Understanding the Use of ColorMatrix and ColorMatrixColorFilter to Modify a Drawable's Hue
This is what I use for my game. This is the compilation of various part found on various articles on websites. Credits goes to the original author from the @see links. Note that a lot more can be done with color matrices. Including inverting, etc...
public class ColorFilterGenerator
{
/**
* Creates a HUE ajustment ColorFilter
* @see http://groups.google.com/group/android-developers/browse_thread/thread/9e215c83c3819953
* @see http://gskinner.com/blog/archives/2007/12/colormatrix_cla.html
* @param value degrees to shift the hue.
* @return
*/
public static ColorFilter adjustHue( float value )
{
ColorMatrix cm = new ColorMatrix();
adjustHue(cm, value);
return new ColorMatrixColorFilter(cm);
}
/**
* @see http://groups.google.com/group/android-developers/browse_thread/thread/9e215c83c3819953
* @see http://gskinner.com/blog/archives/2007/12/colormatrix_cla.html
* @param cm
* @param value
*/
public static void adjustHue(ColorMatrix cm, float value)
{
value = cleanValue(value, 180f) / 180f * (float) Math.PI;
if (value == 0)
{
return;
}
float cosVal = (float) Math.cos(value);
float sinVal = (float) Math.sin(value);
float lumR = 0.213f;
float lumG = 0.715f;
float lumB = 0.072f;
float[] mat = new float[]
{
lumR + cosVal * (1 - lumR) + sinVal * (-lumR), lumG + cosVal * (-lumG) + sinVal * (-lumG), lumB + cosVal * (-lumB) + sinVal * (1 - lumB), 0, 0,
lumR + cosVal * (-lumR) + sinVal * (0.143f), lumG + cosVal * (1 - lumG) + sinVal * (0.140f), lumB + cosVal * (-lumB) + sinVal * (-0.283f), 0, 0,
lumR + cosVal * (-lumR) + sinVal * (-(1 - lumR)), lumG + cosVal * (-lumG) + sinVal * (lumG), lumB + cosVal * (1 - lumB) + sinVal * (lumB), 0, 0,
0f, 0f, 0f, 1f, 0f,
0f, 0f, 0f, 0f, 1f };
cm.postConcat(new ColorMatrix(mat));
}
protected static float cleanValue(float p_val, float p_limit)
{
return Math.min(p_limit, Math.max(-p_limit, p_val));
}
}
To complete this I should add an example:
ImageView Sun = (ImageView)findViewById(R.id.sun);
Sun.setColorFilter(ColorFilterGenerator.adjustHue(162)); // 162 degree rotation
here is the complete code if you want to adjust the bright, contrast, saturation and hue. Enjoy! Thanks a lot to @RichardLalancette
public class ColorFilterGenerator {
private static double DELTA_INDEX[] = {
0, 0.01, 0.02, 0.04, 0.05, 0.06, 0.07, 0.08, 0.1, 0.11,
0.12, 0.14, 0.15, 0.16, 0.17, 0.18, 0.20, 0.21, 0.22, 0.24,
0.25, 0.27, 0.28, 0.30, 0.32, 0.34, 0.36, 0.38, 0.40, 0.42,
0.44, 0.46, 0.48, 0.5, 0.53, 0.56, 0.59, 0.62, 0.65, 0.68,
0.71, 0.74, 0.77, 0.80, 0.83, 0.86, 0.89, 0.92, 0.95, 0.98,
1.0, 1.06, 1.12, 1.18, 1.24, 1.30, 1.36, 1.42, 1.48, 1.54,
1.60, 1.66, 1.72, 1.78, 1.84, 1.90, 1.96, 2.0, 2.12, 2.25,
2.37, 2.50, 2.62, 2.75, 2.87, 3.0, 3.2, 3.4, 3.6, 3.8,
4.0, 4.3, 4.7, 4.9, 5.0, 5.5, 6.0, 6.5, 6.8, 7.0,
7.3, 7.5, 7.8, 8.0, 8.4, 8.7, 9.0, 9.4, 9.6, 9.8,
10.0
};
/**
* @see http://groups.google.com/group/android-developers/browse_thread/thread/9e215c83c3819953
* @see http://gskinner.com/blog/archives/2007/12/colormatrix_cla.html
* @param cm
* @param value
*/
public static void adjustHue(ColorMatrix cm, float value)
{
value = cleanValue(value, 180f) / 180f * (float) Math.PI;
if (value == 0){
return;
}
float cosVal = (float) Math.cos(value);
float sinVal = (float) Math.sin(value);
float lumR = 0.213f;
float lumG = 0.715f;
float lumB = 0.072f;
float[] mat = new float[]
