Add script to extract thumbnails from prusa gcode

scripts/extract_prusa_thumbnails.py

@@ -0,0 +1,47 @@
+
+#
+import re
+import base64
+
+dir = "/home/pi/sdcard/"
+file = "square_tower_0.2mm_PLA_ENDER3_46m.gcode"
+#f = f.open(file, 'r')
+
+thumbnails = []
+cur_thumbnail = {}
+state = 0
+with open(dir + file, 'r') as f:
+    for line in f:
+        if state == 0:
+            match = re.match(r'^; thumbnail begin ([0-9]+)x([0-9]+) ([0-9]+)', line)
+            if match:
+                cur_thumbnail = {
+                    "width": match.group(1),
+                    "height": match.group(2),
+                    "size": match.group(3),
+                    "data": ""
+                }
+                state = 1
+                continue
+        elif state == 1:
+            if re.match (r'^; thumbnail end', line):
+                state = 0
+                thumbnails.append(cur_thumbnail)
+                continue
+            match = re.match(r'^; (\S+)$', line)
+            if match:
+                cur_thumbnail['data'] += match.group(1)
+
+if len(thumbnails) > 0:
+    biggest = 0
+    for i in range(len(thumbnails)):
+        if i == 0:
+            continue
+        if thumbnails[i]['width'] > thumbnails[biggest]['width']:
+            biggest = i
+
+    image = base64.decodestring(thumbnails[biggest]['data'])
+    name = file.split('.gcod')[0] + ".png"
+    f = open(dir + name, 'wb')
+    f.write(image)
+    f.close()