Font custom to this control. By default this returns UIFont, you can override this to return your font. It's OK to return here Nil if font is not ready yet, but during Render (when OpenGL context is available) font must be ready.
procedure FontChanged; virtual;
Called when Font result changed, either by setting CustomFont or when UIFont assigned changed.
destructor Destroy; override;
procedure GLContextClose; override;
function TooltipExists: boolean; override;
procedure TooltipRender; override;
procedure Render; override;
procedure CheckFontChanged;
Check does currently used font (see CustomFont) changed, and eventually call FontChanged method now.
You only need to explicitly call this in very specific circumstances, when you just changed UIFont (changing CustomFont automatically immediately calls FontChanged) and you want control size to be updated immediately (for example, you need TCastleButton.Height to be immediately valid). Without calling this, it could be updated only at next Render call.