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83 lines
2.5 KiB
83 lines
2.5 KiB
15 years ago
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/* This file is part of the KDE project
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Copyright (C) 2002, 2003 The Karbon Developers
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This library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Library General Public
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License as published by the Free Software Foundation; either
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version 2 of the License, or (at your option) any later version.
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This library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public License
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along with this library; see the file COPYING.LIB. If not, write to
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the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
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* Boston, MA 02110-1301, USA.
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*/
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#include "vflattencmd.h"
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#include <klocale.h>
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#include <core/vpath.h>
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#include <core/vsegment.h>
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// TODO: Think about if we want to adapt this:
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/*
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* <cite from GNU ghostscript's gxpflat.c>
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*
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* To calculate how many points to sample along a path in order to
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* approximate it to the desired degree of flatness, we define
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* dist((x,y)) = abs(x) + abs(y);
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* then the number of points we need is
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* N = 1 + sqrt(3/4 * D / flatness),
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* where
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* D = max(dist(p0 - 2*p1 + p2), dist(p1 - 2*p2 + p3)).
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* Since we are going to use a power of 2 for the number of intervals,
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* we can avoid the square root by letting
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* N = 1 + 2^(ceiling(log2(3/4 * D / flatness) / 2)).
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* (Reference: DEC Paris Research Laboratory report #1, May 1989.)
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*
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* We treat two cases specially. First, if the curve is very
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* short, we halve the flatness, to avoid turning short shallow curves
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* into short straight lines. Second, if the curve forms part of a
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* character (indicated by flatness = 0), we let
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* N = 1 + 2 * max(abs(x3-x0), abs(y3-y0)).
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* This is probably too conservative, but it produces good results.
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*
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* </cite from GNU ghostscript's gxpflat.c>
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*/
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VFlattenCmd::VFlattenCmd( VDocument *doc, double flatness )
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: VReplacingCmd( doc, i18n( "Flatten Curves" ) )
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{
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m_flatness = flatness > 0.0 ? flatness : 1.0;
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}
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void
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VFlattenCmd::visitVSubpath( VSubpath& path )
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{
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path.first();
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// Ommit first segment.
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while( path.next() )
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{
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while( !path.current()->isFlat( m_flatness ) )
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{
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// Split at midpoint.
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path.insert(
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path.current()->splitAt( 0.5 ) );
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}
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// Convert to line.
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path.current()->setDegree( 1 );
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if( !success() )
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setSuccess();
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}
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}
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