plasma-framework/effects/blur.cpp
Aaron J. Seigo 1b523b9054 ok, this time JUST the plasma dir ;)
svn path=/trunk/KDE/kdelibs/; revision=879759
2008-11-03 23:08:39 +00:00

148 lines
4.0 KiB
C++

#ifndef BLUR_CPP
#define BLUR_CPP
/*
* Copyright 2007 Jani Huhtanen <jani.huhtanen@tut.fi>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU Library General Public License version 2 as
* published by the Free Software Foundation
*
* This program 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
*
* You should have received a copy of the GNU Library General Public
* License along with this program; if not, write to the
* Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
#include <cmath>
// Exponential blur, Jani Huhtanen, 2006
//
template<int aprec, int zprec>
static inline void blurinner(unsigned char *bptr, int &zR, int &zG, int &zB, int &zA, int alpha);
template<int aprec,int zprec>
static inline void blurrow(QImage &im, int line, int alpha);
template<int aprec, int zprec>
static inline void blurcol(QImage &im, int col, int alpha);
/*
* expblur(QImage &img, int radius)
*
* In-place blur of image 'img' with kernel
* of approximate radius 'radius'.
*
* Blurs with two sided exponential impulse
* response.
*
* aprec = precision of alpha parameter
* in fixed-point format 0.aprec
*
* zprec = precision of state parameters
* zR,zG,zB and zA in fp format 8.zprec
*/
template<int aprec,int zprec>
void expblur(QImage &img, int radius)
{
if(radius < 1) {
return;
}
/* Calculate the alpha such that 90% of
the kernel is within the radius.
(Kernel extends to infinity)
*/
int alpha = (int)((1 << aprec) * (1.0f - std::exp(-2.3f / (radius + 1.f))));
for (int row=0; row<img.height(); row++) {
blurrow<aprec,zprec>(img, row, alpha);
}
for (int col=0; col<img.width(); col++) {
blurcol<aprec,zprec>(img, col, alpha);
}
return;
}
template<int aprec, int zprec>
static inline void blurinner(unsigned char *bptr, int &zR, int &zG, int &zB, int &zA, int alpha)
{
int R, G, B, A;
R = *bptr;
G = *(bptr + 1);
B = *(bptr + 2);
A = *(bptr + 3);
zR += (alpha * ((R << zprec) - zR)) >> aprec;
zG += (alpha * ((G << zprec) - zG)) >> aprec;
zB += (alpha * ((B << zprec) - zB)) >> aprec;
zA += (alpha * ((A << zprec) - zA)) >> aprec;
*bptr = zR >> zprec;
*(bptr+1) = zG >> zprec;
*(bptr+2) = zB >> zprec;
*(bptr+3) = zA >> zprec;
}
template<int aprec,int zprec>
static inline void blurrow(QImage &im, int line, int alpha)
{
int zR, zG, zB, zA;
QRgb *ptr = (QRgb *)im.scanLine(line);
zR = *((unsigned char *)ptr ) << zprec;
zG = *((unsigned char *)ptr + 1) << zprec;
zB = *((unsigned char *)ptr + 2) << zprec;
zA = *((unsigned char *)ptr + 3) << zprec;
for (int index=1; index<im.width(); index++) {
blurinner<aprec,zprec>((unsigned char *)&ptr[index],zR,zG,zB,zA,alpha);
}
for (int index=im.width()-2; index>=0; index--) {
blurinner<aprec,zprec>((unsigned char *)&ptr[index],zR,zG,zB,zA,alpha);
}
}
template<int aprec, int zprec>
static inline void blurcol(QImage &im, int col, int alpha)
{
int zR, zG, zB, zA;
QRgb *ptr = (QRgb *)im.bits();
ptr += col;
zR = *((unsigned char *)ptr ) << zprec;
zG = *((unsigned char *)ptr + 1) << zprec;
zB = *((unsigned char *)ptr + 2) << zprec;
zA = *((unsigned char *)ptr + 3) << zprec;
for (int index=im.width(); index<(im.height()-1)*im.width(); index+=im.width()) {
blurinner<aprec,zprec>((unsigned char *)&ptr[index], zR, zG, zB, zA, alpha);
}
for (int index=(im.height()-2)*im.width(); index>=0; index-=im.width()) {
blurinner<aprec,zprec>((unsigned char *)&ptr[index], zR, zG, zB, zA, alpha);
}
}
template<class T>
inline const T &qClamp(const T &x, const T &low, const T &high)
{
if (x < low) {
return low;
} else if (x > high) {
return high;
} else {
return x;
}
}
#endif