mirror of
https://github.com/mozilla/gecko-dev.git
synced 2024-12-02 01:48:05 +00:00
123 lines
4.7 KiB
C++
123 lines
4.7 KiB
C++
/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*-
|
|
* ***** BEGIN LICENSE BLOCK *****
|
|
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
|
|
*
|
|
* The contents of this file are subject to the Mozilla Public License Version
|
|
* 1.1 (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.mozilla.org/MPL/
|
|
*
|
|
* Software distributed under the License is distributed on an "AS IS" basis,
|
|
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
|
|
* for the specific language governing rights and limitations under the
|
|
* License.
|
|
*
|
|
* The Original Code is Mozilla Corporation code.
|
|
*
|
|
* The Initial Developer of the Original Code is Mozilla Foundation.
|
|
* Portions created by the Initial Developer are Copyright (C) 2011
|
|
* the Initial Developer. All Rights Reserved.
|
|
*
|
|
* Contributor(s):
|
|
* Matt Woodrow <mwoodrow@mozilla.com>
|
|
*
|
|
* Alternatively, the contents of this file may be used under the terms of
|
|
* either the GNU General Public License Version 2 or later (the "GPL"), or
|
|
* the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
|
|
* in which case the provisions of the GPL or the LGPL are applicable instead
|
|
* of those above. If you wish to allow use of your version of this file only
|
|
* under the terms of either the GPL or the LGPL, and not to allow others to
|
|
* use your version of this file under the terms of the MPL, indicate your
|
|
* decision by deleting the provisions above and replace them with the notice
|
|
* and other provisions required by the GPL or the LGPL. If you do not delete
|
|
* the provisions above, a recipient may use your version of this file under
|
|
* the terms of any one of the MPL, the GPL or the LGPL.
|
|
*
|
|
* ***** END LICENSE BLOCK ***** */
|
|
|
|
#ifndef MOZILLA_GFX_PATHHELPERS_H_
|
|
#define MOZILLA_GFX_PATHHELPERS_H_
|
|
|
|
#include "2D.h"
|
|
|
|
#ifndef M_PI
|
|
#define M_PI 3.14159265358979323846
|
|
#endif
|
|
|
|
namespace mozilla {
|
|
namespace gfx {
|
|
|
|
template <typename T>
|
|
void ArcToBezier(T* aSink, const Point &aOrigin, float aRadius, float aStartAngle,
|
|
float aEndAngle, bool aAntiClockwise)
|
|
{
|
|
Point startPoint(aOrigin.x + cos(aStartAngle) * aRadius,
|
|
aOrigin.y + sin(aStartAngle) * aRadius);
|
|
|
|
aSink->LineTo(startPoint);
|
|
|
|
// Clockwise we always sweep from the smaller to the larger angle, ccw
|
|
// it's vice versa.
|
|
if (!aAntiClockwise && (aEndAngle < aStartAngle)) {
|
|
Float correction = ceil((aStartAngle - aEndAngle) / (2.0f * M_PI));
|
|
aEndAngle += correction * 2.0f * M_PI;
|
|
} else if (aAntiClockwise && (aStartAngle < aEndAngle)) {
|
|
Float correction = ceil((aEndAngle - aStartAngle) / (2.0f * M_PI));
|
|
aStartAngle += correction * 2.0f * M_PI;
|
|
}
|
|
|
|
// Sweeping more than 2 * pi is a full circle.
|
|
if (!aAntiClockwise && (aEndAngle - aStartAngle > 2 * M_PI)) {
|
|
aEndAngle = aStartAngle + 2.0f * M_PI;
|
|
} else if (aAntiClockwise && (aStartAngle - aEndAngle > 2.0f * M_PI)) {
|
|
aEndAngle = aStartAngle - 2.0f * M_PI;
|
|
}
|
|
|
|
// Calculate the total arc we're going to sweep.
|
|
Float arcSweepLeft = fabs(aEndAngle - aStartAngle);
|
|
|
|
Float sweepDirection = aAntiClockwise ? -1.0f : 1.0f;
|
|
|
|
Float currentStartAngle = aStartAngle;
|
|
|
|
while (arcSweepLeft > 0) {
|
|
// We guarantee here the current point is the start point of the next
|
|
// curve segment.
|
|
Float currentEndAngle;
|
|
|
|
if (arcSweepLeft > M_PI / 2.0f) {
|
|
currentEndAngle = currentStartAngle + M_PI / 2.0f * sweepDirection;
|
|
} else {
|
|
currentEndAngle = currentStartAngle + arcSweepLeft * sweepDirection;
|
|
}
|
|
|
|
Point currentStartPoint(aOrigin.x + cos(currentStartAngle) * aRadius,
|
|
aOrigin.y + sin(currentStartAngle) * aRadius);
|
|
Point currentEndPoint(aOrigin.x + cos(currentEndAngle) * aRadius,
|
|
aOrigin.y + sin(currentEndAngle) * aRadius);
|
|
|
|
// Calculate kappa constant for partial curve. The sign of angle in the
|
|
// tangent will actually ensure this is negative for a counter clockwise
|
|
// sweep, so changing signs later isn't needed.
|
|
Float kappa = (4.0f / 3.0f) * tan((currentEndAngle - currentStartAngle) / 4.0f) * aRadius;
|
|
|
|
Point tangentStart(-sin(currentStartAngle), cos(currentStartAngle));
|
|
Point cp1 = currentStartPoint;
|
|
cp1 += tangentStart * kappa;
|
|
|
|
Point revTangentEnd(sin(currentEndAngle), -cos(currentEndAngle));
|
|
Point cp2 = currentEndPoint;
|
|
cp2 += revTangentEnd * kappa;
|
|
|
|
aSink->BezierTo(cp1, cp2, currentEndPoint);
|
|
|
|
arcSweepLeft -= M_PI / 2.0f;
|
|
currentStartAngle = currentEndAngle;
|
|
}
|
|
}
|
|
|
|
}
|
|
}
|
|
|
|
#endif /* MOZILLA_GFX_PATHHELPERS_H_ */
|