android 画图之setXfermode

直接看代码把

/* * Copyright (C) 2007 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 com.example.android.apis.graphics;import android.content.Context;import android.graphics.Bitmap;import android.graphics.BitmapShader;import android.graphics.Canvas;import android.graphics.Color;import android.graphics.Matrix;import android.graphics.Paint;import android.graphics.PorterDuff;import android.graphics.PorterDuffXfermode;import android.graphics.RectF;import android.graphics.Shader;import android.graphics.Xfermode;import android.os.Bundle;import android.view.View;public class Xfermodes extends GraphicsActivity {    // create a bitmap with a circle, used for the "dst" image    static Bitmap makeDst(int w, int h) {        Bitmap bm = Bitmap.createBitmap(w, h, Bitmap.Config.ARGB_8888);        Canvas c = new Canvas(bm);        Paint p = new Paint(Paint.ANTI_ALIAS_FLAG);        p.setColor(0xFFFFCC44);        c.drawOval(new RectF(0, 0, w*3/4, h*3/4), p);        return bm;    }    // create a bitmap with a rect, used for the "src" image    static Bitmap makeSrc(int w, int h) {        Bitmap bm = Bitmap.createBitmap(w, h, Bitmap.Config.ARGB_8888);        Canvas c = new Canvas(bm);        Paint p = new Paint(Paint.ANTI_ALIAS_FLAG);        p.setColor(0xFF66AAFF);        c.drawRect(w/3, h/3, w*19/20, h*19/20, p);        return bm;    }    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(new SampleView(this));    }    private static class SampleView extends View {        private static final int W = 64;        private static final int H = 64;        private static final int ROW_MAX = 4;   // number of samples per row        private Bitmap mSrcB;        private Bitmap mDstB;        private Shader mBG;     // background checker-board pattern        private static final Xfermode[] sModes = {            new PorterDuffXfermode(PorterDuff.Mode.CLEAR),            new PorterDuffXfermode(PorterDuff.Mode.SRC),            new PorterDuffXfermode(PorterDuff.Mode.DST),            new PorterDuffXfermode(PorterDuff.Mode.SRC_OVER),            new PorterDuffXfermode(PorterDuff.Mode.DST_OVER),            new PorterDuffXfermode(PorterDuff.Mode.SRC_IN),            new PorterDuffXfermode(PorterDuff.Mode.DST_IN),            new PorterDuffXfermode(PorterDuff.Mode.SRC_OUT),            new PorterDuffXfermode(PorterDuff.Mode.DST_OUT),            new PorterDuffXfermode(PorterDuff.Mode.SRC_ATOP),            new PorterDuffXfermode(PorterDuff.Mode.DST_ATOP),            new PorterDuffXfermode(PorterDuff.Mode.XOR),            new PorterDuffXfermode(PorterDuff.Mode.DARKEN),            new PorterDuffXfermode(PorterDuff.Mode.LIGHTEN),            new PorterDuffXfermode(PorterDuff.Mode.MULTIPLY),            new PorterDuffXfermode(PorterDuff.Mode.SCREEN)        };        private static final String[] sLabels = {            "Clear", "Src", "Dst", "SrcOver",            "DstOver", "SrcIn", "DstIn", "SrcOut",            "DstOut", "SrcATop", "DstATop", "Xor",            "Darken", "Lighten", "Multiply", "Screen"        };        public SampleView(Context context) {            super(context);            mSrcB = makeSrc(W, H);            mDstB = makeDst(W, H);            // make a ckeckerboard pattern            Bitmap bm = Bitmap.createBitmap(new int[] { 0xFFFFFFFF, 0xFFCCCCCC,                                            0xFFCCCCCC, 0xFFFFFFFF }, 2, 2,                                            Bitmap.Config.RGB_565);            mBG = new BitmapShader(bm,                                   Shader.TileMode.REPEAT,                                   Shader.TileMode.REPEAT);            Matrix m = new Matrix();            m.setScale(6, 6);            mBG.setLocalMatrix(m);        }        @Override protected void onDraw(Canvas canvas) {            canvas.drawColor(Color.WHITE);            Paint labelP = new Paint(Paint.ANTI_ALIAS_FLAG);            labelP.setTextAlign(Paint.Align.CENTER);            Paint paint = new Paint();            paint.setFilterBitmap(false);            canvas.translate(15, 35);            int x = 0;            int y = 0;            for (int i = 0; i < sModes.length; i++) {                // draw the border                paint.setStyle(Paint.Style.STROKE);                paint.setShader(null);                canvas.drawRect(x - 0.5f, y - 0.5f,                                x + W + 0.5f, y + H + 0.5f, paint);                // draw the checker-board pattern                paint.setStyle(Paint.Style.FILL);                paint.setShader(mBG);                canvas.drawRect(x, y, x + W, y + H, paint);                // draw the src/dst example into our offscreen bitmap                int sc = canvas.saveLayer(x, y, x + W, y + H, null,                                          Canvas.MATRIX_SAVE_FLAG |                                          Canvas.CLIP_SAVE_FLAG |                                          Canvas.HAS_ALPHA_LAYER_SAVE_FLAG |                                          Canvas.FULL_COLOR_LAYER_SAVE_FLAG |                                          Canvas.CLIP_TO_LAYER_SAVE_FLAG);                canvas.translate(x, y);                canvas.drawBitmap(mDstB, 0, 0, paint);                paint.setXfermode(sModes[i]);                canvas.drawBitmap(mSrcB, 0, 0, paint);                paint.setXfermode(null);                canvas.restoreToCount(sc);                // draw the label                canvas.drawText(sLabels[i],                                x + W/2, y - labelP.getTextSize()/2, labelP);                x += W + 10;                // wrap around when we've drawn enough for one row                if ((i % ROW_MAX) == ROW_MAX - 1) {                    x = 0;                    y += H + 30;                }            }        }    }}