Android ColorMatrix | Explanation With Examples

 What is Color Matrix ?

Color Matrix is a 4x5 matrix (4 Rows and 5 Columns Matrix ) for transforming the color and alpha components of a Bitmap. The matrix can be passed as single array, and is treated as follows:

[ a, b, c, d, e,
    f, g, h, i, j,
    k, l, m, n, o,
    p, q, r, s, t ]

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When applied to a color [R, G, B, A], the resulting color is computed as:                          

R’ = a*R + b*G + c*B + d*A + e;
G’ = f*R + g*G + h*B + i*A + j;
B’ = k*R + l*G + m*B + n*A + o;
A’ = p*R + q*G + r*B + s*A + t;


That resulting color [R’, G’, B’, A’] then has each channel clamped to the 0 to 255 range.
The sample ColorMatrix below inverts incoming colors by scaling each channel by -1, and then shifting the result up by 255 to remain in the standard color space.
 [ -1, 0, 0, 0, 255,
     0, -1, 0, 0, 255,
     0, 0, -1, 0, 255,
     0, 0, 0, 1, 0 ]

In Android, we uses floatArray to describe the color matrix.