Blend2D Kiva backend TODO

[jwiggins]

The Kiva blend2d backend is still in a very alpha-quality state. Here's what we know is missing:

• [ ] Some of the graphics state needs to be tracked by the Kiva backend. (see instance attributes path, font, _kiva_font, text_pos, and text_drawing_mode)
• [ ] Only RGBA32 is supported right now. This might be the only [color] format supported by Blend2D.
• [ ] Not all CTM manipulations are supported
• [ ] Enable/Disable of anti-aliasing. Is it even possible?
• [ ] Line dashing (Unsupported in Blend2D as of May 2021)
• [ ] arc and arc_to are incomplete/incosistent
• [ ] get_path_bounding_box returns an object which can't be introspected by the user because it's a thin wrapper around a C++ object.
• [ ] Most of the clipping functions aren't implemented
• [ ] draw_image doesn't yet handled rect=None as an argument. Also doesn't correctly handling flipping the image along the Y-axis
• [ ] *_character_spacing methods are not implemented
• [ ] *_text_matrix methods are not implemented
• [ ] Not all text drawing modes are implemented
• [ ] get_text_extent is not implemented
• [ ] eof_fill_path and EOF filling rule is not implemented
• [ ] draw_path_at_points/draw_marker_at_points not implemented