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matplotlib.backend_bases

Abstract base classes define the primitives that renderers and graphics contexts must implement to serve as a matplotlib backend

RendererBase
An abstract base class to handle drawing/rendering operations.
FigureCanvasBase
The abstraction layer that separates the matplotlib.figure.Figure from the backend specific details like a user interface drawing area
GraphicsContextBase
An abstract base class that provides color, line styles, etc...
Event
The base class for all of the matplotlib event handling. Derived classes suh as KeyEvent and MouseEvent store the meta data like keys and buttons pressed, x and y locations in pixel and Axes coordinates.
ShowBase
The base class for the Show class of each interactive backend; the ‘show’ callable is then set to Show.__call__, inherited from ShowBase.
class matplotlib.backend_bases.CloseEvent(name, canvas, guiEvent=None)

Bases: matplotlib.backend_bases.Event

An event triggered by a figure being closed

In addition to the Event attributes, the following event attributes are defined:

class matplotlib.backend_bases.Cursors
HAND = 0
MOVE = 3
POINTER = 1
SELECT_REGION = 2
class matplotlib.backend_bases.DrawEvent(name, canvas, renderer)

Bases: matplotlib.backend_bases.Event

An event triggered by a draw operation on the canvas

In addition to the Event attributes, the following event attributes are defined:

renderer
the RendererBase instance for the draw event
class matplotlib.backend_bases.Event(name, canvas, guiEvent=None)

A matplotlib event. Attach additional attributes as defined in FigureCanvasBase.mpl_connect(). The following attributes are defined and shown with their default values

name
the event name
canvas
the FigureCanvas instance generating the event
guiEvent
the GUI event that triggered the matplotlib event
class matplotlib.backend_bases.FigureCanvasBase(figure)

Bases: object

The canvas the figure renders into.

Public attributes

figure
A matplotlib.figure.Figure instance
blit(bbox=None)

blit the canvas in bbox (default entire canvas)

button_press_event(x, y, button, dblclick=False, guiEvent=None)

Backend derived classes should call this function on any mouse button press. x,y are the canvas coords: 0,0 is lower, left. button and key are as defined in MouseEvent.

This method will be call all functions connected to the ‘button_press_event’ with a MouseEvent instance.

button_release_event(x, y, button, guiEvent=None)

Backend derived classes should call this function on any mouse button release.

x
the canvas coordinates where 0=left
y
the canvas coordinates where 0=bottom
guiEvent
the native UI event that generated the mpl event

This method will be call all functions connected to the ‘button_release_event’ with a MouseEvent instance.

close_event(guiEvent=None)

This method will be called by all functions connected to the ‘close_event’ with a CloseEvent

draw(*args, **kwargs)

Render the Figure

draw_cursor(event)

Draw a cursor in the event.axes if inaxes is not None. Use native GUI drawing for efficiency if possible

draw_event(renderer)

This method will be call all functions connected to the ‘draw_event’ with a DrawEvent

draw_idle(*args, **kwargs)

draw() only if idle; defaults to draw but backends can overrride

enter_notify_event(guiEvent=None, xy=None)

Backend derived classes should call this function when entering canvas

guiEvent
the native UI event that generated the mpl event
xy
the coordinate location of the pointer when the canvas is entered
events = [u'resize_event', u'draw_event', u'key_press_event', u'key_release_event', u'button_press_event', u'button_release_event', u'scroll_event', u'motion_notify_event', u'pick_event', u'idle_event', u'figure_enter_event', u'figure_leave_event', u'axes_enter_event', u'axes_leave_event', u'close_event']
filetypes = {u'pgf': u'PGF code for LaTeX', u'svgz': u'Scalable Vector Graphics', u'tiff': u'Tagged Image File Format', u'jpg': u'Joint Photographic Experts Group', u'raw': u'Raw RGBA bitmap', u'jpeg': u'Joint Photographic Experts Group', u'png': u'Portable Network Graphics', u'ps': u'Postscript', u'svg': u'Scalable Vector Graphics', u'eps': u'Encapsulated Postscript', u'rgba': u'Raw RGBA bitmap', u'pdf': u'Portable Document Format', u'tif': u'Tagged Image File Format'}
fixed_dpi = None
flush_events()

