Function _draw_list_compositing_images

lib/matplotlib/image.py:115–159

Draw a sorted list of artists, compositing images into a single image where possible. For internal Matplotlib use only: It is here to reduce duplication between `Figure.draw` and `Axes.draw`, but otherwise should not be generally useful.

(
        renderer, parent, artists, suppress_composite=None)

def _draw_list_compositing_images(
        renderer, parent, artists, suppress_composite=None):
    """
    Draw a sorted list of artists, compositing images into a single
    image where possible.

    For internal Matplotlib use only: It is here to reduce duplication
    between `Figure.draw` and `Axes.draw`, but otherwise should not be
    generally useful.
    """
    has_images = any(isinstance(x, _ImageBase) for x in artists)

    # override the renderer default if suppressComposite is not None
    not_composite = (suppress_composite if suppress_composite is not None
                     else renderer.option_image_nocomposite())

    if not_composite or not has_images:
        for a in artists:
            a.draw(renderer)
    else:
        # Composite any adjacent images together
        image_group = []
        mag = renderer.get_image_magnification()

        def flush_images():
            if len(image_group) == 1:
                image_group[0].draw(renderer)
            elif len(image_group) > 1:
                data, l, b = composite_images(image_group, renderer, mag)
                if data.size != 0:
                    gc = renderer.new_gc()
                    gc.set_clip_rectangle(parent.bbox)
                    gc.set_clip_path(parent.get_clip_path())
                    renderer.draw_image(gc, round(l), round(b), data)
                    gc.restore()
            del image_group[:]

        for a in artists:
            if (isinstance(a, _ImageBase) and a.can_composite() and
                    a.get_clip_on() and not a.get_clip_path()):
                image_group.append(a)
            else:
                flush_images()
                a.draw(renderer)
        flush_images()


def _resample(