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OpenGL Button Widget

A button widget for the OpenGL display service. Sends a message when clicked or an assigned key is pressed.

This component is a subclass of OpenGLComponent and therefore uses the OpenGL display service.

Example Usage

4 Buttons which could be used for playback control (output to the console):

    BUTTON1 = Button(caption="<<", msg="Previous", position=(-3,0,-10)),
    BUTTON2 = Button(caption=">>", msg="Next", position=(3,0,-10)),
    BUTTON3 = Button(caption="Play", msg="Play", position=(-1,0,-10)),
    BUTTON4 = Button(caption="Stop", msg="Stop", position=(1,0,-10)),
    ECHO = ConsoleEchoer(),
    linkages = {
        (BUTTON1, "outbox") : (ECHO, "inbox"),
        (BUTTON2, "outbox") : (ECHO, "inbox"),
        (BUTTON3, "outbox") : (ECHO, "inbox"),
        (BUTTON4, "outbox") : (ECHO, "inbox"),

How does it work?

This component is a subclass of OpenGLComponent (for OpenGLComponent functionality see its documentation). It overrides __init__(), setup(), draw(), handleEvents() and frame().

In setup() it requests to receive mouse events and calls buildCaption() where the set caption is rendered on a pygame surface. This surface is then set as OpenGL texture.

In draw() a flat cuboid is drawn (if size is not specified) with the caption texture on both the front and the back surface.

In handleEvents() the component reacts to mouse events and, if a key is assigned, to the keydown event. If a mouse click happens when the mouse pointer is over the button it gets "grabbed", which is visualised by shrinking the button by a little amount, until the button is released again. Only if the mouse button is released over the button widget it gets activated. On activation the button gets rotated by 360 degrees around the X axis.

In frame() the button gets rotated when it has been activated.


class Button(Kamaelia.UI.OpenGL.OpenGLComponent.OpenGLComponent)

Button(...) -> A new Button component.

A button widget for the OpenGL display service. Sends a message when clicked or an assigned key is pressed.

Keyword arguments:

  • caption -- Button caption (default="Button")
  • bgcolour -- Colour of surfaces behind caption (default=(244,244,244))
  • fgcolour -- Colour of the caption text (default=(0,0,0)
  • sidecolour -- Colour of side planes (default=(200,200,244))
  • margin -- Margin size in pixels (default=8)
  • key -- Key to activate button (default=None)
  • fontsize -- Font size for caption text (default=50)
  • pixelscaling -- Factor to convert pixels to units in 3d, ignored if size is specified (default=100)
  • thickness -- Thickness of button widget, ignored if size is specified (default=0.3)
  • msg -- Message which gets sent when button is activated (default="CLICK")



Methods defined here


You should be using the inbox/outbox interface, not these methods (except construction). This documentation is designed as a roadmap as to their functionalilty for maintainers and new component developers.

__init__(self, **argd)

x.__init__(...) initializes x; see x.__class__.__doc__ for signature


Rotate button stepwise by 360 degrees when it has been activated.


Pre-render the text to go on the label.


Draw button cuboid.


Rotate button if it has been activated.


Handle events.


Build caption and request reception of events.

Methods inherited from Kamaelia.UI.OpenGL.OpenGLComponent.OpenGLComponent :


Got a problem with the documentation? Something unclear that could be clearer? Want to help improve it? Constructive criticism is very welcome - especially if you can suggest a better rewording!

Please leave you feedback here in reply to the documentation thread in the Kamaelia blog.

-- Automatic documentation generator, 05 Jun 2009 at 03:01:38 UTC/GMT