SIMD implementation of Convolver for Lanczos filter etc.

skia/ext/image_operations_bench.cc

 // Copyright (c) 2011 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.
 
 // This small program is used to measure the performance of the various
 // resize algorithms offered by the ImageOperations::Resize function.
 // It will generate an empty source bitmap, and rescale it to specified
 // dimensions. It will repeat this operation multiple time to get more accurate
 // average throughput. Because it uses elapsed time to do its math, it is only
 // accurate on an idle system (but that approach was deemed more accurate
@@ skipping 214 matching lines @@
   }
   return true;
 }
 
 // actual benchmark.
 bool Benchmark::Run() const {
   SkBitmap source;
   source.setConfig(SkBitmap::kARGB_8888_Config,
                    source_.width(), source_.height());
   source.allocPixels();
-  source.eraseARGB(0, 0, 0, 0);
+
+  // Randomize the image for testing.
+  srand(time(0));
+  unsigned char* src_ptr = static_cast<unsigned char*>(source.getPixels());
+  for (int y = 0; y < source_.height(); y++) {
+    for (int x = 0; x < source_.width()*4; x++) {

[evannier, 2011/02/14 23:45:13]

I am not much of a fan of the hard coded '4', but I have tons of code doing this
in Chrome (which I correct when I find it, and need to modify it).

[fbarchard, 2011/02/15 23:16:45]

The width()*4 should also have a space.
Maybe you should fill source.rowBytes() instead?

[jiesun, 2011/02/17 20:17:58]

Done.

[jiesun, 2011/02/17 20:17:58]

Done.

+      src_ptr[x] = rand() % 255;
+    }
+    src_ptr += source.rowBytes();
+  }
 
   SkBitmap dest;
 
   const base::TimeTicks start = base::TimeTicks::Now();
 
   for (int i = 0; i < num_iterations_; ++i) {
     dest = skia::ImageOperations::Resize(source,
                                          method_,
                                          dest_.width(), dest_.height());
   }
@@ skipping 38 matching lines @@
     return 1;
   }
 
   if (!bench.Run()) {
     printf("Failed to run benchmark\n");
     return 1;
   }
 
   return 0;
 }