# matplotlib.backends.backend_cairo¶

## A Cairo backend for matplotlib¶

Author: Steve Chaplin and others

This backend depends on cairocffi or pycairo.

matplotlib.backends.backend_cairo.FigureCanvas
class matplotlib.backends.backend_cairo.FigureCanvasCairo(figure=None)[source]
copy_from_bbox(self, bbox)[source]
print_pdf(self, fobj, *args, **kwargs)[source]
print_png(self, fobj)[source]
print_ps(self, fobj, *args, **kwargs)[source]
print_raw(self, fobj)
print_rgba(self, fobj)[source]
print_svg(self, fobj, *args, **kwargs)[source]
print_svgz(self, fobj, *args, **kwargs)[source]
restore_region(self, region)[source]
class matplotlib.backends.backend_cairo.GraphicsContextCairo(renderer)[source]
get_rgb(self)[source]

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

restore(self)[source]

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

set_alpha(self, alpha)[source]

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(self, b)[source]

Set whether object should be drawn with antialiased rendering.

set_capstyle(self, cs)[source]

Set how to draw endpoints of lines.

Parameters: csCapStyle or {'butt', 'projecting', 'round'}
set_clip_path(self, path)[source]

Set the clip path to a TransformedPath or None.

set_clip_rectangle(self, rectangle)[source]

Set the clip rectangle to a Bbox or None.

set_dashes(self, offset, dashes)[source]

Set the dash style for the gc.

Parameters: dash_offsetfloat or NoneThe offset (usually 0). dash_listarray-like or NoneThe on-off sequence as points.

Notes

(None, None) specifies a solid line.

set_foreground(self, fg, isRGBA=None)[source]

Set the foreground color.

Parameters: fgcolor isRGBAboolIf fg is known to be an (r, g, b, a) tuple, isRGBA can be set to True to improve performance.
set_joinstyle(self, js)[source]

Set how to draw connections between line segments.

Parameters: jsJoinStyle or {'miter', 'round', 'bevel'}
set_linewidth(self, w)[source]

Set the linewidth in points.

class matplotlib.backends.backend_cairo.RendererCairo(dpi)[source]
draw_image(self, gc, x, y, im)[source]

Draw an RGBA image.

Parameters: gcGraphicsContextBaseA graphics context with clipping information. xscalarThe distance in physical units (i.e., dots or pixels) from the left hand side of the canvas. yscalarThe distance in physical units (i.e., dots or pixels) from the bottom side of the canvas. im(N, M, 4) array-like of np.uint8An array of RGBA pixels. transformmatplotlib.transforms.Affine2DBaseIf and only if the concrete backend is written such that option_scale_image() returns True, an affine transformation (i.e., an Affine2DBase) may be passed to draw_image(). 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(self, gc, marker_path, marker_trans, path, transform, rgbFace=None)[source]

Draw a marker at each of path's vertices (excluding control points).

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: gcGraphicsContextBaseThe graphics context. marker_transmatplotlib.transforms.TransformAn affine transform applied to the marker. transmatplotlib.transforms.TransformAn affine transform applied to the path.
draw_path(self, gc, path, transform, rgbFace=None)[source]

Draw a Path instance using the given affine transform.

draw_text(self, gc, x, y, s, prop, angle, ismath=False, mtext=None)[source]

Draw the text instance.

Parameters: gcGraphicsContextBaseThe graphics context. xfloatThe x location of the text in display coords. yfloatThe y location of the text baseline in display coords. sstrThe text string. propmatplotlib.font_manager.FontPropertiesThe font properties. anglefloatThe rotation angle in degrees anti-clockwise. mtextmatplotlib.text.TextThe original text object to be rendered.

Notes

Note for backend implementers:

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.

property fontangles
property fontweights
get_canvas_width_height(self)[source]

Return the canvas width and height in display coords.

get_text_width_height_descent(self, s, prop, ismath)[source]

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

property mathtext_parser
new_gc(self)[source]

Return an instance of a GraphicsContextBase.

points_to_pixels(self, points)[source]

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 * dpi/72

Parameters: pointsfloat or array-likea float or a numpy array of float Points converted to pixels
set_ctx_from_surface(self, surface)[source]
set_width_height(self, width, height)[source]