CircularImageView.java 文件源码

private BitmapShader updateShaderMatrix(BitmapShader shader) {
    float scale;
    float dx = 0;
    float dy = 0;

    calculateBounds();

    Matrix shaderMatrix = new Matrix();
    shaderMatrix.set(null);

    if (mBitmapWidth * mBoundsRect.height() > mBitmapHeight * mBoundsRect.width()) {
        scale = mBoundsRect.height() / (float) mBitmapHeight;
        dx = (mBoundsRect.width() - mBitmapWidth * scale) * 0.5f;

    } else {
        scale = mBoundsRect.width() / (float) mBitmapWidth;
        dy = (mBoundsRect.height() - mBitmapHeight * scale) * 0.5f;
    }

    shaderMatrix.setScale(scale, scale);
    shaderMatrix.postTranslate((int)(dx + 0.5f) + mBoundsRect.left, (int)(dy + 0.5f) + mBoundsRect.top);

    shader.setLocalMatrix(shaderMatrix);

    return shader;
}