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OnBeforeRenderData


Unit:SDL_rot3d
Class: TRot3D
Declaration: OnBeforeRenderData: TRenderEvent;
{ TRenderEvent = procedure (Sender: TObject; Canvas: TCanvas) of object; }

The events OnDataRendered and OnBeforeRenderData provide a hook for adding user defined graphics to the 3D data display. The event OnBeforeRenderData occurs before the data and any axes are drawn. The variable parameter Canvas provides access to the canvas of the data area. Please note that the state of the canvas (e.g. the color of its pen, or the fill mode of the brush) is undefined.

Hint 1: The declaration of this event has been changed with the introduction of release 10.1 of the SDL Suite. Please see the corresponding type declaration and the section How to Deal with a Canvas Reference Change for details.

Hint 2: In order to avoid unwanted size effects regarding characters displayed on canvases of different resolution (i.e. the screen and a printer) you should never directly assign the font size within the event. Use SetCanvasFontSizeScaled instead. So, for example, the statement Canvas.Font.Size := 12; should be replaced by SetCanvasFontSizeScaled (Canvas, 12);



Last Update: 2012-Oct-26