Flush the GUI events for the figure. Implemented only for backends with GUIs.

get_default_filename()

Return a string, which includes extension, suitable for use as a default filename.

classmethod get_default_filetype()

Get the default savefig file format as specified in rcParam savefig.format. Returned string excludes period. Overridden in backends that only support a single file type.

classmethod get_supported_filetypes()

Return dict of savefig file formats supported by this backend

classmethod get_supported_filetypes_grouped()

Return a dict of savefig file formats supported by this backend, where the keys are a file type name, such as ‘Joint Photographic Experts Group’, and the values are a list of filename extensions used for that filetype, such as [‘jpg’, ‘jpeg’].

get_width_height()

Return the figure width and height in points or pixels (depending on the backend), truncated to integers

get_window_title()

Get the title text of the window containing the figure. Return None if there is no window (eg, a PS backend).

grab_mouse(ax)

Set the child axes which are currently grabbing the mouse events. Usually called by the widgets themselves. It is an error to call this if the mouse is already grabbed by another axes.

idle_event(guiEvent=None)

Called when GUI is idle.

is_saving()

Returns True when the renderer is in the process of saving to a file, rather than rendering for an on-screen buffer.

key_press_event(key, guiEvent=None)

This method will be call all functions connected to the ‘key_press_event’ with a KeyEvent

key_release_event(key, guiEvent=None)

This method will be call all functions connected to the ‘key_release_event’ with a KeyEvent

leave_notify_event(guiEvent=None)

Backend derived classes should call this function when leaving canvas

guiEvent
the native UI event that generated the mpl event
motion_notify_event(x, y, guiEvent=None)

Backend derived classes should call this function on any motion-notify-event.

x
the canvas coordinates where 0=left
y
the canvas coordinates where 0=bottom
guiEvent
the native UI event that generated the mpl event

This method will be call all functions connected to the ‘motion_notify_event’ with a MouseEvent instance.

mpl_connect(s, func)

Connect event with string s to func. The signature of func is:

def func(event)

where event is a matplotlib.backend_bases.Event. The following events are recognized

  • ‘button_press_event’
  • ‘button_release_event’
  • ‘draw_event’
  • ‘key_press_event’
  • ‘key_release_event’
  • ‘motion_notify_event’
  • ‘pick_event’
  • ‘resize_event’
  • ‘scroll_event’
  • ‘figure_enter_event’,
  • ‘figure_leave_event’,
  • ‘axes_enter_event’,
  • ‘axes_leave_event’
  • ‘close_event’

For the location events (button and key press/release), if the mouse is over the axes, the variable event.inaxes will be set to the Axes the event occurs is over, and additionally, the variables event.xdata and event.ydata will be defined. This is the mouse location in data coords. See KeyEvent and MouseEvent for more info.

Return value is a connection id that can be used with mpl_disconnect().

Example usage:

def on_press(event):
    print('you pressed', event.button, event.xdata, event.ydata)

cid = canvas.mpl_connect('button_press_event', on_press)
mpl_disconnect(cid)

Disconnect callback id cid

Example usage:

cid = canvas.mpl_connect('button_press_event', on_press)
#...later
canvas.mpl_disconnect(cid)
new_timer(*args, **kwargs)

Creates a new backend-specific subclass of backend_bases.Timer. This is useful for getting periodic events through the backend’s native event loop. Implemented only for backends with GUIs.

optional arguments:

interval
Timer interval in milliseconds
callbacks
Sequence of (func, args, kwargs) where func(args, **kwargs) will be executed by the timer every *interval.
onHilite(ev)

Mouse event processor which highlights the artists under the cursor. Connect this to the ‘motion_notify_event’ using:

canvas.mpl_connect('motion_notify_event',canvas.onHilite)
onRemove(ev)

Mouse event processor which removes the top artist under the cursor. Connect this to the ‘mouse_press_event’ using:

canvas.mpl_connect('mouse_press_event',canvas.onRemove)
pick(mouseevent)
pick_event(mouseevent, artist, **kwargs)

This method will be called by artists who are picked and will fire off PickEvent callbacks registered listeners

print_figure(filename, dpi=None, facecolor=u'w', edgecolor=u'w', orientation=u'portrait', format=None, **kwargs)

Render the figure to hardcopy. Set the figure patch face and edge colors. This is useful because some of the GUIs have a gray figure face color background and you’ll probably want to override this on hardcopy.

