Concepts and Definitions

The LEADTOOLS COM Objects let you load images from files, manipulate them as bitmaps in memory, display them, manipulate the way they are displayed, prints them, and save them to files.

The following illustrates the fundamental components and their relationships:

ILEADRaster is the COM interface for managing a bitmap in memory. This interface provides functions for getting information about a bitmap, creating a new bitmap, working with the clipboard, etc.

ILEADRasterIO is the COM interface for performing image file formation input and output. This interface provides functions for reading and writing image files to disk, memory, or network locations. This interface also provides the functionality for doing image data compression and decompression.

ILEADRasterProcess is the COM interface for performing image processing on bitmaps. This interface provides functions for image filters, transforms, effects, etc.

ILEADRasterView is the COM object for displaying bitmaps. This is a full ActiveX Control that provides functionality for displaying, scrolling, zooming, printing, etc. The ILEADRasterView object contains an instance of ILEADRaster, which can be used with the other LEADTOOLS COM objects. This object is an ActiveX control that you add to your application. In the illustration, the control is the box inside the window where the image is displayed.

The bitmap is the image data in memory. The LEAD RasterView control references the bitmap. Most LEAD methods that alter an image (such as Grayscale or Rotate) actually alter the bitmap. If you alter a bitmap, the changes you make do not appear in the control until the image repaints. When you save a bitmap, the changes you have made are saved in the file.

The displayed image is the rectangle on the screen that shows all or part of the bitmap. It can be positioned, scaled, and cropped without affecting the image data in memory. For information on the source and destination rectangles that control which part of an image is displayed, refer to Specifying Only the Destination Rectangles, Specifying Both the Source and Destination Rectangles, Specifying the Source Clipping Rectangle and Specifying the Destination Clipping Rectangle. For more information about how to position, scale, and crop an image, refer to Displaying an Image.