A Text Object


In example 2b we wrapped our image loading function in an object for convenience and additional functionality.  Now we will do the same for the text loading function from example 3a.

Because the results of loading an image and loading a font are very similar it makes sense to wrap them both in very similar objects.  So we create a Text object that inherits from Image, and uses Image's draw and destructor functions directly.
    1 from Image import Image
    2 import gutil
    3 
    4 class Text(Image):
    5 
    6     def __init__(self, text, fontsize = 24, color = (0,0,0,0), font = None, antialias = 1):
    7         texttexture = gutil.loadText(text, fontsize, color, font, antialias)
    8         self.texture = texttexture[0]
    9         self.width = texttexture[1]
   10         self.height = texttexture[2]
   11         self.texture_width = texttexture[3]
   12         self.texture_height = texttexture[4]
   13         self.displayList = gutil.createTexDL(self.texture, self.texture_width, self.texture_height)
The init method takes roughly the same arguments that the loadText function takes.  It calls the loadText function, stores the texture id, the text image size, and the actual OpenGL texture size.  It then creates a display list.

Because we are storing the same information, we do not need to define destructor or draw methods.  The Image class takes care of this for us.

Now lets look at an example using the new class.

    1 #!/usr/bin/python
    2 
    3 import gutil
    4 import pygame
    5 from pygame.locals import *
    6 from OpenGL.GL import *
    7 
    8 from Image import Image
    9 from Text import Text
   10 
   11 
   12 def main():
   13     pygame.init()
   14     gutil.initializeDisplay(800, 600)
   15 
   16     done = False
   17 
   18     cow = Image('cow')
   19     alien = Image('alien')
   20 
   21     white = (255,255,255,255)
   22     string1 = Text("Cow!", fontsize=256, color=white)
   23     string2 = Text("Rotation!", color=white)
   24 
   25     while not done:
   26         glClear(GL_COLOR_BUFFER_BIT)
   27         cow.draw(pos=(100,100),width=128,height=128)
   28         string1.draw(pos=(100,0), width=128,height=128)
   29         alien.draw(pos=(400, 400),rotation=-15,color=(.9,.3,.2,1))
   30         string2.draw(pos=(600, 400), rotation=20, color=(.2,.3,.9,1))
   31 
   32         pygame.display.flip()
   33 
   34         eventlist = pygame.event.get()
   35         for event in eventlist:
   36             if event.type == QUIT \
   37                or event.type == KEYDOWN and event.key == K_ESCAPE:
   38                 done = True
   39 
   40 if __name__ == '__main__':
   41     main()
Very little has changed here from previous examples.  We import the new class on line 9.  We create two Text objects on lines 22 and 23, and we draw these two objects on lines 28 and 30.



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Back to Example 3a