add image decoder

img_codec.py

@@ -0,0 +1,34 @@
+from PIL import Image, ImagePalette
+
+
+def load_lut_file(filename):
+    tbl = {}
+    flat = bytearray([0]*512*4)
+    with open(filename, 'r') as f:
+        for line in f:
+            reg, data = line.strip().split('=')
+            reg = int(reg, 16)
+            # BGRA -> RGBA, ignore alpha
+            data = bytes.fromhex(data)
+            data = bytes((data[2], data[1], data[0], 0xFF))
+            tbl[reg] = data
+            flat[reg*4:reg*4+4] = data
+    return tbl, flat
+
+
+def get_palette(lut, shift=0):
+    pal = ImagePalette.ImagePalette('RGBA', lut[shift:shift+256*4], 256*4)
+    return pal
+
+
+def decode_img(src, lut, w, h, shift=0):
+    dst = Image.frombytes('P', (w, h), src)
+    pal = get_palette(lut)
+    dst.putpalette(pal.palette, rawmode=pal.mode)
+    return dst
+
+
+tbl, lut = load_lut_file('lut.txt')
+with open('dump_img1.bin', 'rb') as in_file:
+    img = decode_img(in_file.read(), lut, 480, 480, 0)
+    img.save('out.png')