{
lumR + cosVal * (1 - lumR) + sinVal * (-lumR), lumG + cosVal * (-lumG) + sinVal * (-lumG), lumB + cosVal * (-lumB) + sinVal * (1 - lumB), 0, 0,
lumR + cosVal * (-lumR) + sinVal * (0.143f), lumG + cosVal * (1 - lumG) + sinVal * (0.140f), lumB + cosVal * (-lumB) + sinVal * (-0.283f), 0, 0,
lumR + cosVal * (-lumR) + sinVal * (-(1 - lumR)), lumG + cosVal * (-lumG) + sinVal * (lumG), lumB + cosVal * (1 - lumB) + sinVal * (lumB), 0, 0,
0f, 0f, 0f, 1f, 0f,
0f, 0f, 0f, 0f, 1f };
cm.postConcat(new ColorMatrix(mat));
}
public static void adjustBrightness(ColorMatrix cm, float value) {
value = cleanValue(value,100);
if (value == 0) {
return;
}
float[] mat = new float[]
{
1,0,0,0,value,
0,1,0,0,value,
0,0,1,0,value,
0,0,0,1,0,
0,0,0,0,1
};
cm.postConcat(new ColorMatrix(mat));
}
public static void adjustContrast(ColorMatrix cm, int value) {
value = (int)cleanValue(value,100);
if (value == 0) {
return;
}
float x;
if (value < 0) {
x = 127 + (float) value / 100*127;
} else {
x = value % 1;
if (x == 0) {
x = (float)DELTA_INDEX[value];
} else {
//x = DELTA_INDEX[(p_val<<0)]; // this is how the IDE does it.
x = (float)DELTA_INDEX[(value<<0)]*(1-x) + (float)DELTA_INDEX[(value<<0)+1] * x; // use linear interpolation for more granularity.
}
x = x*127+127;
}
float[] mat = new float[]
{
x/127,0,0,0, 0.5f*(127-x),
0,x/127,0,0, 0.5f*(127-x),
0,0,x/127,0, 0.5f*(127-x),
0,0,0,1,0,
0,0,0,0,1
};
cm.postConcat(new ColorMatrix(mat));
}
public static void adjustSaturation(ColorMatrix cm, float value) {
value = cleanValue(value,100);
if (value == 0) {
return;
}
float x = 1+((value > 0) ? 3 * value / 100 : value / 100);
float lumR = 0.3086f;
float lumG = 0.6094f;
float lumB = 0.0820f;
float[] mat = new float[]
{
lumR*(1-x)+x,lumG*(1-x),lumB*(1-x),0,0,
lumR*(1-x),lumG*(1-x)+x,lumB*(1-x),0,0,
lumR*(1-x),lumG*(1-x),lumB*(1-x)+x,0,0,
0,0,0,1,0,
0,0,0,0,1
};
cm.postConcat(new ColorMatrix(mat));
}
protected static float cleanValue(float p_val, float p_limit)
{
return Math.min(p_limit, Math.max(-p_limit, p_val));
}
public static ColorFilter adjustColor(int brightness, int contrast, int saturation, int hue){
ColorMatrix cm = new ColorMatrix();
adjustHue(cm, hue);
adjustContrast(cm, contrast);
adjustBrightness(cm, brightness);
adjustSaturation(cm, saturation);
return new ColorMatrixColorFilter(cm);
}
}
For anyone who is interested in how to use the ColorMatrixColorFilter. The sample I used here, converted every pixel into red when I draw the bitmap on the canvas.
The comment in the class is from: http://developer.android.com/reference/android/graphics/ColorMatrix.html this gives you some insights on how this is working
@Override
protected void onDraw(Canvas canvas) {
// The matrix is stored in a single array, and its treated as follows: [ a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p, q, r, s, t ]
// When applied to a color [r, g, b, a], the resulting color is computed as (after clamping) ;
// 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;
Paint paint = new Paint();
float[] matrix = {
1, 1, 1, 1, 1, //red
0, 0, 0, 0, 0, //green
0, 0, 0, 0, 0, //blue
1, 1, 1, 1, 1 //alpha
};
paint.setColorFilter(new ColorMatrixColorFilter(matrix));
Rect source = new Rect(0, 0, 100, 100);
Rect dest = new Rect(0, 0, 100, 100);
Bitmap bitmap = BitmapFactory.decodeResource(context.getResources(), R.drawable.sampleimage);
canvas.drawBitmap(bitmap , source, dest, paint);
}