artifacts. Take a look at this url