Android中利用matrix 控製圖片的旋轉、縮放、移動

本文主要講解利用android中Matrix控製圖形的旋轉縮放移動，具體參見一下代碼： 複製代碼 代碼如下:/**
* 使用矩陣控製圖片移動、縮放、旋轉
*/
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; //縮放值
private Point lastPoint ;
private Point prePivot , lastPivot;
private float preDegree , lastDegree ;
private short currentSelectedPointindex; //當前操作點擊點
private Point symmetricPoint = new Point(); //當前操作點對稱點

/**
* 圖片操作類型
*/
public static final int OPER_DEFAULT = -1; //預設
public static final int OPER_TRANSLATE = 0; //移動
public static final int OPER_SCALE = 1; //縮放
public static final int OPER_ROTATE = 2; //旋轉
public static final int OPER_SELECTED = 3; //選擇
public int lastOper = OPER_DEFAULT;

/* 圖片控制點
* 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();
}

/**
* 初始化資料
* @author 張進
*/
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);
}

/**
* 矩陣變換，達到圖形平移的目的
* @author 張進
*/
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;

}

/**
* 判斷點所在的控制點
* @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();//重繪
return true;
}

/**
* 移動
* @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); //設定矩陣

}

/**
* 縮放
* 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);
}

/**
* 旋轉圖片
* 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;
}

/**
* 計算兩點與垂直方向夾角
* @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;
}

/**
* 計算兩個點之間的距離
* @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);//繪製背景,以便測試矩形的映射
canvas.drawBitmap(mainBmp, matrix, paint);//繪製主圖片
drawFrame(canvas);//繪製邊框,以便測試點的映射
drawControlPoints(canvas);//繪製控制點圖片
}

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：