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 // Need the following import to get access to the app resources, since this 20 // class is in a sub-package. 21 //import com.example.android.apis.R; 22 23 import android.app.Activity; 24 import android.content.Context; 25 import android.graphics.*; 26 import android.os.Bundle; 27 import android.view.View; 28 29 public class PolyToPoly extends GraphicsActivity { 30 31 @Override onCreate(Bundle savedInstanceState)32 protected void onCreate(Bundle savedInstanceState) { 33 super.onCreate(savedInstanceState); 34 setContentView(new SampleView(this)); 35 } 36 37 private static class SampleView extends View { 38 private Paint mPaint = new Paint(Paint.ANTI_ALIAS_FLAG); 39 private Matrix mMatrix = new Matrix(); 40 private Paint.FontMetrics mFontMetrics; 41 doDraw(Canvas canvas, float src[], float dst[])42 private void doDraw(Canvas canvas, float src[], float dst[]) { 43 canvas.save(); 44 mMatrix.setPolyToPoly(src, 0, dst, 0, src.length >> 1); 45 canvas.concat(mMatrix); 46 47 mPaint.setColor(Color.GRAY); 48 mPaint.setStyle(Paint.Style.STROKE); 49 canvas.drawRect(0, 0, 64, 64, mPaint); 50 canvas.drawLine(0, 0, 64, 64, mPaint); 51 canvas.drawLine(0, 64, 64, 0, mPaint); 52 53 mPaint.setColor(Color.RED); 54 mPaint.setStyle(Paint.Style.FILL); 55 // how to draw the text center on our square 56 // centering in X is easy... use alignment (and X at midpoint) 57 float x = 64/2; 58 // centering in Y, we need to measure ascent/descent first 59 float y = 64/2 - (mFontMetrics.ascent + mFontMetrics.descent)/2; 60 canvas.drawText(src.length/2 + "", x, y, mPaint); 61 62 canvas.restore(); 63 } 64 SampleView(Context context)65 public SampleView(Context context) { 66 super(context); 67 68 // for when the style is STROKE 69 mPaint.setStrokeWidth(4); 70 // for when we draw text 71 mPaint.setTextSize(40); 72 mPaint.setTextAlign(Paint.Align.CENTER); 73 mFontMetrics = mPaint.getFontMetrics(); 74 } 75 onDraw(Canvas canvas)76 @Override protected void onDraw(Canvas canvas) { 77 Paint paint = mPaint; 78 79 canvas.drawColor(Color.WHITE); 80 81 canvas.save(); 82 canvas.translate(10, 10); 83 // translate (1 point) 84 doDraw(canvas, new float[] { 0, 0 }, new float[] { 5, 5 }); 85 canvas.restore(); 86 87 canvas.save(); 88 canvas.translate(160, 10); 89 // rotate/uniform-scale (2 points) 90 doDraw(canvas, new float[] { 32, 32, 64, 32 }, 91 new float[] { 32, 32, 64, 48 }); 92 canvas.restore(); 93 94 canvas.save(); 95 canvas.translate(10, 110); 96 // rotate/skew (3 points) 97 doDraw(canvas, new float[] { 0, 0, 64, 0, 0, 64 }, 98 new float[] { 0, 0, 96, 0, 24, 64 }); 99 canvas.restore(); 100 101 canvas.save(); 102 canvas.translate(160, 110); 103 // perspective (4 points) 104 doDraw(canvas, new float[] { 0, 0, 64, 0, 64, 64, 0, 64 }, 105 new float[] { 0, 0, 96, 0, 64, 96, 0, 64 }); 106 canvas.restore(); 107 } 108 } 109 } 110 111