图形与动画在Android中的实现

时间：2014-05-12 20:14:55 收藏：0 阅读：402
public class MyView extends 
View{
    Bitmap myBitmap;
    Paint paint;
    public 
MyView(Context context, AttributeSet attrs) {
        super(context, attrs);
        this.initBitmap();
    }
    public 
void initBitmap(){
        paint = new 
Paint();
        myBitmap = BitmapFactory.decodeResource(getResources(), R.drawable.img);
         
    }
    @Override
    protected 
void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        paint.setAntiAlias(true);
        paint.setColor(Color.WHITE);
        paint.setTextSize(15);
        canvas.drawBitmap(myBitmap, 10,  10, paint);
         
        //Saves the current matrix and clip onto a private stack. 
        //Subsequent calls to translate,scale,rotate,skew,concat or clipRect,clipPath 
        //will all operate as usual, but when the balancing call to restore() is made, 
        //those calls will be forgotten, and the settings that existed before the save() will be reinstated(恢复).
        //Returns:
        //The value to pass to restoreToCount() to balance this save()
        int 
i = canvas.save();  
        System.out.println("current count -- > " 
+ i);
         
        Matrix m1 = new 
Matrix();
        m1.setTranslate(500, 10);
        Matrix m2 = new 
Matrix();
        m2.setRotate(15);
        Matrix m3 = new 
Matrix();
        m3.setConcat(m1, m2);
        m1.setScale(0.8f, 0.8f);
        m2.setConcat(m3, m1);
        canvas.drawBitmap(myBitmap, m2, paint);
         
        //This call balances a previous call to save(), and is used to 
        //remove all modifications to the matrix/clip state since the last save call. 
        //It is an error to call restore() more times than save() was called.
        canvas.restore();
        int 
j = canvas.save();
        System.out.println("current count -- > " 
+ j);
        paint.setAlpha(180);
        m1.setTranslate(200, 100);
        m2.setScale(1.3f, 1.3f);
        m2.setConcat(m1, m2);
        canvas.drawBitmap(myBitmap, m3, paint);
         
        //Restores the paint to its default settings. 
        paint.reset();
        canvas.restore();
        paint.setTextSize(40);
        paint.setColor(Color.BLUE);
        canvas.drawText("图片的宽度:" 
+ myBitmap.getWidth(), 150, 220, paint);
        canvas.drawText("图片的高度:" 
+ myBitmap.getHeight(), 150, 300, paint);
        paint.reset();
         
    }
 
}
效果图：
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