Fix the pixel mapping and improve image processing

The indexing of the byte array was wrong, which is why the images
produced had that funky spiral shape (which wasn't real). The polar
mapping was also incorrect (the tracks were mapped to cylinders and vice
versa).

Besides correcting these issues, improve the output by:
- Point scaling the source vertically by 3x to produce better-defined
  tracks
- Overlaying a "venetian blinds" pattern to add gaps between tracks
- Resizing horizontally to 3072 pixels to reduce aliasing
- 2x oversampling on the polar conversion again to reduce aliasing

DSK Image/DSK-Image.py

@@ -50,9 +50,8 @@ PIXELS = []
 try:
     byte = DSK.read(1) 			# read a byte
     while byte !="":			# while the file still has bytes in it
-        byte = DSK.read(1)	
-	if len(byte) > 0: 		# the last byte, for whatever reason, is length 0. Bah.
-	    BYTES.append(ord(byte))	# append the number representing the byte (0-255) to the BYTES array
+        BYTES.append(ord(byte))	# append the number representing the byte (0-255) to the BYTES array
+        byte = DSK.read(1)
 	
 except:
     print("\n\nOops. Is " + INPUTFILE + " a DSK file of 143kb?\n\n")
@@ -62,11 +61,10 @@ finally:
     sys.stdout.write("\r Starting.\n\n")
 
 
-    for TRACK in range(0,TRACKS,1):		# for each of the 35 tracks
+    for TRACK in range(TRACKS):		# for each of the 35 tracks
 	LINE=[]				# start a new line of pixels
-	for SECTOR in range(0,SECTORS*BYTESPERSECTOR,1):	# write the bytes for the sectors in that track to the line array
-	    offset = (SECTOR * TRACK) + SECTOR
-	    LINE.append(BYTES[(SECTOR * TRACK) + SECTOR])
+	for SECTOR in range(SECTORS*BYTESPERSECTOR):	# write the bytes for the sectors in that track to the line array
+	    LINE.append(BYTES[(SECTORS*BYTESPERSECTOR * TRACK) + SECTOR])
 
 	sys.stdout.write("\r Track: " + str(TRACK))
 	sys.stdout.flush()
@@ -92,7 +90,8 @@ OUTPUTFILE = os.path.join(INPUTFILE + ".png")
 
 
 try:
-	subprocess.call(['convert', 'DiskImageTEMP.png', '-matte', '-virtual-pixel', 'transparent', '-resize', '1024x1024!', '-rotate', '90', '-distort', 'Polar', '512 110 512,512 -180,180', OUTPUTFILE])
+	subprocess.call(['convert', 'DiskImageTEMP.png', '-scale', '100%x300%', '-resize', '3072x!', '(', '-size', '3072x115', 'pattern:horizontal3', '-negate', '-alpha', 'copy', '-fx', '#000', ')', '-composite', '-virtual-pixel', 'HorizontalTile', '-flip', '+distort', 'Polar', '1024 220', '-resize', '50%x50%', OUTPUTFILE])
+
 					# convert the 4096x35px image to a square, rotate, then rotate around an axis.
 except OSError:
     print("\n\nOops. This script requires ImageMagick: http://www.imagemagick.org/")