TRasterImage.BeginUpdate procedure
BeginUpdate - start the update process.Declaration
procedure BeginUpdate(ACanvasOnly: Boolean=False)Arguments
ACanvasOnly | True when only the Canvas is updating; False when image data is loading. |
Description
BeginUpdate is a method used to initiate an update to the image.
BeginUpdate uses the value in an internal member to track the number of
active updates for the image. When the counter has a non-zero value,
BeginUpdate has already been called and EndUpdate has not yet been
executed. If the value in the counter is 0, the shared image is
released and the value in ACanvasOnly is stored in the class
instance.
BeginUpdate can raise an EInvalidGraphicOperation exception if a
pending update was for a canvas only and a subsequent update requests a full
update. The default value for ACanvasOnly is False (full update).
BeginUpdate increments the value in the internal counter prior to exiting from the method.
Errors
Raises an EInvalidGraphicOperation exception with the message in
rsRasterImageUpdateAll if a pending update was for a canvas only
and a subsequent update requests a full update.
An experiment, built from development snapshots. Not the official Free Pascal or Lazarus documentation.