VDKCanvas Class Reference

This class provides a canvas widget. More...

#include <canvas.h>

Inheritance diagram for VDKCanvas:

List of all members.

Public Member Functions

• void Clear ()
• void Redraw ()
• void SetForeground (VDKRgb color, GtkStateType state=GTK_STATE_NORMAL)
• void SetBackground (VDKRgb color, GtkStateType state=GTK_STATE_NORMAL)
• void SetFont (VDKFont *f)

Public Attributes

• VDKReadWriteValueProp
  < VDKCanvas, bool > EnableClear

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Detailed Description

This class provides a canvas widget.

Widget operation notes:

Drawing operation on canvas aren't done directly on the screen but using an offscreen backing pixmap. When necessary relevant portion of (or all) backing image is copied to screen.This makes drwaing muchfaster and avoids flickering. All user drawing operations should be followed by Draw() or Redraw() to effectively see the wanted effect. When applicable the best way is to connect with and write an expose-event response function where make all necessary drawing operations followed by a Redraw() call. See canvaswin.cc on ./testvdk directory for more detailed informations.

Tips:

By default canvas uses owner background and foreground, these can be set using properties.

Examples:

in ./testvdk/canvascompo.cc

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Member Function Documentation

void VDKCanvas::Clear

(

)

clears canvas area

Reimplemented in VDKChart.

void VDKCanvas::Redraw

(

)

force a redrawing without expose_event

void VDKCanvas::SetBackground	(	VDKRgb	color,
		GtkStateType	state = GTK_STATE_NORMAL
	)		[virtual]

Sets object background

Parameters:

color	a VDKRgb object
state	can be one of the gtk+ widget states

Reimplemented from VDKObject.

void VDKCanvas::SetFont

(

VDKFont *

f

)

[virtual]

Sets object font

Reimplemented from VDKObject.

void VDKCanvas::SetForeground	(	VDKRgb	color,
		GtkStateType	state = GTK_STATE_NORMAL
	)		[virtual]

Sets object foreground

Parameters:

color	a VDKRgb object
state	can be one of the gtk+ widget states

Reimplemented from VDKObject.

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Member Data Documentation

VDKReadWriteValueProp<VDKCanvas,bool> VDKCanvas::EnableClear

default is true. It clears and refreshes the screen during the configure event. User can disable it to control the draw during the configure event

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The documentation for this class was generated from the following files:

• canvas.h
• canvas.cc