LCOV - code coverage report
Current view: directory - objdir/dist/include/mozilla/gfx - PathHelpers.h (source / functions) Found Hit Coverage
Test: app.info Lines: 33 0 0.0 %
Date: 2012-06-02 Functions: 1 0 0.0 %

       1                 : /* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*-
       2                 :  * ***** BEGIN LICENSE BLOCK *****
       3                 :  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
       4                 :  *
       5                 :  * The contents of this file are subject to the Mozilla Public License Version
       6                 :  * 1.1 (the "License"); you may not use this file except in compliance with
       7                 :  * the License. You may obtain a copy of the License at
       8                 :  * http://www.mozilla.org/MPL/
       9                 :  *
      10                 :  * Software distributed under the License is distributed on an "AS IS" basis,
      11                 :  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
      12                 :  * for the specific language governing rights and limitations under the
      13                 :  * License.
      14                 :  *
      15                 :  * The Original Code is Mozilla Corporation code.
      16                 :  *
      17                 :  * The Initial Developer of the Original Code is Mozilla Foundation.
      18                 :  * Portions created by the Initial Developer are Copyright (C) 2011
      19                 :  * the Initial Developer. All Rights Reserved.
      20                 :  *
      21                 :  * Contributor(s):
      22                 :  *   Matt Woodrow <mwoodrow@mozilla.com>
      23                 :  *
      24                 :  * Alternatively, the contents of this file may be used under the terms of
      25                 :  * either the GNU General Public License Version 2 or later (the "GPL"), or
      26                 :  * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
      27                 :  * in which case the provisions of the GPL or the LGPL are applicable instead
      28                 :  * of those above. If you wish to allow use of your version of this file only
      29                 :  * under the terms of either the GPL or the LGPL, and not to allow others to
      30                 :  * use your version of this file under the terms of the MPL, indicate your
      31                 :  * decision by deleting the provisions above and replace them with the notice
      32                 :  * and other provisions required by the GPL or the LGPL. If you do not delete
      33                 :  * the provisions above, a recipient may use your version of this file under
      34                 :  * the terms of any one of the MPL, the GPL or the LGPL.
      35                 :  *
      36                 :  * ***** END LICENSE BLOCK ***** */
      37                 : 
      38                 : #ifndef MOZILLA_GFX_PATHHELPERS_H_
      39                 : #define MOZILLA_GFX_PATHHELPERS_H_
      40                 : 
      41                 : #include "2D.h"
      42                 : 
      43                 : #ifndef M_PI
      44                 : #define M_PI 3.14159265358979323846
      45                 : #endif
      46                 : 
      47                 : namespace mozilla {
      48                 : namespace gfx {
      49                 : 
      50                 : template <typename T>
      51               0 : void ArcToBezier(T* aSink, const Point &aOrigin, float aRadius, float aStartAngle,
      52                 :                  float aEndAngle, bool aAntiClockwise)
      53                 : {
      54                 :   Point startPoint(aOrigin.x + cos(aStartAngle) * aRadius, 
      55               0 :                    aOrigin.y + sin(aStartAngle) * aRadius); 
      56                 :   
      57               0 :   aSink->LineTo(startPoint); 
      58                 : 
      59                 :   // Clockwise we always sweep from the smaller to the larger angle, ccw 
      60                 :   // it's vice versa.
      61               0 :   if (!aAntiClockwise && (aEndAngle < aStartAngle)) {
      62               0 :     Float correction = ceil((aStartAngle - aEndAngle) / (2.0f * M_PI));
      63               0 :     aEndAngle += correction * 2.0f * M_PI;
      64               0 :   } else if (aAntiClockwise && (aStartAngle < aEndAngle)) {
      65               0 :     Float correction = ceil((aEndAngle - aStartAngle) / (2.0f * M_PI));
      66               0 :     aStartAngle += correction * 2.0f * M_PI;
      67                 :   }
      68                 :   
      69                 :   // Sweeping more than 2 * pi is a full circle.
      70               0 :   if (!aAntiClockwise && (aEndAngle - aStartAngle > 2 * M_PI)) {
      71               0 :     aEndAngle = aStartAngle + 2.0f * M_PI;
      72               0 :   } else if (aAntiClockwise && (aStartAngle - aEndAngle > 2.0f * M_PI)) {
      73               0 :     aEndAngle = aStartAngle - 2.0f * M_PI;
      74                 :   }
      75                 : 
      76                 :   // Calculate the total arc we're going to sweep.
      77               0 :   Float arcSweepLeft = fabs(aEndAngle - aStartAngle);
      78                 :   
      79               0 :   Float sweepDirection = aAntiClockwise ? -1.0f : 1.0f;
      80                 :   
      81               0 :   Float currentStartAngle = aStartAngle;
      82                 :   
      83               0 :   while (arcSweepLeft > 0) {
      84                 :     // We guarantee here the current point is the start point of the next
      85                 :     // curve segment.
      86                 :     Float currentEndAngle;
      87                 :     
      88               0 :     if (arcSweepLeft > M_PI / 2.0f) {
      89               0 :       currentEndAngle = currentStartAngle + M_PI / 2.0f * sweepDirection;                                                               
      90                 :     } else {
      91               0 :       currentEndAngle = currentStartAngle + arcSweepLeft * sweepDirection;
      92                 :     }
      93                 :     
      94                 :     Point currentStartPoint(aOrigin.x + cos(currentStartAngle) * aRadius,
      95               0 :                             aOrigin.y + sin(currentStartAngle) * aRadius);
      96                 :     Point currentEndPoint(aOrigin.x + cos(currentEndAngle) * aRadius,
      97               0 :                           aOrigin.y + sin(currentEndAngle) * aRadius);
      98                 :     
      99                 :     // Calculate kappa constant for partial curve. The sign of angle in the
     100                 :     // tangent will actually ensure this is negative for a counter clockwise                                                            
     101                 :     // sweep, so changing signs later isn't needed.
     102               0 :     Float kappa = (4.0f / 3.0f) * tan((currentEndAngle - currentStartAngle) / 4.0f) * aRadius;
     103                 :     
     104               0 :     Point tangentStart(-sin(currentStartAngle), cos(currentStartAngle));
     105               0 :     Point cp1 = currentStartPoint;
     106               0 :     cp1 += tangentStart * kappa;
     107                 :     
     108               0 :     Point revTangentEnd(sin(currentEndAngle), -cos(currentEndAngle));
     109               0 :     Point cp2 = currentEndPoint;
     110               0 :     cp2 += revTangentEnd * kappa;
     111                 :     
     112               0 :     aSink->BezierTo(cp1, cp2, currentEndPoint);
     113                 :     
     114               0 :     arcSweepLeft -= M_PI / 2.0f;
     115               0 :     currentStartAngle = currentEndAngle;
     116                 :   }
     117               0 : }
     118                 : 
     119                 : }
     120                 : }
     121                 : 
     122                 : #endif /* MOZILLA_GFX_PATHHELPERS_H_ */

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