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Diffstat (limited to '')
| -rw-r--r-- | basegfx/source/polygon/WaveLine.cxx | 52 |
1 files changed, 52 insertions, 0 deletions
diff --git a/basegfx/source/polygon/WaveLine.cxx b/basegfx/source/polygon/WaveLine.cxx new file mode 100644 index 000000000..bc85c4536 --- /dev/null +++ b/basegfx/source/polygon/WaveLine.cxx @@ -0,0 +1,52 @@ +/* -*- 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/. + * + */ + +#include <basegfx/polygon/WaveLine.hxx> +#include <basegfx/point/b2dpoint.hxx> + +namespace basegfx +{ +BASEGFX_DLLPUBLIC B2DPolygon createWaveLinePolygon(basegfx::B2DRectangle const& rRectangle) +{ + basegfx::B2DPolygon aPolygon; + + double fWaveHeight = rRectangle.getHeight(); + // Wavelength depends on the wave height so it looks nice + double fHalfWaveLength = fWaveHeight + 1.0; + double fWaveAmplitude = fWaveHeight / 2.0; + + double fLastX = rRectangle.getMinX(); + double fBaseY = rRectangle.getMinY() + fWaveAmplitude; + double fDirection = 1.0; + + // In quadratic bezier the curve is 1/2 of the control height + // so we need to compensate for that. + constexpr double fHeightCompensation = 2.0; + + aPolygon.append(basegfx::B2DPoint(fLastX, fBaseY)); + + for (double fI = fHalfWaveLength; fI <= rRectangle.getWidth(); fI += fHalfWaveLength) + { + basegfx::B2DPoint aPoint(fLastX + fHalfWaveLength, fBaseY); + basegfx::B2DPoint aControl(fLastX + (fHalfWaveLength / 2.0), + fBaseY + fDirection * fWaveAmplitude * fHeightCompensation); + + aPolygon.appendQuadraticBezierSegment(aControl, aPoint); + + fLastX = aPoint.getX(); // next iteration + fDirection *= -1.0; // fDirection iterates between 1 and -1 + } + + return aPolygon; +} + +} // end of namespace basegfx + +/* vim:set shiftwidth=4 softtabstop=4 expandtab: */ |