Android实现图片单点旋转缩放保存-仿百度魔图

当拖动右下角区域时执行围绕图像中心旋转，缩放的操作，拖动其他区域执行平移。

采用Matrix变换实现，最后可以保存在文件。

效果如下：

 

View的代码如下：

package com.hu.imagepro;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.graphics.Paint.Style;
import android.graphics.PaintFlagsDrawFilter;
import android.graphics.PointF;
import android.graphics.RectF;
import android.os.Environment;
import android.view.MotionEvent;
import android.view.View;

import com.example.imageprocess.R;

public class ProcessView extends View{
	
	Context context = null;
	Matrix matrixPaint = null;
	Bitmap bmpMotion = null;
	Bitmap bmpRotate = null;
	Bitmap bmpBack = null;
	
	RectF rectMotionPre = null;
	RectF rectMotion = null;
	RectF rectRotateMark = null;
	RectF rectRotatePre = null;
	RectF rectRotate = null;
	
	Paint paint = null;
	PaintFlagsDrawFilter paintFilter = null;
	ViewStatus status = ViewStatus.STATUS_MOVE;
	
	PointF pointMotionMid = null;
	PointF prePoint = null;
	PointF curPoint = null;
	PointF rotateCenterP = null;
	
	String savePath = null;
	
	enum ViewStatus{
		STATUS_ROTATE,
		STATUS_MOVE,
	}

	public ProcessView(Context context) {
		super(context);
		// TODO Auto-generated constructor stub
		this.context = context;
		//创建变幻图形用的Matrix
		matrixPaint = new Matrix();
		//创建画笔
		paint = new Paint();
		//画笔抗锯齿
		paint.setAntiAlias(true);
		paint.setColor(Color.BLUE);
		//设置画笔绘制空心图形
		paint.setStyle(Style.STROKE);
		try {
			//加载相应的图片资源
			bmpMotion = BitmapFactory.decodeStream(context.getAssets().open("wenzi_14.png"));
			bmpBack = BitmapFactory.decodeStream(context.getAssets().open("background.png"));
			bmpRotate = BitmapFactory.decodeResource(getResources(), R.drawable.btn_rotate_a);
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		//记录表情最初的矩形
		rectMotionPre = new RectF(0, 0, bmpMotion.getWidth(), bmpMotion.getHeight());
		//记录表情当前的矩形
		rectMotion = new RectF(rectMotionPre);
		//标记旋转图标位置的矩形
		rectRotateMark = new RectF(rectMotion.right - bmpRotate.getWidth() / 2,
				rectMotion.bottom - bmpRotate.getHeight() / 2,
				rectMotion.right + bmpRotate.getWidth() / 2,
				rectMotion.bottom + bmpRotate.getHeight() / 2);
		//记录旋转图标矩形最初的矩形
		rectRotatePre = new RectF(rectRotateMark);
		//记录当前旋转图标位置的矩形
		rectRotate = new RectF(rectRotateMark);
		//记录表情矩形的中点
		pointMotionMid = new PointF(bmpMotion.getWidth() / 2, bmpMotion.getHeight() / 2);
		//记录上次动作的坐标
		prePoint = new PointF();
		//记录当前动作的坐标
		curPoint = new PointF();
		//记录旋转图标中点
		rotateCenterP = new PointF(rectMotion.right, rectMotion.bottom);
		//画布参数
		paintFilter = new PaintFlagsDrawFilter(0, Paint.ANTI_ALIAS_FLAG|Paint.FILTER_BITMAP_FLAG);
		
		savePath = Environment.getExternalStorageDirectory().getAbsolutePath() + File.separator + "test123.png";
	}
	
	@Override
	protected void onDraw(Canvas canvas) {
		// TODO Auto-generated method stub
		canvas.setDrawFilter(paintFilter);
		canvas.drawBitmap(bmpBack, 0, 0, paint);
		canvas.drawBitmap(bmpMotion, matrixPaint, null);
		canvas.drawBitmap(bmpRotate, null, rectRotate, null);
//		canvas.drawRect(rectPaint, paint);
//		canvas.drawRect(rectRotate, paint);
//		canvas.drawCircle(picMidPoint.x, picMidPoint.y, 5, paint);
		super.onDraw(canvas);
	}
	
