Update app.py

app.py

@@ -11,29 +11,43 @@ MASK = (1 << BITS_PER_CHANNEL) - 1
 MAX_BYTES = 5 * 1024 * 1024
 MIN_SIZE = 200
 
-def calc_size(payload_bytes):
-    total_bits = (len(payload_bytes) + 4) * 8
-    pixels_needed = math.ceil(total_bits / 6)
-    side = max(MIN_SIZE, math.ceil(math.sqrt(pixels_needed * 1.6)))
-    return side, side
+def get_font_for_size(target_px):
+    font_path = "/usr/share/fonts/truetype/dejavu/DejaVuSans-Bold.ttf"
+    size = target_px
+    for _ in range(30):
+        try:
+            font = ImageFont.truetype(font_path, size)
+        except:
+            font = ImageFont.load_default()
+            return font
+        dummy = Image.new("RGB", (1, 1))
+        draw = ImageDraw.Draw(dummy)
+        bbox = draw.textbbox((0, 0), "CC", font=font)
+        h = bbox[3] - bbox[1]
+        if abs(h - target_px) <= 2:
+            break
+        size = max(1, size + (target_px - h))
+    return font
 
 def make_base_image(w, h):
     img = Image.new("RGB", (w, h), BG_COLOR)
     draw = ImageDraw.Draw(img)
-    font_size = max(10, int(min(w, h) * 0.40))
-    try:
-        font = ImageFont.truetype("/usr/share/fonts/truetype/dejavu/DejaVuSans-Bold.ttf", font_size)
-    except:
-        font = ImageFont.load_default()
-    text = "CC"
-    bbox = draw.textbbox((0, 0), text, font=font)
+    target_h = int(min(w, h) * 0.40)
+    font = get_font_for_size(target_h)
+    bbox = draw.textbbox((0, 0), "CC", font=font)
     tw = bbox[2] - bbox[0]
     th = bbox[3] - bbox[1]
     x = (w - tw) // 2 - bbox[0]
     y = (h - th) // 2 - bbox[1]
-    draw.text((x, y), text, fill=TEXT_COLOR, font=font)
+    draw.text((x, y), "CC", fill=TEXT_COLOR, font=font)
     return img
 
+def calc_size(payload_bytes):
+    total_bits = (len(payload_bytes) + 4) * 8
+    pixels_needed = math.ceil(total_bits / 6)
+    side = max(MIN_SIZE, math.ceil(math.sqrt(pixels_needed * 2.2)))
+    return side, side
+
 def get_carriers(w, h):
     base = make_base_image(w, h)
     pixels = base.load()
@@ -70,7 +84,7 @@ def embed(payload):
     data = header + payload
     bits = bits_from_bytes(data)
     if len(bits) > len(carriers) * BITS_PER_CHANNEL * 3:
-        raise ValueError("Data too large even after sizing. Try compressing your file.")
+        raise ValueError("Data too large even after sizing.")
     pixels = img.load()
     bit_idx = 0
     for (x, y) in carriers: