property OnMouseDown: TImgMouseEvent;

type TImgMouseEvent = procedure(Sender: TObject; Button: TMouseButton; Shift: TShiftState; X, Y: Integer; Layer: TCustomLayer) of object;


This event occurs when user pushes the mouse button in the image area. The Layer parameter indicates the layer under the mouse, or nil in case the mouse is over the background area.

Whether the layer is under the mouse or not, is determined by the HitTest function and by the LOB_MOUSE_EVENTS bit in LayerOptions. The top-most layer which passes the test is passed into the Layer parameter of the event.

Note, that once mouse was pressed, the layer (or the background) captures the mouse messages until the mouse button is released.

See Also

OnMouseMove, OnMouseUp, TCustomLayer, TCustomLayer.HitTest, TCustomLayer.LayerOptions