android vanvas scale translate 的理解

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package com.example.canvasdemo;

import android.app.Activity;
import android.os.Bundle;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.drawable.ColorDrawable;
import android.graphics.drawable.Drawable;
import android.view.View;
import java.util.Random;
import android.util.Log;
public class CanvasDemoActivity extends Activity{
  private static final String TAG = "CanvasDemoActivity";
  Drawable d;
      @Override
      public void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         d = new ColorDrawable(Color.RED);
t = " + canvas.getHeight());            canvas
         setContentView(new CanvasView(this));
      }
      class CanvasView extends View {
         Random random = new Random();
      
         public CanvasView(Context context) {
            super(context);
         }
         @Override
         protected void onDraw(Canvas canvas) {
            //canvas.drawRGB(random.nextInt(256), random.nextInt(256), random.nextInt(256));
            //canvas.drawRGB(1, 1, 1);
            Log.d(TAG,"onDraw canvas.width = " + canvas.getWidth() + " canvas.height = " + canvas.getHeight());
          
           canvas.save(); 
           canvas.translate(500,500);

            canvas.scale(0.1f, 0.1f);
            //canvas.translate(500, 500);
            Paint paint = new Paint();
            paint.setColor(Color.GREEN);
            canvas.drawCircle(0, 0, 500, paint);
            //d.draw(canvas);
            canvas.restore();
            //canvas.drawColor(Color.BLUE);
         }
      }
}

1、原图：没有scale translate

1、canvas.scale(0.1f,0.1f);

canvas.translate(500,500);

canvas先压缩为原来的0.1倍,然后原点平移500个px，但是此时的500 在屏幕上显示只有 500 * 0.1 = 50px，也及时其平移是相对于canvas 本身的，其原点位置相对于屏幕为50px 见图1

2、canvas.translate(500,500);

canvas.scale(0.1f,0.1f);

canvas原点先平移到（500,500），然后再压缩为原来的0.1倍，其原点位置相对于屏幕为（500,500）见图2