BookPageView.java 文件源码

/**
     * 绘制C区域内容
     * @param canvas
     * @param pathA
     */
    private void drawPathCContent(Canvas canvas, Path pathA){
        canvas.save();
        canvas.clipPath(pathA);
        canvas.clipPath(getPathC(), Region.Op.REVERSE_DIFFERENCE);//裁剪出C区域不同于A区域的部分
//        canvas.drawPath(getPathC(),pathCPaint);

        float eh = (float) Math.hypot(f.x - e.x,h.y - f.y);
        float sin0 = (f.x - e.x) / eh;
        float cos0 = (h.y - f.y) / eh;
        //设置翻转和旋转矩阵
        mMatrixArray[0] = -(1-2 * sin0 * sin0);
        mMatrixArray[1] = 2 * sin0 * cos0;
        mMatrixArray[3] = 2 * sin0 * cos0;
        mMatrixArray[4] = 1 - 2 * sin0 * sin0;

        mMatrix.reset();
        mMatrix.setValues(mMatrixArray);//翻转和旋转
        mMatrix.preTranslate(-e.x, -e.y);//沿当前XY轴负方向位移得到 矩形A₃B₃C₃D₃
        mMatrix.postTranslate(e.x, e.y);//沿原XY轴方向位移得到 矩形A4 B4 C4 D4
        canvas.drawBitmap(pathCContentBitmap, mMatrix, null);

        drawPathCShadow(canvas);
        canvas.restore();
    }