paint.py 文件源码

def projection(self, tile: HipsTile) -> ProjectiveTransform:
        """Estimate projective transformation on a HiPS tile."""
        corners = tile.meta.skycoord_corners.to_pixel(self.geometry.wcs)
        src = np.array(corners).T.reshape((4, 2))
        dst = tile_corner_pixel_coordinates(tile.meta.width)
        pt = ProjectiveTransform()
        pt.estimate(src, dst)
        return pt