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Diffstat (limited to 'basebmp/inc/basebmp/linerenderer.hxx')
| -rw-r--r-- | basebmp/inc/basebmp/linerenderer.hxx | 181 |
1 files changed, 181 insertions, 0 deletions
diff --git a/basebmp/inc/basebmp/linerenderer.hxx b/basebmp/inc/basebmp/linerenderer.hxx new file mode 100644 index 000000000000..7c5f09dbb2d1 --- /dev/null +++ b/basebmp/inc/basebmp/linerenderer.hxx @@ -0,0 +1,181 @@ +/************************************************************************* + * + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. + * + * Copyright 2000, 2010 Oracle and/or its affiliates. + * + * OpenOffice.org - a multi-platform office productivity suite + * + * This file is part of OpenOffice.org. + * + * OpenOffice.org is free software: you can redistribute it and/or modify + * it under the terms of the GNU Lesser General Public License version 3 + * only, as published by the Free Software Foundation. + * + * OpenOffice.org 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 Lesser General Public License version 3 for more details + * (a copy is included in the LICENSE file that accompanied this code). + * + * You should have received a copy of the GNU Lesser General Public License + * version 3 along with OpenOffice.org. If not, see + * <http://www.openoffice.org/license.html> + * for a copy of the LGPLv3 License. + * + ************************************************************************/ + +#ifndef INCLUDED_BASEBMP_LINERENDERER_HXX +#define INCLUDED_BASEBMP_LINERENDERER_HXX + +#include <basegfx/point/b2ipoint.hxx> + +#include <vigra/diff2d.hxx> +#include <vigra/iteratortraits.hxx> + + +/* Scan-converting lines */ + +namespace basebmp +{ + +/** Render line with Bresenham + + This function renders the line given by rPt1 and rPt2 using the + Bresenham algorithm with the specified color value. Make sure rPt1 + and rPt1 are valid coordinates in the image given by begin and + end, since no clipping takes place. + + @param aPt1 + Start point of the line + + @param aPt2 + End point of the line + + @param color + Color value to render the line with + + @param begin + left-top image iterator + + @param end + right-bottom image iterator + + @param acc + Image accessor + + @param bRoundTowardsPt2 + Rounding mode to use. Giving false here results in line pixel tend + towards pt1, i.e. when a pixel exactly hits the middle between two + pixel, the pixel closer to pt1 will be chosen. Giving true here + makes renderClippedLine() choose pt2 in those cases. + */ +template< class Iterator, class Accessor > +void renderLine( const basegfx::B2IPoint& rPt1, + const basegfx::B2IPoint& rPt2, + typename Accessor::value_type color, + Iterator begin, + Accessor acc, + bool bRoundTowardsPt2=false ) +{ + // code inspired by Paul Heckbert's Digital Line Drawing + // (Graphics Gems, Academic Press 1990) + const sal_Int32 x1 = rPt1.getX(); + const sal_Int32 x2 = rPt2.getX(); + const sal_Int32 y1 = rPt1.getY(); + const sal_Int32 y2 = rPt2.getY(); + + // TODO(E1): This might overflow + sal_Int32 adx = x2 - x1; + int sx = 1; + if( adx < 0 ) + { + adx *= -1; + sx = -1; + } + + // TODO(E1): This might overflow + sal_Int32 ady = y2 - y1; + int sy = 1; + if( ady < 0 ) + { + ady *= -1; + sy = -1; + } + + // TODO(P3): handle horizontal and vertical lines specially + sal_Int32 xs = x1; + sal_Int32 ys = y1; + if( adx >= ady ) + { + // semi-horizontal line + sal_Int32 rem = 2*ady - adx - !bRoundTowardsPt2; + adx *= 2; + ady *= 2; + + Iterator currIter( begin + vigra::Diff2D(0,ys) ); + typename vigra::IteratorTraits<Iterator>::row_iterator + rowIter( currIter.rowIterator() + xs ); + while(true) + { + acc.set(color, rowIter); + + if( xs == x2 ) + return; + + if( rem >= 0 ) + { + ys += sy; + xs += sx; + currIter.y += sy; + rowIter = currIter.rowIterator() + xs; + rem -= adx; + } + else + { + xs += sx; + rowIter += sx; + } + + rem += ady; + } + } + else + { + // semi-vertical line + sal_Int32 rem = 2*adx - ady - !bRoundTowardsPt2; + adx *= 2; + ady *= 2; + + Iterator currIter( begin + vigra::Diff2D(xs,0) ); + typename vigra::IteratorTraits<Iterator>::column_iterator + colIter( currIter.columnIterator() + ys ); + while(true) + { + acc.set(color, colIter); + + if( ys == y2 ) + return; + + if( rem >= 0 ) + { + xs += sx; + ys += sy; + currIter.x += sx; + colIter = currIter.columnIterator() + ys; + rem -= ady; + } + else + { + ys += sy; + colIter += sy; + } + + rem += adx; + } + } +} + +} // namespace basebmp + +#endif /* INCLUDED_BASEBMP_LINERENDERER_HXX */ |