Overview

INFO

This section describes the behavior and properties of the TCustomImage32 base class and its derived class, the TImage32 control, as well as their realization of layers.

Since TCustomImage32 and TImage32 share the same behavior, we will denote both of them here as TImage32. Most of the description applies to the TImgView32 control as well.

TImage32 is an image displaying visual control, which also holds a collection of layers.

The internal image of the control is a TBitmap32 object. The scale and position of the image within the control’s boundaries can be controlled with several properties. See Bitmap Image for details.

TImage32 maintains a collection of layers. A layer is, generally speaking, an entity which ‘knows’ how to combine itself with the back buffer of the control. See ‘Using Layers‘ for details.

When the image paints itself, it runs through several Paint Stages which determine the order in which layers and the bitmap image are painted. This order is completely customizeable.

To avoid flicker and to speed-up scaling and blending operations, each layer and the bitmap image is painted to a back-buffer of the control. See the description of Repaint Optimization for details on this.

Finally, TImage32 supports change notification via the OnChange event, which is done similar to change notification in TBitmap32. Basically, it redirects change notification from its layers and the bitmap image.