OpenSceneGraph/src/osgText/FTVectoriser.cpp

#include	"FTVectoriser.h"
#include	"FTGL.h"


FTContour::FTContour()
:	kMAXPOINTS( 1000)
{	
	pointList.reserve( kMAXPOINTS);
}


FTContour::~FTContour()
{
	pointList.clear();
}


void FTContour::AddPoint( const float x, const float y)
{
	ftPoint point( x, y, 0.0); 
	
	// Eliminate duplicate points.
	if( pointList.empty() || ( pointList[pointList.size() - 1] != point && pointList[0] != point))
	{
		pointList.push_back( point);
	}
}


FTVectoriser::FTVectoriser( const FT_Glyph glyph)
:	contour(0),
	contourFlag(0),
	kBSTEPSIZE( 0.2)
{
	FT_OutlineGlyph outline = (FT_OutlineGlyph)glyph;
	ftOutline = outline->outline;
	
	contourList.reserve( ftOutline.n_contours);
}


FTVectoriser::~FTVectoriser()
{
	for( int c = 0; c < contours(); ++c)
	{
		delete contourList[c];
	}

	contourList.clear();
}


int FTVectoriser::points()
{
	int s = 0;
	for( int c = 0; c < contours(); ++c)
	{
		s += contourList[c]->size();
	}
	
	return s;
}


bool FTVectoriser::Process()
{
	short first = 0;
	short last;
	const short cont = ftOutline.n_contours;
	
	for( short c = 0; c < cont; ++c)
	{
		contour = new FTContour;
		contourFlag = ftOutline.flags;
		last = ftOutline.contours[c];

		for( short p = first; p <= last; ++p)
		{
			switch( ftOutline.tags[p])
			{
				case FT_Curve_Tag_Conic:
					p += Conic( p, first, last);
					break;
				case FT_Curve_Tag_Cubic:
					p += Cubic( p, first, last);
					break;
				case FT_Curve_Tag_On:
				default:
 					contour->AddPoint( ftOutline.points[p].x, ftOutline.points[p].y);
			}
		}
		
		contourList.push_back( contour);
		first = last + 1;
	}
	
	return true;
}


int FTVectoriser::Conic( const int index, const int first, const int last)
{
	int next = index + 1;
	int prev = index - 1;
	
	if( index == last)
		next = first; 
	
	if( index == first)
		prev = last; 
	
	if( ftOutline.tags[next] != FT_Curve_Tag_Conic)
	{
		ctrlPtArray[0][0] = ftOutline.points[prev].x;	ctrlPtArray[0][1] = ftOutline.points[prev].y;
		ctrlPtArray[1][0] = ftOutline.points[index].x;	ctrlPtArray[1][1] = ftOutline.points[index].y;
		ctrlPtArray[2][0] = ftOutline.points[next].x;	ctrlPtArray[2][1] = ftOutline.points[next].y;
		
		evaluateCurve( 2);
		return 1;
	}
	else
	{
		int next2 = next + 1;
		if( next == last)
			next2 = first;
		
		//create a phantom point
		float x = ( ftOutline.points[index].x + ftOutline.points[next].x) / 2;
		float y = ( ftOutline.points[index].y + ftOutline.points[next].y) / 2;
		
		// process first curve
		ctrlPtArray[0][0] = ftOutline.points[prev].x;	ctrlPtArray[0][1] = ftOutline.points[prev].y;
		ctrlPtArray[1][0] = ftOutline.points[index].x;	ctrlPtArray[1][1] = ftOutline.points[index].y;
		ctrlPtArray[2][0] = x;							ctrlPtArray[2][1] = y;
		
		evaluateCurve( 2);
		
		// process second curve
		ctrlPtArray[0][0] = x;							ctrlPtArray[0][1] = y;
		ctrlPtArray[1][0] = ftOutline.points[next].x;	ctrlPtArray[1][1] = ftOutline.points[next].y;
		ctrlPtArray[2][0] = ftOutline.points[next2].x;	ctrlPtArray[2][1] = ftOutline.points[next2].y;
		evaluateCurve( 2);
		
		return 2;
	}
}


int FTVectoriser::Cubic( const int index, const int first, const int last)
{
	int next = index + 1;
	int prev = index - 1;
	
	if( index == last)
		next = first; 
	
	int next2 = next + 1;
	
	if( next == last)
		next2 = first;
	
	if( index == first)
		prev = last; 

	ctrlPtArray[0][0] = ftOutline.points[prev].x;		ctrlPtArray[0][1] = ftOutline.points[prev].y;
	ctrlPtArray[1][0] = ftOutline.points[index].x;		ctrlPtArray[1][1] = ftOutline.points[index].y;
	ctrlPtArray[2][0] = ftOutline.points[next].x;		ctrlPtArray[2][1] = ftOutline.points[next].y;
	ctrlPtArray[3][0] = ftOutline.points[next2].x;		ctrlPtArray[3][1] = ftOutline.points[next2].y;

	evaluateCurve( 3);
	return 2;
}


// De Casteljau algorithm contributed by Jed Soane
void FTVectoriser::deCasteljau( const float t, const int n)
{
    //Calculating successive b(i)'s using de Casteljau algorithm.
    for( int i = 1; i <= n; i++)
        for( int k = 0; k <= (n - i); k++)
        {
			bValues[i][k][0] = (1 - t) * bValues[i - 1][k][0] + t * bValues[i - 1][k + 1][0];
			bValues[i][k][1] = (1 - t) * bValues[i - 1][k][1] + t * bValues[i - 1][k + 1][1];
		}
		
    //Specify next vertex to be included on curve
	contour->AddPoint( bValues[n][0][0], bValues[n][0][1]);
}


// De Casteljau algorithm contributed by Jed Soane
void FTVectoriser::evaluateCurve( const int n)
{
    // setting the b(0) equal to the control points
    for( int i = 0; i <= n; i++)
	{
		bValues[0][i][0] = ctrlPtArray[i][0];
		bValues[0][i][1] = ctrlPtArray[i][1];
    }

    float t;            					//parameter for curve point calc. [0.0, 1.0]

    for( int m = 0; m <= ( 1 / kBSTEPSIZE); m++)
    {
    	t = m * kBSTEPSIZE;
        deCasteljau( t, n);  //calls to evaluate point on curve att.
    }
}


void FTVectoriser::MakeOutline( double* data)
{
	int i = 0;
	
	for( int c= 0; c < contours(); ++c)
	{
		const FTContour* contour = contourList[c];
		
		for( int p = 0; p < contour->size(); ++p)
		{
			data[i] = static_cast<double>(contour->pointList[p].x / 64.0f); // is 64 correct?
			data[i + 1] = static_cast<double>(contour->pointList[p].y / 64.0f);
			data[i + 2] = 0.0; // static_cast<double>(contour->pointList[p].z / 64.0f);
			i += 3;
		}
	}
}