Arguments are:

filename
can also be a file object on image backends
orientation
only currently applies to PostScript printing.
dpi
the dots per inch to save the figure in; if None, use savefig.dpi
facecolor
the facecolor of the figure
edgecolor
the edgecolor of the figure
orientation
landscape’ | ‘portrait’ (not supported on all backends)
format
when set, forcibly set the file format to save to
bbox_inches
Bbox in inches. Only the given portion of the figure is saved. If ‘tight’, try to figure out the tight bbox of the figure. If None, use savefig.bbox
pad_inches
Amount of padding around the figure when bbox_inches is ‘tight’. If None, use savefig.pad_inches
bbox_extra_artists
A list of extra artists that will be considered when the tight bbox is calculated.
release_mouse(ax)

Release the mouse grab held by the axes, ax. Usually called by the widgets. It is ok to call this even if you ax doesn’t have the mouse grab currently.

resize(w, h)

set the canvas size in pixels

resize_event()

This method will be call all functions connected to the ‘resize_event’ with a ResizeEvent

scroll_event(x, y, step, guiEvent=None)

Backend derived classes should call this function on any scroll wheel event. x,y are the canvas coords: 0,0 is lower, left. button and key are as defined in MouseEvent.

This method will be call all functions connected to the ‘scroll_event’ with a MouseEvent instance.

set_window_title(title)

Set the title text of the window containing the figure. Note that this has no effect if there is no window (eg, a PS backend).

start_event_loop(timeout)

Start an event loop. This is used to start a blocking event loop so that interactive functions, such as ginput and waitforbuttonpress, can wait for events. This should not be confused with the main GUI event loop, which is always running and has nothing to do with this.

This is implemented only for backends with GUIs.

start_event_loop_default(timeout=0)

Start an event loop. This is used to start a blocking event loop so that interactive functions, such as ginput and waitforbuttonpress, can wait for events. This should not be confused with the main GUI event loop, which is always running and has nothing to do with this.

This function provides default event loop functionality based on time.sleep that is meant to be used until event loop functions for each of the GUI backends can be written. As such, it throws a deprecated warning.

Call signature:

start_event_loop_default(self,timeout=0)

This call blocks until a callback function triggers stop_event_loop() or timeout is reached. If timeout is <=0, never timeout.

stop_event_loop()

Stop an event loop. This is used to stop a blocking event loop so that interactive functions, such as ginput and waitforbuttonpress, can wait for events.

This is implemented only for backends with GUIs.

stop_event_loop_default()

Stop an event loop. This is used to stop a blocking event loop so that interactive functions, such as ginput and waitforbuttonpress, can wait for events.

Call signature:

stop_event_loop_default(self)
supports_blit = True
switch_backends(FigureCanvasClass)

Instantiate an instance of FigureCanvasClass

This is used for backend switching, eg, to instantiate a FigureCanvasPS from a FigureCanvasGTK. Note, deep copying is not done, so any changes to one of the instances (eg, setting figure size or line props), will be reflected in the other

class matplotlib.backend_bases.FigureManagerBase(canvas, num)

Bases: object

Helper class for pyplot mode, wraps everything up into a neat bundle

Public attibutes:

canvas
A FigureCanvasBase instance
num
The figure number
destroy()
full_screen_toggle()
get_window_title()

Get the title text of the window containing the figure. Return None for non-GUI backends (eg, a PS backend).

key_press(event)

Implement the default mpl key bindings defined at Navigation Keyboard Shortcuts

key_press_handler_id = None

The returned id from connecting the default key handler via FigureCanvasBase.mpl_connnect().

