/*
* Copyright (C) 2008 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package android.graphics;
public class SweepGradient extends GradientShader {
private SweepGradientPaint mPaint;
/**
* A subclass of Shader that draws a sweep gradient around a center point.
*
* @param cx The x-coordinate of the center
* @param cy The y-coordinate of the center
* @param colors The colors to be distributed between around the center.
* There must be at least 2 colors in the array.
* @param positions May be NULL. The relative position of
* each corresponding color in the colors array, beginning
* with 0 and ending with 1.0. If the values are not
* monotonic, the drawing may produce unexpected results.
* If positions is NULL, then the colors are automatically
* spaced evenly.
*/
public SweepGradient(float cx, float cy,
int colors[], float positions[]) {
super(colors, positions);
mPaint = new SweepGradientPaint(cx, cy, mColors, mPositions);
}
/**
* A subclass of Shader that draws a sweep gradient around a center point.
*
* @param cx The x-coordinate of the center
* @param cy The y-coordinate of the center
* @param color0 The color to use at the start of the sweep
* @param color1 The color to use at the end of the sweep
*/
public SweepGradient(float cx, float cy, int color0, int color1) {
this(cx, cy, new int[] { color0, color1}, null /*positions*/);
}
@Override
java.awt.Paint getJavaPaint() {
return mPaint;
}
private static class SweepGradientPaint extends GradientPaint {
private final float mCx;
private final float mCy;
public SweepGradientPaint(float cx, float cy, int[] colors, float[] positions) {
super(colors, positions, null /*tileMode*/);
mCx = cx;
mCy = cy;
}
public java.awt.PaintContext createContext(
java.awt.image.ColorModel colorModel,
java.awt.Rectangle deviceBounds,
java.awt.geom.Rectangle2D userBounds,
java.awt.geom.AffineTransform xform,
java.awt.RenderingHints hints) {
precomputeGradientColors();
return new SweepGradientPaintContext(colorModel);
}
private class SweepGradientPaintContext implements java.awt.PaintContext {
private final java.awt.image.ColorModel mColorModel;
public SweepGradientPaintContext(java.awt.image.ColorModel colorModel) {
mColorModel = colorModel;
}
public void dispose() {
}
public java.awt.image.ColorModel getColorModel() {
return mColorModel;
}
public java.awt.image.Raster getRaster(int x, int y, int w, int h) {
java.awt.image.BufferedImage image = new java.awt.image.BufferedImage(w, h,
java.awt.image.BufferedImage.TYPE_INT_ARGB);
int[] data = new int[w*h];
// compute angle from each point to the center, and figure out the distance from
// it.
int index = 0;
for (int iy = 0 ; iy < h ; iy++) {
for (int ix = 0 ; ix < w ; ix++) {
float dx = x + ix - mCx;
float dy = y + iy - mCy;
float angle;
if (dx == 0) {
angle = (float) (dy < 0 ? 3 * Math.PI / 2 : Math.PI / 2);
} else if (dy == 0) {
angle = (float) (dx < 0 ? Math.PI : 0);
} else {
angle = (float) Math.atan(dy / dx);
if (dx > 0) {
if (dy < 0) {
angle += Math.PI * 2;
}
} else {
angle += Math.PI;
}
}
// convert to 0-1. value and get color
data[index++] = getGradientColor((float) (angle / (2 * Math.PI)));
}
}
image.setRGB(0 /*startX*/, 0 /*startY*/, w, h, data, 0 /*offset*/, w /*scansize*/);
return image.getRaster();
}
}
}
}