Java Code Examples for java.awt.Color#getRGBColorComponents()

/**
 * A method to produce a color (either black or white) that contrasts with the given color.
 * This is useful for finding a readable foreground color for a given background.
 * 
 * @param color the color for which to find a contrast.
 * @return the contrasting color.
 */
public static Color contrastForegroundColor(Color color) {
	float[] rgbs = new float[3];
	color.getRGBColorComponents(rgbs);
	int fR = rgbs[0] > 0.5 ? 0 : 1;
	int fG = rgbs[1] > 0.5 ? 0 : 1;
	int fB = rgbs[2] > 0.5 ? 0 : 1;

	// Note: the more accurate operation for calculating luminance is:
	// float gamma = 2.2;
	// float luminance = 0.2126 * pow(r, gamma) + 
	//                   0.7152 * pow(g, gamma) + 
	//                   0.0722 * pow(b, gamma);

	// less precise, faster calculation
	double luminance = 0.2126 * (fR * fR) + 0.7152 * (fG * fG) + 0.0722 * (fB * fB);
	Color foreground = Color.WHITE;
	if (luminance < 0.54) { // about half (a bit fudge, since we are approximating the pow())
		foreground = Color.BLACK;
	}
	return foreground;
}
 

void emitPSColor(Color color) {
    if (color != null && color.equals(mColor) == false) {
        float[] rgb = color.getRGBColorComponents(null);

        /* If the color is a gray value then use
         * setgray.
         */
        if (rgb[0] == rgb[1] && rgb[1] == rgb[2]) {
            mPSStream.println(rgb[0] + SETGRAY_STR);

        /* It's not gray so use setrgbcolor.
         */
        } else {
            mPSStream.println(rgb[0] + " "
                              + rgb[1] + " "
                              + rgb[2] + " "
                              + SETRGBCOLOR_STR);
        }

        mColor = color;

    }
}
 

void emitPSColor(Color color) {
    if (color != null && color.equals(mColor) == false) {
        float[] rgb = color.getRGBColorComponents(null);

        /* If the color is a gray value then use
         * setgray.
         */
        if (rgb[0] == rgb[1] && rgb[1] == rgb[2]) {
            mPSStream.println(rgb[0] + SETGRAY_STR);

        /* It's not gray so use setrgbcolor.
         */
        } else {
            mPSStream.println(rgb[0] + " "
                              + rgb[1] + " "
                              + rgb[2] + " "
                              + SETRGBCOLOR_STR);
        }

        mColor = color;

    }
}
 

private static boolean compareWithTolerance(Color a, Color b, float delta) {
    float[] a_rgb = new float[3];
    a_rgb = a.getRGBColorComponents(a_rgb);
    float[] b_rgb = new float[3];
    b_rgb = b.getRGBColorComponents(b_rgb);

    for (int i = 0; i < 3; i++) {
        if (Math.abs(a_rgb[i] - b_rgb[i]) > delta) {
            return false;
        }
    }
    return true;
}
 

protected void selectSolidBrush(Color color) {

        /* We only need to select a brush if the color has changed.
        */
        if (color.equals(mLastColor) == false) {
            mLastColor = color;
            float[] rgb = color.getRGBColorComponents(null);

            selectSolidBrush(getPrintDC(),
                             (int) (rgb[0] * MAX_WCOLOR),
                             (int) (rgb[1] * MAX_WCOLOR),
                             (int) (rgb[2] * MAX_WCOLOR));
        }
    }
 

protected boolean selectStylePen(int cap, int join, float width,
                                 Color color) {

    long endCap;
    long lineJoin;

    float[] rgb = color.getRGBColorComponents(null);

    switch(cap) {
    case BasicStroke.CAP_BUTT: endCap = PS_ENDCAP_FLAT; break;
    case BasicStroke.CAP_ROUND: endCap = PS_ENDCAP_ROUND; break;
    default:
    case BasicStroke.CAP_SQUARE: endCap = PS_ENDCAP_SQUARE; break;
    }

    switch(join) {
    case BasicStroke.JOIN_BEVEL:lineJoin = PS_JOIN_BEVEL; break;
    default:
    case BasicStroke.JOIN_MITER:lineJoin = PS_JOIN_MITER; break;
    case BasicStroke.JOIN_ROUND:lineJoin = PS_JOIN_ROUND; break;
    }

    return (selectStylePen(getPrintDC(), endCap, lineJoin, width,
                           (int) (rgb[0] * MAX_WCOLOR),
                           (int) (rgb[1] * MAX_WCOLOR),
                           (int) (rgb[2] * MAX_WCOLOR)));
}
 

