Android 圖片截取人物頭像(仿逗拍)

要求

根據給定的頭部模板，截取資源圖。背景圖可支持拖動，縮放，拖動旋轉

分析

定義剪切浮層，實現背景資源圖的操作view

實現

/**
     * 初始化繪制筆
     */
    private void initRectPaint()
    {
        mFloatPaint = new Paint();
        mFloatPaint.setAlpha(mAlpha);
        mFloatPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.XOR));

        mEdgePaint = new Paint();
        mEdgePaint.setColor(Color.parseColor(#ff000000));
        mEdgePaint.setAlpha(mAlpha);
    }


@Override
    public void draw(Canvas canvas)
    {

        /** 繪制周圍的背景色 **/
        drawEdge(canvas);

        /** 繪制中間浮層 **/
        canvas.drawBitmap(mCropDrawable, mFloatRect.left, mFloatRect.top,
                mFloatPaint);

    }

@Override
    protected void onDraw(Canvas canvas)
    {
        canvas.save();
        canvas.drawColor(Color.parseColor(#ff1c1c22));
        canvas.drawBitmap(mBGHeadBitmap, mFloatRect.left, mFloatRect.top, null);
        canvas.drawBitmap(mBGBitmap, mBGgmatrix, null);
        mFloatView.draw(canvas);
        canvas.restore();
    }




//手勢操作


public boolean onTouchEvent(MotionEvent event)
    {
        switch (event.getAction() & MotionEvent.ACTION_MASK)
        {
            case MotionEvent.ACTION_DOWN :
                eventMode = EventMode.DRAG;
                x_down = event.getX();
                y_down = event.getY();
                savedMatrix.set(mBGgmatrix);
                break;
            case MotionEvent.ACTION_POINTER_DOWN :
                eventMode = EventMode.ZOOM;
                oldDist = spacing(event);
                mRotation = rotation(event);
                savedMatrix.set(mBGgmatrix);
                midPoint(midPoint, event);
                break;
            case MotionEvent.ACTION_MOVE :

                if (eventMode == EventMode.DRAG)
                {
                    matrix1.set(savedMatrix);
                    matrix1.postTranslate(event.getX() - x_down, event.getY()
                            - y_down);
                    mBGgmatrix.set(matrix1);
                    invalidate();
                } else if (eventMode == EventMode.ZOOM)
                {

                    float rotation = rotation(event) - mRotation;
                    float newDist = spacing(event);
                    float scale = newDist / oldDist;

                    /** 縮放 **/
                    float values[] = new float[9];

                    {
                        matrix1.set(savedMatrix);
                        matrix1.postScale(scale, scale, midPoint.x, midPoint.y);
                    }

                    /** 旋轉 **/
                    matrix1.postRotate(rotation, midPoint.x, midPoint.y);

                    mBGgmatrix.set(matrix1);

                    invalidate();
                }

                break;
            case MotionEvent.ACTION_UP :
            case MotionEvent.ACTION_POINTER_UP :

                eventMode = EventMode.NONE;
                break;
        }

        return true;
    }

        Bitmap tmpBitmap = Bitmap.createBitmap(mScrrenWidth, mScrrenHeight,
                Config.ARGB_8888); // 背景圖片
        Canvas canvas = new Canvas(tmpBitmap); // 新建畫布
        canvas.drawBitmap(mBGHeadBitmap, mFloatRect.left, mFloatRect.top, null);
        canvas.drawBitmap(mBGBitmap, mBGgmatrix, null); // 畫圖片
        canvas.save(Canvas.ALL_SAVE_FLAG); // 保存畫布
        canvas.restore();

        Bitmap ret = Bitmap.createBitmap(tmpBitmap, mFloatRect.left,
                mFloatRect.top, mFloatRect.width(), mFloatRect.height(), null,
                true);
        tmpBitmap.recycle();
        tmpBitmap = null;

        Bitmap newRet = Bitmap.createBitmap(mFloatRect.width(),
                mFloatRect.height(), Config.ARGB_8888);

        Canvas canvasHead = new Canvas(newRet);
        canvasHead.drawBitmap(ret, 0, 0, null);
        Paint paintHead = new Paint();
        paintHead.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.DST_OUT));
        Bitmap crop = BitmapFactory.decodeResource(mContext.getResources(),
                R.drawable.headmask);

        canvasHead.drawBitmap(crop, 0, 0, paintHead);

        return newRet;

效果