效果图
cliptest.gif
实现
1.实现裁剪矩形（裁剪矩形可放大缩小、可拖拽移动）
要确定一个矩形我们只需确定矩形的左上角坐标和长宽,因此我们可以定义变量startPoint来确定左上角坐标,width、height分别来确定矩形的宽高
,在放大或缩小的时候我们只需要改变宽高再进行绘制,在移动的时候我们只需改变startPont的x,y再进行绘制便可实现矩形的放大缩小和移动.
在拖拽移动时分2种情况:
1.手指在矩形宽外进行拖拽移动: 在这种情况下startPoint就等于手指当前位置的坐标点
2.手指在矩形宽内进行拖拽移动: 在这种情况下startPoint就应该加或减手指移动的距离
public class ClipView extends ImageView{
private int currentStauts; //是否为拖到状态
private static final int STATUS_INSIDE_DRAG = 1; //矩形宽内拖拽
private static final int STATUS_OUTSIDE_DRAG = 2;//矩形宽外拖拽
private static final int STATUS_ZOOM = 3; //缩放状态
private final int minWidth = 100; //最小宽度
private final int minHeight = 50; //最小高度
private final int maxWidth = 400; //最大宽度
private final int maxHeight = 450; //最大高度
private int width = minWidth;
private int height = minHeight;
private Paint mRectPaint = new Paint(); //矩形画笔
private Paint mCirclePaint = new Paint();
private Point startPoint = new Point(10,10); //起始点
private boolean isInitDrawRect = false; //是否进行绘制矩形
private final int radius = 30; //半径
private final int STROKE_width = 5;
private Point circlePoint = new Point(); //圆心
private int lastX;
private int lastY;
public ClipView(Context context) {
super(context);
init();
}
public ClipView(Context context, AttributeSet attrs) {
super(context, attrs);
init();
}
public ClipView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
init();
}
private void init() {
mRectPaint.setColor(Color.RED);
mRectPaint.setAntiAlias(true);
mRectPaint.setStyle(Paint.Style.STROKE);
mRectPaint.setStrokeWidth(STROKE_width);
mCirclePaint.setColor(Color.BLACK);
mCirclePaint.setAntiAlias(true);
}
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
if (!isInitDrawRect) return;
// canvas.drawColor(0, PorterDuff.Mode.CLEAR);
int left = startPoint.x;
int top = startPoint.y;
if (width < minWidth){
width = minWidth;
}
if (width > maxWidth){
width = maxWidth;
}
if (height < minHeight){
height = minHeight;
}
if (height > maxHeight){
height = maxHeight;
}
int right = startPoint.x + width;
int bottom = startPoint.y + height;
canvas.drawRect(left, top, right, bottom, mRectPaint); //绘制矩形
circlePoint.set(right, bottom);
canvas.drawCircle(right, bottom, radius, mCirclePaint); //绘制矩形右下角的原型
}
@Override
public boolean onTouchEvent(MotionEvent event) {
int x = (int)event.getX();
int y = (int)event.getY();
switch (event.getAction()){
case MotionEvent.ACTION_DOWN:
if (!isInitDrawRect){
isInitDrawRect = true;
startPoint.set(checkBorderX(x), checkBorderY(y));
postInvalidate();
}else {
if (isTouchCircle(x,y)){
currentStauts = STATUS_ZOOM;
}else {
if (!insideRect(x,y)){
currentStauts = STATUS_OUTSIDE_DRAG;
startPoint.set(checkBorderX(x), checkBorderY(y));
postInvalidate();
}else {
currentStauts = STATUS_INSIDE_DRAG;
}
}
}
lastX = x;
lastY = y;
break;
case MotionEvent.ACTION_MOVE:
if (currentStauts == STATUS_OUTSIDE_DRAG){
startPoint.set(checkBorderX(x),checkBorderY(y));
}else if(currentStauts == STATUS_INSIDE_DRAG){
int distanceX = x - lastX;
int distanceY = y - lastY;
if (checkBorderMoveX(distanceX) && checkBorderMoveY(distanceY)){
startPoint.offset(distanceX,distanceY);
}
} else {
int moveDistance = get2PointDistance(lastX,lastY,x,y);
if (y - lastY > 0){
if (checkBorderMoveX(moveDistance) && checkBorderMoveY(moveDistance)){
width += moveDistance;
height += moveDistance;
}
}else {
width -= moveDistance;
height -= moveDistance;
}
}
lastX = x;
lastY = y;
postInvalidate();
break;
case MotionEvent.ACTION_UP:
break;
}
return true;
}
/**
* X-拖拽状态下的边界检查
* @param distanceX
* @return
*/
private boolean checkBorderMoveX(int distanceX){
if (startPoint.x > 0 && startPoint.x + width + distanceX < getMeasuredWidth()){
return true;
}
return false;
}
/**
* Y-拖拽状态下的边界检查
* @param distanceY
* @return
*/
private boolean checkBorderMoveY(int distanceY){
if (startPoint.y > 0 && startPoint.y + height + distanceY < getMeasuredHeight()){
return true;
}
return false;
}
/**
* X-边界检查
* @param x
* @return
*/
private int checkBorderX(int x){
int resultX = 0;
if (x > 0 && (x + width < getMeasuredWidth())){
resultX = x;
}else {
if (x + width > getMeasuredWidth()){
resultX = x - ((x + width) - getMeasuredWidth());
}
if (x < 0){
resultX = 0;
}
}
return resultX;
}
/**
* Y-边界检查
* @param y
* @return
*/
private int checkBorderY(int y){
int resultY = 0;
if (y > 0 && (y + height) < getMeasuredHeight()){
resultY = y;
}else {
if (y + height > getMeasuredHeight()){
resultY = y - ((y + height) - getMeasuredHeight());
}
if (y < 0){
resultY = 0;
}
}
return resultY;
}
/**
* 是否在矩形内
* @return
*/
private boolean insideRect(int x,int y) {
if ((x > startPoint.x && x < startPoint.x + width) && (y > startPoint.y && y < startPoint.y + height)){
return true;
}
return false;
}
/**
* 是否在圆上
* @return
*/
private boolean isTouchCircle(int x,int y){
int distance = get2PointDistance(x,y,circlePoint.x,circlePoint.y);
if (distance <= radius){
return true;
}
return false;
}
/**
* 获取2点之间直线距离
* @param startX
* @param startY
* @param endX
* @param endY
* @return
*/
private int get2PointDistance(int startX,int startY,int endX,int endY){
return (int) Math.sqrt(Math.pow(startX - endX, 2) + Math.pow(startY - endY, 2));
}
....
}
2.根据裁剪矩形对图片进行裁剪
public class ClipView extends ImageView{
...
/**
* 进行裁剪
* @return
*/
public Bitmap clip(){
Drawable drawable = getDrawable();
if (drawable == null || !(drawable instanceof BitmapDrawable)){
return null;
}
Bitmap bitmap = ((BitmapDrawable)drawable).getBitmap();
final float[] matrixValues = new float[9];
getImageMatrix().getValues(matrixValues);
final float scaleX = matrixValues[Matrix.MSCALE_X];
final float scaleY = matrixValues[Matrix.MSCALE_Y];
final float transX = matrixValues[Matrix.MTRANS_X];
final float transY = matrixValues[Matrix.MTRANS_Y];
float bitmapLeft = (transX < 0) ? Math.abs(transX) : 0;
float bitmapTop = (transY < 0) ? Math.abs(transY) : 0;
float clipX = (bitmapLeft + startPoint.x - transX) / scaleX;
float clipY = (bitmapTop + startPoint.y - transY) / scaleY;
float clipWidth = width / scaleX ;
float clipHeight = height / scaleY ;
if (clipX + clipWidth > bitmap.getWidth()){
clipWidth = bitmap.getWidth() - clipX;
}
if (clipY + clipHeight > bitmap.getHeight()){
clipHeight = bitmap.getHeight() - clipY;
}
return Bitmap.createBitmap(bitmap,(int)clipX,(int)clipY,(int)clipWidth,(int)clipHeight);
}
...
}
