安卓绘图 canvas 绘图 平移缩放

package org.crazyit.image; import android.content.Context; import android.graphics.Bitmap; import android.graphics.Bitmap.Config; import android.graphics.Canvas; import android.graphics.Color; import android.graphics.Matrix; import android.graphics.Paint; import android.graphics.Path; import android.graphics.Rect; import android.util.AttributeSet; import android.view.MotionEvent; import android.view.View; /** * Description: * <br/>网站: <a href="http://www.crazyit.org">疯狂Java联盟</a> * <br/>Copyright (C), 2001-2012, Yeeku.H.Lee * <br/>This program is protected by copyright laws. * <br/>Program Name: * <br/>Date: * @author Yeeku.H.Lee kongyeeku@163.com * @version 1.0 */ public class DrawView extends View { float preX; float preY; private Path path; public Paint paint = null; final int VIEW_WIDTH = 320; final int VIEW_HEIGHT = 480; Paint mPaint=null; float xMove=0; float yMove=0; float fscale=1.0f; public Matrix matrix=new Matrix(); public void MoveXY(float x,float y) { xMove+=x; yMove+=y; invalidate(); } public void MyScale(float much) { fscale*=much; invalidate(); } public DrawView(Context context, AttributeSet set) { super(context, set); mPaint=new Paint(); mPaint.setStyle(Paint.Style.STROKE); //mPaint.setStrokeWidth(1); mPaint.setAntiAlias(true); // 设置取消锯齿效果 } @Override public void onDraw(Canvas canvas) { super.onDraw(canvas); int x0 = getMeasuredWidth()/2; int y0 = getMeasuredHeight()/2; canvas.drawColor(Color.BLACK); mPaint.setColor(Color.WHITE); canvas.drawLine(0, y0, 2*x0, y0, mPaint); canvas.drawLine(x0, 0, x0, 2*y0, mPaint); mPaint.setColor(Color.GREEN); canvas.translate(xMove, yMove); canvas.scale(fscale, fscale, x0+xMove, y0+yMove); DrawSomeThing(canvas,2*x0,2*y0); } private void DrawSomeThing(Canvas canvas,float width,float height) { //画矩形和圆形。 canvas.save(); canvas.translate(width/2, height/2);//原点移动到中间 canvas.scale(width/100, width/100); //缩放 canvas.drawRect(-30, 20, 30, -20, mPaint); //画矩形，长、宽分别为60%和40% canvas.drawCircle(0, 0, 25, mPaint);//画圆形，半径为width的25% canvas.restore(); } }