utils.py 文件源码

def get_inner_paths(grid, regions):
    """Create 1 pixel width paths connecting the loose ends surrounding the
    regions to their center. Each region is defined by its top-left
    and bottom-right corners points expressed in [x, y] coordinates. Grid must
    be a black and white image"""
    color = 255  # white
    height, width = grid.shape
    inner_paths = sparse.lil_matrix(grid.shape, dtype=np.uint8)
    for (cx1, cy1), (cx2, cy2) in regions:
        center = (cx1 + cx2) // 2, (cy1 + cy2) // 2
        cx1_min = max(cx1 - 1, 0)
        cy1_min = max(cy1 - 1, 0)
        cx2_max = min(cx2 + 1, width - 1)
        cy2_max = min(cy2 + 1, height - 1)
        borders = (
            # border, border_x, border_y, border_horizontal
            (grid[cy1_min, cx1_min:cx2_max], cx1_min, cy1, True),  # top
            (grid[cy2_max, cx1_min:cx2_max], cx1_min, cy2, True),  # bottom
            (grid[cy1_min:cy2_max, cx1_min], cx1, cy1_min, False),  # left
            (grid[cy1_min:cy2_max, cx2_max], cx2, cy1_min, False),  # right
        )
        for border, border_x, border_y, border_horizontal in borders:
            for border_step in np.argwhere(border).ravel():
                if border_horizontal:
                    point = border_x + border_step, border_y
                else:
                    point = border_x, border_y + border_step
                line = draw.line(point[1], point[0], center[1], center[0])
                inner_paths[line] = color
    return inner_paths.tocsc()