[SGI] Save uncompressed SGI/BW/RGB/RGBA files

Save feature added to SgiImagePlugin.py, uncompressed method only

PIL/SgiImagePlugin.py

@@ -7,9 +7,12 @@
 # See "The SGI Image File Format (Draft version 0.97)", Paul Haeberli.
 # <ftp://ftp.sgi.com/graphics/SGIIMAGESPEC>
 #
+#
 # History:
+# 2016-16-10 mb   Add save method without compression
 # 1995-09-10 fl   Created
 #
+# Copyright (c) 2016 by Mickael Bonfill.
 # Copyright (c) 2008 by Karsten Hiddemann.
 # Copyright (c) 1997 by Secret Labs AB.
 # Copyright (c) 1995 by Fredrik Lundh.
@@ -19,8 +22,10 @@
 
 
 from PIL import Image, ImageFile, _binary
+import struct
+import os
 
-__version__ = "0.2"
+__version__ = "0.3"
 
 i8 = _binary.i8
 i16 = _binary.i16be
@@ -76,12 +81,83 @@ class SgiImageFile(ImageFile.ImageFile):
         elif compression == 1:
             raise ValueError("SGI RLE encoding not supported")
 
+
+def _save(im, fp, filename):
+    if im.mode != "RGB" and im.mode != "RGBA" and im.mode != "L":
+        raise ValueError("Unsupported SGI image mode")
+
+    # Flip the image, since the origin of SGI file is the bottom-left corner
+    im = im.transpose(Image.FLIP_TOP_BOTTOM)
+    # Define the file as SGI File Format
+    magicNumber = 474
+    # Run-Length Encoding Compression - Unsupported at this time
+    rle = 0
+    # Byte-per-pixel precision, 1 = 8bits per pixel
+    bpc = 1
+    # Number of dimensions (x,y,z)
+    dim = 3
+    # X Dimension = width / Y Dimension = height
+    x, y = im.size
+    if im.mode == "L" and y == 1:
+        dim = 1
+    elif im.mode == "L":
+        dim = 2
+    # Z Dimension: Number of channels
+    z = len(im.mode)
+    if dim == 1 or dim == 2:
+        z = 1
+    # Minimum Byte value
+    pinmin = 0
+    # Maximum Byte value (255 = 8bits per pixel)
+    pinmax = 255
+    # Image name (79 characters max)
+    imgName = os.path.splitext(os.path.basename(filename))[0][0:78]
+    # Standard representation of pixel in the file
+    colormap = 0
+    channels = []
+    for channelIndex in range(0, z):
+        channelData = list(im.getdata(channelIndex))
+        channels.append(channelData)
+    fp.write(struct.pack('>h', magicNumber))
+    fp.write(struct.pack('c', chr(rle)))
+    fp.write(struct.pack('c', chr(bpc)))
+    fp.write(struct.pack('>H', dim))
+    fp.write(struct.pack('>H', x))
+    fp.write(struct.pack('>H', y))
+    fp.write(struct.pack('>H', z))
+    fp.write(struct.pack('>l', pinmin))
+    fp.write(struct.pack('>l', pinmax))
+    for i in range(0, 4):
+        fp.write(struct.pack('c', chr(0)))
+    for c in imgName:
+        fp.write(struct.pack('c', c))
+    fp.write(struct.pack('c', chr(0)))
+    if len(imgName) < 78:
+        charIndex = len(imgName)
+        for charIndex in range(len(imgName), 79):
+            fp.write(struct.pack('c', chr(0)))
+    fp.write(struct.pack('>l', colormap))
+    for i in range(0, 404):
+        fp.write(struct.pack('c', chr(0)))
+    for zChannel in range(0, z):
+        dIndex = 0
+        for yPos in range(0, y):
+            for xPos in range(0, x):
+                fp.write(struct.pack('c', chr(channels[zChannel][dIndex])))
+                dIndex += 1
+    fp.close()
+
+
 #
 # registry
 
 Image.register_open(SgiImageFile.format, SgiImageFile, _accept)
-
+Image.register_save(SgiImageFile.format, _save)
+Image.register_mime(SgiImageFile.format, "image/sgi")
+Image.register_mime(SgiImageFile.format, "image/rgb")
 Image.register_extension(SgiImageFile.format, ".bw")
 Image.register_extension(SgiImageFile.format, ".rgb")
 Image.register_extension(SgiImageFile.format, ".rgba")
 Image.register_extension(SgiImageFile.format, ".sgi")
+
+# End of file