added subprocess calls

more error checking, changed sys to subprocess

DSK Image/DSK-Image.py

@@ -8,7 +8,15 @@
 
 
 import os,sys				# filesystem functions
-import png				# PNG image library
+import subprocess
+
+
+try:
+	import png # PNG image library
+except:
+	print("This script requires the python PNG module: https://pypi.python.org/pypi/pypng (or: pip install pypng)\n\n")
+	sys.exit(0)
+
 
 try:
     INPUTFILE = sys.argv[1]             # what DSK file to parse
@@ -17,12 +25,23 @@ except:
     print("\n\nUsage: python [filename]\n\n [filename] should be a DSK file of 143kb.\n\n")
     sys.exit(0)				# exit on exception - no file chosen
 finally:
-
-    PNG = open("DiskImageTEMP.png", "wb")	# open a PNG for writing
-
+	print("Checking " + INPUTFILE + "...\n")
+	
+# to do: check for 140k 5.25'' disks vs 400k/800k 3.5''	and adjust accordingly
+	
+if (os.path.getsize(INPUTFILE)) != 143360:		# check file size. for 5.25'', it needs to be 143k
+	print("\n\nOops. Is " + INPUTFILE + " a DSK file of 143kb?\n\n")
+	sys.exit(0)				# exit on exception - file is empty, etc
+		
 					# The point: Make a PNG image from the data on a floppy disk image.
-					# 35 tracks, each with 16 sectors of 256 bytes each, for a total of 143,360 bytes
+					# 5.15'' disks have 35 tracks, each with 16 sectors of 256 bytes each, for a total of 143,360 bytes
 					# so 35 lines of 4096 px.
+TRACKS = 35
+SECTORS = 16
+BYTESPERSECTOR = 256
+
+PNG = open("DiskImageTEMP.png", "wb")	# open a PNG for writing
+
 
 					# new, empty arrays
 BYTES = []
@@ -43,9 +62,9 @@ finally:
     sys.stdout.write("\r Starting.\n\n")
 
 
-    for TRACK in range(0,35,1):		# for each of the 35 tracks
+    for TRACK in range(0,TRACKS,1):		# for each of the 35 tracks
 	LINE=[]				# start a new line of pixels
-	for SECTOR in range(0,4096,1):	# write the bytes for the sectors in that track to the line array
+	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])
 
@@ -57,10 +76,10 @@ finally:
     sys.stdout.flush()
  
 					# write to the PNG file 
-w = png.Writer(4096,35, greyscale=True, bitdepth=8) 
+w = png.Writer(SECTORS*BYTESPERSECTOR,TRACKS, greyscale=True, bitdepth=8) 
 w.write(PNG, PIXELS)			# each number in the array becomes a pixel in the image. each array becomes a line.
 
-sys.stdout.write("\n\n\r Writing to disk. Chunka-chunk-cka. Whirr.\n\n")
+sys.stdout.write("\n\n\r Writing bytes to disk. Chunka-chunka-chunk. Whirr.\n\n")
 sys.stdout.flush()
 
 
@@ -71,8 +90,13 @@ PNG.close()
 OUTPUTFILE = os.path.join(INPUTFILE + ".png")
 					# set a destination file same as DSK, but with PNG extension
 
-os.system('convert DiskImageTEMP.png -matte -virtual-pixel transparent -resize 1024x1024! -rotate 90 -distort Polar \'512 110 512,512 -180,180\' ' + OUTPUTFILE)
+
+try:
+	subprocess.call(['convert', 'DiskImageTEMP.png', '-matte', '-virtual-pixel', 'transparent', '-resize', '1024x1024!', '-rotate', '90', '-distort', 'Polar', '512 110 512,512 -180,180', OUTPUTFILE])
 					# convert the 4096x35px image to a square, rotate, then rotate around an axis.
-
-os.system('open ' + OUTPUTFILE)		# opens the resulting image in the default image viewer (Preview.app)
+except OSError:
+    print("\n\nOops. This script requires ImageMagick: http://www.imagemagick.org/")
+    sys.exit(0)				# exit on exception - needs imagemagick installed
+	
+subprocess.call(['open', OUTPUTFILE])		# opens the resulting image in the default image viewer (Preview.app)