/**
 * Set the GDI color for text drawing.
 */
protected void setTextColor(Color color) {

    /* We only need to select a brush if the color has changed.
    */
    if (color.equals(mLastTextColor) == false) {
        mLastTextColor = color;
        float[] rgb = color.getRGBColorComponents(null);

        setTextColor(getPrintDC(),
                     (int) (rgb[0] * MAX_WCOLOR),
                     (int) (rgb[1] * MAX_WCOLOR),
                     (int) (rgb[2] * MAX_WCOLOR));
    }
}
 

protected void selectPen(float width, Color color) {

        float[] rgb = color.getRGBColorComponents(null);

        selectPen(getPrintDC(), width,
                  (int) (rgb[0] * MAX_WCOLOR),
                  (int) (rgb[1] * MAX_WCOLOR),
                  (int) (rgb[2] * MAX_WCOLOR));
    }
 

/**
 * Set the GDI color for text drawing.
 */
protected void setTextColor(Color color) {

    /* We only need to select a brush if the color has changed.
    */
    if (color.equals(mLastTextColor) == false) {
        mLastTextColor = color;
        float[] rgb = color.getRGBColorComponents(null);

        setTextColor(getPrintDC(),
                     (int) (rgb[0] * MAX_WCOLOR),
                     (int) (rgb[1] * MAX_WCOLOR),
                     (int) (rgb[2] * MAX_WCOLOR));
    }
}
 

protected boolean selectStylePen(int cap, int join, float width,
                                 Color color) {

    long endCap;
    long lineJoin;

    float[] rgb = color.getRGBColorComponents(null);

    switch(cap) {
    case BasicStroke.CAP_BUTT: endCap = PS_ENDCAP_FLAT; break;
    case BasicStroke.CAP_ROUND: endCap = PS_ENDCAP_ROUND; break;
    default:
    case BasicStroke.CAP_SQUARE: endCap = PS_ENDCAP_SQUARE; break;
    }

    switch(join) {
    case BasicStroke.JOIN_BEVEL:lineJoin = PS_JOIN_BEVEL; break;
    default:
    case BasicStroke.JOIN_MITER:lineJoin = PS_JOIN_MITER; break;
    case BasicStroke.JOIN_ROUND:lineJoin = PS_JOIN_ROUND; break;
    }

    return (selectStylePen(getPrintDC(), endCap, lineJoin, width,
                           (int) (rgb[0] * MAX_WCOLOR),
                           (int) (rgb[1] * MAX_WCOLOR),
                           (int) (rgb[2] * MAX_WCOLOR)));
}
 

protected void selectPen(float width, Color color) {

        float[] rgb = color.getRGBColorComponents(null);

        selectPen(getPrintDC(), width,
                  (int) (rgb[0] * MAX_WCOLOR),
                  (int) (rgb[1] * MAX_WCOLOR),
                  (int) (rgb[2] * MAX_WCOLOR));
    }
 

protected void fillRect(float x, float y, float width, float height,
                        Color color) {
    float[] rgb = color.getRGBColorComponents(null);

    fillRect(getPrintDC(), x, y, width, height,
             (int) (rgb[0] * MAX_WCOLOR),
             (int) (rgb[1] * MAX_WCOLOR),
             (int) (rgb[2] * MAX_WCOLOR));
}
 

protected void fillRect(float x, float y, float width, float height,
                        Color color) {
    float[] rgb = color.getRGBColorComponents(null);

    fillRect(getPrintDC(), x, y, width, height,
             (int) (rgb[0] * MAX_WCOLOR),
             (int) (rgb[1] * MAX_WCOLOR),
             (int) (rgb[2] * MAX_WCOLOR));
}
 

protected Color getHilightColor(Color rgbColor) {
  Color h = (Color) hilightColors.get(rgbColor);
  if (h == null) {
    float[] rgb = rgbColor.getRGBColorComponents(null);
    float[] hsb = Color.RGBtoHSB((int) rgb[0], (int) rgb[1], (int) rgb[2], null);
    h = Color.getHSBColor(hsb[0]+0.5F, hsb[1], Math.max(1.0F, hsb[2]*2));
    hilightColors.put(rgbColor, h);
  }
  return h;
}
 

protected boolean selectStylePen(int cap, int join, float width,
                                 Color color) {

    long endCap;
    long lineJoin;

    float[] rgb = color.getRGBColorComponents(null);

