diff --git a/README b/README
index 45d4296..efa6524 100644
--- a/README
+++ b/README
@@ -8,7 +8,7 @@ Python 3, pillow
 
 Usage
 -----
-$ gff <font path> <font size> <output image>
+$ gff <font path> <font size> <output image> [initial char index] [char range]
 Example:
 $ gff "$HOME/.fonts/Kenney Future Narrow" 16 kenney_future_narrow.png
 
diff --git a/gff b/gff
index 6906e68..79869ff 100755
--- a/gff
+++ b/gff
@@ -1,14 +1,23 @@
 #!/usr/bin/env python3
+from math import ceil
 from sys import argv
 from PIL import Image, ImageDraw, ImageFont
 
-if (len(argv) != 4):
-    raise BaseException("Three arguments expected: " + \
-        "<font path> <font size> <output image>")
+if (len(argv) < 4):
+    raise BaseException("At least three arguments expected: " + \
+        "<font path> <font size> <output image> " + \
+        "[initial char index] [char range]")
 
 font_path = argv[1]
 font_size = int(argv[2])
 image_out = argv[3]
+initial_char_index = int(argv[4]) if len(argv) > 4 else 0x20
+char_range = int(argv[5]) if len(argv) > 5 else 96
+line_count = ceil(char_range / 16)
+scan_index = 0x20 if len(argv) > 4 else initial_char_index
+scan_range = 0x30ff - 0x20 if len(argv) > 4 else char_range
+
+assert char_range > 1
 
 mode = '1' # 1-bit depth
 background_color = (1) # white
@@ -20,8 +29,8 @@ font = ImageFont.truetype(font_path, font_size)
 # find max char size
 char_width = 0
 char_height = 0
-for i in range(95):
-    bbox = list(font.getbbox(chr(32 + i)))
+for i in range(scan_range):
+    bbox = list(font.getbbox(chr(scan_index + i)))
     # don't you dare overlap
     if (bbox[0] < 0):
         bbox[2] = -bbox[0]
@@ -33,7 +42,7 @@ for i in range(95):
         char_height = bbox[3]
 
 image_out_width = char_width * 16
-image_out_height = char_height * 6
+image_out_height = char_height * line_count
 
 # fxconv metadata
 print(f"{image_out.split('/')[-1]}:")
@@ -50,9 +59,9 @@ draw.rectangle((0, 0, image_out_width, image_out_height), fill=background_color)
 
 x = -char_width
 y = 0
-for i in range(95):
+for i in range(char_range):
     x += char_width
-    char = chr(32 + i)
+    char = chr(initial_char_index + i)
     bbox = font.getbbox(char)
     x_mod = 0
     y_mod = 0