To disable default key press handling:

manager, canvas = figure.canvas.manager, figure.canvas
canvas.mpl_disconnect(manager.key_press_handler_id)
resize(w, h)

“For gui backends, resize the window (in pixels).

set_window_title(title)

Set the title text of the window containing the figure. Note that this has no effect for non-GUI backends (eg, a PS backend).

show()

For GUI backends, show the figure window and redraw. For non-GUI backends, raise an exception to be caught by show(), for an optional warning.

show_popup(msg)

Display message in a popup – GUI only

class matplotlib.backend_bases.GraphicsContextBase

An abstract base class that provides color, line styles, etc...

copy_properties(gc)

Copy properties from gc to self

dashd = {u'solid': (None, None), u'dashed': (0, (6.0, 6.0)), u'dotted': (0, (1.0, 3.0)), u'dashdot': (0, (3.0, 5.0, 1.0, 5.0))}
get_alpha()

Return the alpha value used for blending - not supported on all backends

get_antialiased()

Return true if the object should try to do antialiased rendering

get_capstyle()

Return the capstyle as a string in (‘butt’, ‘round’, ‘projecting’)

get_clip_path()

Return the clip path in the form (path, transform), where path is a Path instance, and transform is an affine transform to apply to the path before clipping.

get_clip_rectangle()

Return the clip rectangle as a Bbox instance

get_dashes()

Return the dash information as an offset dashlist tuple.

The dash list is a even size list that gives the ink on, ink off in pixels.

See p107 of to PostScript BLUEBOOK for more info.

Default value is None

get_forced_alpha()

Return whether the value given by get_alpha() should be used to override any other alpha-channel values.

get_gid()

Return the object identifier if one is set, None otherwise.

get_hatch()

Gets the current hatch style

get_hatch_path(density=6.0)

Returns a Path for the current hatch.

get_joinstyle()

Return the line join style as one of (‘miter’, ‘round’, ‘bevel’)

get_linestyle(style)

Return the linestyle: one of (‘solid’, ‘dashed’, ‘dashdot’, ‘dotted’).

get_linewidth()

Return the line width in points as a scalar

get_rgb()

returns a tuple of three or four floats from 0-1.

get_sketch_params()

Returns the sketch parameters for the artist.

Returns:

sketch_params : tuple or None

A 3-tuple with the following elements: :

  • scale: The amplitude of the wiggle perpendicular to the source line.
  • length: The length of the wiggle along the line.
  • randomness: The scale factor by which the length is shrunken or expanded.

May return `None` if no sketch parameters were set. :

get_snap()

returns the snap setting which may be:

  • True: snap vertices to the nearest pixel center
  • False: leave vertices as-is
  • None: (auto) If the path contains only rectilinear line segments, round to the nearest pixel center
get_url()

returns a url if one is set, None otherwise

restore()

Restore the graphics context from the stack - needed only for backends that save graphics contexts on a stack

set_alpha(alpha)

Set the alpha value used for blending - not supported on all backends. If alpha=None (the default), the alpha components of the foreground and fill colors will be used to set their respective transparencies (where applicable); otherwise, alpha will override them.

set_antialiased(b)

True if object should be drawn with antialiased rendering

set_capstyle(cs)

Set the capstyle as a string in (‘butt’, ‘round’, ‘projecting’)

set_clip_path(path)

Set the clip path and transformation. Path should be a TransformedPath instance.

set_clip_rectangle(rectangle)

Set the clip rectangle with sequence (left, bottom, width, height)

set_dashes(dash_offset, dash_list)

Set the dash style for the gc.

dash_offset
is the offset (usually 0).
dash_list
specifies the on-off sequence as points. (None, None) specifies a solid line
set_foreground(fg, isRGBA=False)

Set the foreground color. fg can be a MATLAB format string, a html hex color string, an rgb or rgba unit tuple, or a float between 0 and 1. In the latter case, grayscale is used.

