gen_image: Use python OpenCV instead of ImageMagick

Python with opencv provides us a lot more control of what's going on and
its interface shouldn't change arbitrarily.

2 files changed, 15 insertions, 29 deletions

diff --git a/Makefile.am b/Makefile.am
index de720c7..5b75bfd 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -212,9 +212,7 @@ data/grass-2048x1024.jpg: $(srcdir)/data/grass-2014x1536.jpg
 data/grass-%.png: \
     $(srcdir)/data/grass-2048x1024.jpg \
     $(srcdir)/misc/gen_image
-	$(AM_V_GEN) $(PYTHON3) $(srcdir)/misc/gen_image \
-	    --convert-tool="$(IMAGEMAGICK_CONVERT)" \
-	    $< $@
+	$(AM_V_GEN) $(PYTHON2) $(srcdir)/misc/gen_image $< $@
 
 data/pink-leaves-2048x1024.jpg: $(srcdir)/data/pink-leaves-3264x2448.jpg
 	$(AM_V_GEN)
@@ -224,9 +222,7 @@ data/pink-leaves-2048x1024.jpg: $(srcdir)/data/pink-leaves-3264x2448.jpg
 data/pink-leaves-%.png: \
     $(srcdir)/data/pink-leaves-2048x1024.jpg \
     $(srcdir)/misc/gen_image
-	$(AM_V_GEN) $(PYTHON3) $(srcdir)/misc/gen_image \
-	    --convert-tool="$(IMAGEMAGICK_CONVERT)" \
-	    $< $@
+	$(AM_V_GEN) $(PYTHON2) $(srcdir)/misc/gen_image $< $@
 
 TESTS = \
 	src/tests/self/bad-test-names.bash \
diff --git a/misc/gen_image b/misc/gen_image
index f9d6f5e..2575d41 100755
--- a/misc/gen_image
+++ b/misc/gen_image
@@ -1,12 +1,13 @@
-#!/usr/bin/env python3
+#!/usr/bin/env python2
+
+from __future__ import print_function
 
 import argparse
+import cv2
 import os
 import re
 import sys
 
-from subprocess import check_call
-
 PROG_NAME = os.path.basename(sys.argv[0])
 
 def die(msg):
@@ -15,8 +16,6 @@ def die(msg):
 
 def parse_args():
     p = argparse.ArgumentParser()
-    p.add_argument('--convert-tool', default='convert')
-    p.add_argument('-d', '--debug', action='store_true')
     p.add_argument('src_filename')
     p.add_argument('dest_filename')
     return p.parse_args()
@@ -27,32 +26,23 @@ def main():
     src_filename = args.src_filename
     dest_filename = args.dest_filename
 
-    # The badly named "convert" tool is an ImageMagick tool.
-    convert_args = [args.convert_tool, src_filename]
-
     if re.search('grayscale', dest_filename):
-        convert_args += [
-            '-set', 'colorspace', 'Gray',
-            '-separate',
-            '-average',
-        ]
+        imread_flags = cv2.IMREAD_GRAYSCALE
+    else:
+        imread_flags = cv2.IMREAD_COLOR
+
+    img = cv2.imread(src_filename, imread_flags)
 
     match = re.search(r'(\d+)x(\d+)', dest_filename)
     if match is None:
         die('dest_filename {!r} contains no size'.format(dest_filename))
 
-    width = match.groups(0)[0]
-    height = match.groups(0)[1]
-
-    convert_args += [
-        '-adaptive-resize', '{}x{}'.format(width, height),
-        dest_filename,
-    ]
+    width = int(match.groups(0)[0])
+    height = int(match.groups(0)[1])
 
-    if args.debug:
-        print('run: ' + ' '.join(map(repr, convert_args)))
+    res = cv2.resize(img, (width, height), interpolation = cv2.INTER_CUBIC)
 
-    check_call(convert_args)
+    cv2.imwrite(dest_filename, res)
 
 if __name__ == '__main__':
     main()