    switch(cap) {
    case BasicStroke.CAP_BUTT: endCap = PS_ENDCAP_FLAT; break;
    case BasicStroke.CAP_ROUND: endCap = PS_ENDCAP_ROUND; break;
    default:
    case BasicStroke.CAP_SQUARE: endCap = PS_ENDCAP_SQUARE; break;
    }

    switch(join) {
    case BasicStroke.JOIN_BEVEL:lineJoin = PS_JOIN_BEVEL; break;
    default:
    case BasicStroke.JOIN_MITER:lineJoin = PS_JOIN_MITER; break;
    case BasicStroke.JOIN_ROUND:lineJoin = PS_JOIN_ROUND; break;
    }

    return (selectStylePen(getPrintDC(), endCap, lineJoin, width,
                           (int) (rgb[0] * MAX_WCOLOR),
                           (int) (rgb[1] * MAX_WCOLOR),
                           (int) (rgb[2] * MAX_WCOLOR)));
}
 

private static boolean compareWithTolerance(Color a, Color b, float delta) {
    float[] a_rgb = new float[3];
    a_rgb = a.getRGBColorComponents(a_rgb);
    float[] b_rgb = new float[3];
    b_rgb = b.getRGBColorComponents(b_rgb);

    for (int i = 0; i < 3; i++) {
        if (Math.abs(a_rgb[i] - b_rgb[i]) > delta) {
            return false;
        }
    }
    return true;
}
 

protected void fillRect(float x, float y, float width, float height,
                        Color color) {
    float[] rgb = color.getRGBColorComponents(null);

    fillRect(getPrintDC(), x, y, width, height,
             (int) (rgb[0] * MAX_WCOLOR),
             (int) (rgb[1] * MAX_WCOLOR),
             (int) (rgb[2] * MAX_WCOLOR));
}
 

protected void selectPen(float width, Color color) {

        float[] rgb = color.getRGBColorComponents(null);

        selectPen(getPrintDC(), width,
                  (int) (rgb[0] * MAX_WCOLOR),
                  (int) (rgb[1] * MAX_WCOLOR),
                  (int) (rgb[2] * MAX_WCOLOR));
    }
 

protected boolean selectStylePen(int cap, int join, float width,
                                 Color color) {

    long endCap;
    long lineJoin;

    float[] rgb = color.getRGBColorComponents(null);

    switch(cap) {
    case BasicStroke.CAP_BUTT: endCap = PS_ENDCAP_FLAT; break;
    case BasicStroke.CAP_ROUND: endCap = PS_ENDCAP_ROUND; break;
    default:
    case BasicStroke.CAP_SQUARE: endCap = PS_ENDCAP_SQUARE; break;
    }

    switch(join) {
    case BasicStroke.JOIN_BEVEL:lineJoin = PS_JOIN_BEVEL; break;
    default:
    case BasicStroke.JOIN_MITER:lineJoin = PS_JOIN_MITER; break;
    case BasicStroke.JOIN_ROUND:lineJoin = PS_JOIN_ROUND; break;
    }

    return (selectStylePen(getPrintDC(), endCap, lineJoin, width,
                           (int) (rgb[0] * MAX_WCOLOR),
                           (int) (rgb[1] * MAX_WCOLOR),
                           (int) (rgb[2] * MAX_WCOLOR)));
}
 

/**
 *  Convert a RGB Color to it corresponding HSL values.
 *
 *  @return an array containing the 3 HSL values.
 */
public static float[] fromRGB(Color color)
{
	//  Get RGB values in the range 0 - 1

	float[] rgb = color.getRGBColorComponents( null );
	float r = rgb[0];
	float g = rgb[1];
	float b = rgb[2];

	//	Minimum and Maximum RGB values are used in the HSL calculations

	float min = Math.min(r, Math.min(g, b));
	float max = Math.max(r, Math.max(g, b));

	//  Calculate the Hue

	float h = 0;

	if (max == min)
		h = 0;
	else if (max == r)
		h = ((60 * (g - b) / (max - min)) + 360) % 360;
	else if (max == g)
		h = (60 * (b - r) / (max - min)) + 120;
	else if (max == b)
		h = (60 * (r - g) / (max - min)) + 240;

	//  Calculate the Luminance

	float l = (max + min) / 2;
	//System.out.println(max + " : " + min + " : " + l);

	//  Calculate the Saturation

	float s = 0;

	if (max == min)
		s = 0;
	else if (l <= .5f)
		s = (max - min) / (max + min);
	else
		s = (max - min) / (2 - max - min);

	return new float[] {h, s * 100, l * 100};
}