If you know fg is rgba, set isRGBA=True for efficiency.

set_gid(id)

Sets the id.

set_graylevel(frac)

Set the foreground color to be a gray level with frac

set_hatch(hatch)

Sets the hatch style for filling

set_joinstyle(js)

Set the join style to be one of (‘miter’, ‘round’, ‘bevel’)

set_linestyle(style)

Set the linestyle to be one of (‘solid’, ‘dashed’, ‘dashdot’, ‘dotted’). One may specify customized dash styles by providing a tuple of (offset, dash pairs). For example, the predefiend linestyles have following values.:

‘dashed’ : (0, (6.0, 6.0)), ‘dashdot’ : (0, (3.0, 5.0, 1.0, 5.0)), ‘dotted’ : (0, (1.0, 3.0)),
set_linewidth(w)

Set the linewidth in points

set_sketch_params(scale=None, length=None, randomness=None)

Sets the the sketch parameters.

Parameters:

scale : float, optional

The amplitude of the wiggle perpendicular to the source line, in pixels. If scale is None, or not provided, no sketch filter will be provided.

length : float, optional

The length of the wiggle along the line, in pixels (default 128.0)

randomness : float, optional

The scale factor by which the length is shrunken or expanded (default 16.0)

set_snap(snap)

Sets the snap setting which may be:

  • True: snap vertices to the nearest pixel center
  • False: leave vertices as-is
  • None: (auto) If the path contains only rectilinear line segments, round to the nearest pixel center
set_url(url)

Sets the url for links in compatible backends

class matplotlib.backend_bases.IdleEvent(name, canvas, guiEvent=None)

Bases: matplotlib.backend_bases.Event

An event triggered by the GUI backend when it is idle – useful for passive animation

class matplotlib.backend_bases.KeyEvent(name, canvas, key, x=0, y=0, guiEvent=None)

Bases: matplotlib.backend_bases.LocationEvent

A key event (key press, key release).

Attach additional attributes as defined in FigureCanvasBase.mpl_connect().

In addition to the Event and LocationEvent attributes, the following attributes are defined:

key
the key(s) pressed. Could be None, a single case sensitive ascii character (“g”, “G”, “#”, etc.), a special key (“control”, “shift”, “f1”, “up”, etc.) or a combination of the above (e.g., “ctrl+alt+g”, “ctrl+alt+G”).

Note

Modifier keys will be prefixed to the pressed key and will be in the order “ctrl”, “alt”, “super”. The exception to this rule is when the pressed key is itself a modifier key, therefore “ctrl+alt” and “alt+control” can both be valid key values.

Example usage:

def on_key(event):
    print('you pressed', event.key, event.xdata, event.ydata)

cid = fig.canvas.mpl_connect('key_press_event', on_key)
class matplotlib.backend_bases.LocationEvent(name, canvas, x, y, guiEvent=None)

Bases: matplotlib.backend_bases.Event

An event that has a screen location

The following additional attributes are defined and shown with their default values.

In addition to the Event attributes, the following event attributes are defined:

x
x position - pixels from left of canvas
y
y position - pixels from bottom of canvas
inaxes
the Axes instance if mouse is over axes
xdata
x coord of mouse in data coords
ydata
y coord of mouse in data coords

x, y in figure coords, 0,0 = bottom, left

inaxes = None
lastevent = None
x = None
xdata = None
y = None
ydata = None
class matplotlib.backend_bases.MouseEvent(name, canvas, x, y, button=None, key=None, step=0, dblclick=False, guiEvent=None)

Bases: matplotlib.backend_bases.LocationEvent

A mouse event (‘button_press_event’,
‘button_release_event’, ‘scroll_event’, ‘motion_notify_event’).

