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https://gitlab.com/freepascal.org/lazarus/lazarus.git
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134 lines
4.6 KiB
PHP
134 lines
4.6 KiB
PHP
{%MainUnit ../controls.pp}
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{******************************************************************************
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TCustomControl
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******************************************************************************
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*****************************************************************************
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* *
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* This file is part of the Lazarus Component Library (LCL) *
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* *
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* See the file COPYING.modifiedLGPL, included in this distribution, *
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* for details about the copyright. *
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* *
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* This program is distributed in the hope that it will be useful, *
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* but WITHOUT ANY WARRANTY; without even the implied warranty of *
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. *
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* *
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*****************************************************************************
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}
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{------------------------------------------------------------------------------
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Method: TCustomControl.Create
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Params: none
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Returns: Nothing
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Constructor for the class.
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------------------------------------------------------------------------------}
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constructor TCustomControl.Create(AOwner: TComponent);
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begin
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inherited Create(AOwner);
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FCanvas := TControlCanvas.Create;
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TControlCanvas(FCanvas).Control := Self;
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// ----PREVIOUS COMMENT-----
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// custom controls are painted by the LCL, not the interface, so enable
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// double buffering. It's up to the interface to do the actual
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// doublebuffering.
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// ----Micha's comment----
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// If double buffering has to be enabled before LCL can draw anything,
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// something is wrong. In the overridden Paint method you should always be
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// able to draw, independent of DoubleBuffered setting.
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//
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// Disable the switch by default:
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// 1) it greatly improves resizing speed (it doesn't feel like java then ;) )
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// 2) VCL compatible
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// 3) users of LCL should enable switch per control if they so desire
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DoubleBuffered:=false;
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end;
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{------------------------------------------------------------------------------
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Method: TCustomControl.Destroy
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Params: None
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Returns: Nothing
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Destructor for the class.
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------------------------------------------------------------------------------}
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Destructor TCustomControl.Destroy;
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begin
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FCanvas.Free;
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FCanvas:=nil;
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inherited Destroy;
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end;
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procedure TCustomControl.DestroyWnd;
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begin
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if FCanvas<>nil then
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TControlCanvas(FCanvas).FreeHandle;
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inherited DestroyWnd;
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end;
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{------------------------------------------------------------------------------
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Method: TCustomControl.Paint
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Params: none
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Returns: nothing
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Default paint handler. Derived classed should paint themselves
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------------------------------------------------------------------------------}
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Procedure TCustomControl.Paint;
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begin
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if Assigned(FOnPaint) then FOnPaint(Self);
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end;
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procedure TCustomControl.FontChanged(Sender: TObject);
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begin
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Canvas.Font:=Font;
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inherited FontChanged(Sender);
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end;
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procedure TCustomControl.SetColor(Value: TColor);
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begin
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if Value=Color then exit;
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inherited SetColor(Value);
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Canvas.Brush.Color:=Color;
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end;
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{------------------------------------------------------------------------------
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Method: TCustomControl.LMPaint
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Params: Msg: The paint message
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Returns: nothing
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Paint event handler.
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------------------------------------------------------------------------------}
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procedure TCustomControl.WMPaint(var Message: TLMPaint);
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begin
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if (csDestroying in ComponentState) or (not HandleAllocated) then exit;
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Include(FControlState, csCustomPaint);
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inherited WMPaint(Message);
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Exclude(FControlState, csCustomPaint);
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end;
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{------------------------------------------------------------------------------
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Method: TCustomControl.PaintWindow
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Params: DC: The device context to paint on
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Returns: nothing
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This is a plug-in in TWinControl to get the DC, assign it to our canvas and
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call the paint method for descendents to do the actual painting
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------------------------------------------------------------------------------}
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procedure TCustomControl.PaintWindow(DC: HDC);
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var
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DCChanged: boolean;
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begin
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DCChanged:=(not FCanvas.HandleAllocated) or (FCanvas.Handle<>DC);
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if DCChanged then
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FCanvas.Handle := DC;
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try
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Paint;
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finally
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if DCChanged then FCanvas.Handle := 0;
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end;
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end;
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// included by controls.pp
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