wx.lib.floatcanvas.FloatCanvas.FloatCanvas

The main class of the floatcanvas package FloatCanvas.

Class Hierarchy

Inheritance diagram for class FloatCanvas:

Known Superclasses

wx.Panel

Methods Summary

__init__	Default class constructor.
AddObject	Add an object to the canvas
AddObjects	Add objects to the canvas
addshape	Creates Circle and adds its reference to the canvas.
ClearAll	ClearAll(ResetBB=True)
Draw	Canvas.Draw(Force=False)
FlatEarthProjection	Compute the scaling array for the flat-earth projection
GetHitTestColor	Get the hit test colour
HitTest	Check if any objects in the dict for this event.
InitAll	Sets everything in the Canvas to default state.
InitializePanel	Initialize the panel.
KeyDownEvent	Key down event.
KeyUpEvent	Key up event.
LeftDoubleClickEvent	Left double click event.
LeftDownEvent	Left down event.
LeftUpEvent	Left up event.
MakeHitDict	Initialize the Hit dictionary.
MakeNewBuffers	Make a new buffer.
MakeNewForegroundHTBitmap	Off screen Bitmap used for Hit tests on foreground objects
MakeNewHTBitmap	Off screen Bitmap used for Hit tests on background objects
MiddleDoubleClickEvent	Middle double click event.
MiddleDownEvent	Middle down event.
MiddleUpEvent	Middle up event.
MotionEvent	Motion event.
MouseOverTest	Check if mouse is over an object.
MoveImage	Move the image in the window.
OnPaint	On paint handler.
OnSize	On size handler.
OnSizeTimer	On size timer handler.
PixelToWorld	Converts coordinates from Pixel coordinates to world coordinates.
RemoveObject	“
RemoveObjects	“
RightDoubleCLickEvent	Right double click event.
RightDownEvent	Right down event.
RightUpEvent	Right up event.
SaveAsImage	Saves the current image as an image file.
ScalePixelToWorld	This function computes a pair of x.y lengths,
ScaleWorldToPixel	This function will get passed to the drawing functions of the objects,
SetMode	Set the GUImode to any of the available mode.
SetProjectionFun	Set a custom projection function
SetToNewScale	Set to the new scale
UnBindAll	Removes all bindings to Objects.
WheelEvent	Wheel event.
WorldToPixel	This function will get passed to the drawing functions of the objects,
Zoom	Zoom(factor, center) changes the amount of zoom of the image by factor.
ZoomToBB	Zooms the image to the bounding box given, or to the bounding

Class API

class FloatCanvas(wx.Panel)

The main class of the floatcanvas package FloatCanvas.

Methods

__init__(self, parent, id = -1, size = wx.DefaultSize, ProjectionFun = None, BackgroundColor = "WHITE", Debug = False, **kwargs)

Default class constructor.

Parameters

• parent (wx.Window) – parent window. Must not be None;

• id (integer) – window identifier. A value of -1 indicates a default value;

• size – a tuple or wx.Size

• ProjectionFun –

  This allows you to change the transform from world to pixel coordinates. We can point to FlatEarthProjection for an example – though that should really be a class method, or even better, simply a function in the module. There is a tiny bit on info in the error message in FloatCanvas.SetProjectionFun()

  (Note: this really should get re-factored to allow more generic projections…)

• BackgroundColor (string) – any value accepted by wx.Brush

• Debug – activate debug, currently it prints some debugging information, could be improved.

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AddObject(self, obj)

Add an object to the canvas

Parameters

obj (DrawObject) – the object to add

Returns

DrawObject

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AddObjects(self, Objects)

Add objects to the canvas

Parameters

Objects (list) – a list of DrawObject

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addshape(self, *args, **kwargs)

Creates Circle and adds its reference to the canvas. Argument protocol same as Circle class, whose docstring is: Draws a circle

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ClearAll(self, ResetBB=True)

ClearAll(ResetBB=True)

Removes all DrawObjects from the Canvas

If ResetBB is set to False, the original bounding box will remain

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Draw(self, Force=False)

Canvas.Draw(Force=False)

Re-draws the canvas.

Note that the buffer will not be re-drawn unless something has changed. If you change a DrawObject directly, then the canvas will not know anything has changed. In this case, you can force a re-draw by passing int True for the Force flag:

Canvas.Draw(Force=True)

There is a main buffer set up to double buffer the screen, so you can get quick re-draws when the window gets uncovered.

If there are any objects in self._ForeDrawList, then the background gets drawn to a new buffer, and the foreground objects get drawn on top of it. The final result if blitted to the screen, and stored for future Paint events. This is done so that you can have a complicated background, but have something changing on the foreground, without having to wait for the background to get re-drawn. This can be used to support simple animation, for instance.

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FlatEarthProjection(self, CenterPoint)

Compute the scaling array for the flat-earth projection

Parameters

CenterPoint –

center point of viewport (lon, lat) – the longitude is scaled to the latitude of this point. a 2-tuple, or a (2,) NumPy array of point coordinates

:returnsa (2,) numpy array that scales world coordinates. This

scaling is applied when converting to-from world to pixel coordinates.

