pystack exhausted error in load_glyphs

[kmatch98]

When using bitmap_label I can sometimes trigger a RuntimeError: pystack exhausted.

Hardware: PyPortal
CircuitPython version: Adafruit CircuitPython 6.2.0-beta.3-5-g2ae8a44b2 on 2021-03-04; Adafruit PyPortal with samd51j20

Traceback (most recent call last):
  File "code.py", line 84, in <module>
  File "/lib/adafruit_displayio_layout/widgets/dial.py", line 300, in __init__
  File "/lib/adafruit_displayio_layout/widgets/dial.py", line 567, in draw_labels
  File "/lib/adafruit_display_text/bitmap_label.py", line 137, in __init__
  File "/lib/adafruit_display_text/bitmap_label.py", line 244, in _reset_text
  File "/lib/adafruit_display_text/bitmap_label.py", line 370, in _text_bounding_box
  File "/lib/adafruit_bitmap_font/glyph_cache.py", line 48, in get_glyph
  File "/lib/adafruit_bitmap_font/pcf.py", line 346, in load_glyphs
  File "/lib/adafruit_bitmap_font/pcf.py", line 184, in _read_metrics
RuntimeError: pystack exhausted

Code done running.

This Error happens when I load the font (see snippet below) and then use bitmap_label to generate the bitmap. I tried with various PCF font files generated with the adafruit web BDF->PCF converter code.

font_file2 = "fonts/BitstreamVeraSans-Bold-16.pcf"
my_font2 = bitmap_font.load_font(font_file2)

Strangely, if I perform load_glyphs earlier in my code then it works just fine, like so:

font_file2 = "fonts/BitstreamVeraSans-Bold-16.pcf"
my_font2 = bitmap_font.load_font(font_file2)
glyphs = "0123456789"
my_font2.load_glyphs(glyphs)

The error seems to be triggered in this self._read:

        if compressed_metrics:
            (
                left_side_bearing,
                right_side_bearing,
                character_width,
                character_ascent,
                character_descent,
            ) = self._read("5B")

[tannewt]

This can happen with deep call trees. I hear about it occasionally. We can increase the size. We'd just need to determine how much more space we need.

[kmatch98]

This seems to have been fixed with: #40.

Thanks Jeff! Closing.