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//
// libavg - Media Playback Engine.
// Copyright (C) 2003-2014 Ulrich von Zadow
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2 of the License, or (at your option) any later version.
//
// This library 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
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
//
// Current versions can be found at www.libavg.de
//
#ifndef _FilterFloodfill_H_
#define _FilterFloodfill_H_
#include "../api.h"
#include "Filter.h"
#include "../base/GLMHelper.h"
#include <stack>
namespace avg {
struct Segment {
Segment(int iy, int ix1, int ix2, int idy)
: y(iy),
x1(ix1),
x2(ix2),
dy(idy)
{}
int y;
int x1;
int x2;
int dy;
};
class ColorTester {
public:
ColorTester(Pixel32 color)
: m_Color(color)
{
}
bool operator()(unsigned char * pPixel)
{
return *(Pixel32*)(pPixel) == m_Color;
}
private:
Pixel32 m_Color;
};
// Flood fill filter. The comparison functor used to determine whether a pixel
// belongs to the area is passed as template parameter. Pixels in the flooded area
// are made transparent.
template<class PixelTester>
class AVG_TEMPLATE_API FilterFloodfill : public Filter
{
public:
FilterFloodfill(PixelTester tester, const IntPoint& pt);
virtual ~FilterFloodfill();
virtual void applyInPlace(BitmapPtr pBmp) ;
private:
void pushSeg(BitmapPtr pBmp, std::stack<Segment>& segments,
int y, int x1, int x2, int dy);
void setTransparent(unsigned char* pPixel);
PixelTester m_Tester;
IntPoint m_Pt;
};
template<class PixelTester>
FilterFloodfill<PixelTester>::FilterFloodfill(PixelTester tester, const IntPoint& pt)
: m_Tester(tester),
m_Pt(pt)
{
}
template<class PixelTester>
FilterFloodfill<PixelTester>::~FilterFloodfill()
{
}
template<class PixelTester>
void FilterFloodfill<PixelTester>::applyInPlace(BitmapPtr pBmp)
{
// Algorithm from Graphics Gems I, pp 296ff.
std::stack<Segment> segments;
unsigned char * pPixels = (unsigned char *)(pBmp->getPixels());
int stride = pBmp->getStride();
pushSeg(pBmp, segments, m_Pt.y, m_Pt.x, m_Pt.x, 1);
pushSeg(pBmp, segments, m_Pt.y+1, m_Pt.x, m_Pt.x, -1);
int l;
while (!segments.empty()) {
Segment seg = segments.top();
seg.y += seg.dy;
segments.pop();
int x = seg.x1;
unsigned char * pCurPixel = pPixels+x*4+seg.y*stride;
for (; x>=0 && m_Tester(pCurPixel); x--) {
setTransparent(pCurPixel);
pCurPixel-=4;
}
if (x >= seg.x1) {
goto skip;
}
l = x+1;
if (l<seg.x1) {
pushSeg(pBmp, segments, seg.y, l, seg.x1-1, -seg.dy);
}
x = seg.x1+1;
do {
pCurPixel = pPixels+x*4+seg.y*stride;
for (; x<pBmp->getSize().x && m_Tester(pCurPixel); x++) {
setTransparent(pCurPixel);
pCurPixel+=4;
}
pushSeg(pBmp, segments, seg.y, l, x-1, seg.dy);
if (x>seg.x2+1) {
pushSeg(pBmp, segments, seg.y, seg.x2+1, x-1, -seg.dy);
}
skip: x++;
pCurPixel = pPixels+x*4+seg.y*stride;
for (; x<=seg.x2 && !m_Tester(pCurPixel); x++) {
pCurPixel+=4;
}
l = x;
} while (x<=seg.x2);
}
}
template<class PixelTester>
void FilterFloodfill<PixelTester>::pushSeg(BitmapPtr pBmp, std::stack<Segment>& segments,
int y, int x1, int x2, int dy)
{
if (y+dy >= 0 && y+dy < pBmp->getSize().y) {
segments.push(Segment(y, x1, x2, dy));
}
}
template<class PixelTester>
void FilterFloodfill<PixelTester>::setTransparent(unsigned char* pPixel)
{
*(Pixel32*)(pPixel) = Pixel32(0,0,255,0);
}
}
#endif
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