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 such 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.

ToolContainerBase

The base class for the Toolbar class of each interactive backend.

StatusbarBase

The base class for the messaging area.

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

Bases: matplotlib.backend_bases.Event

An event triggered by a figure being closed

class matplotlib.backend_bases.DrawEvent(name, canvas, renderer)

Bases: matplotlib.backend_bases.Event

An event triggered by a draw operation on the canvas

In most backends callbacks subscribed to this callback will be fired after the rendering is complete but before the screen is updated. Any extra artists drawn to the canvas's renderer will be reflected without an explicit call to blit.

Warning

Calling canvas.draw and canvas.blit in these callbacks may not be safe with all backends and may cause infinite recursion.

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

Attributes:

renderer : RendererBase

the renderer for the draw event

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

Bases: object

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

Attributes:

name : str

the event name

canvas : FigureCanvasBase

the backend-specific canvas 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

Attributes:

figure : matplotlib.figure.Figure

A high-level 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.

This method will call all functions connected to the 'button_release_event' with a MouseEvent instance.

Parameters:

x : scalar

the canvas coordinates where 0=left

y : scalar

the canvas coordinates where 0=bottom

guiEvent

the native UI event that generated the mpl event

close_event(guiEvent=None)

Pass a CloseEvent to all functions connected to close_event.

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)

Pass a DrawEvent to all functions connected to draw_event.

draw_idle(*args, **kwargs)

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

enter_notify_event(guiEvent=None, xy=None)

Backend derived classes should call this function when entering canvas

Parameters:

guiEvent

the native UI event that generated the mpl event

xy : (float, float)

the coordinate location of the pointer when the canvas is entered

events = ['resize_event', 'draw_event', 'key_press_event', 'key_release_event', 'button_press_event', 'button_release_event', 'scroll_event', 'motion_notify_event', 'pick_event', 'idle_event', 'figure_enter_event', 'figure_leave_event', 'axes_enter_event', 'axes_leave_event', 'close_event']

filetypes = {'eps': 'Encapsulated Postscript', 'jpeg': 'Joint Photographic Experts Group', 'jpg': 'Joint Photographic Experts Group', 'pdf': 'Portable Document Format', 'pgf': 'PGF code for LaTeX', 'png': 'Portable Network Graphics', 'ps': 'Postscript', 'raw': 'Raw RGBA bitmap', 'rgba': 'Raw RGBA bitmap', 'svg': 'Scalable Vector Graphics', 'svgz': 'Scalable Vector Graphics', 'tif': 'Tagged Image File Format', 'tiff': 'Tagged Image File Format'}

fixed_dpi = None

flush_events()

Flush the GUI events for the figure.

Interactive backends need to reimplement this method.

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 (e.g., 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.

is_saving()

Returns whether 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)

Pass a KeyEvent to all functions connected to key_press_event.

key_release_event(key, guiEvent=None)

Pass a KeyEvent to all functions connected to key_release_event.

leave_notify_event(guiEvent=None)

Backend derived classes should call this function when leaving canvas

Parameters:

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.

This method will call all functions connected to the 'motion_notify_event' with a MouseEvent instance.

Parameters:

x : scalar

the canvas coordinates where 0=left

y : scalar

the canvas coordinates where 0=bottom

guiEvent

the native UI event that generated the mpl event

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().

Examples

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

Examples

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.

Other Parameters:

interval : scalar

Timer interval in milliseconds

callbacks : List[Tuple[callable, Tuple, Dict]]

Sequence of (func, args, kwargs) where func(*args, **kwargs) will be executed by the timer every interval.

callbacks which return False or 0 will be removed from the timer.

Examples

>>> timer = fig.canvas.new_timer(callbacks=[(f1, (1, ), {'a': 3}),])

onRemove(ev)

Deprecated since version 2.2: The onRemove function was deprecated in Matplotlib 2.2 and will be removed in 3.1.

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=None, edgecolor=None, orientation='portrait', format=None, *, bbox_inches=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.

Parameters:

filename

can also be a file object on image backends

orientation : {'landscape', 'portrait'}, optional

only currently applies to PostScript printing.

dpi : scalar, optional

the dots per inch to save the figure in; if None, use savefig.dpi

facecolor : color spec or None, optional

the facecolor of the figure; if None, defaults to savefig.facecolor

edgecolor : color spec or None, optional

the edgecolor of the figure; if None, defaults to savefig.edgecolor

format : str, optional

when set, forcibly set the file format to save to

bbox_inches : str or Bbox, optional

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 : scalar, optional

Amount of padding around the figure when bbox_inches is 'tight'. If None, use savefig.pad_inches

bbox_extra_artists : list of Artist, optional

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()

Pass a ResizeEvent to all functions connected to resize_event.

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 (e.g., a PS backend).

start_event_loop(timeout=0)

Start a blocking event loop.

Such an event loop is used by interactive functions, such as ginput and waitforbuttonpress, to wait for events.

The event loop blocks until a callback function triggers stop_event_loop, or timeout is reached.

If timeout is negative, never timeout.

Only interactive backends need to reimplement this method and it relies on flush_events being properly implemented.

