316 lines
9.4 KiB
C++
316 lines
9.4 KiB
C++
/*
|
|
* This program source code file is part of KICAD, a free EDA CAD application.
|
|
*
|
|
* Copyright (C) 2021 Ola Rinta-Koski <gitlab@rinta-koski.net>
|
|
* Copyright (C) 2021 Kicad Developers, see AUTHORS.txt for contributors.
|
|
*
|
|
* Outline font class
|
|
*
|
|
* This program 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 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 General Public License
|
|
* along with this program; if not, you may find one here:
|
|
* http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
|
|
* or you may search the http://www.gnu.org website for the version 2 license,
|
|
* or you may write to the Free Software Foundation, Inc.,
|
|
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
|
|
*/
|
|
|
|
#include <font/outline_decomposer.h>
|
|
#include <bezier_curves.h>
|
|
|
|
using namespace KIFONT;
|
|
|
|
OUTLINE_DECOMPOSER::OUTLINE_DECOMPOSER( FT_Outline& aOutline ) :
|
|
m_outline( aOutline ),
|
|
m_contours( nullptr )
|
|
{
|
|
}
|
|
|
|
|
|
static VECTOR2D toVector2D( const FT_Vector* aFreeTypeVector )
|
|
{
|
|
return VECTOR2D( aFreeTypeVector->x * GLYPH_SIZE_SCALER,
|
|
aFreeTypeVector->y * GLYPH_SIZE_SCALER );
|
|
}
|
|
|
|
|
|
void OUTLINE_DECOMPOSER::newContour()
|
|
{
|
|
CONTOUR contour;
|
|
contour.orientation = FT_Outline_Get_Orientation( &m_outline );
|
|
m_contours->push_back( contour );
|
|
}
|
|
|
|
|
|
void OUTLINE_DECOMPOSER::addContourPoint( const VECTOR2D& p )
|
|
{
|
|
// don't add repeated points
|
|
if( m_contours->back().points.empty() || m_contours->back().points.back() != p )
|
|
m_contours->back().points.push_back( p );
|
|
}
|
|
|
|
|
|
int OUTLINE_DECOMPOSER::moveTo( const FT_Vector* aEndPoint, void* aCallbackData )
|
|
{
|
|
OUTLINE_DECOMPOSER* decomposer = static_cast<OUTLINE_DECOMPOSER*>( aCallbackData );
|
|
|
|
decomposer->m_lastEndPoint = toVector2D( aEndPoint );
|
|
|
|
decomposer->newContour();
|
|
decomposer->addContourPoint( decomposer->m_lastEndPoint );
|
|
|
|
return 0;
|
|
}
|
|
|
|
|
|
int OUTLINE_DECOMPOSER::lineTo( const FT_Vector* aEndPoint, void* aCallbackData )
|
|
{
|
|
OUTLINE_DECOMPOSER* decomposer = static_cast<OUTLINE_DECOMPOSER*>( aCallbackData );
|
|
|
|
decomposer->m_lastEndPoint = toVector2D( aEndPoint );
|
|
|
|
decomposer->addContourPoint( decomposer->m_lastEndPoint );
|
|
|
|
return 0;
|
|
}
|
|
|
|
|
|
int OUTLINE_DECOMPOSER::quadraticTo( const FT_Vector* aControlPoint, const FT_Vector* aEndPoint,
|
|
void* aCallbackData )
|
|
{
|
|
return cubicTo( aControlPoint, nullptr, aEndPoint, aCallbackData );
|
|
}
|
|
|
|
|
|
int OUTLINE_DECOMPOSER::cubicTo( const FT_Vector* aFirstControlPoint,
