TGA: Read and write LA data

Tests/test_file_tga.py

@@ -41,9 +41,6 @@ def test_save(self):
         test_im = Image.open(test_file)
         self.assertEqual(test_im.size, (100, 100))
 
-        # Unsupported mode save
-        self.assertRaises(IOError, lambda: im.convert("LA").save(test_file))
-
     def test_save_rle(self):
         test_file = "Tests/images/rgb32rle.tga"
         im = Image.open(test_file)
@@ -60,8 +57,25 @@ def test_save_rle(self):
         test_im = Image.open(test_file)
         self.assertEqual(test_im.size, (199, 199))
 
-        # Unsupported mode save
-        self.assertRaises(IOError, lambda: im.convert("LA").save(test_file))
+    def test_save_l_transparency(self):
+        # There are 559 transparent pixels in la.tga.
+        num_transparent = 559
+
+        in_file = "Tests/images/la.tga"
+        im = Image.open(in_file)
+        self.assertEqual(im.mode, "LA")
+        self.assertEqual(
+            im.getchannel("A").getcolors()[0][0], num_transparent)
+
+        test_file = self.tempfile("temp.tga")
+        im.save(test_file)
+
+        test_im = Image.open(test_file)
+        self.assertEqual(test_im.mode, "LA")
+        self.assertEqual(
+            test_im.getchannel("A").getcolors()[0][0], num_transparent)
+
+        self.assert_image_equal(im, test_im)
 
 
 if __name__ == '__main__':

docs/handbook/image-file-formats.rst

@@ -558,6 +558,13 @@ For more information about the SPIDER image processing package, see the
 .. _SPIDER homepage: https://spider.wadsworth.org/spider_doc/spider/docs/spider.html
 .. _Wadsworth Center: https://www.wadsworth.org/
 
+TGA
+^^^
+
+PIL reads and writes TGA images containing ``L``, ``LA``, ``P``,
+``RGB``, and ``RGBA`` data. PIL can read both uncompressed and
+run-length encoded TGAs, but writes only uncompressed data.
+
 TIFF
 ^^^^
 
@@ -927,11 +934,6 @@ PSD
 PIL identifies and reads PSD files written by Adobe Photoshop 2.5 and 3.0.
 
 
-TGA
-^^^
-
-PIL reads 24- and 32-bit uncompressed and run-length encoded TGA files.
-
 WAL
 ^^^
 

src/PIL/TgaImagePlugin.py

@@ -33,6 +33,7 @@
     (1, 8):  "P",
     (3, 1):  "1",
     (3, 8):  "L",
+    (3, 16): "LA",
     (2, 16): "BGR;5",
     (2, 24): "BGR",
     (2, 32): "BGRA",
@@ -74,6 +75,8 @@ def _open(self):
             self.mode = "L"
             if depth == 1:
                 self.mode = "1"  # ???
+            elif depth == 16:
+                self.mode = "LA"
         elif imagetype in (1, 9):
             self.mode = "P"
         elif imagetype in (2, 10):
@@ -134,6 +137,7 @@ def _open(self):
 SAVE = {
     "1": ("1", 1, 0, 3),
     "L": ("L", 8, 0, 3),
+    "LA": ("LA", 16, 0, 3),
     "P": ("P", 8, 1, 1),
     "RGB": ("BGR", 24, 0, 2),
     "RGBA": ("BGRA", 32, 0, 2),
@@ -152,7 +156,7 @@ def _save(im, fp, filename):
     else:
         colormapfirst, colormaplength, colormapentry = 0, 0, 0
 
-    if im.mode == "RGBA":
+    if im.mode in ("LA", "RGBA"):
         flags = 8
     else:
         flags = 0