In addition to the Event and LocationEvent attributes, the following attributes are defined:

button
button pressed None, 1, 2, 3, ‘up’, ‘down’ (up and down are used for scroll events)
key
the key depressed when the mouse event triggered (see KeyEvent)
step
number of scroll steps (positive for ‘up’, negative for ‘down’)

Example usage:

def on_press(event):
    print('you pressed', event.button, event.xdata, event.ydata)

cid = fig.canvas.mpl_connect('button_press_event', on_press)

x, y in figure coords, 0,0 = bottom, left button pressed None, 1, 2, 3, ‘up’, ‘down’

button = None
dblclick = None
inaxes = None
step = None
x = None
xdata = None
y = None
ydata = None
class matplotlib.backend_bases.NavigationToolbar2(canvas)

Bases: object

Base class for the navigation cursor, version 2

backends must implement a canvas that handles connections for ‘button_press_event’ and ‘button_release_event’. See FigureCanvasBase.mpl_connect() for more information

They must also define

save_figure()
save the current figure
set_cursor()
if you want the pointer icon to change
_init_toolbar()
create your toolbar widget
draw_rubberband() (optional)
draw the zoom to rect “rubberband” rectangle
press() (optional)
whenever a mouse button is pressed, you’ll be notified with the event
release() (optional)
whenever a mouse button is released, you’ll be notified with the event
dynamic_update() (optional)
dynamically update the window while navigating
set_message() (optional)
display message
set_history_buttons() (optional)
you can change the history back / forward buttons to indicate disabled / enabled state.

That’s it, we’ll do the rest!

back(*args)

move back up the view lim stack

drag_pan(event)

the drag callback in pan/zoom mode

drag_zoom(event)

the drag callback in zoom mode

draw()

Redraw the canvases, update the locators

draw_rubberband(event, x0, y0, x1, y1)

Draw a rectangle rubberband to indicate zoom limits

dynamic_update()
forward(*args)

Move forward in the view lim stack

home(*args)

Restore the original view

mouse_move(event)
pan(*args)

Activate the pan/zoom tool. pan with left button, zoom with right

press(event)

Called whenver a mouse button is pressed.

press_pan(event)

the press mouse button in pan/zoom mode callback

press_zoom(event)

the press mouse button in zoom to rect mode callback

push_current()

push the current view limits and position onto the stack

release(event)

this will be called whenever mouse button is released

release_pan(event)

the release mouse button callback in pan/zoom mode

release_zoom(event)

the release mouse button callback in zoom to rect mode

save_figure(*args)

Save the current figure

set_cursor(cursor)

Set the current cursor to one of the Cursors enums values

set_history_buttons()

Enable or disable back/forward button

set_message(s)

Display a message on toolbar or in status bar

toolitems = ((u'Home', u'Reset original view', u'home', u'home'), (u'Back', u'Back to previous view', u'back', u'back'), (u'Forward', u'Forward to next view', u'forward', u'forward'), (None, None, None, None), (u'Pan', u'Pan axes with left mouse, zoom with right', u'move', u'pan'), (u'Zoom', u'Zoom to rectangle', u'zoom_to_rect', u'zoom'), (None, None, None, None), (u'Subplots', u'Configure subplots', u'subplots', u'configure_subplots'), (u'Save', u'Save the figure', u'filesave', u'save_figure'))
update()

Reset the axes stack

zoom(*args)

Activate zoom to rect mode

exception matplotlib.backend_bases.NonGuiException

Bases: exceptions.Exception

class matplotlib.backend_bases.PickEvent(name, canvas, mouseevent, artist, guiEvent=None, **kwargs)

Bases: matplotlib.backend_bases.Event

a pick event, fired when the user picks a location on the canvas sufficiently close to an artist.

Attrs: all the Event attributes plus

mouseevent
the MouseEvent that generated the pick
artist
the Artist picked
other
extra class dependent attrs – eg a Line2D pick may define different extra attributes than a PatchCollection pick event

Example usage:

line, = ax.plot(rand(100), 'o', picker=5)  # 5 points tolerance

def on_pick(event):
    thisline = event.artist
    xdata, ydata = thisline.get_data()
    ind = event.ind
    print('on pick line:', zip(xdata[ind], ydata[ind]))

cid = fig.canvas.mpl_connect('pick_event', on_pick)
class matplotlib.backend_bases.RendererBase

Bases: object

An abstract base class to handle drawing/rendering operations.

