Move the image loader to shared

pytools/font.py

@@ -25,29 +25,22 @@ def main(font_name, n_glyphs, fname_png, fname_c):
 
 
 def load_glyphs(fname_png: str):
-    with Image.open(fname_png) as im:
-        width = im.width
-        height = im.height
+    width, height, data = shared.load_image(fname_png)
+    monochrome = [pixel_to_monochrome(p) for p in data]
 
-        assert width % 8 == 0, "width must be a multiple of 8"
-        assert height % 8 == 0, "height must be a multiple of 8"
+    glyphs = []
+    for gy in range(0, height, 8):
+        for gx in range(0, width, 8):
+            glyph = 0
+            for py in range(0, 8):
+                for px in range(0, 8):
+                    x = gx + px
+                    y = gy + py
+                    if monochrome[y * width + x]:
+                        glyph |= 1 << (py * 8 + px)
+            glyphs.append(glyph)
 
-        data = list(im.convert("RGBA").getdata())
-        monochrome = [pixel_to_monochrome(p) for p in data]
-
-        glyphs = []
-        for gy in range(0, height, 8):
-            for gx in range(0, width, 8):
-                glyph = 0
-                for py in range(0, 8):
-                    for px in range(0, 8):
-                        x = gx + px
-                        y = gy + py
-                        if monochrome[y * width + x]:
-                            glyph |= 1 << (py * 8 + px)
-                glyphs.append(glyph)
-
-        return glyphs
+    return glyphs
 
 
 def pixel_to_monochrome(rgba: Tuple[int, int, int, int]):

pytools/shared.py

@@ -1,6 +1,17 @@
+from PIL import Image
 from jinja2 import Environment, BaseLoader, select_autoescape
 
 templates = Environment(
     loader=BaseLoader(),
     autoescape=select_autoescape(),
-)
+)
+
+def load_image(fname):
+    with Image.open(fname) as im:
+        width = im.width
+        height = im.height
+
+        assert width % 8 == 0, "width must be a multiple of 8"
+        assert height % 8 == 0, "height must be a multiple of 8"
+
+        return width, height, list(im.convert("RGBA").getdata())