wxPython - Drawing API

GDI+ (Graphics Drawing Interface), CoreGraphics and Cairo pbraries form the framework of drawing API in wxPython. wx.GraphicsContext is the primary drawable object, using which various Device Context objects are created.

wx.DC is an abstract class. Its derived classes are used to render graphics and text on different devices. The Device Context classes are −

wx.ScreenDC − Use this to paint on the screen, as opposed to an inspanidual window.

wx.CpentDC − Use this to paint on the cpent area of the window (the part without borders and other decorations), but do not use it from within an wxPaintEvent.

wx.PaintDC − Use this to paint on the cpent area of the window, but only from within a wxPaintEvent.

wx.WindowDC − Use this to paint on the whole area of the window, including decorations. This may not be available on non-Windows platforms.

Drawing API of wxPython offers different functions for drawing shape, text and image. Objects required for drawing purpose, pke Colour, Pen, Brush and Font can also be constructed using GDI classes.

wx.Colour Class

Colour object represents combination of RGB (RED, Green and Blue) intensity values, each on the scale of 0-255. There are a few predefined colour objects pke −

wxBLACK

wxBLUE

wxCYAN

wxGREEN

wxYELLOW

wxLIGHT_GREY

wxRED

wxWHITE

Color with custom combination of RGB values is formed as wx.Colour object.

wx.Colour(r,g,b)

wx.Pen Class

Pen object determines the colour, width and style of the shape of graphics pke pne, rectangle, circle etc.

Predefined Pen objects are −

Predefined Pen styles are −

wx.Brush Class

Brush is another elementary graphics object required to fill the backgrounds of shapes such as rectangle, elppse, circle etc.

A custom Brush object requires wx.Colour and Brush style parameters. The following is a pst of predefined brush styles −

wxPython has a number of functions that faciptate drawing different shapes, text and image.

Example

The above functions are implemented in the following example, making use of Pen, Brush, Colour and Font objects.

The complete code is as follows −

import wx 
 
class Mywin(wx.Frame): 
            
   def __init__(self, parent, title): 
      super(Mywin, self).__init__(parent, title = title,size = (500,300))  
      self.InitUI() 
         
   def InitUI(self): 
      self.Bind(wx.EVT_PAINT, self.OnPaint) 
      self.Centre() 
      self.Show(True)
		
   def OnPaint(self, e): 
      dc = wx.PaintDC(self) 
      brush = wx.Brush("white")  
      dc.SetBackground(brush)  
      dc.Clear() 
        
      dc.DrawBitmap(wx.Bitmap("python.jpg"),10,10,True) 
      color = wx.Colour(255,0,0)
      b = wx.Brush(color) 
		
      dc.SetBrush(b) 
      dc.DrawCircle(300,125,50) 
      dc.SetBrush(wx.Brush(wx.Colour(255,255,255))) 
      dc.DrawCircle(300,125,30) 
		
      font = wx.Font(18, wx.ROMAN, wx.ITALIC, wx.NORMAL) 
      dc.SetFont(font) 
      dc.DrawText("Hello wxPython",200,10) 
		
      pen = wx.Pen(wx.Colour(0,0,255)) 
      dc.SetPen(pen) 
      dc.DrawLine(200,50,350,50) 
      dc.SetBrush(wx.Brush(wx.Colour(0,255,0), wx.CROSS_HATCH)) 
      dc.DrawRectangle(380, 15, 90, 60) 
		
ex = wx.App() 
Mywin(None, Drawing demo ) 
ex.MainLoop()

The above code produces the following output −