New image Editor color correction tools preview modes in 0.9.0

In DigikamImagePlugins 0.8.x, i have created a new widget using tabs to display and playing with original and target image under all image editor color correction tools (like Adjust Curves for example).

I was not satisfied by this way, for any reasons (usability, performance in memory, etc.) and i have recently building from scratch a new widget with a new design !

The code is now complete in svn and will be available at 0.9.0 release. I have added a new buttons collection on the top of preview image area to select the right preview mode to use :

- Original image only.
- Original and target images together displayed in contiguous (vertically or horizontally).
- Original and target images together duplicated (vertically or horizontally).
- Target image only.
- Toogle automaticly between target/orginal image when the mouse is over/out image area

There is a screenshot of current Curves Adjust plugin joined to this blog entry. The image corrected is a CRW RAW file in 16 bits per color per pixel...