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Diffstat (limited to 'basebmp/inc/basebmp/clippedlinerenderer.hxx')
-rw-r--r-- | basebmp/inc/basebmp/clippedlinerenderer.hxx | 415 |
1 files changed, 415 insertions, 0 deletions
diff --git a/basebmp/inc/basebmp/clippedlinerenderer.hxx b/basebmp/inc/basebmp/clippedlinerenderer.hxx new file mode 100644 index 000000000000..c227d4942e4d --- /dev/null +++ b/basebmp/inc/basebmp/clippedlinerenderer.hxx @@ -0,0 +1,415 @@ +/************************************************************************* + * + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. + * + * Copyright 2008 by Sun Microsystems, Inc. + * + * OpenOffice.org - a multi-platform office productivity suite + * + * $RCSfile: clippedlinerenderer.hxx,v $ + * $Revision: 1.10 $ + * + * 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_CLIPPEDLINERENDERER_HXX +#define INCLUDED_BASEBMP_CLIPPEDLINERENDERER_HXX + +#include <basegfx/tools/rectcliptools.hxx> +#include <basegfx/point/b2ipoint.hxx> +#include <basegfx/range/b2irange.hxx> + +#include <vigra/diff2d.hxx> +#include <vigra/iteratortraits.hxx> + +namespace basebmp +{ + +// factored-out bresenham setup code, which is used from two different +// places in renderClippedLine() below. Admittedly messy for the long +// parameter list... +inline bool prepareClip( sal_Int32 a1, + sal_Int32 a2, + sal_Int32 b1, + sal_Int32 da, + sal_Int32 db, + sal_Int32& o_as, + sal_Int32& o_bs, + int sa, + int sb, + sal_Int32& io_rem, + int& o_n, + sal_uInt32 clipCode1, + sal_uInt32 clipCount1, + sal_uInt32 clipCode2, + sal_uInt32 clipCount2, + sal_Int32 aMin, + sal_uInt32 aMinFlag, + sal_Int32 aMax, + sal_uInt32 aMaxFlag, + sal_Int32 bMin, + sal_uInt32 bMinFlag, + sal_Int32 bMax, + sal_uInt32 bMaxFlag, + bool bRoundTowardsPt2 ) +{ + int ca(0), cb(0); + if( clipCode1 ) + { + if( clipCode1 & aMinFlag ) + { + ca = 2*db*(aMin - a1); + o_as = aMin; + } + else if( clipCode1 & aMaxFlag ) + { + ca = 2*db*(a1 - aMax); + o_as = aMax; + } + + if( clipCode1 & bMinFlag ) + { + cb = 2*da*(bMin - b1); + o_bs = bMin; + } + else if( clipCode1 & bMaxFlag ) + { + cb = 2*da*(b1 - bMax); + o_bs = bMax; + } + + if( clipCount1 == 2 ) + clipCode1 &= (ca + da < cb + !bRoundTowardsPt2) ? ~(aMinFlag|aMaxFlag) : ~(bMinFlag|bMaxFlag); + + if( clipCode1 & (aMinFlag|aMaxFlag) ) + { + cb = (ca + da - !bRoundTowardsPt2) / (2*da); + + if( sb >= 0 ) + { + o_bs = b1 + cb; + if( o_bs > bMax ) + return false; + } + else + { + o_bs = b1 - cb; + if( o_bs < bMin ) + return false; + } + + io_rem += ca - 2*da*cb; + } + else + { + ca = (cb - da + 2*db - bRoundTowardsPt2) / (2*db); + if( sa >= 0 ) + { + o_as = a1 + ca; + if( o_as > aMax ) + return false; + } + else + { + o_as = a1 - ca; + if( o_as < aMin ) + return false; + } + + io_rem += 2*db*ca - cb; + } + } + else + { + o_as = a1; o_bs = b1; + } + + bool bRetVal = false; + if( clipCode2 ) + { + if( clipCount2 == 2 ) + { + ca = 2*db*((clipCode2 & aMinFlag) ? a1 - aMin : aMax - a1); + cb = 2*da*((clipCode2 & bMinFlag) ? b1 - bMin : bMax - b1); + clipCode2 &= (cb + da < ca + bRoundTowardsPt2) ? ~(aMinFlag|aMaxFlag) : ~(bMinFlag|bMaxFlag); + } + + if( clipCode2 & (aMinFlag|aMaxFlag) ) + o_n = (clipCode2 & aMinFlag) ? o_as - aMin : aMax - o_as; + else + { + o_n = (clipCode2 & bMinFlag) ? o_bs - bMin : bMax - o_bs; + bRetVal = true; + } + } + else + o_n = (a2 >= o_as) ? a2 - o_as : o_as - a2; + + return bRetVal; +} + + +/** Render line to image iterators, clip against given rectangle + + This method renders a line from aPt1 to aPt2, clipped against + rClipRect (the clipping will take place pixel-perfect, i.e. as if + the original bresenham-rendered line would have been clipped each + pixel individually. No slight shifts compared to unclipped lines). + + @param aPt1 + Start point of the line + + @param aPt2 + End point of the line + + @param rClipRect + Rectangle to clip against + + @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 renderClippedLine( basegfx::B2IPoint aPt1, + basegfx::B2IPoint aPt2, + const basegfx::B2IRange& rClipRect, + typename Accessor::value_type color, + Iterator begin, + Accessor acc, + bool bRoundTowardsPt2=false ) +{ + // Algorithm according to Steven Eker's 'Pixel-perfect line clipping', + // Graphics Gems V, pp. 314-322 + sal_uInt32 clipCode1 = basegfx::tools::getCohenSutherlandClipFlags(aPt1, + rClipRect); + sal_uInt32 clipCode2 = basegfx::tools::getCohenSutherlandClipFlags(aPt2, + rClipRect); + + if( clipCode1 & clipCode2 ) + return; // line fully clipped away + + sal_uInt32 clipCount1 = basegfx::tools::getNumberOfClipPlanes(clipCode1); + sal_uInt32 clipCount2 = basegfx::tools::getNumberOfClipPlanes(clipCode2); + + if( (clipCode1 != 0 && clipCode2 == 0) + || (clipCount1 == 2 && clipCount2 == 1) ) + { + std::swap(clipCount2,clipCount1); + std::swap(clipCode2,clipCode1); + std::swap(aPt1,aPt2); + bRoundTowardsPt2 = !bRoundTowardsPt2; + } + + const sal_Int32 x1 = aPt1.getX(); + const sal_Int32 x2 = aPt2.getX(); + const sal_Int32 y1 = aPt1.getY(); + const sal_Int32 y2 = aPt2.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; + } + + int n = 0; + sal_Int32 xs = x1; + sal_Int32 ys = y1; + if( adx >= ady ) + { + // semi-horizontal line + sal_Int32 rem = 2*ady - adx - !bRoundTowardsPt2; + + const bool bUseAlternateBresenham( + prepareClip(x1, x2, y1, adx, ady, xs, ys, sx, sy, + rem, n, clipCode1, clipCount1, clipCode2, clipCount2, + rClipRect.getMinX(), basegfx::tools::RectClipFlags::LEFT, + rClipRect.getMaxX(), basegfx::tools::RectClipFlags::RIGHT, + rClipRect.getMinY(), basegfx::tools::RectClipFlags::TOP, + rClipRect.getMaxY(), basegfx::tools::RectClipFlags::BOTTOM, + bRoundTowardsPt2 )); + + Iterator currIter( begin + vigra::Diff2D(0,ys) ); + typename vigra::IteratorTraits<Iterator>::row_iterator + rowIter( currIter.rowIterator() + xs ); + + adx *= 2; + ady *= 2; + + if( bUseAlternateBresenham ) + { + while(true) + { + acc.set(color, rowIter); + + if( rem >= 0 ) + { + if( --n < 0 ) + break; + + ys += sy; + xs += sx; + rem -= adx; + + currIter.y += sy; + rowIter = currIter.rowIterator() + xs; + } + else + { + xs += sx; + rowIter += sx; + } + + rem += ady; + } + } + else + { + while(true) + { + acc.set(color, rowIter); + + if( --n < 0 ) + break; + + if( rem >= 0 ) + { + ys += sy; + xs += sx; + rem -= adx; + + currIter.y += sy; + rowIter = currIter.rowIterator() + xs; + } + else + { + xs += sx; + rowIter += sx; + } + + rem += ady; + } + } + } + else + { + // semi-vertical line + sal_Int32 rem = 2*adx - ady - !bRoundTowardsPt2; + + const bool bUseAlternateBresenham( + prepareClip(y1, y2, x1, ady, adx, ys, xs, sy, sx, + rem, n, clipCode1, clipCount1, clipCode2, clipCount2, + rClipRect.getMinY(), basegfx::tools::RectClipFlags::TOP, + rClipRect.getMaxY(), basegfx::tools::RectClipFlags::BOTTOM, + rClipRect.getMinX(), basegfx::tools::RectClipFlags::LEFT, + rClipRect.getMaxX(), basegfx::tools::RectClipFlags::RIGHT, + bRoundTowardsPt2 )); + + Iterator currIter( begin + vigra::Diff2D(xs,0) ); + typename vigra::IteratorTraits<Iterator>::column_iterator + colIter( currIter.columnIterator() + ys ); + + adx *= 2; + ady *= 2; + + if( bUseAlternateBresenham ) + { + while(true) + { + acc.set(color, colIter); + + if( rem >= 0 ) + { + if( --n < 0 ) + break; + + xs += sx; + ys += sy; + rem -= ady; + + currIter.x += sx; + colIter = currIter.columnIterator() + ys; + } + else + { + ys += sy; + colIter += sy; + } + + rem += adx; + } + } + else + { + while(true) + { + acc.set(color, colIter); + + if( --n < 0 ) + break; + + if( rem >= 0 ) + { + xs += sx; + ys += sy; + rem -= ady; + + currIter.x += sx; + colIter = currIter.columnIterator() + ys; + } + else + { + ys += sy; + colIter += sy; + } + + rem += adx; + } + } + } +} + +} // namespace basebmp + +#endif /* INCLUDED_BASEBMP_CLIPPEDLINERENDERER_HXX */ |