viewportToDrawerRectangle(rectangle) {
        var topLeft = this.viewport.pixelFromPointNoRotate(rectangle.getTopLeft(), true);
        var size = this.viewport.deltaPixelsFromPointsNoRotate(rectangle.getSize(), true);

        return new $.Rect(
            topLeft.x * $.pixelDensityRatio,
            topLeft.y * $.pixelDensityRatio,
            size.x * $.pixelDensityRatio,
            size.y * $.pixelDensityRatio
        );
    }
Scale from OpenSeadragon viewer rectangle to drawer rectangle
(ignoring rotation)
@param {OpenSeadragon.Rect} rectangle - The rectangle in viewport coordinate system.
@returns {OpenSeadragon.Rect} Rectangle in drawer coordinate system.