Bug 333734

I cannot stress how important it is to get an accurate and hassle-free preview when manipulating images. If you open an image in Gwenview and click on Plugins > Batch Processing > Filter Images and select any of those filters, you are taken back to the 90s where image processing in Linux was... different. We need to see the image preview at 100% when sharpening, blurring, adding noise, etc. Try doing this now - it's so frustrating it's on the verge of impossible!

What needs to change for this to be usable:
- Clicking on [Preview] immediately opens a zoomed-to-100% preview.

- The preview is either a two-pane before/after, or a before-on-hover and after-not-on-hover as in digiKam.

- There is a button to zoom-to-fit, but the default is zoomed to 100% (or else it should remember the last used option).

- "small preview" should use the center of the image, not the corner which is usually sky or some other non-subject.

- Filter parameters should be universal, when possible they should match those in other software. For instance any digital photographer knows the optimal unsharp mask parameters which best fit his images (images of a certain resolution from his camera, of a certain sharpness depending on his lens, etc). For Unsharp Mask I expect to see Radius/Std.Dev where I know 0.55 is optimal for my images, and Amount/Scale where I know 4.00 is best. Instead I see four sliders whose interactions are foreign to me and there is no usable preview. New sliders could be good if it was some new powerful sharpening technique, but it's not, it's unsharp masking, and there is no need to complicate things.

- Overwrite mode "Ask". I thought it would ask me "File exists, do you want to overwrite or rename?" and let me click "[Overwrite] [Rename] [Cancel]". Instead it asks "The destination file "foo.tif" already exists; do you want overwrite it?" and my choices are "[Continue] [No] [Cancel]" One must guess "continue" overwrites it. But I don't want to overwrite it, I want to rename it, so I click "No" hoping it lets me set a new name, and instead the dialog closes, and I can't retry, because the [start] button turned into [close]!

Reproducible: Always




Severity: "Grave: The software is basically unusable now"