Method updateMatrix

snap_drawing/src/snap_drawing/cpp/Layers/Layer.cpp:347–378

}

void Layer::updateMatrix(Scalar width, Scalar height) {
    _matrix.setIdentity();

    auto scaledWidth = width;
    auto scaledHeight = height;
    auto translationX = _translation.width;
    auto translationY = _translation.height;

    // Compensate for the change of size so that it appears as if we are scaling from the center
    if (_scaleX != 1.0f) {
        scaledWidth *= _scaleX;

        translationX += (width - scaledWidth) / 2.0f;
        _matrix.setScaleX(_scaleX);
    }

    if (_scaleY != 1.0f) {
        scaledHeight *= _scaleY;

        translationY += (height - scaledHeight) / 2.0f;
        _matrix.setScaleY(_scaleY);
    }

    _matrix.setTranslateX(_frame.left + translationX);
    _matrix.setTranslateY(_frame.top + translationY);

    if (_rotation != 0.0f) {
        Scalar centerX = _matrix.getTranslateX() + scaledWidth / 2.0f;
        Scalar centerY = _matrix.getTranslateY() + scaledHeight / 2.0f;
        _matrix.postRotate(_rotation, centerX, centerY);
    }
}

void Layer::setTouchAreaExtension(Scalar left, Scalar right, Scalar top, Scalar bottom) {
    _touchAreaExtensionLeft = left;