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## Editing a continuous color table

Figure 22

There are a handful of controls in the editor portion of the Color table window, shown in figure, that are used to change the definition of a color table. To change a color table definition, you must alter its color control points. This means adding and removing color control points as well as changing their colors and locations.

To change the number of color control points in a color table, type a new number of color control points into the Number of colors spin box or use the up/down arrows to increase or decrease the number of color control points. When a new color control point is added, it appears to the right of the selected color control point and to the left of the next color control point. Color control points are represented as a pointy box just above the color spectrum. The color control point that has a small triangular mark is the selected color control point. When a color control point is removed, the color control point that was created before the deleted color control point becomes the new selected color control point. Clicking the Align button makes all color control points have equal spacing.

Clicking on a color control point makes it active. You can also use the Space bar if the color spectrum has keyboard focus. Clicking and dragging on a color control point changes its position. Clicking the arrow keys on the keyboard also moves a color control point. To change a color control point's color, right click on it and choose a new color from the Popup color menu that appears under the mouse cursor.

The Color table window also has a couple of toggles that can be set to influence a color table's appearance without having permanent effects on the color table. The Smooth toggle turns on color interpolation between color control points. When this toggle is enabled, colors are smoothly blended into each other. The Equal spacing toggle can temporarily tell the color table to ignore the positions of its color control points and use equal spacing instead. The Equal spacing toggle is often used with Smooth turned off.