Render raster images by using a copy of a portion of the image
Instead of directly rendering the image, we now copy the visible area of the image and render that. This allows us to perform color correction on the copy which does not impact the original data and thus should preserve the original pixels. As a bonus, this also allows us to use QImage's improved smooth scaling so reduces aliasing artifacts at small zoom values.
Showing with 292 additions and 117 deletions