pcf: Support vewwy big letters

When glyphs lie entirely within 127 pixels of the glyph origin,
they get "compressed metrics".  Otherwise, they get "uncompressed
metrics".  Some of the calculations for "uncompressed metrics"
were wrong.  This only affects extremely unusual or large
point-size fonts, which is why it wasn't found initially.

Testing performed: rendered the letter 'a' at 200 points from
pcf.

Author: jepler

adafruit_bitmap_font/pcf.py

@@ -233,7 +233,7 @@ def _read_accelerator_tables(self):
         format_ = self._seek_table(accelerators)
 
         has_inkbounds = format_ & _PCF_ACCEL_W_INKBOUNDS
-        compressed_metrics = False  # format_ & _PCF_COMPRESSED_METRICS
+        compressed_metrics = format_ & _PCF_COMPRESSED_METRICS
 
         (
             no_overlap,
@@ -325,7 +325,7 @@ def load_glyphs(self, code_points):
         )
         metrics_compressed = self.tables[_PCF_METRICS].format & _PCF_COMPRESSED_METRICS
         first_metric_offset = (
-            self.tables[_PCF_METRICS].offset + 6 if metrics_compressed else 8
+            self.tables[_PCF_METRICS].offset + (6 if metrics_compressed else 8)
         )
         metrics_size = 5 if metrics_compressed else 12