Android自定义多点触摸图片缩放控件

package com.yazuo.zoomimagedemo; import java.util.Observable; import java.util.Observer; import android.content.Context; import android.graphics.Bitmap; import android.graphics.Canvas; import android.graphics.Paint; import android.graphics.Rect; import android.util.AttributeSet; import android.util.Log; import android.view.MotionEvent; import android.view.View; public class ZoomImageView extends View implements Observer{ /** Paint object used when drawing bitmap. */ private final Paint mPaint = new Paint(Paint.FILTER_BITMAP_FLAG); /** Rectangle used (and re-used) for cropping source image. */ private final Rect mRectSrc = new Rect(); /** Rectangle used (and re-used) for specifying drawing area on canvas. */ private final Rect mRectDst = new Rect(); /** Object holding aspect quotient */ private final AspectQuotient mAspectQuotient = new AspectQuotient(); /** The bitmap that we're zooming in, and drawing on the screen. */ private Bitmap mBitmap; /** State of the zoom. */ private ZoomState mState; private BasicZoomControl mZoomControl; private BasicZoomListener mZoomListener; public ZoomImageView(Context context, AttributeSet attrs) { super(context, attrs); mZoomControl = new BasicZoomControl(); mZoomListener = new BasicZoomListener(); mZoomListener.setZoomControl(mZoomControl); setZoomState(mZoomControl.getZoomState()); setOnTouchListener(mZoomListener); mZoomControl.setAspectQuotient(getAspectQuotient()); } public void zoomImage(float f, float x, float y) { mZoomControl.zoom(f, x, y); } public void setImage(Bitmap bitmap) { mBitmap = bitmap; mAspectQuotient.updateAspectQuotient(getWidth(), getHeight(), mBitmap.getWidth(), mBitmap .getHeight()); mAspectQuotient.notifyObservers(); invalidate(); } private void setZoomState(ZoomState state) { if (mState != null) { mState.deleteObserver(this); } mState = state; mState.addObserver(this); invalidate(); } private AspectQuotient getAspectQuotient() { return mAspectQuotient; } @Override protected void onDraw(Canvas canvas) { if (mBitmap != null && mState != null) { Log.d("ZoomImageView", "OnDraw"); final float aspectQuotient = mAspectQuotient.get(); final int viewWidth = getWidth(); final int viewHeight = getHeight(); final int bitmapWidth = mBitmap.getWidth(); final int bitmapHeight = mBitmap.getHeight(); Log.d("ZoomImageView", "viewWidth = " + viewWidth); Log.d("ZoomImageView", "viewHeight = " + viewHeight); Log.d("ZoomImageView", "bitmapWidth = " + bitmapWidth); Log.d("ZoomImageView", "bitmapHeight = " + bitmapHeight); final float panX = mState.getPanX(); final float panY = mState.getPanY(); final float zoomX = mState.getZoomX(aspectQuotient) * viewWidth / bitmapWidth; final float zoomY = mState.getZoomY(aspectQuotient) * viewHeight / bitmapHeight; // Setup source and destination rectangles mRectSrc.left = (int)(panX * bitmapWidth - viewWidth / (zoomX * 2)); mRectSrc.top = (int)(panY * bitmapHeight - viewHeight / (zoomY * 2)); mRectSrc.right = (int)(mRectSrc.left + viewWidth / zoomX); mRectSrc.bottom = (int)(mRectSrc.top + viewHeight / zoomY); // mRectDst.left = getLeft(); mRectDst.left = 0; mRectDst.top = 0; // mRectDst.right = getRight(); mRectDst.right = getWidth(); mRectDst.bottom = getHeight(); // Adjust source rectangle so that it fits within the source image. if (mRectSrc.left < 0) { mRectDst.left += -mRectSrc.left * zoomX; mRectSrc.left = 0; } if (mRectSrc.right > bitmapWidth) { mRectDst.right -= (mRectSrc.right - bitmapWidth) * zoomX; mRectSrc.right = bitmapWidth; } if (mRectSrc.top < 0) { mRectDst.top += -mRectSrc.top * zoomY; mRectSrc.top = 0; } if (mRectSrc.bottom > bitmapHeight) { mRectDst.bottom -= (mRectSrc.bottom - bitmapHeight) * zoomY; mRectSrc.bottom = bitmapHeight; } // int width = mRectDst.right - mRectDst.left; // int heigth = mRectDst.bottom - mRectDst.top; mRectDst.left = 0; mRectDst.top = 0; // mRectDst.right = width; // mRectDst.bottom = heigth; mRectDst.right = viewWidth; mRectDst.bottom = viewHeight; Log.d("ZoomImageView", "mRectSrc.top" + mRectSrc.top); Log.d("ZoomImageView", "mRectSrc.bottom" + mRectSrc.bottom); Log.d("ZoomImageView", "mRectSrc.left" + mRectSrc.left); Log.d("ZoomImageView", "mRectSrc.right" + mRectSrc.right); Log.d("ZoomImageView", "mRectDst.top" + mRectDst.top); Log.d("ZoomImageView", "mRectDst.bottom" + mRectDst.bottom); Log.d("ZoomImageView", "mRectDst.left" + mRectDst.left); Log.d("ZoomImageView", "mRectDst.right" + mRectDst.right); canvas.drawBitmap(mBitmap, mRectSrc, mRectDst, mPaint); } } @Override protected void onLayout(boolean changed, int left, int top, int right, int bottom) { super.onLayout(changed, left, top, right, bottom); mAspectQuotient.updateAspectQuotient(right - left, bottom - top, mBitmap.getWidth(), mBitmap.getHeight()); mAspectQuotient.notifyObservers(); } @Override public void update(Observable observable, Object data) { invalidate(); } private class BasicZoomListener implements View.OnTouchListener { /** Zoom control to manipulate */ private BasicZoomControl mZoomControl; private float mFirstX = -1; private float mFirstY = -1; private float mSecondX = -1; private float mSecondY = -1; private int mOldCounts = 0; /** * Sets the zoom control to manipulate * * @param control Zoom control */ public void setZoomControl(BasicZoomControl control) { mZoomControl = control; } public boolean onTouch(View v, MotionEvent event) { switch (event.getAction()) { case MotionEvent.ACTION_DOWN: mOldCounts = 1; mFirstX = event.getX(); mFirstY = event.getY(); break; case MotionEvent.ACTION_MOVE: { float fFirstX = event.getX(); float fFirstY = event.getY(); int nCounts = event.getPointerCount(); if (1 == nCounts) { mOldCounts = 1; float dx = (fFirstX - mFirstX) / v.getWidth(); float dy = (fFirstY - mFirstY) / v.getHeight(); mZoomControl.pan(-dx, -dy); } else if (1 == mOldCounts) { mSecondX = event.getX(event.getPointerId(nCounts - 1)); mSecondY = event.getY(event.getPointerId(nCounts - 1)); mOldCounts = nCounts; } else { float fSecondX = event.getX(event.getPointerId(nCounts - 1)); float fSecondY = event.getY(event.getPointerId(nCounts - 1)); double nLengthOld = getLength(mFirstX, mFirstY, mSecondX, mSecondY); double nLengthNow = getLength(fF