Interactive backends should implement this in a more native way.

stop_event_loop()

Stop the current blocking event loop.

Interactive backends need to reimplement this to match start_event_loop

supports_blit = True

switch_backends(FigureCanvasClass)

Instantiate an instance of FigureCanvasClass

This is used for backend switching, e.g., to instantiate a FigureCanvasPS from a FigureCanvasGTK. Note, deep copying is not done, so any changes to one of the instances (e.g., 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

Attributes:

canvas : FigureCanvasBase

The backend-specific canvas instance

num : int or str

The figure number

key_press_handler_id : int

The default key handler cid, when using the toolmanager. Can be used to disable default key press handling

figure.canvas.mpl_disconnect(
    figure.canvas.manager.key_press_handler_id)

destroy()

full_screen_toggle()

get_window_title()

Get the title text of the window containing the figure.

Return None for non-GUI (e.g., PS) backends.

key_press(event)

Implement the default mpl key bindings defined at Navigation Keyboard Shortcuts

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.

This has no effect for non-GUI (e.g., PS) backends.

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)

Deprecated since version 2.2: The show_popup function was deprecated in Matplotlib 2.2 and will be removed in 3.1.

Display message in a popup -- GUI only.

class matplotlib.backend_bases.GraphicsContextBase

Bases: object

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

copy_properties(gc)

Copy properties from gc to self

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_color()

Gets the color to use for hatching.

get_hatch_linewidth()

Gets the linewidth to use for hatching.

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_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.

Parameters:

dash_offset : float

is the offset (usually 0).

dash_list : array_like

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_hatch(hatch)

Sets the hatch style for filling

set_hatch_color(hatch_color)

sets the color to use for hatching.

set_joinstyle(js)

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

set_linewidth(w)

Set the linewidth in points

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

Sets 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)

randomness : float, optional

The scale factor by which the length is shrunken or expanded (default 16)

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.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:

Notes

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.

Examples

Usage:

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

cid = fig.canvas.mpl_connect('key_press_event', on_key)

Attributes:

key : None or str

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").

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:

Attributes:

x : scalar

x position - pixels from left of canvas

y : scalar

y position - pixels from bottom of canvas

inaxes : bool

the Axes instance if mouse is over axes

xdata : scalar

x coord of mouse in data coords

ydata : scalar

y coord of mouse in data coords

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

lastevent = 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:

Examples

Usage:

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

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

Attributes:

button : {None, 1, 2, 3, 'up', 'down'}

The button pressed. 'up' and 'down' are used for scroll events. Note that in the nbagg backend, both the middle and right clicks return 3 since right clicking will bring up the context menu in some browsers.

key : None or str

The key pressed when the mouse event triggered, e.g. 'shift'. See KeyEvent.

step : scalar

The Number of scroll steps (positive for 'up', negative for 'down').

dblclick : bool

True if the event is a double-click.

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

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

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)

Callback for dragging in pan/zoom mode.

drag_zoom(event)

Callback for dragging 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.

Note that it is not guaranteed that x0 <= x1 and y0 <= y1.

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 whenever a mouse button is pressed.

press_pan(event)

Callback for mouse button press in pan/zoom mode.

press_zoom(event)

Callback for mouse button press in zoom to rect mode.

push_current()

Push the current view limits and position onto the stack.

release(event)

Callback for mouse button release.

release_pan(event)

Callback for mouse button release in pan/zoom mode.

release_zoom(event)

Callback for mouse button release in zoom to rect mode.

remove_rubberband()

Remove the rubberband.

save_figure(*args)

Save the current figure.

set_cursor(cursor)

Set the current cursor to one of the Cursors enums values.

If required by the backend, this method should trigger an update in the backend event loop after the cursor is set, as this method may be called e.g. before a long-running task during which the GUI is not updated.

set_history_buttons()

Enable or disable the back/forward button.

set_message(s)

Display a message on toolbar or in status bar.

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

update()

Reset the axes stack.

zoom(*args)

Activate zoom to rect mode.

exception matplotlib.backend_bases.NonGuiException

Bases: 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

Examples

Usage:

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

def on_pick(event):
    line = event.artist
    xdata, ydata = line.get_data()
    ind = event.ind
    print('on pick line:', np.array([xdata[ind], ydata[ind]]).T)

cid = fig.canvas.mpl_connect('pick_event', on_pick)

Attributes:

mouseevent : MouseEvent

the mouse event that generated the pick

artist : matplotlib.artist.Artist

the picked artist

other

extra class dependent attrs -- e.g., a Line2D pick may define different extra attributes than a PatchCollection pick event

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):

• draw_path()
• draw_image()
• draw_gouraud_triangle()

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

• draw_text()
• draw_markers()
• draw_path_collection()
• draw_quad_mesh()

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.

Parameters:

points : array_like, shape=(3, 2)

Array of (x, y) points for the triangle.

colors : array_like, shape=(3, 4)

RGBA colors for each point of the triangle.

transform : matplotlib.transforms.Transform

An affine transform to apply to the points.

draw_gouraud_triangles(gc, triangles_array, colors_array, transform)

Draws a series of Gouraud triangles.

