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/* This file is part of the KDE project
Copyright (C) 2002, 2003 The Karbon Developers
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public License
along with this library; see the file COPYING.LIB. If not, write to
the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
* Boston, MA 02110-1301, USA.
*/
#include "vflattencmd.h"
#include <klocale.h>
#include <core/vpath.h>
#include <core/vsegment.h>
// TODO: Think about if we want to adapt this:
/*
* <cite from GNU ghostscript's gxpflat.c>
*
* To calculate how many points to sample along a path in order to
* approximate it to the desired degree of flatness, we define
* dist((x,y)) = abs(x) + abs(y);
* then the number of points we need is
* N = 1 + sqrt(3/4 * D / flatness),
* where
* D = max(dist(p0 - 2*p1 + p2), dist(p1 - 2*p2 + p3)).
* Since we are going to use a power of 2 for the number of intervals,
* we can avoid the square root by letting
* N = 1 + 2^(ceiling(log2(3/4 * D / flatness) / 2)).
* (Reference: DEC Paris Research Laboratory report #1, May 1989.)
*
* We treat two cases specially. First, if the curve is very
* short, we halve the flatness, to avoid turning short shallow curves
* into short straight lines. Second, if the curve forms part of a
* character (indicated by flatness = 0), we let
* N = 1 + 2 * max(abs(x3-x0), abs(y3-y0)).
* This is probably too conservative, but it produces good results.
*
* </cite from GNU ghostscript's gxpflat.c>
*/
VFlattenCmd::VFlattenCmd( VDocument *doc, double flatness )
: VReplacingCmd( doc, i18n( "Flatten Curves" ) )
{
m_flatness = flatness > 0.0 ? flatness : 1.0;
}
void
VFlattenCmd::visitVSubpath( VSubpath& path )
{
path.first();
// Ommit first segment.
while( path.next() )
{
while( !path.current()->isFlat( m_flatness ) )
{
// Split at midpoint.
path.insert(
path.current()->splitAt( 0.5 ) );
}
// Convert to line.
path.current()->setDegree( 1 );
if( !success() )
setSuccess();
}
}
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