Add a --verbose option to output progress

convert.py

@@ -61,6 +61,9 @@ def main():
         '--show_palette', type=str, choices=list(palette_py.PALETTES.keys()),
         help="RGB colour palette to use when --show_output (default: "
              "value of --palette)")
+    parser.add_argument(
+        '--verbose', action=argparse.BooleanOptionalAction,
+        default=False, help="Show progress during conversion")
     args = parser.parse_args()
 
     palette = palette_py.PALETTES[args.palette]()
@@ -88,7 +91,7 @@ def main():
 
     dither = dither_pattern.PATTERNS[args.dither]()
     output_nbit, _ = dither_pyx.dither_image(
-        screen, resized, dither, lookahead)
+        screen, resized, dither, lookahead, args.verbose)
     bitmap = screen.pack(output_nbit)
 
     # Show output image by rendering in target palette

dither.pyx

@@ -201,7 +201,7 @@ cdef find_nearest_colour(screen, float[3] pixel_rgb, unsigned char[::1] options_
 
 @cython.boundscheck(False)
 @cython.wraparound(False)
-def dither_image(screen, float[:, :, ::1] image_rgb, dither, int lookahead):
+def dither_image(screen, float[:, :, ::1] image_rgb, dither, int lookahead, unsigned char verbose):
     cdef (unsigned char)[:, ::1] image_nbit = np.empty(
         (image_rgb.shape[0], image_rgb.shape[1]), dtype=np.uint8)
 
@@ -240,6 +240,8 @@ def dither_image(screen, float[:, :, ::1] image_rgb, dither, int lookahead):
             cdither.pattern[i * cdither.x_shape + j] = dither.PATTERN[i, j, 0]
 
     for y in range(yres):
+        if verbose:
+            print("%d/%d" % (y, yres))
         output_pixel_nbit = 0
         for x in range(xres):
             for i in range(3):