1 files changed, 245 insertions, 0 deletions
diff --git a/src/ftgl/FTContour.cpp b/src/ftgl/FTContour.cpp
new file mode 100644
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+++ b/src/ftgl/FTContour.cpp
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+/*
+ * FTGL - OpenGL font library
+ *
+ * Copyright (c) 2001-2004 Henry Maddocks <ftgl@opengl.geek.nz>
+ * Copyright (c) 2008 Sam Hocevar <sam@zoy.org>
+ * Copyright (c) 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 unsigned int BEZIER_STEPS = 5;
+
+
+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 = 1; i < BEZIER_STEPS; i++)
+    {
+        float t = static_cast<float>(i) / BEZIER_STEPS;
+
+        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 < BEZIER_STEPS; i++)
+    {
+        float t = static_cast<float>(i) / BEZIER_STEPS;
+
+        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);
+    }
+}
+
+
+// This function is a bit tricky. Given a path ABC, it returns the
+// coordinates of the outset point facing B on the left at a distance
+// of 64.0.
+//                                         M
+//                            - - - - - - X
+//                             ^         / '
+//                             | 64.0   /   '
+//  X---->-----X     ==>    X--v-------X     '
+// A          B \          A          B \   .>'
+//               \                       \<'  64.0
+//                \                       \                  .
+//                 \                       \                 .
+//                C X                     C X
+//
+FTPoint FTContour::ComputeOutsetPoint(FTPoint A, FTPoint B, FTPoint C)
+{
+    /* Build the rotation matrix from 'ba' vector */
+    FTPoint ba = (A - B).Normalise();
+    FTPoint bc = C - B;
+
+    /* Rotate bc to the left */
+    FTPoint tmp(bc.X() * -ba.X() + bc.Y() * -ba.Y(),
+                bc.X() * ba.Y() + bc.Y() * -ba.X());
+
+    /* Compute the vector bisecting 'abc' */
+    FTGL_DOUBLE norm = sqrt(tmp.X() * tmp.X() + tmp.Y() * tmp.Y());
+    FTGL_DOUBLE dist = 64.0 * sqrt((norm - tmp.X()) / (norm + tmp.X()));
+    tmp.X(tmp.Y() < 0.0 ? dist : -dist);
+    tmp.Y(64.0);
+
+    /* Rotate the new bc to the right */
+    return FTPoint(tmp.X() * -ba.X() + tmp.Y() * ba.Y(),
+                   tmp.X() * -ba.Y() + tmp.Y() * -ba.X());
+}
+
+
+void FTContour::SetParity(int parity)
+{
+    size_t size = PointCount();
+    FTPoint vOutset;
+
+    if(((parity & 1) && clockwise) || (!(parity & 1) && !clockwise))
+    {
+        // Contour orientation is wrong! We must reverse all points.
+        // FIXME: could it be worth writing FTVector::reverse() for this?
+        for(size_t i = 0; i < size / 2; i++)
+        {
+            FTPoint tmp = pointList[i];
+            pointList[i] = pointList[size - 1 - i];
+            pointList[size - 1 -i] = tmp;
+        }
+
+        clockwise = !clockwise;
+    }
+
+    for(size_t i = 0; i < size; i++)
+    {
+        size_t prev, cur, next;
+
+        prev = (i + size - 1) % size;
+        cur = i;
+        next = (i + size + 1) % size;
+
+        vOutset = ComputeOutsetPoint(Point(prev), Point(cur), Point(next));
+        AddOutsetPoint(vOutset);
+    }
+}
+
+
+FTContour::FTContour(FT_Vector* contour, char* tags, unsigned int n)
+{
+    FTPoint prev, cur(contour[(n - 1) % n]), next(contour[0]);
+    FTPoint a, b = next - cur;
+    double olddir, dir = atan2((next - cur).Y(), (next - cur).X());
+    double angle = 0.0;
+
+    // See http://freetype.sourceforge.net/freetype2/docs/glyphs/glyphs-6.html
+    // for a full description of FreeType tags.
+    for(unsigned int i = 0; i < n; i++)
+    {
+        prev = cur;
+        cur = next;
+        next = FTPoint(contour[(i + 1) % n]);
+        olddir = dir;
+        dir = atan2((next - cur).Y(), (next - cur).X());
+
+        // Compute our path's new direction.
+        double t = dir - olddir;
+        if(t < -M_PI) t += 2 * M_PI;
+        if(t > M_PI) t -= 2 * M_PI;
+        angle += t;
+
+        // Only process point tags we know.
+        if(n < 2 || FT_CURVE_TAG(tags[i]) == FT_Curve_Tag_On)
+        {
+            AddPoint(cur);
+        }
+        else if(FT_CURVE_TAG(tags[i]) == FT_Curve_Tag_Conic)
+        {
+            FTPoint prev2 = prev, next2 = next;
+
+            // Previous point is either the real previous point (an "on"
+            // point), or the midpoint between the current one and the
+            // previous "conic off" point.
+            if(FT_CURVE_TAG(tags[(i - 1 + n) % n]) == FT_Curve_Tag_Conic)
+            {
+                prev2 = (cur + prev) * 0.5;
+                AddPoint(prev2);
+            }
+
+            // Next point is either the real next point or the midpoint.
+            if(FT_CURVE_TAG(tags[(i + 1) % n]) == FT_Curve_Tag_Conic)
+            {
+                next2 = (cur + next) * 0.5;
+            }
+
+            evaluateQuadraticCurve(prev2, cur, next2);
+        }
+        else if(FT_CURVE_TAG(tags[i]) == FT_Curve_Tag_Cubic
+                 && FT_CURVE_TAG(tags[(i + 1) % n]) == FT_Curve_Tag_Cubic)
+        {
+            evaluateCubicCurve(prev, cur, next,
+                               FTPoint(contour[(i + 2) % n]));
+        }
+    }
+
+    // If final angle is positive (+2PI), it's an anti-clockwise contour,
+    // otherwise (-2PI) it's clockwise.
+    clockwise = (angle < 0.0);
+}
+
+
+void FTContour::buildFrontOutset(float outset)
+{
+    for(size_t i = 0; i < PointCount(); ++i)
+    {
+        AddFrontPoint(Point(i) + Outset(i) * outset);
+    }
+}
+
+
+void FTContour::buildBackOutset(float outset)
+{
+    for(size_t i = 0; i < PointCount(); ++i)
+    {
+        AddBackPoint(Point(i) + Outset(i) * outset);
+    }
+}
+