Пример компонента "HotSpot"

Вот пример HotSpot-компонента, основанного на TPanel (небольшая переделка). Управляя событиями MouseDown и MouseUp можно получить эффект резинового контура.

unit Newpanel;

interface
Uses WinTypes, Classes, Controls, StdCtrls, ExtCtrls;

Type
tHotSpotClickEvent = Procedure ( Sender : tObject;Button : tMouseButton;Shift : tShiftState ) Of Object;
TNewPanel = Class ( tPanel )PrivatefHotSpotClick : 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 );ProtectedProcedure Paint; override;Procedure MouseDown ( Button : tMouseButton; Shift : tShiftState; X, Y : Integer ); override;Procedure MouseUp ( Button : tMouseButton; Shift : tShiftState; X, Y : Integer ); override;PublicProcedure Click; override;
Property HotSpot : tRect Read fHotSpot Write fHotSpot;PublishedProperty 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 ) ) AndAssigned ( fHotSpotClick ) ThenfInHotSpot := 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 ThenBeginIf Assigned ( fHotSpotClick ) ThenfHotSpotClick ( Self, Button, Shift );fInHotSpot := False;End;End;

Procedure TNewPanel.Click;
Begin
If Not fInHotSpot ThenInherited Click;End;

Procedure TNewPanel.Paint;
Var
OldStyle : tPenStyle;Begin
Inherited Paint;
If csDesigning in ComponentState ThenBeginOldStyle := 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.TopEnd;

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.

Надеюсь, с моей помощью вы найдете правильное направление,
Robert Wittig [000547]

Содержание раздела