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GREG offers the possibility of editing the color look-up table (LUT) for
bitmaps. The colors are represented by three SIC variables:
- HUE
The HUE array, with values between 0 and 360, represent the color
on a standard color cycle (from Red to Yellow, Green, Blue, Violet and
Red again).
- SATURATION The SATURATION array, with values between 0 and
1, indicates the fraction of the original (saturated) color mixed with
white. 0 is pure white, 1 a purely saturated color.
- VALUE The VALUE array, with values between 0 and 1,
indicates the intensity. 0 is black, 1 is maximum lightness.
These variable can be modified by any standard SIC expression. The new
values get transferred to the display by typing the command LUT. This
command also accepts other arguments:
- COLOR Load a default color table
- WHITE Load a black and white color table (White background,
black sources)
- BLACK Load a black and white color table (Black background,
white sources).
- LUT Load the color table defined by the arrays. Same as without
any argument.
- EDIT Calls an interactive look-up table editor (on X-Window
systems onlyt) not yet implemented.
- Any other Red Green Blue values are read from the formatted file
specified as argument. The RGB representation is converted to HSV before
being used.
The color associated with the blanking value can be modified using the B_HUE, B_SATURATION and B_VALUE scalar variables.
Next: Pen Colors
Up: Greyscale and Color plots
Previous: Filled Areas
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Gildas manager
2024-04-18