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Diffstat (limited to 'karbon/commands/vflattencmd.cpp')
-rw-r--r-- | karbon/commands/vflattencmd.cpp | 82 |
1 files changed, 82 insertions, 0 deletions
diff --git a/karbon/commands/vflattencmd.cpp b/karbon/commands/vflattencmd.cpp new file mode 100644 index 00000000..21d5b50c --- /dev/null +++ b/karbon/commands/vflattencmd.cpp @@ -0,0 +1,82 @@ +/* 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 <tdelocale.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(); + } +} + |