1 /* 2 * Copyright (C) 2007 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package com.example.android.apis.graphics; 18 19 import com.example.android.apis.R; 20 21 import android.content.Context; 22 import android.graphics.*; 23 import android.os.Bundle; 24 import android.view.*; 25 26 import java.io.InputStream; 27 28 public class AlphaBitmap extends GraphicsActivity { 29 30 @Override 31 protected void onCreate(Bundle savedInstanceState) { 32 super.onCreate(savedInstanceState); 33 setContentView(new SampleView(this)); 34 } 35 36 private static class SampleView extends View { 37 private Bitmap mBitmap; 38 private Bitmap mBitmap2; 39 private Bitmap mBitmap3; 40 private Shader mShader; 41 42 private static void drawIntoBitmap(Bitmap bm) { 43 float x = bm.getWidth(); 44 float y = bm.getHeight(); 45 Canvas c = new Canvas(bm); 46 Paint p = new Paint(); 47 p.setAntiAlias(true); 48 49 p.setAlpha(0x80); 50 c.drawCircle(x/2, y/2, x/2, p); 51 52 p.setAlpha(0x30); 53 p.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC)); 54 p.setTextSize(60); 55 p.setTextAlign(Paint.Align.CENTER); 56 Paint.FontMetrics fm = p.getFontMetrics(); 57 c.drawText("Alpha", x/2, (y-fm.ascent)/2, p); 58 } 59 60 public SampleView(Context context) { 61 super(context); 62 setFocusable(true); 63 64 InputStream is = context.getResources().openRawResource(R.drawable.app_sample_code); 65 mBitmap = BitmapFactory.decodeStream(is); 66 mBitmap2 = mBitmap.extractAlpha(); 67 mBitmap3 = Bitmap.createBitmap(200, 200, Bitmap.Config.ALPHA_8); 68 drawIntoBitmap(mBitmap3); 69 70 mShader = new LinearGradient(0, 0, 100, 70, new int[] { 71 Color.RED, Color.GREEN, Color.BLUE }, 72 null, Shader.TileMode.MIRROR); 73 } 74 75 @Override protected void onDraw(Canvas canvas) { 76 canvas.drawColor(Color.WHITE); 77 78 Paint p = new Paint(); 79 float y = 10; 80 81 p.setColor(Color.RED); 82 canvas.drawBitmap(mBitmap, 10, y, p); 83 y += mBitmap.getHeight() + 10; 84 canvas.drawBitmap(mBitmap2, 10, y, p); 85 y += mBitmap2.getHeight() + 10; 86 p.setShader(mShader); 87 canvas.drawBitmap(mBitmap3, 10, y, p); 88 } 89 } 90 } 91 92
