aldrin.canvas.Canvas

Package aldrin :: Module canvas :: Class Canvas

[show private | hide private]

Type Canvas

object --+            
         |            
    Object --+        
             |        
    EvtHandler --+    
                 |    
            Window --+
                     |
                    Canvas

Known Subclasses:: AmpView, EnvelopeView, PatternView, RouteView, SequencerView

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.

Method Summary
	`__init__(self, parent, id, pos, size, style)` Creates a canvas instance and initializes the off-screen buffer.
	`Blit(self, dc)` Performs the blit of the buffer contents on-screen.
	`DrawBuffer(self, args, *kargs)` Actual drawing function for drawing into the off-screen buffer.
	`GetBoundingRect(self)` Returns a tuple that contains the co-ordinates of the top-left and bottom-right corners of the canvas.
	`MakeNewBuffer(self)`
	`onEraseBackground(self, event)`
	`onPaint(self, event)` Renders the off-screen buffer on-screen.
	`onPostPaint(self, dc)`
	`onSize(self, event)` Perform actual redraw to off-screen buffer only when the size of the canvas has changed.
	`ReDraw(self, args, *kargs)` Explicitly tells the canvas to redraw it's contents.
	`Refresh(self)`
Inherited from object
	`__delattr__(...)` x.__delattr__('name') <==> del x.name
	`__getattribute__(...)` x.__getattribute__('name') <==> x.name
	`__hash__(x)` x.__hash__() <==> hash(x)
	`__new__(T, S, ...)` T.__new__(S, ...) -> a new object with type S, a subtype of T
	`__reduce__(...)` helper for pickle
	`__reduce_ex__(...)` helper for pickle
	`__setattr__(...)` x.__setattr__('name', value) <==> x.name = value
	`__str__(x)` x.__str__() <==> str(x)

Class Variable Summary
`bool`	`doublebuffered` = `True`

Instance Method Details

init(self, parent, id, pos=wx.Point(-1, -1), size=wx.Size(-1, -1), style=33554432)
(Constructor)

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.

Overrides:: wx._core.Window.__init__

Blit(self, dc)

Performs the blit of the buffer contents on-screen.

DrawBuffer(self, *args, **kargs)

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

GetBoundingRect(self)

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

onPaint(self, event)

Renders the off-screen buffer on-screen.

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.

ReDraw(self, *args, **kargs)

Explicitly tells the canvas to redraw it's contents.

Class Variable Details

doublebuffered

Type:: bool
Value:: True

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