The Free version of SiMPLE has only 16 standard colors available for displaying information. These 16 colors are:

Notice, for example, that there are only two different shades of red (color=4 and color=12). So how is it possible to display more than two shades of red?

If we look at a magnified view of the five "red" samples shown above, we see that each of the the new shades of red is actually a tiny "checker board" arrangement of two different standard color pixels:

When viewed from afar, each of these tiny checker board patterns appears to blend into a solid color (which we call the "effective" color).

Since SiMPLE has 16 different standard colors with which to work, there are a total of 256 such effective colors that it can produce:

However, since the result of "checker-boarding" color A with color B is virtually indistinguishable from "checker-boarding" color B with color A, there are (at most) only 136 different effective colors. (I.e., the upper-right half of the above color grid is essentially a mirror image the lower-left half.)

We define the term "scrunching an image" as the process of converting that image into a 16-color bitmap image whose pixels have been prearranged into tiny checker board patterns so as to produce effective colors that most closely match the actual colors of the original image.

Matching the Colors

Every displayed pixel is composed of three primary colors: Red, Green, and Blue. The amounts (0-255) of each of these three primary colors determine the resulting color that is produced. Therefore, the color of every pixel can be defined in terms of its three RGB values. For example, black would be (0,0,0), white would be (255,255,255), bright blue would be (0,0,255), a dark purple might be (100,0,100), and so on.

Let's look at the RGB values for each of SiMPLE's 16 colors:

Notice that each of the RGB values shown above are multiples of 84.
It would have been nicer if multiples of 85 could have been choosen.
That way the values would have ranged from zero through 255.
But unfortunately, the color palette requires that all color
values be multiples of 4. Therefore, 85 couldn't be used.

When we create a checker board pattern of two colors, the RGB values of the effective color that results are essentially the averages of the corresponding RGB values of the two colors being used in the checker board. For example, if we "checker-board together" yellow (252,252,84) and dark red (168,0,0), the effective color that results is very close to (210,126,42):

Yellow and Dark Red	(210,126,42)

However, most of the colors in a typical image will generally be different from the limited number of effective colors that can be produce by "checker-boarding" the 16 standard colors. In those cases we must choose the effective color whose RGB components most closely match (in the sense of a least-square error) those of the desired color.