kc3-lang/ftgl/src/FTContour.cpp

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• Hash : 1f4a94f8
  Author :
  Date : 2008-04-29T14:39:28
  

  * Since the MIT license is LGPL-compatible, there is no real point in shipping FTGL under a dual license. Consequently removing LGPL references from the code, in agreement with Sean.

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• src/FTContour.cpp

• /*
   * FTGL - OpenGL font library
   *
   * Copyright (c) 2001-2004 Henry Maddocks <ftgl@opengl.geek.nz>
   *               2008 Sam Hocevar <sam@zoy.org>
   *               2008 Éric Beets <ericbeets@free.fr>
   *
   * Permission is hereby granted, free of charge, to any person obtaining
   * a copy of this software and associated documentation files (the
   * "Software"), to deal in the Software without restriction, including
   * without limitation the rights to use, copy, modify, merge, publish,
   * distribute, sublicense, and/or sell copies of the Software, and to
   * permit persons to whom the Software is furnished to do so, subject to
   * the following conditions:
   *
   * The above copyright notice and this permission notice shall be
   * included in all copies or substantial portions of the Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
   * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
   * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
   * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
   * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
   * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
   * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
   */
  
  #include "config.h"
  
  #include "FTContour.h"
  
  #include <math.h>
  
  static const float BEZIER_STEP_SIZE = 0.2f;
  
  
  void FTContour::AddPoint(FTPoint point)
  {
      if(pointList.empty() || (point != pointList[pointList.size() - 1]
                                && point != pointList[0]))
      {
          pointList.push_back(point);
      }
  }
  
  
  void FTContour::AddOutsetPoint(FTPoint point)
  {
      outsetPointList.push_back(point);
  }
  
  
  void FTContour::AddFrontPoint(FTPoint point)
  {
      frontPointList.push_back(point);
  }
  
  
  void FTContour::AddBackPoint(FTPoint point)
  {
      backPointList.push_back(point);
  }
  
  
  void FTContour::evaluateQuadraticCurve(FTPoint A, FTPoint B, FTPoint C)
  {
      for(unsigned int i = 0; i <= (1.0f / BEZIER_STEP_SIZE); i++)
      {
          float t = static_cast<float>(i) * BEZIER_STEP_SIZE;
  
          FTPoint U = (1.0f - t) * A + t * B;
          FTPoint V = (1.0f - t) * B + t * C;
  
          AddPoint((1.0f - t) * U + t * V);
      }
  }
  
  void FTContour::evaluateCubicCurve(FTPoint A, FTPoint B, FTPoint C, FTPoint D)
  {
      for(unsigned int i = 0; i <= (1.0f / BEZIER_STEP_SIZE); i++)
      {
          float t = static_cast<float>(i) * BEZIER_STEP_SIZE;
  
          FTPoint U = (1.0f - t) * A + t * B;
          FTPoint V = (1.0f - t) * B + t * C;
          FTPoint W = (1.0f - t) * C + t * D;
  
          FTPoint M = (1.0f - t) * U + t * V;
          FTPoint N = (1.0f - t) * V + t * W;
  
          AddPoint((1.0f - t) * M + t * N);
      }
  }
  
  FTGL_DOUBLE FTContour::NormVector(const FTPoint &v)
  {
      return sqrt(v.X() * v.X() + v.Y() * v.Y());
  }
  
  void FTContour::RotationMatrix(const FTPoint &a, const FTPoint &b, FTGL_DOUBLE *matRot, FTGL_DOUBLE *invRot)
  {
      FTPoint abVect(b.X() - a.X(), b.Y() - a.Y(), 0);
      FTGL_DOUBLE abNorm = NormVector(abVect);
      invRot[0] = matRot[0] = -abVect.X() / abNorm;
      invRot[2] = matRot[1] = -abVect.Y() / abNorm;
      invRot[1] = matRot[2] =  abVect.Y() / abNorm;
      invRot[3] = matRot[3] = -abVect.X() / abNorm;
  }
  
  void FTContour::MultMatrixVect(FTGL_DOUBLE *mat, FTPoint &v)
  {
      FTPoint res;
      res.X(v.X() * mat[0] + v.Y() * mat[1]);
      res.Y(v.X() * mat[2] + v.Y() * mat[3]);
      v.X(res.X());
      v.Y(res.Y());
  }
  
  void FTContour::ComputeBisec(FTPoint &v)
  {
      FTGL_DOUBLE sgn = -64.0;
      if((v.Y() / NormVector(v)) < 0)
          sgn = 64.0;
      v.X(sgn * sqrt((NormVector(v) - v.X()) / (NormVector(v) + v.X())));
      v.Y(64.0);
  }
  