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GetHitTestColor(self, xy)

Get the hit test colour

Parameters

xy – the position to get the hit test colour for

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HitTest(self, event, HitEvent)

Check if any objects in the dict for this event.

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InitAll(self)

Sets everything in the Canvas to default state.

It can be used to reset the Canvas

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InitializePanel(self)

Initialize the panel.

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KeyDownEvent(self, event)

Key down event.

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KeyUpEvent(self, event)

Key up event.

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LeftDoubleClickEvent(self, event)

Left double click event.

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LeftDownEvent(self, event)

Left down event.

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LeftUpEvent(self, event)

Left up event.

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MakeHitDict(self)

Initialize the Hit dictionary.

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MakeNewBuffers(self)

Make a new buffer.

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MakeNewForegroundHTBitmap(self)

Off screen Bitmap used for Hit tests on foreground objects

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MakeNewHTBitmap(self)

Off screen Bitmap used for Hit tests on background objects

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MiddleDoubleClickEvent(self, event)

Middle double click event.

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MiddleDownEvent(self, event)

Middle down event.

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MiddleUpEvent(self, event)

Middle up event.

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MotionEvent(self, event)

Motion event.

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MouseOverTest(self, event)

Check if mouse is over an object.

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MoveImage(self, shift, CoordType, ReDraw=True)

Move the image in the window.

Parameters

• shift (tuple) – is an (x, y) tuple defining amount to shift in each direction

• CoordType (string) –

  defines what coordinates to use, valid entries are:

  Coordtype	Description
  Panel	shift the image by some fraction of the size of the displayed image
  Pixel	shift the image by some number of pixels
  World	shift the image by an amount of floating point world coordinates

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OnPaint(self, event)

On paint handler.

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OnSize(self, event=None)

On size handler.

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OnSizeTimer(self, event=None)

On size timer handler.

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PixelToWorld(self, Points)

Converts coordinates from Pixel coordinates to world coordinates.

Points is a tuple of (x,y) coordinates, or a list of such tuples, or a NX2 Numpy array of x,y coordinates.

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RemoveObject(self, Object, ResetBB=True)

” Remove object from canvas

Parameters

• Object (DrawObject) – a DrawObjects to remove

• ResetBB (boolean) – reset the bounding box

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RemoveObjects(self, Objects)

” Remove objects from canvas

Parameters

Objects (list) – a list of DrawObjects to remove

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RightDoubleCLickEvent(self, event)

Right double click event.

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RightDownEvent(self, event)

Right down event.

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RightUpEvent(self, event)

Right up event.

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SaveAsImage(self, filename, ImageType=wx.BITMAP_TYPE_PNG)

Saves the current image as an image file.

Parameters

• filename (string) – the name of the image file

• ImageType – format to use, see wx.BitmapType and the note in wx.Bitmap.SaveFile

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ScalePixelToWorld(self, Lengths)

This function computes a pair of x.y lengths, to change then from pixel to world coordinates.

Lengths should be a NX2 array of (x,y) coordinates, or a 2-tuple, or sequence of 2-tuples.

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ScaleWorldToPixel(self, Lengths)

This function will get passed to the drawing functions of the objects, to Change a length from world to pixel coordinates.

Lengths should be a NX2 array of (x,y) coordinates, or a 2-tuple, or sequence of 2-tuples.

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SetMode(self, Mode)

Set the GUImode to any of the available mode.

Parameters

Mode – a valid GUI Mode, out of the box valid modes are subclassed from GUIBase or a mode can also be user defined.

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SetProjectionFun(self, ProjectionFun)

Set a custom projection function

Parameters

ProjectionFun – valid entries are FlatEarth, None or a callable object that takes the ViewPortCenter and returns MapProjectionVector

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SetToNewScale(self, DrawFlag=True)

Set to the new scale

Parameters

DrawFlag (boolean) – draw the canvas

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UnBindAll(self)

Removes all bindings to Objects.

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WheelEvent(self, event)

Wheel event.

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WorldToPixel(self, Coordinates)

This function will get passed to the drawing functions of the objects, to transform from world to pixel coordinates. Coordinates should be a NX2 array of (x,y) coordinates, or a 2-tuple, or sequence of 2-tuples.

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Zoom(self, factor, center = None, centerCoords="World", keepPointInPlace=False)

Zoom(factor, center) changes the amount of zoom of the image by factor. If factor is greater than one, the image gets larger. If factor is less than one, the image gets smaller. :param factor: amount to zoom in or out If factor is greater than one,

the image gets larger. If factor is less than one, the image gets smaller.

Parameters

• center – a tuple of (x,y) coordinates of the center of the viewport, after zooming. If center is not given, the center will stay the same.

• centerCoords – flag indicating whether the center given is in pixel or world coords. Options are: “World” or “Pixel”

• keepPointInPlace – boolean flag. If False, the center point is what’s given. If True, the image is shifted so that the given center point is kept in the same pixel space. This facilitates keeping the same point under the mouse when zooming with the scroll wheel.

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ZoomToBB(self, NewBB=None, DrawFlag=True)

Zooms the image to the bounding box given, or to the bounding box of all the objects on the canvas, if none is given.