initial commit, 4.5 stable

thirdparty/harfbuzz/src/hb-geometry.hh

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+/*
+ * Copyright © 2022 Behdad Esfahbod
+ *
+ *  This is part of HarfBuzz, a text shaping library.
+ *
+ * Permission is hereby granted, without written agreement and without
+ * license or royalty fees, to use, copy, modify, and distribute this
+ * software and its documentation for any purpose, provided that the
+ * above copyright notice and the following two paragraphs appear in
+ * all copies of this software.
+ *
+ * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
+ * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
+ * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
+ * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
+ * DAMAGE.
+ *
+ * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
+ * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
+ * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
+ * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
+ * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
+ */
+#ifndef HB_GEOMETRY_HH
+#define HB_GEOMETRY_HH
+
+#include "hb.hh"
+
+#include "hb-algs.hh"
+
+
+template <typename Float = float>
+struct hb_extents_t
+{
+  hb_extents_t () {}
+  hb_extents_t (const hb_glyph_extents_t &extents) :
+		xmin (hb_min (extents.x_bearing, extents.x_bearing + extents.width)),
+		ymin (hb_min (extents.y_bearing, extents.y_bearing + extents.height)),
+		xmax (hb_max (extents.x_bearing, extents.x_bearing + extents.width)),
+		ymax (hb_max (extents.y_bearing, extents.y_bearing + extents.height)) {}
+  hb_extents_t (Float xmin, Float ymin, Float xmax, Float ymax) :
+    xmin (xmin), ymin (ymin), xmax (xmax), ymax (ymax) {}
+
+  bool is_empty () const { return xmin >= xmax || ymin >= ymax; }
+  bool is_void () const { return xmin > xmax; }
+
+  void union_ (const hb_extents_t &o)
+  {
+    if (o.is_empty ()) return;
+    if (is_empty ())
+    {
+      *this = o;
+      return;
+    }
+    xmin = hb_min (xmin, o.xmin);
+    ymin = hb_min (ymin, o.ymin);
+    xmax = hb_max (xmax, o.xmax);
+    ymax = hb_max (ymax, o.ymax);
+  }
+
+  void intersect (const hb_extents_t &o)
+  {
+    if (o.is_empty () || is_empty ())
+    {
+      *this = hb_extents_t {};
+      return;
+    }
+    xmin = hb_max (xmin, o.xmin);
+    ymin = hb_max (ymin, o.ymin);
+    xmax = hb_min (xmax, o.xmax);
+    ymax = hb_min (ymax, o.ymax);
+  }
+
+  void
+  add_point (Float x, Float y)
+  {
+    if (unlikely (is_void ()))
+    {
+      xmin = xmax = x;
+      ymin = ymax = y;
+    }
+    else
+    {
+      xmin = hb_min (xmin, x);
+      ymin = hb_min (ymin, y);
+      xmax = hb_max (xmax, x);
+      ymax = hb_max (ymax, y);
+    }
+  }
+
+  hb_glyph_extents_t to_glyph_extents (bool xneg = false, bool yneg = false) const
+  {
+    hb_position_t x0 = (hb_position_t) roundf (xmin);
+    hb_position_t y0 = (hb_position_t) roundf (ymin);
+    hb_position_t x1 = (hb_position_t) roundf (xmax);
+    hb_position_t y1 = (hb_position_t) roundf (ymax);
+    return hb_glyph_extents_t {xneg ? x1 : x0,
+			       yneg ? y0 : y1,
+			       xneg ? x0 - x1 : x1 - x0,
+			       yneg ? y1 - y0 : y0 - y1};
+  }
+
+  Float xmin = 0;
+  Float ymin = 0;
+  Float xmax = -1;
+  Float ymax = -1;
+};
+
+template <typename Float = float>
+struct hb_transform_t
+{
+  hb_transform_t () {}
+  hb_transform_t (Float xx, Float yx,
