52 lines
1.7 KiB
C++
52 lines
1.7 KiB
C++
/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
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/*
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* This file is part of the LibreOffice project.
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*
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* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/.
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*
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*/
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#include <basegfx/polygon/WaveLine.hxx>
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#include <basegfx/point/b2dpoint.hxx>
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namespace basegfx
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{
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BASEGFX_DLLPUBLIC B2DPolygon createWaveLinePolygon(basegfx::B2DRectangle const& rRectangle)
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{
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basegfx::B2DPolygon aPolygon;
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double fWaveHeight = rRectangle.getHeight();
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// Wavelength depends on the wave height so it looks nice
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double fHalfWaveLength = fWaveHeight + 1.0;
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double fWaveAmplitude = fWaveHeight / 2.0;
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double fLastX = rRectangle.getMinX();
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double fBaseY = rRectangle.getMinY() + fWaveAmplitude;
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double fDirection = 1.0;
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// In quadratic bezier the curve is 1/2 of the control height
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// so we need to compensate for that.
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constexpr double fHeightCompensation = 2.0;
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aPolygon.append(basegfx::B2DPoint(fLastX, fBaseY));
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for (double fI = fHalfWaveLength; fI <= rRectangle.getWidth(); fI += fHalfWaveLength)
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{
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basegfx::B2DPoint aPoint(fLastX + fHalfWaveLength, fBaseY);
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basegfx::B2DPoint aControl(fLastX + (fHalfWaveLength / 2.0),
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fBaseY + fDirection * fWaveAmplitude * fHeightCompensation);
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aPolygon.appendQuadraticBezierSegment(aControl, aPoint);
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fLastX = aPoint.getX(); // next iteration
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fDirection *= -1.0; // fDirection iterates between 1 and -1
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}
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return aPolygon;
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}
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} // end of namespace basegfx
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/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
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