+/*! ========================================================================
+** Extended Template Library
+** Gaussian Blur Template Implementation
+** $Id$
+**
+** Copyright (c) 2002 Robert B. Quattlebaum Jr.
+**
+** This package is free software; you can redistribute it and/or
+** modify it under the terms of the GNU General Public License as
+** published by the Free Software Foundation; either version 2 of
+** the License, or (at your option) any later version.
+**
+** This package is distributed in the hope that it will be useful,
+** but WITHOUT ANY WARRANTY; without even the implied warranty of
+** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+** General Public License for more details.
+**
+** === N O T E S ===========================================================
+**
+** This is an internal header file, included by other ETL headers.
+** You should not attempt to use it directly.
+**
+** ========================================================================= */
+
+/* === S T A R T =========================================================== */
+
+#ifndef __ETL_GAUSSIAN_H
+#define __ETL_GAUSSIAN_H
+
+/* === H E A D E R S ======================================================= */
+
+#include <cstring> // for memset()
+#include <iterator>
+
+/* === M A C R O S ========================================================= */
+
+/* === T Y P E D E F S ===================================================== */
+
+/* === C L A S S E S & S T R U C T S ======================================= */
+
+_ETL_BEGIN_NAMESPACE
+
+template<typename T> void
+gaussian_blur_5x5_(T pen,int w, int h,
+typename T::pointer SC0,
+typename T::pointer SC1,
+typename T::pointer SC2,
+typename T::pointer SC3)
+{
+ int x,y;
+ typename T::value_type Tmp1,Tmp2,SR0,SR1,SR2,SR3;
+
+ //typename T::iterator_x iter;
+
+ // Setup the row buffers
+ for(x=0;x<w;x++)SC0[x+2]=pen.x()[x]*24;
+ memset(SC1,0,(w+2)*sizeof(typename T::value_type));
+ memset(SC2,0,(w+2)*sizeof(typename T::value_type));
+ memset(SC3,0,(w+2)*sizeof(typename T::value_type));
+
+ for(y=0;y<h+2;y++,pen.inc_y())
+ {
+ int yadj;
+ if(y>=h)
+ {yadj=(h-y)-1; SR0=pen.y()[yadj]*1.35;}
+ else
+ {yadj=0; SR0=pen.get_value()*1.35; }
+
+ SR1=SR2=SR3=typename T::value_type();
+ for(x=0;x<w+2;x++,pen.inc_x())
+ {
+ if(x>=w)
+ Tmp1=pen[yadj][(w-x)-1];
+ else
+ Tmp1=*pen[yadj];
+
+ Tmp2=SR0+Tmp1;
+ SR0=Tmp1;
+ Tmp1=SR1+Tmp2;
+ SR1=Tmp2;
+ Tmp2=SR2+Tmp1;
+ SR2=Tmp1;
+ Tmp1=SR3+Tmp2;
+ SR3=Tmp2;
+
+ // Column Machine
+ Tmp2=SC0[x]+Tmp1;
+ SC0[x]=Tmp1;
+ Tmp1=SC1[x]+Tmp2;
+ SC1[x]=Tmp2;
+ Tmp2=SC2[x]+Tmp1;
+ SC2[x]=Tmp1;
+ if(y>1&&x>1)
+ pen[-2][-2]=(SC3[x]+Tmp2)/256;
+ SC3[x]=Tmp2;
+ }
+ pen.dec_x(x);
+ }
+
+}
+
+template<typename T> void
+gaussian_blur_5x5(T pen, int w, int h)
+{
+ typename T::pointer SC0=new typename T::value_type[w+2];
+ typename T::pointer SC1=new typename T::value_type[w+2];
+ typename T::pointer SC2=new typename T::value_type[w+2];
+ typename T::pointer SC3=new typename T::value_type[w+2];
+
+ gaussian_blur_5x5_(pen,w,h,SC0,SC1,SC2,SC3);
+
+ delete [] SC0;
+ delete [] SC1;
+ delete [] SC2;
+ delete [] SC3;
+}
+
+template<typename T> void
+gaussian_blur_5x5(T begin, T end)
+{
+ typename T::difference_type size(end-begin);
+
+ typename T::pointer SC0=new typename T::value_type[size.x+2];
+ typename T::pointer SC1=new typename T::value_type[size.x+2];
+ typename T::pointer SC2=new typename T::value_type[size.x+2];
+ typename T::pointer SC3=new typename T::value_type[size.x+2];
+
+ gaussian_blur_5x5_(begin,size.x,size.y,SC0,SC1,SC2,SC3);
+
+ delete [] SC0;
+ delete [] SC1;
+ delete [] SC2;
+ delete [] SC3;
