wx.lib.colourchooser.canvas.Canvas

A canvas class for arbitrary drawing.

The Canvas class implements a window that allows for drawing arbitrary graphics. It implements a double buffer scheme and blits the off-screen buffer to the window during paint calls by the windowing system for speed.

Some other methods for determining the canvas colour and size are also provided.

Class Hierarchy

Inheritance diagram for class Canvas:

Known Subclasses

wx.lib.colourchooser.pycolourslider.PyColourSlider, wx.lib.colourchooser.pypalette.PyPalette

Known Superclasses

wx.Window

Methods Summary

__init__	Creates a canvas instance and initializes the off-screen
Blit	Performs the blit of the buffer contents on-screen.
DrawBuffer	Actual drawing function for drawing into the off-screen
GetBoundingRect	Returns a tuple that contains the co-ordinates of the
MakeNewBuffer
onPaint	Renders the off-screen buffer on-screen.
onSize	Perform actual redraw to off-screen buffer only when the
ReDraw	Explicitly tells the canvas to redraw it’s contents.
Refresh	Re-draws the buffer contents on-screen.

Class API

class Canvas(wx.Window)

A canvas class for arbitrary drawing.

The Canvas class implements a window that allows for drawing arbitrary graphics. It implements a double buffer scheme and blits the off-screen buffer to the window during paint calls by the windowing system for speed.

Some other methods for determining the canvas colour and size are also provided.

Methods

__init__(self, parent, id, pos=wx.DefaultPosition, style=wx.SIMPLE_BORDER, forceClientSize=None)

Creates a canvas instance and initializes the off-screen buffer. Also sets the handler for rendering the canvas automatically via size and paint calls from the windowing system.

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Blit(self, dc)

Performs the blit of the buffer contents on-screen.

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DrawBuffer(self)

Actual drawing function for drawing into the off-screen buffer. To be overrideen in the implementing class. Do nothing by default.

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GetBoundingRect(self)

Returns a tuple that contains the co-ordinates of the top-left and bottom-right corners of the canvas.

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MakeNewBuffer(self)

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onPaint(self, event)

Renders the off-screen buffer on-screen.

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onSize(self, event)

Perform actual redraw to off-screen buffer only when the size of the canvas has changed. This saves a lot of computation since the same image can be re-used, provided the canvas size hasn’t changed.

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ReDraw(self)

Explicitly tells the canvas to redraw it’s contents.

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Refresh(self)

Re-draws the buffer contents on-screen.