1 files changed, 120 insertions, 0 deletions
diff --git a/agg/source/agg_image_filters.cpp b/agg/source/agg_image_filters.cpp
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+++ b/agg/source/agg_image_filters.cpp
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+//----------------------------------------------------------------------------
+// Anti-Grain Geometry - Version 2.3
+// Copyright (C) 2002-2005 Maxim Shemanarev (http://www.antigrain.com)
+//
+// Permission to copy, use, modify, sell and distribute this software
+// is granted provided this copyright notice appears in all copies.
+// This software is provided "as is" without express or implied
+// warranty, and with no claim as to its suitability for any purpose.
+//
+//----------------------------------------------------------------------------
+// Contact: mcseem@antigrain.com
+//          mcseemagg@yahoo.com
+//          http://www.antigrain.com
+//----------------------------------------------------------------------------
+//
+// Filtering class image_filter_lut implemantation
+//
+//----------------------------------------------------------------------------
+
+
+#include "agg_image_filters.h"
+
+
+namespace agg
+{
+
+    //--------------------------------------------------------------------
+    image_filter_lut::~image_filter_lut()
+    {
+        delete [] m_weight_array;
+    }
+
+
+    //--------------------------------------------------------------------
+    image_filter_lut::image_filter_lut() :
+        m_weight_array(0),
+        m_max_size(0)
+    {}
+
+    //--------------------------------------------------------------------
+    void image_filter_lut::realloc(double _radius)
+    {
+        m_radius = _radius;
+        m_diameter = unsigned(ceil(_radius)) * 2;
+        m_start = -int(m_diameter / 2 - 1);
+        unsigned size = m_diameter << image_subpixel_shift;
+        if(size > m_max_size)
+        {
+            delete [] m_weight_array;
+            m_weight_array = new int16 [size];
+            m_max_size = size;
+        }
+    }
+
+
+
+    //--------------------------------------------------------------------
+    // This function normalizes integer values and corrects the rounding
+    // errors. It doesn't do anything with the source floating point values
+    // (m_weight_array_dbl), it corrects only integers according to the rule
+    // of 1.0 which means that any sum of pixel weights must be equal to 1.0.
+    // So, the filter function must produce a graph of the proper shape.
+    //--------------------------------------------------------------------
+    void image_filter_lut::normalize()
+    {
+        unsigned i;
+        int flip = 1;
+
+        for(i = 0; i < image_subpixel_size; i++)
+        {
+            for(;;)
+            {
+                int sum = 0;
+                unsigned j;
+                for(j = 0; j < m_diameter; j++)
+                {
+                    sum += m_weight_array[j * image_subpixel_size + i];
+                }
+
+                if(sum == image_filter_size) break;
+
+                double k = double(image_filter_size) / double(sum);
+                sum = 0;
+                for(j = 0; j < m_diameter; j++)
+                {
+                    sum += m_weight_array[j * image_subpixel_size + i] =
+                        int16(m_weight_array[j * image_subpixel_size + i] * k);
+                }
+
+                sum -= image_filter_size;
+                int16 inc = (sum > 0) ? -1 : 1;
+
+                for(j = 0; j < m_diameter && sum; j++)
+                {
+                    flip ^= 1;
+                    unsigned idx = flip ? m_diameter/2 + j/2 : m_diameter/2 - j/2;
+                    int v = m_weight_array[idx * image_subpixel_size + i];
+                    if(v < image_filter_size)
+                    {
+                        m_weight_array[idx * image_subpixel_size + i] =
+                            m_weight_array[idx * image_subpixel_size + i] + inc;
+                        sum += inc;
+                    }
+                }
+            }
+        }
+
+        unsigned pivot = m_diameter << (image_subpixel_shift - 1);
+
+        for(i = 0; i < pivot; i++)
+        {
+            m_weight_array[pivot + i] = m_weight_array[pivot - i];
+        }
+        unsigned end = (diameter() << image_subpixel_shift) - 1;
+        m_weight_array[0] = m_weight_array[end];
+    }
+
+
+}
+