Cairo 1.18.0 doesn't draw bold or italic text on Mac

[schmave]

I've got what I assume is a bug in cairo, rather than pycairo, but I'm not sure. Is there anything worth looking into in pycairo here or should I take this to the cairo mailing list? Thanks in advance for your help.

When I run the following program with Python 3.9/3.10/3.11 on a Mac (mine is Intel, but it happens on ARM also), pycairo 1.24.0/1.25.1, the same font is used for both calls to show_text() if I am using cairo 1.18.0 installed via homebrew.

import cairo

WIDTH = 3
HEIGHT = 2
PIXEL_SCALE = 200

surface = cairo.ImageSurface(cairo.FORMAT_RGB24,
                             WIDTH*PIXEL_SCALE,
                             HEIGHT*PIXEL_SCALE)
ctx = cairo.Context(surface)
ctx.scale(PIXEL_SCALE, PIXEL_SCALE)

# Drawing code
ctx.set_source_rgb(1, 0, 0)
ctx.set_font_size(0.25)
ctx.select_font_face("Arial",
                     cairo.FONT_SLANT_NORMAL,
                     cairo.FONT_WEIGHT_NORMAL)
ctx.move_to(0.5, 0.5)
ctx.show_text("Normal text")
# End of drawing code

ctx.set_source_rgb(0, 1, 0)
ctx.set_font_size(0.25)
ctx.select_font_face("Arial",
                     cairo.FONT_SLANT_ITALIC,
                     cairo.FONT_WEIGHT_BOLD)
ctx.move_to(0.5, 0.75)
ctx.show_text("Bold + italic text")

surface.write_to_png('text.png')

Output with homebrew's cairo 1.18.0:

Output with homebrew's cairo 1.16.0_5:

[stuaxo]

This kind of thing may be an issue with cairo itself - can you port the example to C ?

(One thing LLMs like ChatGPT are good at is porting small examples like this between languages).

If you still have the issue, there then I would report it upstream to cairo https://gitlab.freedesktop.org/cairo/cairo

[schmave]

Thanks for the quick reply and the tip about using an LLM! That made it very fast to determine that the same thing happens without pycairo. I'll report it upstream.

[schmave]

Bug reported here, in case that is helpful: https://gitlab.freedesktop.org/cairo/cairo/-/issues/811