TImageViewer is a simple component that can provide basic manipulation functionalities to the user. Basically, it shows an image (see the Bitmap property) in a scroll box so that if the image exceeds the viewer's dimensions, scrollbars will appear and the user will be able to pan the image (via the mouse or touch) to view a portion of it.
The image can also be scaled by setting the BitmapScale property (there is also support for user interaction on the desktop since the user can scale the bitmap by rolling the mouse wheel when the MouseScaling property is set to True). The component provides a convenient background for the picture (see the BackgroundFill property, which is implemented with a TBrush object – this means it has the same capabilities we covered for the Fill and Stroke properties of TShape descendants, previously in this book). There is also basic support to let the user change the actual content of the image (an OpenDialog...