The following methods must be implemented in the backend for full functionality (though just implementing draw_path() alone would give a highly capable backend):

The following methods should be implemented in the backend for optimization reasons:

close_group(s)

Close a grouping element with label s Is only currently used by backend_svg

draw_gouraud_triangle(gc, points, colors, transform)

Draw a Gouraud-shaded triangle.

points is a 3x2 array of (x, y) points for the triangle.

colors is a 3x4 array of RGBA colors for each point of the triangle.

transform is an affine transform to apply to the points.

draw_gouraud_triangles(gc, triangles_array, colors_array, transform)

Draws a series of Gouraud triangles.

points is a Nx3x2 array of (x, y) points for the trianglex.

colors is a Nx3x4 array of RGBA colors for each point of the triangles.

transform is an affine transform to apply to the points.

draw_image(gc, x, y, im)

Draw the image instance into the current axes;

gc
a GraphicsContext containing clipping information
x
is the distance in pixels from the left hand side of the canvas.
y
the distance from the origin. That is, if origin is upper, y is the distance from top. If origin is lower, y is the distance from bottom
im
the matplotlib._image.Image instance
draw_markers(gc, marker_path, marker_trans, path, trans, rgbFace=None)

Draws a marker at each of the vertices in path. This includes all vertices, including control points on curves. To avoid that behavior, those vertices should be removed before calling this function.

gc
the GraphicsContextBase instance
marker_trans
is an affine transform applied to the marker.
trans
is an affine transform applied to the path.

This provides a fallback implementation of draw_markers that makes multiple calls to draw_path(). Some backends may want to override this method in order to draw the marker only once and reuse it multiple times.

draw_path(gc, path, transform, rgbFace=None)

Draws a Path instance using the given affine transform.

draw_path_collection(gc, master_transform, paths, all_transforms, offsets, offsetTrans, facecolors, edgecolors, linewidths, linestyles, antialiaseds, urls, offset_position)

Draws a collection of paths selecting drawing properties from the lists facecolors, edgecolors, linewidths, linestyles and antialiaseds. offsets is a list of offsets to apply to each of the paths. The offsets in offsets are first transformed by offsetTrans before being applied. offset_position may be either “screen” or “data” depending on the space that the offsets are in.

This provides a fallback implementation of draw_path_collection() that makes multiple calls to draw_path(). Some backends may want to override this in order to render each set of path data only once, and then reference that path multiple times with the different offsets, colors, styles etc. The generator methods _iter_collection_raw_paths() and _iter_collection() are provided to help with (and standardize) the implementation across backends. It is highly recommended to use those generators, so that changes to the behavior of draw_path_collection() can be made globally.

draw_quad_mesh(gc, master_transform, meshWidth, meshHeight, coordinates, offsets, offsetTrans, facecolors, antialiased, edgecolors)

This provides a fallback implementation of draw_quad_mesh() that generates paths and then calls draw_path_collection().

draw_tex(gc, x, y, s, prop, angle, ismath=u'TeX!', mtext=None)
draw_text(gc, x, y, s, prop, angle, ismath=False, mtext=None)

Draw the text instance

gc
the GraphicsContextBase instance
x
the x location of the text in display coords
y
the y location of the text baseline in display coords
s
the text string
prop
a matplotlib.font_manager.FontProperties instance
angle
the rotation angle in degrees
mtext
a matplotlib.text.Text instance

backend implementers note

When you are trying to determine if you have gotten your bounding box right (which is what enables the text layout/alignment to work properly), it helps to change the line in text.py:

if 0: bbox_artist(self, renderer)

to if 1, and then the actual bounding box will be plotted along with your text.

flipy()

Return true if y small numbers are top for renderer Is used for drawing text (matplotlib.text) and images (matplotlib.image) only

get_canvas_width_height()

return the canvas width and height in display coords

get_image_magnification()

Get the factor by which to magnify images passed to draw_image(). Allows a backend to have images at a different resolution to other artists.

