Don't let "aapt crunch" increase image size.

build/android/gyp/process_resources.py

 #!/usr/bin/env python
 #
 # Copyright (c) 2012 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """Process Android resources to generate R.java, and prepare for packaging.
 
 This will crunch images and generate v14 compatible resources
 (see generate_v14_compatible_resources.py).
@@ skipping 108 matching lines @@
     build_utils.MakeDirectory(package_r_java_dir)
     package_r_java_path = os.path.join(package_r_java_dir, 'R.java')
     open(package_r_java_path, 'w').write(
         re.sub(r'package [.\w]*;', 'package %s;' % package, r_java_contents))
     # TODO(cjhopman): These extra package's R.java files should be filtered to
     # only contain the resources listed in their R.txt files. At this point, we
     # have already compiled those other libraries, so doing this would only
     # affect how the code in this .apk target could refer to the resources.
 
 
+def CrunchDirectory(aapt, input_dir, output_dir):
+  """Crunches the images in input_dir and its subdirectories into output_dir.
+
+  If an image is already optimized, crunching often increases image size. In
+  this case, the crunched image is overwritten with the original image.
+  """
+  aapt_cmd = [aapt,
+              'crunch',
+              '-C', output_dir,
+              '-S', input_dir,
+              '--ignore-assets', build_utils.AAPT_IGNORE_PATTERN]
+  build_utils.CheckOutput(aapt_cmd, stderr_filter=FilterCrunchStderr,
+                          fail_func=DidCrunchFail)
+
+  # Check for images whose size increased during crunching and replace them
+  # with their originals (except for 9-patches, which must be crunched).
+  for dir_, _, files in os.walk(output_dir):
+    for crunched in files:
+      if crunched.endswith('.9.png'):
+        continue
+      if not crunched.endswith('.png'):
+        raise Exception('Unexpected file in crunched dir: ' + crunched)
+      crunched = os.path.join(dir_, crunched)
+      original = os.path.join(input_dir, os.path.relpath(crunched, output_dir))
+      original_size = os.path.getsize(original)
+      crunched_size = os.path.getsize(crunched)
+      if original_size < crunched_size:
+        shutil.copyfile(original, crunched)
+
+
 def FilterCrunchStderr(stderr):
   """Filters out lines from aapt crunch's stderr that can safely be ignored."""
   filtered_lines = []
   for line in stderr.splitlines(True):
     # Ignore this libpng warning, which is a known non-error condition.
     # http://crbug.com/364355
     if ('libpng warning: iCCP: Not recognizing known sRGB profile that has '
         + 'been edited' in line):
       continue
     filtered_lines.append(line)
@@ skipping 114 matching lines @@
     # This is the list of directories with resources to put in the final .zip
     # file. The order of these is important so that crunched/v14 resources
     # override the normal ones.
     zip_resource_dirs = input_resource_dirs + [v14_dir]
 
     base_crunch_dir = os.path.join(temp_dir, 'crunch')
 
     # Crunch image resources. This shrinks png files and is necessary for
     # 9-patch images to display correctly. 'aapt crunch' accepts only a single
     # directory at a time and deletes everything in the output directory.
-    for idx, d in enumerate(input_resource_dirs):
+    for idx, input_dir in enumerate(input_resource_dirs):
       crunch_dir = os.path.join(base_crunch_dir, str(idx))
       build_utils.MakeDirectory(crunch_dir)
       zip_resource_dirs.append(crunch_dir)
-      aapt_cmd = [aapt,
-                  'crunch',
-                  '-C', crunch_dir,
-                  '-S', d,
-                  '--ignore-assets', build_utils.AAPT_IGNORE_PATTERN]
-      build_utils.CheckOutput(aapt_cmd, stderr_filter=FilterCrunchStderr,
-                              fail_func=DidCrunchFail)
+      CrunchDirectory(aapt, input_dir, crunch_dir)
 
     ZipResources(zip_resource_dirs, options.resource_zip_out)
 
     if options.all_resources_zip_out:
       CombineZips([options.resource_zip_out] + dep_zips,
                   options.all_resources_zip_out)
 
     if options.R_dir:
       build_utils.DeleteDirectory(options.R_dir)
       shutil.copytree(gen_dir, options.R_dir)
     else:
       build_utils.ZipDir(options.srcjar_out, gen_dir)
 
   if options.depfile:
     input_files += build_utils.GetPythonDependencies()
     build_utils.WriteDepfile(options.depfile, input_files)
 
   if options.stamp:
     build_utils.Touch(options.stamp)
 
 
 if __name__ == '__main__':
   main()