| /* |
| * 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(); |
| } |
| |
| } |
| } |
| |
| } |
| |