View Issue Details
|ID||Project||Category||View Status||Date Submitted||Last Update|
|0012518||Scribus||Graphics / Image Frames||public||2014-07-14 01:44||2014-10-24 23:00|
|Priority||normal||Severity||feature||Reproducibility||have not tried|
|Summary||0012518: [PATCH] Port BAlpha auto-contrast.patch|
Short version: add auto contrast image effect
This patch adds a new image effect called "Auto contrast".
The default settings for this effect do almost precisely the same thing as GIMP's "auto white balance". Discarding (thus clipping) the top and bottom 0.5% of the pixels, it stretches the red, green, and blue color channels to the full range. This can do magic to enhance photographs, in particular when they're tinted towards a certain color. And it can also do horrible things, depending on the image, so be sure to look at the actual result.
The effect has a few options:
Threshold low and Threshold high: This is the percentage of the image's pixels that are discarded when calculating the range of color values. As mentioned above, the default is 0.5% for both, but this can be adjusted indepently for dark (low) and light (high) values. If, for example, your photo has a large over-exposed area (that you may be cropping away anyway), you'll probably want to increase the high threshold.
Sync colors: If this is checked, then instead of adjusting the color channels independently, the low and high values will be identical for all three color channels (using the lowest low value and the highest high value). This means that there will be no color correction (or distortion); rather this will just increase the image contrast.
Amount: Controls the strenght of the effect from 100% (the default) to 0% (no change at all).
This effect only works on RGB images. Frankly, I've never used CMYK images, and I have now idea how I would treat them for applying this effect. In particular this means that this effect won't do anything when exporting CYMK PDFs unless you also apply the "effects before color management" patch (see its description for the reason).
This is not technically a file format change, however I have not tested how Scribus behaves when a file contains an unknown image effect. Thus opening and/or re-saving a .sla file that contains this effect with an unpatched version of Scribus may have unintended consequences.
Proposed Patch: auto-contrast.patch
|Additional Information||Background: |
User BAlpha provides a set of patches for new features in Scribus v1.4 . They live on a Bitbucket repo and are GPL2+ licensed
- Overview of theses features : https://bitbucket.org/balpha/scribus-patches/wiki/Home
- Patches : https://bitbucket.org/balpha/scribus-patches/src
- Licence is GPL2+ (as stated in Overview page and https://bitbucket.org/balpha/scribus-patches/src/18ffce96072fd5eb6acbb3f5e05e672a854e7138/COPYING?at=default)
|Tags||No tags attached.|
|2014-07-14 01:44||Kunda||New Issue|
|2014-07-14 01:44||Kunda||Issue generated from: 0012517|
|2014-07-14 01:44||Kunda||Relationship added||child of 0012007|
|2014-07-14 02:01||Kunda||Description Updated|
|2014-10-24 23:00||Kunda||Patch||=> Yes|
|2015-09-17 20:10||Kunda||Category||Graphics / Image Frames => Graphics/Img Frames|
|2015-09-17 20:11||Kunda||Category||Graphics/Img Frames => Graphics / Image Frames|