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- """
- A fully functional, do-nothing backend intended as a template for backend
- writers. It is fully functional in that you can select it as a backend e.g.
- with ::
- import matplotlib
- matplotlib.use("template")
- and your program will (should!) run without error, though no output is
- produced. This provides a starting point for backend writers; you can
- selectively implement drawing methods (`~.RendererTemplate.draw_path`,
- `~.RendererTemplate.draw_image`, etc.) and slowly see your figure come to life
- instead having to have a full blown implementation before getting any results.
- Copy this file to a directory outside of the Matplotlib source tree, somewhere
- where Python can import it (by adding the directory to your ``sys.path`` or by
- packaging it as a normal Python package); if the backend is importable as
- ``import my.backend`` you can then select it using ::
- import matplotlib
- matplotlib.use("module://my.backend")
- If your backend implements support for saving figures (i.e. has a `print_xyz`
- method), you can register it as the default handler for a given file type::
- from matplotlib.backend_bases import register_backend
- register_backend('xyz', 'my_backend', 'XYZ File Format')
- ...
- plt.savefig("figure.xyz")
- """
- from matplotlib._pylab_helpers import Gcf
- from matplotlib.backend_bases import (
- FigureCanvasBase, FigureManagerBase, GraphicsContextBase, RendererBase)
- from matplotlib.figure import Figure
- class RendererTemplate(RendererBase):
- """
- The renderer handles drawing/rendering operations.
- This is a minimal do-nothing class that can be used to get started when
- writing a new backend. Refer to `backend_bases.RendererBase` for
- documentation of the methods.
- """
- def __init__(self, dpi):
- super().__init__()
- self.dpi = dpi
- def draw_path(self, gc, path, transform, rgbFace=None):
- pass
-
-
-
-
-
-
-
-
-
- def draw_image(self, gc, x, y, im):
- pass
- def draw_text(self, gc, x, y, s, prop, angle, ismath=False, mtext=None):
- pass
- def flipy(self):
-
- return True
- def get_canvas_width_height(self):
-
- return 100, 100
- def get_text_width_height_descent(self, s, prop, ismath):
- return 1, 1, 1
- def new_gc(self):
-
- return GraphicsContextTemplate()
- def points_to_pixels(self, points):
-
- return points
-
-
-
-
- class GraphicsContextTemplate(GraphicsContextBase):
- """
- The graphics context provides the color, line styles, etc... See the cairo
- and postscript backends for examples of mapping the graphics context
- attributes (cap styles, join styles, line widths, colors) to a particular
- backend. In cairo this is done by wrapping a cairo.Context object and
- forwarding the appropriate calls to it using a dictionary mapping styles
- to gdk constants. In Postscript, all the work is done by the renderer,
- mapping line styles to postscript calls.
- If it's more appropriate to do the mapping at the renderer level (as in
- the postscript backend), you don't need to override any of the GC methods.
- If it's more appropriate to wrap an instance (as in the cairo backend) and
- do the mapping here, you'll need to override several of the setter
- methods.
- The base GraphicsContext stores colors as a RGB tuple on the unit
- interval, e.g., (0.5, 0.0, 1.0). You may need to map this to colors
- appropriate for your backend.
- """
- def draw_if_interactive():
- """
- For image backends - is not required.
- For GUI backends - this should be overridden if drawing should be done in
- interactive python mode.
- """
- def show(*, block=None):
- """
- For image backends - is not required.
- For GUI backends - show() is usually the last line of a pyplot script and
- tells the backend that it is time to draw. In interactive mode, this
- should do nothing.
- """
- for manager in Gcf.get_all_fig_managers():
-
- pass
- def new_figure_manager(num, *args, FigureClass=Figure, **kwargs):
- """Create a new figure manager instance."""
-
-
-
-
-
- thisFig = FigureClass(*args, **kwargs)
- return new_figure_manager_given_figure(num, thisFig)
- def new_figure_manager_given_figure(num, figure):
- """Create a new figure manager instance for the given figure."""
- canvas = FigureCanvasTemplate(figure)
- manager = FigureManagerTemplate(canvas, num)
- return manager
- class FigureCanvasTemplate(FigureCanvasBase):
- """
- The canvas the figure renders into. Calls the draw and print fig
- methods, creates the renderers, etc.
- Note: GUI templates will want to connect events for button presses,
- mouse movements and key presses to functions that call the base
- class methods button_press_event, button_release_event,
- motion_notify_event, key_press_event, and key_release_event. See the
- implementations of the interactive backends for examples.
- Attributes
- ----------
- figure : `matplotlib.figure.Figure`
- A high-level Figure instance
- """
- def draw(self):
- """Draw the figure using the renderer."""
- renderer = RendererTemplate(self.figure.dpi)
- self.figure.draw(renderer)
-
-
-
-
- filetypes = {**FigureCanvasBase.filetypes, 'foo': 'My magic Foo format'}
- def print_foo(self, filename, *args, **kwargs):
- """
- Write out format foo. The dpi, facecolor and edgecolor are restored
- to their original values after this call, so you don't need to
- save and restore them.
- """
- self.draw()
- def get_default_filetype(self):
- return 'foo'
- class FigureManagerTemplate(FigureManagerBase):
- """
- Helper class for pyplot mode, wraps everything up into a neat bundle.
- For non-interactive backends, the base class is sufficient.
- """
- FigureCanvas = FigureCanvasTemplate
- FigureManager = FigureManagerTemplate
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