Normally, if these 4 properties all have their default value of 0, the images within a DicomViewer’ Images collection are displayed in a fixed grid arrangement, controlled by the viewer’s MultiRows, MultiColumns and CurrentIndex  properties.  If however, any of these properties are set non-zero, then the default behaviour is over-ridden, and the image is displayed in a “cell” defined by these properties (coordinates are relative to the viewer’s top-left corner).  All other properties such as StretchedCentred etc. operate exactly as normal, but within this different cell.

One common use for these properties is to create an efficient “magnifying glass”, as it is easy to add a second copy of an image to a viewer’s Images collection, then alter it’s zoom, and positioning properties as the mouse moves, to implement the magnifier.  The re-display is optimised for this purpose, and when these properties are changed, then only the affected area is redrawn (quickly).  Therefore use of the viewer’s Refresh method is not only unnecessary, but it actually slows the application.

DicomImage Object  | DicomImage Members