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