PALETTE Procedure

Standard Library procedure that lets you interactively create a new color table based on the RGB color system.

PALETTE [, colors_out]

None.

colors_out (optional) Contains the color values of the final color table in the form of a two-dimensional array that has the number of colors in the color table as the first dimension and the integer 3 as the second dimension.

The values for red are stored in the first row, the values for green are stored in the second row, and those for blue in the third row; in other words:

red = colors_out(*, 0)

green = colors_out(*, 1)

blue = colors_out(*, 2)

None.

PALETTE works only on displays with window systems. It creates an interactive window that lets you use the mouse to create a new color table. This window is shown in Figure 2-63.

Figure 2-63 The PALETTE window lets you use the mouse to create a new color table interactively.

Figure 2-64 The PALETTE window lets you use the mouse to create a new color table interactively.

The PALETTE window contains the following items:

• Color Ramp Displays the current color table.

• Slider Bars Used to adjust the color values of the selected color index.

• Color Index Grid Contains a representation of each color index that comprise the current color table. There are three rectangular slider bars for the red, green, and blue color vectors. The grid is used to select a color index to adjust and to create a new color ramp. The number of color indices that appear in the grid depend on the number of colors selected with the WINDOW procedure.

• Control Button Area Contains buttons for selecting Help, Undo Current Color, and Undo All. To select a button, click it with the left mouse button.

The Help button displays information about the procedure in the main PV-WAVE window

The Undo All button resets all color indices to their default values.

The Undo Current Color button resets the currently selected color index to its default value.

You can modify any number of color indices, or produce an interpolation between two modified color indices. The default color table is the currently loaded color table.

For information on using the PALETTE window, select the Help button and follow the online instructions provided.

TVSCL, LINDGEN(256, 256)
PALETTE, rgb_array

Modify the color table to your liking and exit the procedure.

SAVE, filename = 'my_colortable', rgb_array
LOADCT, 2
RESTORE, 'my_colortable'
rgb_array = REFORM(rgb_array, $
    N_ELEMENTS(rgb_array)/3, 3)
TVLCT, rgb_array(*, 0), rgb_array(*, 1), rgb_array(*, 2)

TVSCL, LINDGEN(256, 256)
PALETTE

Modify the color table to your liking and exit the procedure.

TVLCT, r, g, b, /Get
SAVE, filename = 'my_colortable_2', r, g, b
LOADCT, 8
RESTORE, 'my_colortable_2'
TVLCT, r, g, b

COLOR_CONVERT, COLOR_EDIT, COLOR_PALETTE, MODIFYCT, WgCeditTool

For more ideas about what can be done with color tables, see Modifying the Color Tables in Chapter 11 of the PV-WAVE User's Guide.