|
|
const FT_Vector* aSecondControlPoint, const FT_Vector* aEndPoint,
|
|
void* aCallbackData )
|
|
{
|
|
OUTLINE_DECOMPOSER* decomposer = static_cast<OUTLINE_DECOMPOSER*>( aCallbackData );
|
|
|
|
GLYPH_POINTS bezier;
|
|
bezier.push_back( decomposer->m_lastEndPoint );
|
|
bezier.push_back( toVector2D( aFirstControlPoint ) );
|
|
|
|
if( aSecondControlPoint )
|
|
{
|
|
// aSecondControlPoint == nullptr for quadratic Beziers
|
|
bezier.push_back( toVector2D( aSecondControlPoint ) );
|
|
}
|
|
|
|
bezier.push_back( toVector2D( aEndPoint ) );
|
|
|
|
GLYPH_POINTS result;
|
|
decomposer->approximateBezierCurve( result, bezier );
|
|
for( const VECTOR2D& p : result )
|
|
decomposer->addContourPoint( p );
|
|
|
|
decomposer->m_lastEndPoint = toVector2D( aEndPoint );
|
|
|
|
return 0;
|
|
}
|
|
|
|
|
|
void OUTLINE_DECOMPOSER::OutlineToSegments( CONTOURS* aContours )
|
|
{
|
|
m_contours = aContours;
|
|
|
|
FT_Outline_Funcs callbacks;
|
|
|
|
callbacks.move_to = moveTo;
|
|
callbacks.line_to = lineTo;
|
|
callbacks.conic_to = quadraticTo;
|
|
callbacks.cubic_to = cubicTo;
|
|
callbacks.shift = 0;
|
|
callbacks.delta = 0;
|
|
|
|
FT_Error e = FT_Outline_Decompose( &m_outline, &callbacks, this );
|
|
|
|
if( e )
|
|
{
|
|
// TODO: handle error != 0
|
|
}
|
|
|
|
for( CONTOUR& c : *m_contours )
|
|
c.winding = winding( c.points );
|
|
}
|
|
|
|
|
|
// use converter in kimath
|
|
bool OUTLINE_DECOMPOSER::approximateQuadraticBezierCurve( GLYPH_POINTS& aResult,
|
|
const GLYPH_POINTS& aBezier ) const
|
|
{
|
|
wxASSERT( aBezier.size() == 3 );
|
|
|
|
// BEZIER_POLY only handles cubic Bezier curves, even though the
|
|
// comments say otherwise...
|
|
//
|
|
// Quadratic to cubic Bezier conversion:
|
|
// cpn = Cubic Bezier control points (n = 0..3, 4 in total)
|
|
// qpn = Quadratic Bezier control points (n = 0..2, 3 in total)
|
|
// cp0 = qp0, cp1 = qp0 + 2/3 * (qp1 - qp0), cp2 = qp2 + 2/3 * (qp1 - qp2), cp3 = qp2
|
|
|
|
GLYPH_POINTS cubic;
|
|
cubic.push_back( aBezier[0] ); // cp0
|
|
cubic.push_back( aBezier[0] + ( ( aBezier[1] - aBezier[0] ) * 2 / 3 ) ); // cp1
|
|
cubic.push_back( aBezier[2] + ( ( aBezier[1] - aBezier[2] ) * 2 / 3 ) ); // cp2
|
|
cubic.push_back( aBezier[2] ); // cp3
|
|
|
|
return approximateCubicBezierCurve( aResult, cubic );
|
|
}
|
|
|
|
|
|
bool OUTLINE_DECOMPOSER::approximateCubicBezierCurve( GLYPH_POINTS& aResult,
|
|
const GLYPH_POINTS& aCubicBezier ) const
|
|
{
|
|
wxASSERT( aCubicBezier.size() == 4 );
|
|
|
|
// minimumSegmentLength defines the "smoothness" of the
|
|
// curve-to-straight-segments conversion: the larger, the coarser
|
|
// TODO: find out what the minimum segment length should really be!