  FTPoint FTContour::ComputeOutsetPoint(FTPoint a, FTPoint b, FTPoint c)
  {
      FTGL_DOUBLE mat[4], inv[4];
      /* Build the rotation matrix from 'ab' vector */
      RotationMatrix(b, a, mat, inv);
      /* 'h' is the second vector 'bc' */
      FTPoint h = c - b;
      /* Apply the rotation to the second vector 'bc' */
      MultMatrixVect(mat, h);
      /* Compute the vector bisecting 'bh' */
      ComputeBisec(h);
      /* Apply the inverted rotation matrix to 'bh' */
      MultMatrixVect(inv, h);
      return h;
  }
  
  void FTContour::outsetContour()
  {
      size_t size = PointCount();
      FTPoint vOutset;
      for(unsigned int pointIndex = 0; pointIndex < size; ++pointIndex)
      {
          int prev = (pointIndex%size + size - 1) % size;
          int cur = pointIndex%size;
          int next = (pointIndex%size + 1) % size;
          /* Build the outset shape with d = 1.0f */
          vOutset = ComputeOutsetPoint(Point(prev), Point(cur), Point(next));
          AddOutsetPoint(vOutset);
      }
  }
  
  FTContour::FTContour(FT_Vector* contour, char* tags, unsigned int n)
  {
      for(unsigned int i = 0; i < n; ++ i)
      {
          if(tags[i] == FT_Curve_Tag_On || n < 2)
          {
              AddPoint(FTPoint(contour[i]));
              continue;
          }
  
          FTPoint cur(contour[i]);
          FTPoint prev = (pointList.size() == 0 || i == 0)
                         ? FTPoint(contour[n - 1])
                         : pointList[pointList.size() - 1];
          FTPoint next = (i == n - 1)
                         ? (pointList.size() == 0)
                           ? FTPoint(contour[0])
                           : pointList[0]
                         : FTPoint(contour[i + 1]);
  
          if(tags[i] == FT_Curve_Tag_Conic)
          {
              while(tags[(i == n - 1) ? 0 : i + 1] == FT_Curve_Tag_Conic)
              {
                  next = (cur + next) * 0.5f;
  
                  evaluateQuadraticCurve(prev, cur, next);
                  ++i;
  
                  prev = next;
                  cur = FTPoint(contour[i]);
                  next = (i == n - 1)
                         ? pointList[0]
                         : FTPoint(contour[i + 1]);
              }
  
              evaluateQuadraticCurve(prev, cur, next);
              continue;
          }
  
          if(tags[i] == FT_Curve_Tag_Cubic)
          {
              FTPoint next2 = (i == n - 2)
                               ? pointList[0]
                               : FTPoint(contour[i + 2]);
              evaluateCubicCurve(prev, cur, next, next2);
              ++i;
              continue;
          }
      }
  
      /* Create (or not) front outset and/or back outset */
      outsetContour();
  }
  
  void FTContour::buildFrontOutset(float outset)
  {
      for(size_t i = 0; i < PointCount(); ++i)
      {
          FTPoint point = FTPoint(Point(i).X() + Outset(i).X() * outset,
                                  Point(i).Y() + Outset(i).Y() * outset,
                                  0);
         AddFrontPoint(point);
      }
  }
  void FTContour::buildBackOutset(float outset)
  {
      for(size_t i = 0; i < PointCount(); ++i)
      {
          FTPoint point = FTPoint(Point(i).X() + Outset(i).X() * outset,
                                  Point(i).Y() + Outset(i).Y() * outset,
                                  0);
         AddBackPoint(point);
      }
  }
  
  

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