Android中利用matrix 控制图片的旋转、缩放、移动

本文主要讲解利用android中Matrix控制图形的旋转缩放移动，具体参见一下代码：


代码如下:

/**
 * 使用矩阵控制图片移动、缩放、旋转
 */ 
public class CommonImgEffectView extends View {

private Context context ; 
    private Bitmap mainBmp , controlBmp ; 
    private int mainBmpWidth , mainBmpHeight , controlBmpWidth , controlBmpHeight ; 
    private Matrix matrix ;  
    private float [] srcPs , dstPs ; 
    private RectF srcRect , dstRect ; 
    private Paint paint ,paintRect , paintFrame; 
    private float deltaX = 0, deltaY = 0; //位移值 
    private float scaleValue = 1; //缩放值 
    private Point lastPoint ; 
    private Point prePivot , lastPivot; 
    private float preDegree , lastDegree ; 
    private short currentSelectedPointindex;        //当前操作点击点 
    private Point symmetricPoint  = new Point();    //当前操作点对称点

/**
     * 图片操作类型
     */ 
    public static final int OPER_DEFAULT = -1;      //默认 
    public static final int OPER_TRANSLATE = 0;     //移动 
    public static final int OPER_SCALE = 1;         //缩放 
    public static final int OPER_ROTATE = 2;        //旋转 
    public static final int OPER_SELECTED = 3;      //选择 
    public int lastOper = OPER_DEFAULT;

/* 图片控制点
     * 0---1---2
     * |       |
     * 7   8   3
     * |       |
     * 6---5---4 
     */ 
    public static final int CTR_NONE = -1; 
    public static final int CTR_LEFT_TOP = 0; 
    public static final int CTR_MID_TOP = 1; 
    public static final int CTR_RIGHT_TOP = 2; 
    public static final int CTR_RIGHT_MID = 3; 
    public static final int CTR_RIGHT_BOTTOM = 4; 
    public static final int CTR_MID_BOTTOM = 5; 
    public static final int CTR_LEFT_BOTTOM = 6; 
    public static final int CTR_LEFT_MID = 7; 
    public static final int CTR_MID_MID = 8; 
    public int current_ctr = CTR_NONE;

public CommonImgEffectView(Context context){ 
        super(context); 
        this.context = context ; 
    }

public CommonImgEffectView(Context context, AttributeSet attrs) { 
        super(context, attrs); 
        this.context = context ; 
        initData(); 
    }

/**
     * 初始化数据
     * @author 张进
     */ 
    private void initData(){ 
        mainBmp = BitmapFactory.decodeResource(this.context.getResources(), R.drawable.flower); 
        controlBmp = BitmapFactory.decodeResource(this.context.getResources(), R.drawable.control); 
        mainBmpWidth = mainBmp.getWidth(); 
        mainBmpHeight = mainBmp.getHeight(); 
        controlBmpWidth = controlBmp.getWidth(); 
        controlBmpHeight = controlBmp.getHeight();

srcPs = new float[]{ 
                                0,0,  
                                mainBmpWidth/2,0,  
                                mainBmpWidth,0,  
                                mainBmpWidth,mainBmpHeight/2, 
                                mainBmpWidth,mainBmpHeight,  
                                mainBmpWidth/2,mainBmpHeight,  
                                0,mainBmpHeight,  
                                0,mainBmpHeight/2,  
                                mainBmpWidth/2,mainBmpHeight/2 
                            }; 
        dstPs = srcPs.clone(); 
        srcRect = new RectF(0, 0, mainBmpWidth, mainBmpHeight); 
        dstRect = new RectF();

matrix = new Matrix();

prePivot = new Point(mainBmpWidth/2, mainBmpHeight/2); 
        lastPivot = new Point(mainBmpWidth/2, mainBmpHeight/2);

lastPoint = new Point(0,0);

paint = new Paint();

paintRect = new Paint(); 
        paintRect.setColor(Color.RED); 
        paintRect.setAlpha(100); 
        paintRect.setAntiAlias(true);

paintFrame = new Paint(); 
        paintFrame.setColor(Color.GREEN); 
        paintFrame.setAntiAlias(true);