get_texmanager()

return the matplotlib.texmanager.TexManager instance

get_text_width_height_descent(s, prop, ismath)

get the width and height, and the offset from the bottom to the baseline (descent), in display coords of the string s with FontProperties prop

new_gc()

Return an instance of a GraphicsContextBase

open_group(s, gid=None)

Open a grouping element with label s. If gid is given, use gid as the id of the group. Is only currently used by backend_svg.

option_image_nocomposite()

override this method for renderers that do not necessarily want to rescale and composite raster images. (like SVG)

option_scale_image()

override this method for renderers that support arbitrary scaling of image (most of the vector backend).

points_to_pixels(points)

Convert points to display units

points
a float or a numpy array of float

return points converted to pixels

You need to override this function (unless your backend doesn’t have a dpi, eg, postscript or svg). Some imaging systems assume some value for pixels per inch:

points to pixels = points * pixels_per_inch/72.0 * dpi/72.0
start_filter()

Used in AggRenderer. Switch to a temporary renderer for image filtering effects.

start_rasterizing()

Used in MixedModeRenderer. Switch to the raster renderer.

stop_filter(filter_func)

Used in AggRenderer. Switch back to the original renderer. The contents of the temporary renderer is processed with the filter_func and is drawn on the original renderer as an image.

stop_rasterizing()

Used in MixedModeRenderer. Switch back to the vector renderer and draw the contents of the raster renderer as an image on the vector renderer.

strip_math(s)
class matplotlib.backend_bases.ResizeEvent(name, canvas)

Bases: matplotlib.backend_bases.Event

An event triggered by a canvas resize

In addition to the Event attributes, the following event attributes are defined:

width
width of the canvas in pixels
height
height of the canvas in pixels
class matplotlib.backend_bases.ShowBase

Bases: object

Simple base class to generate a show() callable in backends.

Subclass must override mainloop() method.

mainloop()
class matplotlib.backend_bases.TimerBase(interval=None, callbacks=None)

Bases: object

A base class for providing timer events, useful for things animations. Backends need to implement a few specific methods in order to use their own timing mechanisms so that the timer events are integrated into their event loops.

Mandatory functions that must be implemented:

  • _timer_start: Contains backend-specific code for starting the timer
  • _timer_stop: Contains backend-specific code for stopping the timer

Optional overrides:

  • _timer_set_single_shot: Code for setting the timer to single shot operating mode, if supported by the timer object. If not, the Timer class itself will store the flag and the _on_timer method should be overridden to support such behavior.
  • _timer_set_interval: Code for setting the interval on the timer, if there is a method for doing so on the timer object.
  • _on_timer: This is the internal function that any timer object should call, which will handle the task of running all callbacks that have been set.

Attributes:

  • interval: The time between timer events in milliseconds. Default is 1000 ms.
  • single_shot: Boolean flag indicating whether this timer should operate as single shot (run once and then stop). Defaults to False.
  • callbacks: Stores list of (func, args) tuples that will be called upon timer events. This list can be manipulated directly, or the functions add_callback and remove_callback can be used.
add_callback(func, *args, **kwargs)

Register func to be called by timer when the event fires. Any additional arguments provided will be passed to func.

interval
remove_callback(func, *args, **kwargs)

Remove func from list of callbacks. args and kwargs are optional and used to distinguish between copies of the same function registered to be called with different arguments.

single_shot
start(interval=None)

Start the timer object. interval is optional and will be used to reset the timer interval first if provided.

stop()

Stop the timer.

matplotlib.backend_bases.get_registered_canvas_class(format)

Return the registered default canvas for given file format. Handles deferred import of required backend.

matplotlib.backend_bases.key_press_handler(event, canvas, toolbar=None)

Implement the default mpl key bindings for the canvas and toolbar described at Navigation Keyboard Shortcuts

event
a KeyEvent instance
canvas
a FigureCanvasBase instance
toolbar
a NavigationToolbar2 instance
matplotlib.backend_bases.register_backend(format, backend, description)

Register a backend for saving to a given file format.

format
File extention
backend
Backend for handling file output (module string or canvas class)
description
Description of the file type