omnicanvas.canvas (The canvas)

This module contains the main Canvas class.

class omnicanvas.canvas.Canvas(width, height, background_color=None)[source]

A backdrop on which other Graphic objects are painted.

Parameters:
  • width – The canvas’s width in pixels.
  • height – The canvas’s height in pixels.
  • background_color – The canvas’s background colour - the default is white
width(width=None)[source]

The canvas’s width in pixels. Passing a value will update the width property.

Parameters:width – If given, the canvas’s width will be set to this.
Return type:int
height(height=None)[source]

The canvas’s height in pixels. Passing a value will update the height property.

Parameters:height – If given, the canvas’s height will be set to this.
Return type:int
background_color(background_color=None)[source]

The canvas’s background colour, as a hex string. Passing a value will update the background_color property (as a hex string).

Parameters:background_color (str) – If given, the canvas’s background_color will be set to this.
Return type:str
graphics()[source]

A list of all the Graphic objects on this canvas.

Return type:list
get_graphic_by_name(name)[source]

Searches the canvas’s Graphic objects and returns the first one with a matching name. Returns None if there are no matches.

Parameters:name (str) – The name to search by.
Return type:str
get_graphics_by_name(name)[source]

Searches the canvas’s Graphic objects and returns all the ones with a matching name. Returns an empty list if there are no matches.

Parameters:name (str) – The name to search by.
Returns:list of Graphic
add_rectangle(*args, **kwargs)[source]

Adds a Rectangle to the canvas.

Parameters:
  • x – The x-coordinate of the Rectangle’s upper left corner.
  • y – The y-coordinate of the Rectangle’s upper left corner.
  • width – The Rectangle’s width.
  • height – The Rectangle’s height.
  • fill_color (str) – The Rectangle’s interior colour.
  • opacity – The degree of transparency, from 0 to 1 (0 being invisible).
  • line_width – The width of the edge of the Rectangle in pixels.
  • line_style (str) – The pattern of the edges. Acceptable values are - (default), .. (dotted) or -- (dashed).
  • line_color (str) – The colour of the edge.
  • rotation (tuple) – Any rotation to be applied, in the format (x of rotation point, y of rotation point, angle).
  • data (dict) – Any data to be associated with the Rectangle.
Return type:

Rectangle
add_line(*args, **kwargs)[source]

Adds a Line to the canvas.

Parameters:
  • x1 – The x-coordinate of the Line’s start point.
  • y1 – The y-coordinate of the Line’s start point.
  • x2 – The x-coordinate of the Line’s end point.
  • y2 – The y-coordinate of the Line’s end point.
  • line_width – The width of the Line in pixels.
  • line_style (str) – The pattern of the Line. Acceptable values are - (default), .. (dotted) or -- (dashed).
  • line_color (str) – The colour of the Line.
  • rotation (tuple) – Any rotation to be applied, in the format (x of rotation point, y of rotation point, angle).
  • data (dict) – Any data to be associated with the Line.
Return type:

Line
add_polygon(*args, **kwargs)[source]

Adds a Polygon to the canvas.

Parameters:
  • *points – The alternating x and y values of the Polygon’s corners.
  • fill_color (str) – The Polygon’s interior colour.
  • opacity – The degree of transparency, from 0 to 1 (0 being invisible).
  • line_width – The width of the edge of the Polygon in pixels.
  • line_style (str) – The pattern of the edges. Acceptable values are - (default), .. (dotted) or -- (dashed).
  • line_color (str) – The colour of the edge.
  • rotation (tuple) – Any rotation to be applied, in the format (x of rotation point, y of rotation point, angle).
  • data (dict) – Any data to be associated with the Polygon.
Return type:

Polygon
add_text(*args, **kwargs)[source]

Adds a Text to the canvas.

Parameters:
  • x – The Text’s x location.
  • y – The Text’s y location.
  • text (str) – The text to display.
  • font_size – The font size of the Text when displayed.
  • horizontal_align – The horizontal alignment of the Text. Acceptable values are left, center (default) and right.
  • vertical_align – The vertical alignment of the Text. Acceptable values are top, middle (default) and bottom.
  • fill_color (str) – Defaults to ‘#FFFFFF’.
  • opacity – The degree of transparency, from 0 to 1 (0 being invisible).
  • line_width – Defaults to 0.
  • line_style (str) – The line pattern. Acceptable values are - (default), .. (dotted) or -- (dashed).
  • line_color (str) – Defaults to ‘#000000’.
  • rotation (tuple) – Any rotation to be applied, in the format (x of rotation point, y of rotation point, angle), in degrees.
  • data (dict) – Any data to be associated with the Text.
Return type:

Text
add_polyline(*args, **kwargs)[source]

Adds a Polyline to the canvas.

Parameters:
  • *points – The alternating x and y values of the Polyline’s corners.
  • line_width – The width of the edge of the Polyline in pixels.
  • line_style (str) – The pattern of the edges. Acceptable values are - (default), .. (dotted) or -- (dashed).
  • line_color (str) – The colour of the edge.
  • rotation (tuple) – Any rotation to be applied, in the format (x of rotation point, y of rotation point, angle).
  • data (dict) – Any data to be associated with the Polyline.
Return type:

Polyline
save(path)[source]

Saves the canvas to file as an SVG file.

Parameters:path (str) – The location and filename to save to.
to_svg(canvas)

Returns the SVG text of the canvas.

Any data attributes of the Graphics contained will be rendered as SVG attributes.

Return type:str