The Gradient Editor allows you to create or edit complex gradients that you can use with, for example, the Blend tool.
You'll find a list of all available gradients under Gradients, and the currently selected gradient can be seen in a preview window. The buttons to the right let you Create, Copy, Delete and, Rename gradients. You can also Save Gradients in a POV-Ray format. Refresh Gradients re-reads all gradients from disk. You can also zoom the gradient with the Zoom buttons present in the main dialog.
The triangles at the bottom of the gradient preview window are color section markings. Two kinds of marks exist: black endpoints and white midpoints. The area between two black points is called a segment. You select a segment simply by clicking on it. A selected segment turns a darker shade of gray. Most work that you do in the gradient editor will be about changing and editing those segments in one way or another.
You can move an entire selection by clicking in the darker gray field and dragging.
Moving a white midpoint affects the color transition.
Dragging a black endpoint will stretch the area between that endpoint and the midpoint.
If you click on an endpoint then press Shift and drag, you will compress or expand the entire selection.
You can extend or add to a selection by pressing the Shift key and clicking on another segment.
Any of the described manipulations can be used on extended selections.
If you press the right mouse button in the gradient preview window, a menu will appear for further editing of the selected segment.
You can edit the left or right color by invoking left or right endpoint color. The Load From and Save To menu options allow you to load a color from an RGBA channel to an endpoint or to save an RGBA channel.
In the Blending function submenu from the Segment menu, you will find some functions that control the appearance of the gradient in your selection.
The Coloring type submenu from the segment menu lets you choose a color model for your selection or segment. You can choose plain RGB or one of two kinds of HSV.
The Segment commands will work on the selected segment. If you have selected more than one segment, they will not be treated as a unit.
Split segment at midpoint: Puts an endpoint at the midpoint and then divides the two new segments.
Split segment uniformly: Splits to a specified amount of segments.
Delete segment: Deletes the entire selection.
Re-center segment's midpoint: Re-centers the midpoints.
Re-distribute handles in segment: Evenly distributes all the points in the segment.
The Selection operations submenu allows you to flip or replicate the segment and also allows you to blend the endpoints' colors and/or opacity.