b9337e22ce
see https://gerrit.libreoffice.org/#/c/3367/ and Change-Id: I00c96fa77d04b33a6f8c8cd3490dfcd9bdc9e84a for details Change-Id: I199a75bc4042af20817265d5ef85b1134a96ff5a
411 lines
12 KiB
C++
411 lines
12 KiB
C++
/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
|
|
/*
|
|
* This file is part of the LibreOffice project.
|
|
*
|
|
* This Source Code Form is subject to the terms of the Mozilla Public
|
|
* License, v. 2.0. If a copy of the MPL was not distributed with this
|
|
* file, You can obtain one at http://mozilla.org/MPL/2.0/.
|
|
*
|
|
* This file incorporates work covered by the following license notice:
|
|
*
|
|
* Licensed to the Apache Software Foundation (ASF) under one or more
|
|
* contributor license agreements. See the NOTICE file distributed
|
|
* with this work for additional information regarding copyright
|
|
* ownership. The ASF licenses this file to you under the Apache
|
|
* License, Version 2.0 (the "License"); you may not use this file
|
|
* except in compliance with the License. You may obtain a copy of
|
|
* the License at http://www.apache.org/licenses/LICENSE-2.0 .
|
|
*/
|
|
|
|
#ifndef INCLUDED_BASEBMP_CLIPPEDLINERENDERER_HXX
|
|
#define INCLUDED_BASEBMP_CLIPPEDLINERENDERER_HXX
|
|
|
|
#include <basegfx/tools/rectcliptools.hxx>
|
|
#include <basegfx/point/b2ipoint.hxx>
|
|
#include <basegfx/range/b2ibox.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,
|
|
bool& o_bUseAlternateBresenham )
|
|
{
|
|
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; // fully clipped
|
|
}
|
|
else
|
|
{
|
|
o_bs = b1 - cb;
|
|
if( o_bs < bMin )
|
|
return false; // fully clipped
|
|
}
|
|
|
|
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; // fully clipped
|
|
}
|
|
else
|
|
{
|
|
o_as = a1 - ca;
|
|
if( o_as < aMin )
|
|
return false; // fully clipped
|
|
}
|
|
|
|
io_rem += 2*db*ca - cb;
|
|
}
|
|
}
|
|
else
|
|
{
|
|
o_as = a1; o_bs = b1;
|
|
}
|
|
|
|
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;
|
|
o_bUseAlternateBresenham = true;
|
|
}
|
|
}
|
|
else
|
|
o_n = (a2 >= o_as) ? a2 - o_as : o_as - a2;
|
|
|
|
return true; // at least one pixel to render
|
|
}
|
|
|
|
|
|
/** 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::B2IBox& 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, both endpoints share a half-plane
|
|
|
|
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;
|
|
bool bUseAlternateBresenham=false;
|
|
if( adx >= ady )
|
|
{
|
|
// semi-horizontal line
|
|
sal_Int32 rem = 2*ady - adx - !bRoundTowardsPt2;
|
|
|
|
if( !prepareClip(x1, x2, y1, adx, ady, xs, ys, sx, sy,
|
|
rem, n, clipCode1, clipCount1, clipCode2, clipCount2,
|
|
rClipRect.getMinX(), basegfx::tools::RectClipFlags::LEFT,
|
|
rClipRect.getMaxX()-1, basegfx::tools::RectClipFlags::RIGHT,
|
|
rClipRect.getMinY(), basegfx::tools::RectClipFlags::TOP,
|
|
rClipRect.getMaxY()-1, basegfx::tools::RectClipFlags::BOTTOM,
|
|
bRoundTowardsPt2, bUseAlternateBresenham ) )
|
|
return; // line fully clipped away, no active pixel inside rect
|
|
|
|
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 )
|
|
{
|
|
// this is intended - we clip endpoint against y
|
|
// plane, so n here denotes y range to render
|
|
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;
|
|
|
|
if( !prepareClip(y1, y2, x1, ady, adx, ys, xs, sy, sx,
|
|
rem, n, clipCode1, clipCount1, clipCode2, clipCount2,
|
|
rClipRect.getMinY(), basegfx::tools::RectClipFlags::TOP,
|
|
rClipRect.getMaxY()-1, basegfx::tools::RectClipFlags::BOTTOM,
|
|
rClipRect.getMinX(), basegfx::tools::RectClipFlags::LEFT,
|
|
rClipRect.getMaxX()-1, basegfx::tools::RectClipFlags::RIGHT,
|
|
bRoundTowardsPt2, bUseAlternateBresenham ) )
|
|
return; // line fully clipped away, no active pixel inside rect
|
|
|
|
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 )
|
|
{
|
|
// this is intended - we clip endpoint against x
|
|
// plane, so n here denotes x range to render
|
|
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 */
|
|
|
|
/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
|