Vcl.Graphics.TPicture.OnProgress
Delphi
property OnProgress: TProgressEvent read FOnProgress write FOnProgress;
C++
__property TProgressEvent OnProgress = {read=FOnProgress, write=FOnProgress};
Properties
| Type | Visibility | Source | Unit | Parent |
|---|---|---|---|---|
| event | public | Vcl.Graphics.pas Vcl.Graphics.hpp |
Vcl.Graphics | TPicture |
Description
Occurs periodically during slow operations that affect the graphic.
OnProgress is generated by the particular graphic that the picture object contains. Whether OnProgress occurs depends upon the type of graphic in the Graphic property. Some graphics generate this event, others do not. Jpeg images, for example, generate an OnProgress event.
Write an OnProgress event handler to provide the user with feedback during slow operations such as loading large compressed images. TImage, for example, hooks the OnProgress event of TPicture.
Note: The PercentDone parameter on the event handler is only an approximation. With some image formats, the value of PercentDone may actually decrease from the value in previous events, as the graphic object discovers there is more work to do.
OnProgress is an event handler of type Vcl.Graphics.TProgressEvent.