1 files changed, 101 insertions, 0 deletions
diff --git a/helium/gaussiansmooth.cpp b/helium/gaussiansmooth.cpp
new file mode 100644
index 0000000..109e79c
--- /dev/null
+++ b/helium/gaussiansmooth.cpp
@@ -0,0 +1,101 @@
+// Copyright 2006 Google Inc.
+// All Rights Reserved.
+// Author: <renn@google.com> (Marius Renn)
+
+// Local includes
+#include "color.h"
+#include "debugging.h"
+#include "gaussiansmooth.h"
+#include "point.h"
+#include "mathfunctions.h"
+
+using namespace helium;
+
+GaussianSmooth::GaussianSmooth(unsigned size) : 
+  kernel_size_(size + 1), 
+  gauss_sum_(0),
+  kernel_(new int[size + 1]) {
+  
+  // Create gaussian mask by calculating the binomial coefficients. We will
+  // later divide by the sum of these coefficients to obtain the output value.
+  for (unsigned i = 0; i < kernel_size_; i ++) {
+    int coeff = Binomi(size + 1, i + 1);
+    kernel_[i] = coeff;
+    gauss_sum_ += coeff;
+  }
+}
+
+GaussianSmooth::~GaussianSmooth() {
+  delete[] kernel_;
+}
+
+Image GaussianSmooth::Smooth(const Image& image) {
+  ASSERT(kernel_);
+  
+  // Create intermediate and destination images
+  Image temp(image.width(), image.height());
+  Image dest(image.width(), image.height());
+  ASSERT(temp.Valid() && dest.Valid());
+  
+  int s = kernel_size_ / 2;
+  Color pixel;
+  Point p;
+  int r, g, b;
+  int row = image.width();
+  
+  // Setup data pointers
+  Color* src_ptr = image.Access(s, s);
+  Color* temp_ptr = temp.Access(s, s);
+  Color* dest_ptr = dest.Access(s, s);
+  
+  // First pass (horizontal smoothing)
+  for (p.y = s; p.y < image.height() - s; p.y++) {
+    for (p.x = s; p.x < image.width() - s; p.x++) {
+      int r_gauss = 0;
+      int g_gauss = 0;
+      int b_gauss = 0;
+      for (int i = 0; i < kernel_size_; i++) {
+        pixel = *(src_ptr + i - s);
+        ColorSeparate(pixel, r, g, b);
+        r_gauss += r * kernel_[i];
+        g_gauss += g * kernel_[i];
+        b_gauss += b * kernel_[i];
+      }
+      r_gauss /= gauss_sum_;
+      g_gauss /= gauss_sum_;
+      b_gauss /= gauss_sum_;
+      
+      *(temp_ptr++) = MakeColor(r_gauss, g_gauss, b_gauss);
+      src_ptr++;
+    }
+    src_ptr += s*2;
+    temp_ptr += s*2;
+  }
+  
+  // Second pass (vertical smoothing)
+  temp_ptr = temp.Access(s, s);
+  for (p.y = s; p.y < image.height() - s; p.y++) {
+    for (p.x = s; p.x < image.width() - s; p.x++) {
+      int r_gauss = 0;
+      int g_gauss = 0;
+      int b_gauss = 0;
+      for (int i = 0; i < kernel_size_; i++) {
+        pixel = *(temp_ptr + (i - s) * row);
+        ColorSeparate(pixel, r, g, b);
+        
+        r_gauss += r * kernel_[i];
+        g_gauss += g * kernel_[i];
+        b_gauss += b * kernel_[i];
+      }
+      r_gauss /= gauss_sum_;
+      g_gauss /= gauss_sum_;
+      b_gauss /= gauss_sum_;
+      
+      *(dest_ptr++) = MakeColor(r_gauss, g_gauss, b_gauss);
+      temp_ptr++;
+    }
+    dest_ptr += s*2;
+    temp_ptr += s*2;
+  }
+  return dest;
+}