setMatrix(OPER_DEFAULT); 
    }

/**
     * 矩阵变换，达到图形平移的目的
     * @author 张进
     */ 
    private void setMatrix(int operationType){ 
        switch (operationType) { 
        case OPER_TRANSLATE: 
            matrix.postTranslate(deltaX , deltaY); 
            break; 
        case OPER_SCALE: 
            matrix.postScale(scaleValue, scaleValue, symmetricPoint.x, symmetricPoint.y); 
            break; 
        case OPER_ROTATE: 
            matrix.postRotate(preDegree - lastDegree, dstPs[CTR_MID_MID * 2], dstPs[CTR_MID_MID * 2 + 1]); 
            break; 
        }

matrix.mapPoints(dstPs, srcPs); 
        matrix.mapRect(dstRect, srcRect); 
    }

private boolean isOnPic(int x , int y){ 
        if(dstRect.contains(x, y)){ 
            return true; 
        }else  
            return false; 
    }

private int getOperationType(MotionEvent event){

int evX = (int)event.getX(); 
        int evY = (int)event.getY(); 
        int curOper = lastOper; 
        switch(event.getAction()) { 
            case MotionEvent.ACTION_DOWN: 
                current_ctr = isOnCP(evX, evY); 
                Log.i("img", "current_ctr is "+current_ctr); 
                if(current_ctr != CTR_NONE || isOnPic(evX, evY)){ 
                    curOper = OPER_SELECTED; 
                } 
                break; 
            case MotionEvent.ACTION_MOVE: 
                    if(current_ctr > CTR_NONE && current_ctr < CTR_MID_MID ){ 
                        curOper = OPER_SCALE; 
                    }else if(current_ctr == CTR_MID_MID ){ 
                        curOper = OPER_ROTATE; 
                    }else if(lastOper == OPER_SELECTED){ 
                        curOper = OPER_TRANSLATE; 
                    } 
                break; 
            case MotionEvent.ACTION_UP: 
                curOper = OPER_SELECTED; 
                break; 
            default: 
                break; 
        } 
        Log.d("img", "curOper is "+curOper); 
        return curOper;

}

/**
     * 判断点所在的控制点
     * @param evX
     * @param evY
     * @return
     */  
    private int isOnCP(int evx, int evy) { 
        Rect rect = new Rect(evx-controlBmpWidth/2,evy-controlBmpHeight/2,evx+controlBmpWidth/2,evy+controlBmpHeight/2); 
        int res = 0 ; 
        for (int i = 0; i < dstPs.length; i+=2) { 
            if(rect.contains((int)dstPs[i], (int)dstPs[i+1])){ 
                return res ; 
            } 
            ++res ;  
        } 
        return CTR_NONE; 
    }

@Override 
    public boolean dispatchTouchEvent(MotionEvent event) { 
        int evX = (int)event.getX(); 
        int evY = (int)event.getY();

int operType = OPER_DEFAULT; 
        operType = getOperationType(event);

switch (operType) { 
        case OPER_TRANSLATE: 
            translate(evX, evY); 
            break; 
        case OPER_SCALE: 
            scale(event); 
            break; 
        case OPER_ROTATE: 
            rotate(event); 
            break; 
        }

lastPoint.x = evX; 
        lastPoint.y = evY;

lastOper = operType; 
        invalidate();//重绘 
        return true; 
    }

/**
     * 移动
     * @param evx
     * @param evy
     * @author zhang_jin1
     */ 
    private void translate(int evx , int evy){

prePivot.x += evx - lastPoint.x; 
        prePivot.y += evy -lastPoint.y;

deltaX = prePivot.x - lastPivot.x; 
        deltaY = prePivot.y - lastPivot.y;

lastPivot.x = prePivot.x; 
        lastPivot.y = prePivot.y;

setMatrix(OPER_TRANSLATE); //设置矩阵

}

/**
     * 缩放
     * 0---1---2
     * |       |
     * 7   8   3
     * |       |
     * 6---5---4
     * @param evX
     * @param evY
     */ 
    private void scale(MotionEvent event) {

int pointIndex = current_ctr*2 ;

float px = dstPs[pointIndex]; 
        float py = dstPs[pointIndex+1];

float evx = event.getX(); 
        float evy = event.getY();

float oppositeX = 0 ; 
        float oppositeY = 0 ; 
        if(current_ctr<4 && current_ctr >= 0){ 
             oppositeX = dstPs[pointIndex+8]; 
             oppositeY = dstPs[pointIndex+9]; 
        }else if(current_ctr >= 4){ 
             oppositeX = dstPs[pointIndex-8]; 
             oppositeY = dstPs[pointIndex-7]; 
        } 
        float temp1 = getDistanceOfTwoPoints(px,py,oppositeX,oppositeY); 
        float temp2 = getDistanceOfTwoPoints(evx,evy,oppositeX,oppositeY);

this.scaleValue = temp2 / temp1 ; 
        symmetricPoint.x = (int) oppositeX; 
        symmetricPoint.y = (int)oppositeY;