Parameters:

points : array_like, shape=(N, 3, 2)

Array of N (x, y) points for the triangles.

colors : array_like, shape=(N, 3, 4)

Array of N RGBA colors for each point of the triangles.

transform : matplotlib.transforms.Transform

An affine transform to apply to the points.

draw_image(gc, x, y, im, transform=None)

Draw an RGBA image.

Parameters:

gc : GraphicsContextBase

a graphics context with clipping information.

x : scalar

the distance in physical units (i.e., dots or pixels) from the left hand side of the canvas.

y : scalar

the distance in physical units (i.e., dots or pixels) from the bottom side of the canvas.

im : array_like, shape=(N, M, 4), dtype=np.uint8

An array of RGBA pixels.

transform : matplotlib.transforms.Affine2DBase

If and only if the concrete backend is written such that option_scale_image() returns True, an affine transformation may be passed to draw_image(). It takes the form of a Affine2DBase instance. The translation vector of the transformation is given in physical units (i.e., dots or pixels). Note that the transformation does not override x and y, and has to be applied before translating the result by x and y (this can be accomplished by adding x and y to the translation vector defined by transform).

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.

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.

Parameters:

gc : GraphicsContextBase

The graphics context

marker_trans : matplotlib.transforms.Transform

An affine transform applied to the marker.

trans : matplotlib.transforms.Transform

An affine transform applied to the path.

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='TeX!', mtext=None)

draw_text(gc, x, y, s, prop, angle, ismath=False, mtext=None)

Draw the text instance

Parameters:

gc : GraphicsContextBase

the graphics context

x : scalar

the x location of the text in display coords

y : scalar

the y location of the text baseline in display coords

s : str

the text string

prop : matplotlib.font_manager.FontProperties

font properties

angle : scalar

the rotation angle in degrees

mtext : matplotlib.text.Text

the original text object to be rendered

Notes

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, height, and descent (offset from the bottom to the baseline), 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 always want to rescale and composite raster images. (like SVG, PDF, or PS)

option_scale_image()

override this method for renderers that support arbitrary affine transformations in draw_image() (most vector backends).

points_to_pixels(points)

Convert points to display units

You need to override this function (unless your backend doesn't have a dpi, e.g., 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

Parameters:

points : scalar or array_like

a float or a numpy array of float

Returns:

Points converted to pixels

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:

Attributes:

width : scalar

width of the canvas in pixels

height : scalar

height of the canvas in pixels

class matplotlib.backend_bases.ShowBase

Bases: matplotlib.backend_bases._Backend

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

Subclass must override mainloop() method.

class matplotlib.backend_bases.StatusbarBase(toolmanager)

Bases: object

Base class for the statusbar

set_message(s)

Display a message on toolbar or in status bar

Parameters:

s : str

Message text

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 : scalar

The time between timer events in milliseconds. Default is 1000 ms.

single_shot : bool

Boolean flag indicating whether this timer should operate as single shot (run once and then stop). Defaults to False.

callbacks : List[Tuple[callable, Tuple, Dict]]

Stores list of (func, args, kwargs) 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.

class matplotlib.backend_bases.ToolContainerBase(toolmanager)

Bases: object

Base class for all tool containers, e.g. toolbars.

Attributes:

toolmanager : ToolManager

The tools with which this ToolContainer wants to communicate.

add_tool(tool, group, position=-1)

Adds a tool to this container

Parameters:

tool : tool_like

The tool to add, see ToolManager.get_tool.

group : str

The name of the group to add this tool to.

position : int (optional)

The position within the group to place this tool. Defaults to end.

add_toolitem(name, group, position, image, description, toggle)

Add a toolitem to the container

This method must get implemented per backend

The callback associated with the button click event, must be EXACTLY self.trigger_tool(name)

Parameters:

name : string

Name of the tool to add, this gets used as the tool's ID and as the default label of the buttons

group : String

Name of the group that this tool belongs to

position : Int

Position of the tool within its group, if -1 it goes at the End

image_file : String

Filename of the image for the button or None

description : String

Description of the tool, used for the tooltips

toggle : Bool

• True : The button is a toggle (change the pressed/unpressed state between consecutive clicks)
• False : The button is a normal button (returns to unpressed state after release)

remove_toolitem(name)

Remove a toolitem from the ToolContainer

This method must get implemented per backend

Called when ToolManager emits a tool_removed_event

Parameters:

name : string

Name of the tool to remove

toggle_toolitem(name, toggled)

Toggle the toolitem without firing event

Parameters:

name : String

Id of the tool to toggle

toggled : bool

Whether to set this tool as toggled or not.

trigger_tool(name)

Trigger the tool

Parameters:

name : String

Name (id) of the tool triggered from within the container

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

Parameters:

event : KeyEvent

a key press/release event

canvas : FigureCanvasBase

the backend-specific canvas instance

toolbar : NavigationToolbar2

the navigation cursor toolbar

matplotlib.backend_bases.register_backend(format, backend, description=None)

Register a backend for saving to a given file format.

Parameters:

format : str

File extension

backend : module string or canvas class

Backend for handling file output

description : str, optional

Description of the file type. Defaults to an empty string