+		  Float xy, Float yy,
+		  Float x0, Float y0) :
+    xx (xx), yx (yx), xy (xy), yy (yy), x0 (x0), y0 (y0) {}
+
+  bool is_identity () const
+  {
+    return xx == 1 && yx == 0 &&
+	   xy == 0 && yy == 1 &&
+	   x0 == 0 && y0 == 0;
+  }
+  bool is_translation () const
+  {
+    return xx == 1 && yx == 0 &&
+	   xy == 0 && yy == 1;
+  }
+
+  void multiply (const hb_transform_t &o, bool before=false)
+  {
+    // Copied from cairo-matrix.c
+    const hb_transform_t &a = before ? o : *this;
+    const hb_transform_t &b = before ? *this : o;
+    *this = {
+      a.xx * b.xx + a.xy * b.yx,
+      a.yx * b.xx + a.yy * b.yx,
+      a.xx * b.xy + a.xy * b.yy,
+      a.yx * b.xy + a.yy * b.yy,
+      a.xx * b.x0 + a.xy * b.y0 + a.x0,
+      a.yx * b.x0 + a.yy * b.y0 + a.y0
+    };
+  }
+
+  HB_ALWAYS_INLINE
+  void transform_distance (Float &dx, Float &dy) const
+  {
+    Float new_x = xx * dx + xy * dy;
+    Float new_y = yx * dx + yy * dy;
+    dx = new_x;
+    dy = new_y;
+  }
+
+  HB_ALWAYS_INLINE
+  void transform_point (Float &x, Float &y) const
+  {
+    Float new_x = x0 + xx * x + xy * y;
+    Float new_y = y0 + yx * x + yy * y;
+    x = new_x;
+    y = new_y;
+  }
+
+  void transform_extents (hb_extents_t<Float> &extents) const
+  {
+    Float quad_x[4], quad_y[4];
+
+    quad_x[0] = extents.xmin;
+    quad_y[0] = extents.ymin;
+    quad_x[1] = extents.xmin;
+    quad_y[1] = extents.ymax;
+    quad_x[2] = extents.xmax;
+    quad_y[2] = extents.ymin;
+    quad_x[3] = extents.xmax;
+    quad_y[3] = extents.ymax;
+
+    extents = hb_extents_t<Float> {};
+    for (unsigned i = 0; i < 4; i++)
+    {
+      transform_point (quad_x[i], quad_y[i]);
+      extents.add_point (quad_x[i], quad_y[i]);
+    }
+  }
+
+  void transform (const hb_transform_t &o, bool before=false) { multiply (o, before); }
+
+  static hb_transform_t translation (Float x, Float y)
+  {
+    return {1, 0, 0, 1, x, y};
+  }
+  void translate (Float x, Float y, bool before=false)
+  {
+    if (before)
+    {
+      x0 += x;
+      y0 += y;
+    }
+    else
+    {
+      if (x == 0 && y == 0)
+	return;
+
+      x0 += xx * x + xy * y;
+      y0 += yx * x + yy * y;
+    }
+  }
+
+  static hb_transform_t scaling (Float scaleX, Float scaleY)
+  {
+    return {scaleX, 0, 0, scaleY, 0, 0};
+  }
+  void scale (Float scaleX, Float scaleY)
+  {
+    if (scaleX == 1 && scaleY == 1)
+      return;
+
+    xx *= scaleX;
+    yx *= scaleX;
+    xy *= scaleY;
+    yy *= scaleY;
+  }
+  static hb_transform_t scaling_around_center (Float scaleX, Float scaleY, Float center_x, Float center_y)
+  {
+    return {scaleX, 0, 0, scaleY,
+	    center_x ? (1 - scaleX) * center_x : 0,
+	    center_y ? (1 - scaleY) * center_y : 0};
+  }
+  void scale_around_center (Float scaleX, Float scaleY, Float center_x, Float center_y)
+  {
+    if (scaleX == 1 && scaleY == 1)
+      return;
+
+    transform (scaling_around_center (scaleX, scaleY, center_x, center_y));
+  }
+
+  static hb_transform_t rotation (Float radians)
+  {
+    // https://github.com/fonttools/fonttools/blob/f66ee05f71c8b57b5f519ee975e95edcd1466e14/Lib/fontTools/misc/transform.py#L240
+    Float c;
+    Float s;
+    hb_sincos (radians, s, c);
+    return {c, s, -s, c, 0, 0};
+  }
+  void rotate (Float radians, bool before=false)
+  {
+    if (radians == 0)
+      return;
+
+    transform (rotation (radians), before);
