Concepts and Definitions

The LEAD control lets you load an image from a file, manipulate it as a bitmap in memory, display it in the control, manipulate the way it is displayed, print the bitmap, and save it to a file.

The following illustrates the fundamental components and their relationships:

The LEAD control is the VCL custom control that you add to your application. In the illustration, the LEAD control is the box inside the window where the image is displayed.

The bitmap is the image data in memory. The LEAD 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 a description of how to position, scale, and crop an image, refer to Displaying an Image.