From a617a5cb97478278c619ef0d894dacfecc143c6e Mon Sep 17 00:00:00 2001
From: rdb <git@rdb.name>
Date: Mon, 17 May 2010 13:11:43 +0000
Subject: [PATCH] Add get_average_xel, get_average_xel_a, get_average_gray

---
 panda/src/pnmimage/pnmImage.cxx | 72 +++++++++++++++++++++++++++++++++
 panda/src/pnmimage/pnmImage.h   |  4 ++
 2 files changed, 76 insertions(+)

diff --git a/panda/src/pnmimage/pnmImage.cxx b/panda/src/pnmimage/pnmImage.cxx
index ec329d790f..d90e03f4d7 100644
--- a/panda/src/pnmimage/pnmImage.cxx
+++ b/panda/src/pnmimage/pnmImage.cxx
@@ -1317,6 +1317,78 @@ setup_rc() {
   }
 }
 
+////////////////////////////////////////////////////////////////////
+//     Function: PNMImage::get_average_xel
+//       Access: Published
+//  Description: Returns the average color of all of the pixels
+//               in the image.
+////////////////////////////////////////////////////////////////////
+RGBColord PNMImage::
+get_average_xel() const {
+  RGBColord color (RGBColord::zero());
+  if (_x_size == 0 || _y_size == 0) {
+    return color;
+  }
+
+  int x, y;
+  for (x = 0; x < _x_size; ++x) {
+    for (y = 0; y < _y_size; ++y) {
+      color += get_xel(x, y);
+    }
+  }
+
+  color *= 1.0 / (_x_size * _y_size);
+  return color;
+}
+
+////////////////////////////////////////////////////////////////////
+//     Function: PNMImage::get_average_xel_a
+//       Access: Published
+//  Description: Returns the average color of all of the pixels
+//               in the image, including the alpha channel.
+////////////////////////////////////////////////////////////////////
+Colord PNMImage::
+get_average_xel_a() const {
+  Colord color (Colord::zero());
+  if (_x_size == 0 || _y_size == 0) {
+    return color;
+  }
+
+  int x, y;
+  for (x = 0; x < _x_size; ++x) {
+    for (y = 0; y < _y_size; ++y) {
+      color += get_xel_a(x, y);
+    }
+  }
+
+  color *= 1.0 / (_x_size * _y_size);
+  return color;
+}
+
+////////////////////////////////////////////////////////////////////
+//     Function: PNMImage::get_average_gray
+//       Access: Published
+//  Description: Returns the average grayscale component of all of
+//               the pixels in the image.
+////////////////////////////////////////////////////////////////////
+double PNMImage::
+get_average_gray() const {
+  double color = 0.0;
+  if (_x_size == 0 || _y_size == 0) {
+    return color;
+  }
+
+  int x, y;
+  for (x = 0; x < _x_size; ++x) {
+    for (y = 0; y < _y_size; ++y) {
+      color += get_gray(x, y);
+    }
+  }
+
+  color *= 1.0 / (_x_size * _y_size);
+  return color;
+}
+
 ////////////////////////////////////////////////////////////////////
 //     Function: PNMImage::operator ~
 //       Access: Published
diff --git a/panda/src/pnmimage/pnmImage.h b/panda/src/pnmimage/pnmImage.h
index 1b7265d23b..f0c8fd9552 100644
--- a/panda/src/pnmimage/pnmImage.h
+++ b/panda/src/pnmimage/pnmImage.h
@@ -236,6 +236,10 @@ PUBLISHED:
                          unsigned long seed = 0);
   void perlin_noise_fill(StackedPerlinNoise2 &perlin);
 
+  RGBColord get_average_xel() const;
+  Colord get_average_xel_a() const;
+  double get_average_gray() const;
+
 private:
   INLINE void allocate_array();
   INLINE void allocate_alpha();