User Guide

GNU Image Manipulation Program
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You can find this filter through Filters → Colors → Color to Alpha.
The Color to Alpha filter makes transparent all pixels with a selected color. An Alpha channel is created. It will attempt to
preserve anti-aliasing information by using a partially intelligent routine that replaces weak color information with weak alpha
information. In this way, areas that contain an element of the selected color will maintain a blended appearance with their
surrounding pixels.
15.3.13.2 Options
Color Clicking on the From color swatch provides a color selection dialog where you can select a color. If selection of a precise
color is required, use the Color Picker then drag and drop the selected color from the color picker to the From color swatch.
Right clicking on the color will display a menu where you can select Foreground or Background colors, White or Black.
15.3.14 Decompose
15.3.14.1 Overview
Figure 15.49: From left to right: Original image, Decomposed image (RGB decomposition).
(a) Original image (b) Filter Decompose applied
You can find this filter through Filters → Colors → Decompose
This filter separates an image into its different components (RGB, HSV...).