/**
* Calculates intersection of the image and the render filter region in the coordinate system relative to the image.
*
* @return <code>null</code> if the image is not allowed, {@link java.util.List} of
* {@link com.itextpdf.text.Rectangle} objects otherwise.
*/
protected internal virtual IList<Rectangle> GetCoveredAreas(ImageRenderInfo renderInfo) {
Rectangle imageRect = CalcImageRect(renderInfo);
IList<Rectangle> coveredAreas = new List<Rectangle>();
if (imageRect == null) {
return null;
}
foreach (Rectangle rectangle in rectangles) {
Rectangle intersectionRect = Intersection(imageRect, rectangle);
if (intersectionRect != null) {
// True if the image is completely covered
if (imageRect.Equals(intersectionRect)) {
return null;
}
coveredAreas.Add(TransformIntersection(renderInfo.GetImageCTM(), intersectionRect));
}
}
return coveredAreas;
}
/// <summary>
/// Converts the Matrix containing the coordinates of an image as stored
/// in an ImageRenderInfo object into a Rectangle.
/// </summary>
/// <param name="imageRenderInfo">Object that contains info about an image</param>
/// <returns>coordinates in the form of a Rectangle object</returns>
private static Rectangle GetRectangle(ImageRenderInfo imageRenderInfo)
{
Matrix ctm = imageRenderInfo.GetImageCTM();
return new Rectangle(ctm[6], ctm[7], ctm[6] + ctm[0], ctm[7] + ctm[4]);
}
/**
* @return Image boundary rectangle in device space.
*/
private Rectangle CalcImageRect(ImageRenderInfo renderInfo) {
Matrix ctm = renderInfo.GetImageCTM();
if (ctm == null) {
return null;
}
Point2D[] points = TransformPoints(ctm, false, new Point(0, 0), new Point(0, 1),
new Point(1, 0), new Point(1, 1));
return GetRectangle(points[0], points[1], points[2], points[3]);
}