+}
+
+template<typename T> void
+gaussian_blur_3x3(T pen,int w, int h)
+{
+ int x,y;
+ typename T::value_type Tmp1,Tmp2,SR0,SR1;
+
+// typename T::iterator_x iter;
+
+ typename T::pointer SC0=new typename T::value_type[w+1];
+ typename T::pointer SC1=new typename T::value_type[w+1];
+
+ // Setup the row buffers
+ for(x=0;x<w;x++)SC0[x+1]=pen.x()[x]*4;
+ memset(SC1,0,(w+1)*sizeof(typename T::value_type));
+
+ for(y=0;y<h+1;y++,pen.inc_y())
+ {
+ int yadj;
+ if(y>=h)
+ {yadj=-1; SR1=SR0=pen.y()[yadj];}
+ else
+ {yadj=0; SR1=SR0=pen.get_value(); }
+
+ for(x=0;x<w+1;x++,pen.inc_x())
+ {
+ if(x>=w)
+ Tmp1=pen[yadj][(w-x)-2];
+ else
+ Tmp1=*pen[yadj];
+
+ Tmp2=SR0+Tmp1;
+ SR0=Tmp1;
+ Tmp1=SR1+Tmp2;
+ SR1=Tmp2;
+
+ Tmp2=SC0[x]+Tmp1;
+ SC0[x]=Tmp1;
+ if(y&&x)
+ pen[-1][-1]=(SC1[x]+Tmp2)/16;
+ SC1[x]=Tmp2;
+ }
+ pen.dec_x(x);
+ }
+
+ delete [] SC0;
+ delete [] SC1;
+}
+
+//! 2D 3x3 pixel gaussian blur
+template<typename _PEN> void
+gaussian_blur_3x3(_PEN begin, _PEN end)
+{
+ typename _PEN::difference_type size(end-begin);
+ gaussian_blur_3x3(begin,size.x,size.y);
+}
+
+//! 1D 3 pixel gaussian blur
+template<typename I> void
+gaussian_blur_3(I begin, I end, bool endpts = true)
+{
+// typedef typename I _itertype;
+// int i;
+ typename std::iterator_traits<I>::value_type Tmp1,Tmp2,SR0,SR1;
+
+ SR0=SR1=*begin;
+ I iter,prev=begin;
+ for(iter=begin;iter!=end;prev=iter++)
+ {
+ Tmp1=*iter;
+ Tmp2=SR0+Tmp1;
+ SR0=Tmp1;
+ Tmp1=SR1+Tmp2;
+ SR1=Tmp2;
+ if(iter!=begin && ( endpts || (prev != begin) ))
+ *prev=(Tmp1)/4;
+ }
+
+ if(endpts)
+ {
+ Tmp1=*prev;
+ Tmp2=SR0+Tmp1;
+ SR0=Tmp1;
+ Tmp1=SR1+Tmp2;
+ SR1=Tmp2;
+ *prev=(Tmp1)/4;
+ }
+}
+
+//! 2D 3x1 pixel gaussian blur
+template<typename _PEN> void
+gaussian_blur_3x1(_PEN begin, _PEN end)
+{
+ typename _PEN::difference_type size=end-begin;
+ for(;size.y>0;size.y--, begin.inc_y())
+ gaussian_blur_3(begin.x(),begin.x()+size.x);
+}
+
+//! 2D 1x3 pixel gaussian blur
+template<typename _PEN> void
+gaussian_blur_1x3(_PEN begin, _PEN end)
+{
+ typename _PEN::difference_type size=end-begin;
+ for(;size.x>0;size.x--,begin.inc_x())
+ gaussian_blur_3(begin.y(),begin.y()+size.y);
+}
+
+template<typename T> void
+gaussian_blur(T pen, int w, int h, int blur_x, int blur_y)
+{
+ typename T::pointer SC0=new typename T::value_type[w+2];
+ typename T::pointer SC1=new typename T::value_type[w+2];
+ typename T::pointer SC2=new typename T::value_type[w+2];
+ typename T::pointer SC3=new typename T::value_type[w+2];
+
+ blur_x--;
+ blur_y--;
+
+ while(blur_x&&blur_y)
+ {
+ if(blur_x>=4 && blur_y>=4)
+ {
+ gaussian_blur_5x5_(pen,w,h,SC0,SC1,SC2,SC3);
+ blur_x-=4,blur_y-=4;
+ }
+ else if(blur_x>=2 && blur_y>=2)
+ {
+ gaussian_blur_3x3(pen,w,h);
+ blur_x-=2,blur_y-=2;
+ }
+ else
+ blur_x--,blur_y--;
+ }
+ while(blur_x)
+ {
+ if(blur_x>=2)
+ {
+ gaussian_blur_3x1(pen,T(pen).move(w,h));
+ blur_x-=2;
+ }
+ else
+ blur_x--;
+ }
+ while(blur_y)
+ {
+ if(blur_y>=2)
+ {
+ gaussian_blur_1x3(pen,T(pen).move(w,h));
+ blur_y-=2;
+ }
+ else
+ blur_y--;
+ }
+
+ delete [] SC0;
+ delete [] SC1;
+ delete [] SC2;
+ delete [] SC3;
+}
+
+template<typename T> void
+gaussian_blur(T begin, T end,int w, int h)
+{
+ typename T::difference_type size(end-begin);
+ gaussian_blur(begin,size.x,size.y,w,h);
+}
+
+template<typename T> void
+gaussian_blur(T begin, T end,int w)
+{
+ typename T::difference_type size(end-begin);
+ gaussian_blur(begin,size.x,size.y,w,w);
+}
+
+_ETL_END_NAMESPACE
+
+/* === E X T E R N S ======================================================= */
+
+/* === E N D =============================================================== */
+
+#endif