Sets the color that will be used for the next printing or drawing operation.
This function expects three or four integers between 0 and 255 to specify the color. The first three specify the color components, the optional fourth specifies the alpha value (opacity). The first number indicates how much of the color red to add. The second is for green, and the third is for blue. Zero indicates nothing of the corresponding color component, while 255 indicates "as much as possible".
Think of the values as how much colored light to add for each of the red, green and blue color components. To have black, you wouldn't add any light at all. Black is thus represented by (0, 0, 0). To have white, you would add all colors at max: (255, 255, 255). You could mix red and blue to have magenta: (255, 0, 255). A more red magenta would appear if you didn't add that much blue: (255, 0, 200).
The alpha value indicates the level of opacity for the color. A value of 0 indicates that the color should be fully transparent. A value of 255 indicates that it should be opaque (solid). The default alpha value is 255.
color(0, 255, 0);
color(0, 255, 0, 128);