matplotlib.backends.backend_agg
¶An agg http://antigrain.com/ backend
Features that are implemented
- capstyles and join styles
- dashes
- linewidth
- lines, rectangles, ellipses
- clipping to a rectangle
- output to RGBA and PNG, optionally JPEG and TIFF
- alpha blending
- DPI scaling properly - everything scales properly (dashes, linewidths, etc)
- draw polygon
- freetype2 w/ ft2font
TODO:
- integrate screen dpi w/ ppi and text
matplotlib.backends.backend_agg.
FigureCanvas
¶matplotlib.backends.backend_agg.
FigureCanvasAgg
(figure)[source]¶Bases: matplotlib.backend_bases.FigureCanvasBase
The canvas the figure renders into. Calls the draw and print fig methods, creates the renderers, etc...
Attributes
figure | (matplotlib.figure.Figure ) A high-level Figure instance |
buffer_rgba
()[source]¶Get the image as an RGBA byte string.
draw
must be called at least once before this function will work and
to update the renderer for any subsequent changes to the Figure.
Returns: | bytes |
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print_jpeg
(filename_or_obj, *args, dryrun=False, **kwargs)¶Write the figure to a JPEG file.
Parameters: | filename_or_obj : str or PathLike or file-like object
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Other Parameters: | quality : int
optimize : bool
progressive : bool
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print_jpg
(filename_or_obj, *args, dryrun=False, **kwargs)[source]¶Write the figure to a JPEG file.
Parameters: | filename_or_obj : str or PathLike or file-like object
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Other Parameters: | quality : int
optimize : bool
progressive : bool
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print_png
(filename_or_obj, *args, **kwargs)[source]¶Write the figure to a PNG file.
Parameters: | filename_or_obj : str or PathLike or file-like object
metadata : dict, optional
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print_rgba
(filename_or_obj, *args, **kwargs)¶print_tiff
(filename_or_obj, *args, dryrun=False, **kwargs)¶matplotlib.backends.backend_agg.
RendererAgg
(width, height, dpi)[source]¶Bases: matplotlib.backend_bases.RendererBase
The renderer handles all the drawing primitives using a graphics context instance that controls the colors/styles
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
lock
= <unlocked _thread.RLock object owner=0 count=0>¶option_image_nocomposite
()[source]¶override this method for renderers that do not necessarily always want to rescale and composite raster images. (like SVG, PDF, or PS)
points_to_pixels
(points)[source]¶convert point measures to pixes using dpi and the pixels per inch of the display
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 tuple of two floasts) 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 plot in the current canvas as a image and apply 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.