Пример компонента HotSpot

Code:

unit Newpanel;

interface

uses WinTypes, Classes, Controls, StdCtrls, ExtCtrls;

type

tHotSpotClickEvent = procedure(Sender: tObject;

   Button: tMouseButton;

   Shift: tShiftState) of object;

TNewPanel = class(tPanel)

private

   fHotSpotClick: tHotSpotClickEvent;

   fHotSpot: tRect;

   fInHotSpot: Boolean;

   function GetHotSpotTop: Word;

   function GetHotSpotLeft: Word;

   function GetHotSpotWidth: Word;

   function GetHotSpotHeight: Word;

   procedure SetHotSpotTop(Value: Word);

   procedure SetHotSpotLeft(Value: Word);

   procedure SetHotSpotWidth(Value: Word);

   procedure SetHotSpotHeight(Value: Word);

protected

   procedure Paint; override;

   procedure MouseDown(Button: tMouseButton; Shift: tShiftState; X, Y: Integer);

     override;

   procedure MouseUp(Button: tMouseButton; Shift: tShiftState; X, Y: Integer);

     override;

public

   procedure Click; override;

   property HotSpot: tRect read fHotSpot write fHotSpot;

published

   property hsTop: Word read GetHotSpotTop write SetHotSpotTop;

   property hsLeft: Word read GetHotSpotLeft write SetHotSpotLeft;

   property hsWidth: Word read GetHotSpotWidth write SetHotSpotWidth;

   property hsHeight: Word read GetHotSpotHeight write SetHotSpotHeight;

   property OnHotSpot: tHotSpotClickEvent read fHotSpotClick write

     fHotSpotClick;

end;

procedure Register;

implementation

uses WinProcs, Graphics;

procedure Register;

begin

RegisterComponents('Custom', [TNewPanel]);

end;

procedure TNewPanel.MouseDown(Button: tMouseButton;

Shift: tShiftState;

X, Y: Integer);

begin

if PtInRect(fHotSpot, Point(X, Y)) and

   Assigned(fHotSpotClick) then

   fInHotSpot := True;

inherited MouseDown(Button, Shift, X, Y);

end;

procedure TNewPanel.MouseUp(Button: tMouseButton;

Shift: tShiftState;

X, Y: Integer);

begin

inherited MouseUp(Button, Shift, X, Y);

if fInHotSpot then

begin

   if Assigned(fHotSpotClick) then

     fHotSpotClick(Self, Button, Shift);

   fInHotSpot := False;

end;

end;

procedure TNewPanel.Click;

begin

if not fInHotSpot then

   inherited Click;

end;

procedure TNewPanel.Paint;

var

OldStyle: tPenStyle;

begin

inherited Paint;

if csDesigning in ComponentState then

begin

   OldStyle := Canvas.Pen.Style;

   Canvas.Pen.Style := psDash;

   Canvas.Rectangle(HotSpot.Left, HotSpot.Top, HotSpot.Right, HotSpot.Bottom);

   Canvas.Pen.Style := OldStyle;

end;

end;

procedure TNewPanel.SetHotSpotTop(Value: Word);

begin

fHotSpot.Bottom := fHotSpot.Bottom + Value - fHotSpot.Top;

fHotSpot.Top := Value;

Paint;

end;

procedure TNewPanel.SetHotSpotLeft(Value: Word);

begin

fHotSpot.Right := fHotSpot.Right + Value - fHotSpot.Left;

fHotSpot.Left := Value;

Paint;

end;

procedure TNewPanel.SetHotSpotWidth(Value: Word);

begin

fHotSpot.Right := fHotSpot.Left + Value;

Paint;

end;

procedure TNewPanel.SetHotSpotHeight(Value: Word);

begin

fHotSpot.Bottom := fHotSpot.Top + Value;

Paint;

end;

function TNewPanel.GetHotSpotTop: Word;

begin

Result := fHotSpot.Top

end;

function TNewPanel.GetHotSpotLeft: Word;

begin

Result := fHotSpot.Left;

end;

function TNewPanel.GetHotSpotWidth: Word;

begin

Result := fHotSpot.Right - fHotSpot.Left;

end;

function TNewPanel.GetHotSpotHeight: Word;

begin

Result := fHotSpot.Bottom - fHotSpot.Top;

end;

end.