Log.i("img", "scaleValue is "+scaleValue); 
        setMatrix(OPER_SCALE); 
    }

/**
     * 旋转图片
     * 0---1---2
     * |       |
     * 7   8   3
     * |       |
     * 6---5---4 
     * @param evX
     * @param evY
     */ 
    private void rotate(MotionEvent event) {

if(event.getPointerCount() == 2){ 
            preDegree = computeDegree(new Point((int)event.getX(0), (int)event.getY(0)), new Point((int)event.getX(1), (int)event.getY(1))); 
        }else{ 
            preDegree = computeDegree(new Point((int)event.getX(), (int)event.getY()), new Point((int)dstPs[16], (int)dstPs[17])); 
        } 
        setMatrix(OPER_ROTATE); 
        lastDegree = preDegree; 
    }

/**
     * 计算两点与垂直方向夹角
     * @param p1
     * @param p2
     * @return
     */ 
    public float computeDegree(Point p1, Point p2){ 
        float tran_x = p1.x - p2.x; 
        float tran_y = p1.y - p2.y; 
        float degree = 0.0f; 
        float angle = (float)(Math.asin(tran_x/Math.sqrt(tran_x*tran_x + tran_y* tran_y))*180/Math.PI); 
        if(!Float.isNaN(angle)){ 
            if(tran_x >= 0 && tran_y <= 0){//第一象限 
                degree = angle; 
            }else if(tran_x <= 0 && tran_y <= 0){//第二象限 
                degree = angle; 
            }else if(tran_x <= 0 && tran_y >= 0){//第三象限 
                degree = -180 - angle; 
            }else if(tran_x >= 0 && tran_y >= 0){//第四象限 
                degree = 180 - angle; 
            } 
        } 
        return degree; 
    }

/**
     * 计算两个点之间的距离
     * @param p1
     * @param p2
     * @return
     */ 
    private float getDistanceOfTwoPoints(Point p1, Point p2){ 
        return (float)(Math.sqrt((p1.x - p2.x) * (p1.x - p2.x) + (p1.y - p2.y) * (p1.y - p2.y))); 
    }

private float getDistanceOfTwoPoints(float x1,float y1,float x2,float y2){ 
        return (float)(Math.sqrt((x1 - x2) * (x1 - x2) + (y1 - y2) * (y1 - y2))); 
    }

@Override 
    public void onDraw(Canvas canvas){ 
        drawBackground(canvas);//绘制背景,以便测试矩形的映射 
        canvas.drawBitmap(mainBmp, matrix, paint);//绘制主图片 
        drawFrame(canvas);//绘制边框,以便测试点的映射 
        drawControlPoints(canvas);//绘制控制点图片 
    }

private void drawBackground(Canvas canvas){ 
        canvas.drawRect(dstRect, paintRect); 
    }

private void drawFrame(Canvas canvas){ 
        canvas.drawLine(dstPs[0], dstPs[1], dstPs[4], dstPs[5], paintFrame); 
        canvas.drawLine(dstPs[4], dstPs[5], dstPs[8], dstPs[9], paintFrame); 
        canvas.drawLine(dstPs[8], dstPs[9], dstPs[12], dstPs[13], paintFrame); 
        canvas.drawLine(dstPs[0], dstPs[1], dstPs[12], dstPs[13], paintFrame); 
        canvas.drawPoint(dstPs[16], dstPs[17], paintFrame); 
    }

private void drawControlPoints(Canvas canvas){

for (int i = 0; i < dstPs.length; i+=2) { 
            canvas.drawBitmap(controlBmp, dstPs[i]-controlBmpWidth/2, dstPs[i+1]-controlBmpHeight/2, paint); 
        }

}

}

Demo效果：