am 93ef9639: Merge "Improve ColorMatrix docs" into lmp-mr1-dev

import java.util.Arrays;

/**

 *  4x5 matrix for transforming the color+alpha components of a Bitmap.

 *  The matrix is stored in a single array, and its treated as follows:

 * 4x5 matrix for transforming the color and alpha components of a Bitmap.

 * The matrix can be passed as single array, and is treated as follows:

 *

 * <pre>

 *  [ a, b, c, d, e,

 *    f, g, h, i, j,

 *    k, l, m, n, o,

 *    p, q, r, s, t ]

 * </pre>

 *    p, q, r, s, t ]</pre>

 *

 * <p>

 * When applied to a color <code>[R, G, B, A]</code>, the resulting color

 * is computed as:

 * </p>

 *

 * When applied to a color <code>[r, g, b, a]</code>, the resulting color

 * is computed as (after clamping):

 * <pre>

 *   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;

 * </pre>

 *   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&rsquo; = p*R + q*G + r*B + s*A + t;</pre>

 *

 * <p>

 * That resulting color <code>[R&rsquo;, G&rsquo;, B&rsquo;, A&rsquo;]</code>

 * then has each channel clamped to the <code>0</code> to <code>255</code>

 * range.

 * </p>

 *

 * <p>

 * The sample ColorMatrix below inverts incoming colors by scaling each

 * channel by <code>-1</code>, and then shifting the result up by

 * <code>255</code> to remain in the standard color space.

 * </p>

 *

 * <pre>

 *   [ -1, 0, 0, 0, 255,

 *     0, -1, 0, 0, 255,

 *     0, 0, -1, 0, 255,

 *     0, 0, 0, 1, 0 ]</pre>

 */

@SuppressWarnings({ "MismatchedReadAndWriteOfArray", "PointlessArithmeticExpression" })

public class ColorMatrix {

    /**

     * Set the rotation on a color axis by the specified values.

     * <p>

     * <code>axis=0</code> correspond to a rotation around the RED color

     * <code>axis=1</code> correspond to a rotation around the GREEN color

     * <code>axis=2</code> correspond to a rotation around the BLUE color

     * </p>

     */

    public void setRotate(int axis, float degrees) {

        reset();

    /**

     * Set this colormatrix to the concatenation of the two specified

     * colormatrices, such that the resulting colormatrix has the same effect

     * as applying matB and then applying matA. It is legal for either matA or

     * matB to be the same colormatrix as this.

     * as applying matB and then applying matA.

     * <p>

     * It is legal for either matA or matB to be the same colormatrix as this.

     * </p>

     */

    public void setConcat(ColorMatrix matA, ColorMatrix matB) {

        float[] tmp;

    }

    /**

     * Concat this colormatrix with the specified prematrix. This is logically

     * the same as calling setConcat(this, prematrix);

     * Concat this colormatrix with the specified prematrix.

     * <p>

     * This is logically the same as calling setConcat(this, prematrix);

     * </p>

     */

    public void preConcat(ColorMatrix prematrix) {

        setConcat(this, prematrix);

    }

    /**

     * Concat this colormatrix with the specified postmatrix. This is logically

     * the same as calling setConcat(postmatrix, this);

     * Concat this colormatrix with the specified postmatrix.

     * <p>

     * This is logically the same as calling setConcat(postmatrix, this);

     * </p>

     */

    public void postConcat(ColorMatrix postmatrix) {

        setConcat(postmatrix, this);

    ///////////////////////////////////////////////////////////////////////////

    /**

     * Set the matrix to affect the saturation of colors. A value of 0 maps the

     * color to gray-scale. 1 is identity.

     * Set the matrix to affect the saturation of colors.

     *

     * @param sat A value of 0 maps the color to gray-scale. 1 is identity.

     */

    public void setSaturation(float sat) {

        reset();

        m[10] = 1;  m[11] = 1.772f;     m[12] = 0;

    }

}