item_drawing_utils.cpp

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/*
 * This program source code file is part of KICAD, a free EDA CAD application.
 *
 * Copyright (C) 2024 Kicad Developers, see AUTHORS.txt for contributors.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, you may find one here:
 * http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
 * or you may search the http://www.gnu.org website for the version 2 license,
 * or you may write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
 */
 
#include "preview_items/item_drawing_utils.h"
 
#include <array>
 
#include <geometry/geometry_utils.h>
#include <geometry/seg.h>
 
using namespace KIGFX;
 
void KIGFX::DrawCross( GAL& aGal, const VECTOR2I& aPosition, int aSize )
{
 const int size = aSize / 2;
 aGal.DrawLine( aPosition - VECTOR2I( size, 0 ), aPosition + VECTOR2I( size, 0 ) );
 aGal.DrawLine( aPosition - VECTOR2I( 0, size ), aPosition + VECTOR2I( 0, size ) );
}
 
 
void KIGFX::DrawDashedLine( GAL& aGal, const SEG& aSeg, double aDashSize )
{
 const std::array<double, 2> strokes = { aDashSize, aDashSize / 2 };
 const double dashCycleLen = strokes[0] + strokes[1];
 // The dash cycle length must be at least 1 pixel.
 wxASSERT( dashCycleLen * aGal.GetWorldScale() > 1 );
 
 const BOX2I clip = BOX2I::ByCorners( aSeg.A, aSeg.B );
 
 const double theta = atan2( aSeg.B.y - aSeg.A.y, aSeg.B.x - aSeg.A.x );
 
 const VECTOR2D cycleVec{
 dashCycleLen * cos( theta ),
 dashCycleLen * sin( theta ),
 };
 const VECTOR2D dashVec{
 strokes[0] * cos( theta ),
 strokes[0] * sin( theta ),
 };
 
 unsigned cyclei = 0;
 while( true )
 {
 const VECTOR2D dashStart = aSeg.A + cycleVec * cyclei;
 const VECTOR2D dashEnd = dashStart + dashVec;
 
 // Drawing each segment can be done rounded to ints.
 SEG dashSeg{ KiROUND( dashStart ), KiROUND( dashEnd ) };
 
 if( ClipLine( &clip, dashSeg.A.x, dashSeg.A.y, dashSeg.B.x, dashSeg.B.y ) )
 break;
 
 aGal.DrawLine( dashSeg.A, dashSeg.B );
 ++cyclei;
 }
}