The color of a gEDA/gaf object is specified via an integer index. The relationship between integer and color is based on object type. Each object type typically has one or more colors. Here is a table of color index to object type:

Index	Object type
0	BACKGROUND_COLOR
1	PIN_COLOR
2	NET_ENDPOINT_COLOR
3	GRAPHIC_COLOR
4	NET_COLOR
5	ATTRIBUTE_COLOR
6	LOGIC_BUBBLE_COLOR
7	DOTS_GRID_COLOR
8	DETACHED_ATTRIBUTE_COLOR
9	TEXT_COLOR
10	BUS_COLOR
11	SELECT_COLOR
12	BOUNDINGBOX_COLOR
13	ZOOM_BOX_COLOR
14	STROKE_COLOR
15	LOCK_COLOR
16	OUTPUT_BACKGROUND_COLOR
17	FREESTYLE1_COLOR
18	FREESTYLE2_COLOR
19	FREESTYLE3_COLOR
20	FREESTYLE4_COLOR
21	JUNCTION_COLOR
22	MESH_GRID_MAJOR_COLOR
23	MESH_GRID_MINOR_COLOR

The actual color associated with the color index is defined on a per tool bases. Objects are typically assigned their corresponding color index, but it is (sometimes) permissible to assign other color index values to different object types.

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