|
|
constexpr int minimumSegmentLength = 10;
|
|
BEZIER_POLY converter( aCubicBezier );
|
|
converter.GetPoly( aResult, minimumSegmentLength );
|
|
|
|
return true;
|
|
}
|
|
|
|
|
|
bool OUTLINE_DECOMPOSER::approximateBezierCurve( GLYPH_POINTS& aResult,
|
|
const GLYPH_POINTS& aBezier ) const
|
|
{
|
|
switch( aBezier.size() )
|
|
{
|
|
case 4: // cubic
|
|
return approximateCubicBezierCurve( aResult, aBezier );
|
|
break;
|
|
case 3: // quadratic
|
|
return approximateQuadraticBezierCurve( aResult, aBezier );
|
|
break;
|
|
default:
|
|
// error, only 3 and 4 are acceptable values
|
|
return false;
|
|
}
|
|
}
|
|
|
|
|
|
int OUTLINE_DECOMPOSER::winding( const GLYPH_POINTS& aContour ) const
|
|
{
|
|
// -1 == counterclockwise, 1 == clockwise
|
|
|
|
const int cw = 1;
|
|
const int ccw = -1;
|
|
|
|
if( aContour.size() < 2 )
|
|
{
|
|
// zero or one points, so not a clockwise contour - in fact not a contour at all
|
|
//
|
|
// It could also be argued that a contour needs 3 extremum points at a minimum to be
|
|
// considered a proper contour (ie. a glyph (subpart) outline, or a hole)
|
|
return 0;
|
|
}
|
|
|
|
unsigned int i_lowest_vertex = 0;
|
|
double lowest_y = std::numeric_limits<double>::max();
|
|
|
|
for( unsigned int i = 0; i < aContour.size(); i++ )
|
|
{
|
|
VECTOR2D p = aContour[i];
|
|
|
|
if( p.y < lowest_y )
|
|
{
|
|
i_lowest_vertex = i;
|
|
lowest_y = p.y;
|
|
|
|
// note: we should also check for p.y == lowest_y and then choose the point with
|
|
// leftmost.x, but as p.x is a double, equality is a dubious concept; however
|
|
// this should suffice in the general case
|
|
}
|
|
}
|
|
|
|
unsigned int i_prev_vertex = ( i_lowest_vertex + aContour.size() - 1 ) % aContour.size();
|
|
unsigned int i_next_vertex = ( i_lowest_vertex + 1 ) % aContour.size();
|
|
|
|
const VECTOR2D& lowest = aContour[i_lowest_vertex];
|
|
VECTOR2D prev( aContour[i_prev_vertex] );
|
|
|
|
while( prev == lowest )
|
|
{
|
|
if( i_prev_vertex == 0 )
|
|
i_prev_vertex = aContour.size() - 1;
|
|
else
|
|
i_prev_vertex--;
|
|
|
|
if( i_prev_vertex == i_lowest_vertex )
|
|
{
|
|
// ERROR: degenerate contour (all points are colinear with equal Y coordinate)
|
|
// TODO: signal error
|
|
// for now let's just return something at random
|
|
return cw;
|
|
}
|
|
|
|
prev = aContour[i_prev_vertex];
|
|
}
|
|
|
|
VECTOR2D next( aContour[i_next_vertex] );
|
|
|
|
while( next == lowest )
|
|
{
|
|
if( i_next_vertex == aContour.size() - 1 )
|
|
i_next_vertex = 0;
|
|
else
|
|
i_next_vertex++;
|
|
|
|
if( i_next_vertex == i_lowest_vertex )
|
|
{
|
|
// ERROR: degenerate contour (all points are equal)
|
|
// TODO: signal error
|
|
// for now let's just return something at random
|
|
return cw;
|
|
}
|
|
|
|
next = aContour[i_next_vertex];
|
|
}
|
|
|
|
// winding is figured out based on the angle between the lowest
|
|
// vertex and its neighbours
|
|
//
|
|
// prev.x < lowest.x && next.x > lowest.x -> ccw
|
|
//
|
|
// prev.x > lowest.x && next.x < lowest.x -> cw
|
|
//
|
|
// prev.x < lowest.x && next.x < lowest.x:
|
|
// ?
|
|
//
|
|
// prev.x > lowest.x && next.x > lowest.x:
|
|
// ?
|
|
//
|
|
if( prev.x < lowest.x && next.x > lowest.x )
|
|
return ccw;
|
|
|
|
if( prev.x > lowest.x && next.x < lowest.x )
|
|
return cw;
|
|
|
|
double prev_deltaX = prev.x - lowest.x;
|
|
double prev_deltaY = prev.y - lowest.y;
|
|
double next_deltaX = next.x - lowest.x;
|
|
double next_deltaY = next.y - lowest.y;
|
|
|
|
double prev_atan = atan2( prev_deltaY, prev_deltaX );
|
|
double next_atan = atan2( next_deltaY, next_deltaX );
|
|
|
|
if( prev_atan > next_atan )
|
|
return ccw;
|
|
else
|
|
return cw;
|
|
}
|