	@Override
	public boolean onTouchEvent(MotionEvent event) {
		// TODO Auto-generated method stub
		float x = event.getX();
		float y = event.getY();
		
		switch (event.getAction()) {
		//手指按下的时候
		case MotionEvent.ACTION_DOWN:
			prePoint.x = x;
			prePoint.y = y;
			//按到了旋转图标上
			if(isInRect(x, y, rectRotate)){
				status = ViewStatus.STATUS_ROTATE;
			}else{
				status = ViewStatus.STATUS_MOVE;
			}
			break;
		case MotionEvent.ACTION_UP:
			if(status == ViewStatus.STATUS_ROTATE){
				saveBitmap();
			}
			break;
		case MotionEvent.ACTION_MOVE:
			curPoint.x = x;
			curPoint.y = y;
			if(status == ViewStatus.STATUS_ROTATE){
				rectRotateMark.set(x - bmpRotate.getWidth() / 2,
						y - bmpRotate.getHeight() / 2,
						x + bmpRotate.getWidth() / 2,
						y + bmpRotate.getHeight() / 2);
				//获取旋转的角度
				float de = getPointsDegree(prePoint, pointMotionMid, curPoint);
				//获取缩放的比例
				float re = getPointsDistance(pointMotionMid, curPoint) / getPointsDistance(pointMotionMid, prePoint);
				if(re > 0.0001){
					//对Matrix进行缩放
					matrixPaint.postScale(re, re, pointMotionMid.x, pointMotionMid.y);
				}
				if(de > 0.0001 || de < -0.0001){
					//对Matrix进行旋转
					matrixPaint.postRotate(de, pointMotionMid.x, pointMotionMid.y);
				}
			}else if(status == ViewStatus.STATUS_MOVE){
				//对Matrix进行移位
				matrixPaint.postTranslate(x - prePoint.x, y - prePoint.y);
			}
			prePoint.x = x;
			prePoint.y = y;
			//将矩阵map到表情矩形上
			matrixPaint.mapRect(rectMotion, rectMotionPre);
			matrixPaint.mapRect(rectRotateMark, rectRotatePre);
			getRectCenter(rectRotateMark, rotateCenterP);
			getRectCenter(rectMotion, pointMotionMid);
			rectRotate.set(rotateCenterP.x - bmpRotate.getWidth() / 2, 
					rotateCenterP.y - bmpRotate.getHeight() / 2,
					rotateCenterP.x + bmpRotate.getWidth() / 2, 
					rotateCenterP.y + bmpRotate.getHeight() / 2);
			postInvalidate();
			break;
		default:
			break;
		}
		return true;
	}
	
	/**
	 * 将当前表情合并到背景并保存
	 */
	private void saveBitmap() {
		File f = new File(savePath);
		//使用背景图的宽高创建一张bitmap
		Bitmap bmpSave = Bitmap.createBitmap(bmpBack.getWidth(), bmpBack.getHeight(), Bitmap.Config.ARGB_8888);
		//创建canvas
		Canvas canvas = new Canvas(bmpSave);
		//将背景图和表情画在bitmap上
		canvas.drawBitmap(bmpBack, 0, 0, paint);
		canvas.drawBitmap(bmpMotion, matrixPaint, paint);
		//保存bitmap
//		canvas.save(Canvas.ALL_SAVE_FLAG); 
//		canvas.restore(); 
		try{
			FileOutputStream out = new FileOutputStream(f);
			bmpSave.compress(Bitmap.CompressFormat.PNG, 100, out);
			out.flush();
			out.close();
		} catch (FileNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		bmpBack.recycle();
		bmpBack = bmpSave;
		//重置Matrix
		matrixPaint.reset();
		//充值旋转图标
		rectRotate.set(rectRotatePre);
	}
	
	//根据矩形获取中心点
	private void getRectCenter(RectF rect, PointF p){
		p.x = rect.left + (rect.right - rect.left) / 2;
		p.y = rect.top + (rect.bottom - rect.top) / 2;
	}
	
	//判断点是否在矩形内
	private boolean isInRect(float x, float y, RectF rect){
		boolean ret = false;
		if(x > rect.left && x < rect.right && y > rect.top && y < rect.bottom){
			ret = true;
		}
		return ret;
	}
	
	//求两点间距离
	private float getPointsDistance(PointF p1, PointF p2) {
		float ret = (float) Math.sqrt(Math.abs((p1.x - p2.x) * (p1.x - p2.x)
				+ (p1.y - p2.y) * (p1.y - p2.y)));
		return ret;
	}
	
	//求角ABC
	private float getPointsDegree(PointF a, PointF b, PointF c){
		if(Math.abs(a.x - c.x) < 2 && Math.abs(a.y - c.y) < 2){
			return 0.0f;
		}
		float ret = (float) (  Math.toDegrees(Math.atan2(c.y - b.y, c.x - b.x) 
				- Math.atan2(a.y - b.y, a.x - b.x)));
		return ret;
	}

}

 

完