+  }
+
+  static hb_transform_t rotation_around_center (Float radians, Float center_x, Float center_y)
+  {
+    Float s, c;
+    hb_sincos (radians, s, c);
+    return {
+      c, s, -s, c,
+      (1 - c) * center_x + s * center_y,
+      -s * center_x +  (1 - c) * center_y
+    };
+  }
+  void rotate_around_center (Float radians, Float center_x, Float center_y, bool before=false)
+  {
+    if (radians == 0)
+      return;
+
+    transform (rotation_around_center (radians, center_x, center_y), before);
+  }
+
+  static hb_transform_t skewing (Float skewX, Float skewY)
+  {
+    return {1, skewY ? tanf (skewY) : 0, skewX ? tanf (skewX) : 0, 1, 0, 0};
+  }
+  void skew (Float skewX, Float skewY)
+  {
+    if (skewX == 0 && skewY == 0)
+      return;
+
+    transform (skewing (skewX, skewY));
+  }
+  static hb_transform_t skewing_around_center (Float skewX, Float skewY, Float center_x, Float center_y)
+  {
+    skewX = skewX ? tanf (skewX) : 0;
+    skewY = skewY ? tanf (skewY) : 0;
+    return {
+	    1, skewY, skewX, 1,
+	    center_y ? -skewX * center_y : 0,
+	    center_x ? -skewY * center_x : 0
+    };
+  }
+  void skew_around_center (Float skewX, Float skewY, Float center_x, Float center_y)
+  {
+    if (skewX == 0 && skewY == 0)
+	    return;
+
+    transform (skewing_around_center (skewX, skewY, center_x, center_y));
+  }
+
+  Float xx = 1;
+  Float yx = 0;
+  Float xy = 0;
+  Float yy = 1;
+  Float x0 = 0;
+  Float y0 = 0;
+};
+
+#define HB_TRANSFORM_IDENTITY {1, 0, 0, 1, 0, 0}
+
+template <typename Float = float>
+struct hb_bounds_t
+{
+  enum status_t {
+    UNBOUNDED,
+    BOUNDED,
+    EMPTY,
+  };
+
+  hb_bounds_t (status_t status = UNBOUNDED) : status (status) {}
+  hb_bounds_t (const hb_extents_t<Float> &extents) :
+    status (extents.is_empty () ? EMPTY : BOUNDED), extents (extents) {}
+
+  void union_ (const hb_bounds_t &o)
+  {
+    if (o.status == UNBOUNDED)
+      status = UNBOUNDED;
+    else if (o.status == BOUNDED)
+    {
+      if (status == EMPTY)
+	*this = o;
+      else if (status == BOUNDED)
+        extents.union_ (o.extents);
+    }
+  }
+
+  void intersect (const hb_bounds_t &o)
+  {
+    if (o.status == EMPTY)
+      status = EMPTY;
+    else if (o.status == BOUNDED)
+    {
+      if (status == UNBOUNDED)
+	*this = o;
+      else if (status == BOUNDED)
+      {
+        extents.intersect (o.extents);
+	if (extents.is_empty ())
+	  status = EMPTY;
+      }
+    }
+  }
+
+  status_t status;
+  hb_extents_t<Float> extents;
+};
+
+template <typename Float = float>
+struct hb_transform_decomposed_t
+{
+  Float translateX = 0;
+  Float translateY = 0;
+  Float rotation = 0;  // in radians, counter-clockwise
+  Float scaleX = 1;
+  Float scaleY = 1;
+  Float skewX = 0;  // in radians, counter-clockwise
+  Float skewY = 0;  // in radians, counter-clockwise
+  Float tCenterX = 0;
+  Float tCenterY = 0;
+
+  operator bool () const
+  {
+    return translateX || translateY ||
+	   rotation ||
+	   scaleX != 1 || scaleY != 1 ||
+	   skewX || skewY ||
+	   tCenterX || tCenterY;
+  }
+
+  hb_transform_t<Float> to_transform () const
+  {
+    hb_transform_t<Float> t;
+    t.translate (translateX + tCenterX, translateY + tCenterY);
+    t.rotate (rotation);
+    t.scale (scaleX, scaleY);
+    t.skew (-skewX, skewY);
+    t.translate (-tCenterX, -tCenterY);
+    return t;
+  }
+};
+
+
+#endif /* HB_GEOMETRY_HH */