WxDC

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[edit] wxDC

A wxDC, or device context, allows you to draw stuff manually. See the official docs: wxDC Overview, wxWindowDC, wxScreenDC, et cetera.

The 'drawing' example that comes with wxWidgets should be worth checking out if you want to learn how to use wxDC.

  • wxPaintDC must be created on paint events if you catch them (even if you draw nothing yourself)
  • wxClientDC can be used outside paint events
  • wxBufferedDC would be used on top of your selected DC, for flickerless Drawing.
  • You can paint into postscript files with wxPostScriptDC
  • SVG files are supported using wxSVGFileDC (compilation instructions here), found in the contrib folder.

DrawRectangle can also be used with 

void DrawRectangle(const wxPoint& pt, const wxSize& sz)
void DrawRectangle(const wxRect& rect)

[edit] Minimal drawing sample

#ifndef _drawPane_
#define _drawPane_
 
#include "wx/wx.h"
#include "wx/glcanvas.h"
 
class BasicDrawPane : public wxPanel
{
    
public:
	BasicDrawPane(wxFrame* parent);
    
	void render(wxPaintEvent& evt);
    
	// events
	void mouseMoved(wxMouseEvent& event);
	void mouseDown(wxMouseEvent& event);
	void mouseWheelMoved(wxMouseEvent& event);
	void mouseReleased(wxMouseEvent& event);
	void rightClick(wxMouseEvent& event);
	void mouseLeftWindow(wxMouseEvent& event);
	void keyPressed(wxKeyEvent& event);
	void keyReleased(wxKeyEvent& event);
    
	DECLARE_EVENT_TABLE()
};
 
#endif 
 
 
 
 
#include "wx/wx.h"
#include "wx/sizer.h"
 
class MyApp: public wxApp
{
    virtual bool OnInit();
 
    wxFrame *frame;
    BasicDrawPane * drawPane;
public:
      
};
 
IMPLEMENT_APP(MyApp)
 
 
bool MyApp::OnInit()
{
    wxBoxSizer* sizer = new wxBoxSizer(wxHORIZONTAL);
    frame = new wxFrame((wxFrame *)NULL, -1,  wxT("Hello wxDC"), wxPoint(50,50), wxSize(400,200));
	
    drawPane = new BasicDrawPane( (wxFrame*) frame );
    sizer->Add(drawPane, 1, wxEXPAND);
	
    frame->SetSizer(sizer);
    frame->SetAutoLayout(true);
	
    frame->Show();
    return true;
} 
 
BEGIN_EVENT_TABLE(BasicDrawPane, wxPanel)
EVT_MOTION(BasicDrawPane::mouseMoved)
EVT_LEFT_DOWN(BasicDrawPane::mouseDown)
EVT_LEFT_UP(BasicDrawPane::mouseReleased)
EVT_RIGHT_DOWN(BasicDrawPane::rightClick)
EVT_LEAVE_WINDOW(BasicDrawPane::mouseLeftWindow)
EVT_KEY_DOWN(BasicDrawPane::keyPressed)
EVT_KEY_UP(BasicDrawPane::keyReleased)
EVT_MOUSEWHEEL(BasicDrawPane::mouseWheelMoved)
EVT_PAINT(BasicDrawPane::render)
END_EVENT_TABLE()
 
 
// some useful events to use
void BasicDrawPane::mouseMoved(wxMouseEvent& event) {}
void BasicDrawPane::mouseDown(wxMouseEvent& event) {}
void BasicDrawPane::mouseWheelMoved(wxMouseEvent& event) {}
void BasicDrawPane::mouseReleased(wxMouseEvent& event) {}
void BasicDrawPane::rightClick(wxMouseEvent& event) {}
void BasicDrawPane::mouseLeftWindow(wxMouseEvent& event) {}
void BasicDrawPane::keyPressed(wxKeyEvent& event) {}
void BasicDrawPane::keyReleased(wxKeyEvent& event) {}
 
BasicDrawPane::BasicDrawPane(wxFrame* parent) :
wxPanel(parent)
{
}
 
 
void BasicDrawPane::render( wxPaintEvent& evt )
{
    wxPaintDC dc(this); // only to be used in paint events. use wxClientDC to paint outside the paint event
	dc.DrawText(wxT("Testing"), 40, 60); 
}
Retrieved from "http://wiki.wxwidgets.org/WxDC"
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