void interpolateDistance(size_t x1, size_t y1, size_t x2, size_t y2, const unsigned char* I)
{
int i1 = iPos(x1, y1);
if ((I[iPos(x2, y2)] > 127) != (I[i1] > 127))
{
//double interpDist = std::abs((128.0 - I[i1]) / (double(I[iPos(x2, y2)]) - I[i1]));
d[i1] = 1;//std::min(d[i1], interpDist);
p[i1][0] = x2;
p[i1][1] = y2;
}
}
inline void check(int x, int y, double delta, size_t i2)
{
int i1 = iPos(x,y);
if (d[i1] + delta < d[i2])
{
p[i2] = p[i1];
const double deltaX = (p[i1][0] - x);
const double deltaY = (p[i1][1] - y);
d[i2] = std::sqrt(deltaX*deltaX + deltaY*deltaY);
}
}
SignedDistanceTransform(unsigned char* I, size_t width, size_t height):
_width(width), _height(height)
{
//The border of the image must be 0
for (size_t x(0); x < _width; ++x)
{ I[iPos(x, 0)] = 0; I[iPos(x, _height - 1)] = 0; }
for (size_t y(0); y < _height; ++y)
{ I[iPos(0, y)] = 0; I[iPos(_width - 1, y)] = 0; }
double floatInf = std::numeric_limits<float>::max() / 2;
p.resize(_width * _height);
d.resize(_width * _height, floatInf);
//Iterate over the image's non-border pixels, finding color
//edge pixels.
for (size_t y(1); y < _height - 1; ++y)
for (size_t x(1); x < _width - 1; ++x)
{
interpolateDistance(x, y, x - 1, y, I);
interpolateDistance(x, y, x + 1, y, I);
interpolateDistance(x, y, x, y - 1, I);
interpolateDistance(x, y, x, y + 1, I);
}
//First "forward" pass
for (int y(1); y < int(_height) - 1; ++y)
for (int x(1); x < int(_width) - 1; ++x)
{
int i2 = iPos(x,y);
check(x-1,y-1,std::sqrt(2), i2);
check(x,y-1,1, i2);
check(x+1,y-1,std::sqrt(2), i2);
check(x-1,y,1, i2);
}
//Second "reverse" pass
for (int y(_height - 2); y > 0; --y)
for (int x(_width - 2); x > 0; --x)
{
size_t i2 = iPos(x,y);
check(x+1,y,1, i2);
check(x-1,y+1,std::sqrt(2), i2);
check(x,y+1,1, i2);
check(x+1,y+1,std::sqrt(2), i2);
}
//Transform the output to a scaled range
for (size_t x(0); x < _width; ++x)
for (size_t y(0); y < _height; ++y)
{
size_t i = iPos(x,y);
double locd = (I[i] > 127) ? d[i] : -d[i];
I[i] = std::min(255.0, std::max(0.0, 128 + locd));
}
}
/** \brief Replace all occurrences of a substring with another string.
\param strFind The string that shall be replaced.
\param strReplaceWith The string that should be inserted instead of strFind
*/
void ParserError::ReplaceSubString( string_type &strSource,
const string_type &strFind,
const string_type &strReplaceWith)
{
string_type strResult;
string_type::size_type iPos(0), iNext(0);
for(;;)
{
iNext = strSource.find(strFind, iPos);
strResult.append(strSource, iPos, iNext-iPos);
if( iNext==string_type::npos )
break;
strResult.append(strReplaceWith);
iPos = iNext + strFind.length();
}
strSource.swap(strResult);
}
