matplotlib.backends.backend_agg
#
An Anti-Grain Geometry (AGG) backend.
Features that are implemented:
capstyles and join styles
dashes
linewidth
lines, rectangles, ellipses
clipping to a rectangle
output to RGBA and Pillow-supported image formats
alpha blending
DPI scaling properly - everything scales properly (dashes, linewidths, etc)
draw polygon
freetype2 w/ ft2font
Still TODO:
integrate screen dpi w/ ppi and text
- matplotlib.backends.backend_agg.FigureCanvas[source]#
alias of
FigureCanvasAgg
- class matplotlib.backends.backend_agg.FigureCanvasAgg(figure=None)[source]#
Bases:
FigureCanvasBase
- buffer_rgba()[source]#
Get the image as a
memoryview
to the renderer's buffer.draw
must be called at least once before this function will work and to update the renderer for any subsequent changes to the Figure.
- draw()[source]#
Render the
Figure
.This method must walk the artist tree, even if no output is produced, because it triggers deferred work that users may want to access before saving output to disk. For example computing limits, auto-limits, and tick values.
- print_jpeg(filename_or_obj, *, metadata=None, pil_kwargs=None)[source]#
Write the figure to a JPEG file.
- Parameters:
- filename_or_objstr or path-like or file-like
The file to write to.
- pil_kwargsdict, optional
Additional keyword arguments that are passed to
PIL.Image.Image.save
when saving the figure.
- print_jpg(filename_or_obj, *, metadata=None, pil_kwargs=None)[source]#
Write the figure to a JPEG file.
- Parameters:
- filename_or_objstr or path-like or file-like
The file to write to.
- pil_kwargsdict, optional
Additional keyword arguments that are passed to
PIL.Image.Image.save
when saving the figure.
- print_png(filename_or_obj, *, metadata=None, pil_kwargs=None)[source]#
Write the figure to a PNG file.
- Parameters:
- filename_or_objstr or path-like or file-like
The file to write to.
- metadatadict, optional
Metadata in the PNG file as key-value pairs of bytes or latin-1 encodable strings. According to the PNG specification, keys must be shorter than 79 chars.
The PNG specification defines some common keywords that may be used as appropriate:
Title: Short (one line) title or caption for image.
Author: Name of image's creator.
Description: Description of image (possibly long).
Copyright: Copyright notice.
Creation Time: Time of original image creation (usually RFC 1123 format).
Software: Software used to create the image.
Disclaimer: Legal disclaimer.
Warning: Warning of nature of content.
Source: Device used to create the image.
Comment: Miscellaneous comment; conversion from other image format.
Other keywords may be invented for other purposes.
If 'Software' is not given, an autogenerated value for Matplotlib will be used. This can be removed by setting it to None.
For more details see the PNG specification.
- pil_kwargsdict, optional
Keyword arguments passed to
PIL.Image.Image.save
.If the 'pnginfo' key is present, it completely overrides metadata, including the default 'Software' key.
- print_tif(filename_or_obj, *, metadata=None, pil_kwargs=None)[source]#
Write the figure to a TIFF file.
- Parameters:
- filename_or_objstr or path-like or file-like
The file to write to.
- pil_kwargsdict, optional
Additional keyword arguments that are passed to
PIL.Image.Image.save
when saving the figure.
- print_tiff(filename_or_obj, *, metadata=None, pil_kwargs=None)[source]#
Write the figure to a TIFF file.
- Parameters:
- filename_or_objstr or path-like or file-like
The file to write to.
- pil_kwargsdict, optional
Additional keyword arguments that are passed to
PIL.Image.Image.save
when saving the figure.
- print_webp(filename_or_obj, *, metadata=None, pil_kwargs=None)[source]#
Write the figure to a WebP file.
- Parameters:
- filename_or_objstr or path-like or file-like
The file to write to.
- pil_kwargsdict, optional
Additional keyword arguments that are passed to
PIL.Image.Image.save
when saving the figure.
- class matplotlib.backends.backend_agg.RendererAgg(width, height, dpi)[source]#
Bases:
RendererBase
The renderer handles all the drawing primitives using a graphics context instance that controls the colors/styles
- draw_mathtext(gc, x, y, s, prop, angle)[source]#
Draw mathtext using
matplotlib.mathtext
.
- draw_path(gc, path, transform, rgbFace=None)[source]#
Draw a
Path
instance using the given affine transform.
- draw_tex(gc, x, y, s, prop, angle, *, mtext=None)[source]#
Draw a TeX instance.
- Parameters:
- gc
GraphicsContextBase
The graphics context.
- xfloat
The x location of the text in display coords.
- yfloat
The y location of the text baseline in display coords.
- sstr
The TeX text string.
- prop
FontProperties
The font properties.
- anglefloat
The rotation angle in degrees anti-clockwise.
- mtext
Text
The original text object to be rendered.
- gc
- draw_text(gc, x, y, s, prop, angle, ismath=False, mtext=None)[source]#
Draw a text instance.
- Parameters:
- gc
GraphicsContextBase
The graphics context.
- xfloat
The x location of the text in display coords.
- yfloat
The y location of the text baseline in display coords.
- sstr
The text string.
- prop
FontProperties
The font properties.
- anglefloat
The rotation angle in degrees anti-clockwise.
- ismathbool or "TeX"
If True, use mathtext parser. If "TeX", use tex for rendering.
- mtext
Text
The original text object to be rendered.
- gc
- get_text_width_height_descent(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.Whitespace at the start and the end of s is included in the reported width.
- option_image_nocomposite()[source]#
Return whether image composition by Matplotlib should be skipped.
Raster backends should usually return False (letting the C-level rasterizer take care of image composition); vector backends should usually return
not rcParams["image.composite_image"]
.
- option_scale_image()[source]#
Return whether arbitrary affine transformations in
draw_image
are supported (True for most vector backends).
- points_to_pixels(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-like
- Returns:
- Points converted to pixels
- restore_region(region, bbox=None, xy=None)[source]#
Restore the saved region. If bbox (instance of BboxBase, or its extents) is given, only the region specified by the bbox will be restored. xy (a pair of floats) optionally specifies the new position (the LLC of the original region, not the LLC of the bbox) where the region will be restored.
>>> region = renderer.copy_from_bbox() >>> x1, y1, x2, y2 = region.get_extents() >>> renderer.restore_region(region, bbox=(x1+dx, y1, x2, y2), ... xy=(x1-dx, y1))
- stop_filter(post_processing)[source]#
Save the current canvas as an image and apply post processing.
The post_processing function:
def post_processing(image, dpi): # ny, nx, depth = image.shape # image (numpy array) has RGBA channels and has a depth of 4. ... # create a new_image (numpy array of 4 channels, size can be # different). The resulting image may have offsets from # lower-left corner of the original image return new_image, offset_x, offset_y
The saved renderer is restored and the returned image from post_processing is plotted (using draw_image) on it.