Class FigureCanvasAgg

lib/matplotlib/backends/backend_agg.py:418–595

class FigureCanvasAgg(FigureCanvasBase):
    # docstring inherited

    _lastKey = None  # Overwritten per-instance on the first draw.

    def copy_from_bbox(self, bbox):
        renderer = self.get_renderer()
        return renderer.copy_from_bbox(bbox)

    def restore_region(self, region, bbox=None, xy=None):
        renderer = self.get_renderer()
        return renderer.restore_region(region, bbox, xy)

    def draw(self):
        # docstring inherited
        self.renderer = self.get_renderer()
        self.renderer.clear()
        # Acquire a lock on the shared font cache.
        with (self.toolbar._wait_cursor_for_draw_cm() if self.toolbar
              else nullcontext()):
            self.figure.draw(self.renderer)
            # A GUI class may be need to update a window using this draw, so
            # don't forget to call the superclass.
            super().draw()

    def get_renderer(self):
        w, h = self.figure.bbox.size
        key = w, h, self.figure.dpi
        reuse_renderer = (self._lastKey == key)
        if not reuse_renderer:
            self.renderer = RendererAgg(w, h, self.figure.dpi)
            self._lastKey = key
        return self.renderer

    def tostring_argb(self):
        """
        Get the image as ARGB `bytes`.

        `draw` must be called at least once before this function will work and
        to update the renderer for any subsequent changes to the Figure.
        """
        return self.renderer.tostring_argb()

    def buffer_rgba(self):
        """
        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.
        """
        return self.renderer.buffer_rgba()

    def print_raw(self, filename_or_obj, *, metadata=None):
        if metadata is not None:
            raise ValueError("metadata not supported for raw/rgba")
        FigureCanvasAgg.draw(self)
        renderer = self.get_renderer()
        with cbook.open_file_cm(filename_or_obj, "wb") as fh: