285 lines
6.5 KiB
C++
285 lines
6.5 KiB
C++
/*
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* Copyright © 2022 Behdad Esfahbod
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*
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* This is part of HarfBuzz, a text shaping library.
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*
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* Permission is hereby granted, without written agreement and without
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* license or royalty fees, to use, copy, modify, and distribute this
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* software and its documentation for any purpose, provided that the
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* above copyright notice and the following two paragraphs appear in
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* all copies of this software.
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*
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* IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
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* DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
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* ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
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* IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
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* DAMAGE.
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*
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* THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
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* BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
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* FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
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* ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
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* PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
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*/
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#ifndef HB_GEOMETRY_HH
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#define HB_GEOMETRY_HH
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#include "hb.hh"
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struct hb_extents_t
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{
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hb_extents_t () {}
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hb_extents_t (float xmin, float ymin, float xmax, float ymax) :
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xmin (xmin), ymin (ymin), xmax (xmax), ymax (ymax) {}
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bool is_empty () const { return xmin >= xmax || ymin >= ymax; }
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bool is_void () const { return xmin > xmax; }
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void union_ (const hb_extents_t &o)
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{
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xmin = hb_min (xmin, o.xmin);
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ymin = hb_min (ymin, o.ymin);
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xmax = hb_max (xmax, o.xmax);
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ymax = hb_max (ymax, o.ymax);
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}
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void intersect (const hb_extents_t &o)
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{
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xmin = hb_max (xmin, o.xmin);
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ymin = hb_max (ymin, o.ymin);
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xmax = hb_min (xmax, o.xmax);
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ymax = hb_min (ymax, o.ymax);
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}
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void
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add_point (float x, float y)
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{
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if (unlikely (is_void ()))
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{
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xmin = xmax = x;
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ymin = ymax = y;
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}
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else
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{
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xmin = hb_min (xmin, x);
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ymin = hb_min (ymin, y);
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xmax = hb_max (xmax, x);
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ymax = hb_max (ymax, y);
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}
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}
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float xmin = 0.f;
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float ymin = 0.f;
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float xmax = -1.f;
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float ymax = -1.f;
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};
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struct hb_transform_t
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{
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hb_transform_t () {}
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hb_transform_t (float xx, float yx,
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float xy, float yy,
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float x0, float y0) :
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xx (xx), yx (yx), xy (xy), yy (yy), x0 (x0), y0 (y0) {}
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void multiply (const hb_transform_t &o)
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{
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/* Copied from cairo, with "o" being "a" there and "this" being "b" there. */
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hb_transform_t r;
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r.xx = o.xx * xx + o.yx * xy;
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r.yx = o.xx * yx + o.yx * yy;
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r.xy = o.xy * xx + o.yy * xy;
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r.yy = o.xy * yx + o.yy * yy;
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r.x0 = o.x0 * xx + o.y0 * xy + x0;
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r.y0 = o.x0 * yx + o.y0 * yy + y0;
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*this = r;
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}
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void transform_distance (float &dx, float &dy) const
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{
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float new_x = xx * dx + xy * dy;
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float new_y = yx * dx + yy * dy;
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dx = new_x;
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dy = new_y;
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}
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void transform_point (float &x, float &y) const
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{
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transform_distance (x, y);
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x += x0;
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y += y0;
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}
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void transform_extents (hb_extents_t &extents) const
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{
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float quad_x[4], quad_y[4];
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quad_x[0] = extents.xmin;
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quad_y[0] = extents.ymin;
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quad_x[1] = extents.xmin;
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quad_y[1] = extents.ymax;
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quad_x[2] = extents.xmax;
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quad_y[2] = extents.ymin;
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quad_x[3] = extents.xmax;
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quad_y[3] = extents.ymax;
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extents = hb_extents_t {};
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for (unsigned i = 0; i < 4; i++)
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{
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transform_point (quad_x[i], quad_y[i]);
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extents.add_point (quad_x[i], quad_y[i]);
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}
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}
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void transform (const hb_transform_t &o) { multiply (o); }
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void translate (float x, float y)
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{
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if (x == 0.f && y == 0.f)
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return;
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x0 += xx * x + xy * y;
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y0 += yx * x + yy * y;
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}
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void scale (float scaleX, float scaleY)
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{
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if (scaleX == 1.f && scaleY == 1.f)
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return;
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xx *= scaleX;
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yx *= scaleX;
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xy *= scaleY;
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yy *= scaleY;
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}
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void rotate (float rotation)
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{
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if (rotation == 0.f)
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return;
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// https://github.com/fonttools/fonttools/blob/f66ee05f71c8b57b5f519ee975e95edcd1466e14/Lib/fontTools/misc/transform.py#L240
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rotation = rotation * HB_PI;
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float c;
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float s;
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#ifdef HAVE_SINCOSF
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sincosf (rotation, &s, &c);
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#else
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c = cosf (rotation);
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s = sinf (rotation);
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#endif
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auto other = hb_transform_t{c, s, -s, c, 0.f, 0.f};
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transform (other);
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}
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void skew (float skewX, float skewY)
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{
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if (skewX == 0.f && skewY == 0.f)
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return;
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// https://github.com/fonttools/fonttools/blob/f66ee05f71c8b57b5f519ee975e95edcd1466e14/Lib/fontTools/misc/transform.py#L255
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skewX = skewX * HB_PI;
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skewY = skewY * HB_PI;
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auto other = hb_transform_t{1.f,
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skewY ? tanf (skewY) : 0.f,
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skewX ? tanf (skewX) : 0.f,
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1.f,
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0.f, 0.f};
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transform (other);
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}
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float xx = 1.f;
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float yx = 0.f;
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float xy = 0.f;
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float yy = 1.f;
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float x0 = 0.f;
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float y0 = 0.f;
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};
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struct hb_bounds_t
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{
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enum status_t {
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UNBOUNDED,
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BOUNDED,
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EMPTY,
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};
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hb_bounds_t (status_t status) : status (status) {}
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hb_bounds_t (const hb_extents_t &extents) :
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status (extents.is_empty () ? EMPTY : BOUNDED), extents (extents) {}
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void union_ (const hb_bounds_t &o)
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{
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if (o.status == UNBOUNDED)
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status = UNBOUNDED;
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else if (o.status == BOUNDED)
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{
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if (status == EMPTY)
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*this = o;
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else if (status == BOUNDED)
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extents.union_ (o.extents);
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}
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}
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void intersect (const hb_bounds_t &o)
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{
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if (o.status == EMPTY)
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status = EMPTY;
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else if (o.status == BOUNDED)
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{
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if (status == UNBOUNDED)
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*this = o;
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else if (status == BOUNDED)
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{
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extents.intersect (o.extents);
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if (extents.is_empty ())
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status = EMPTY;
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}
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}
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}
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status_t status;
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hb_extents_t extents;
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};
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struct hb_transform_decomposed_t
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{
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float translateX = 0;
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float translateY = 0;
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float rotation = 0; // in degrees, counter-clockwise
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float scaleX = 1;
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float scaleY = 1;
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float skewX = 0; // in degrees, counter-clockwise
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float skewY = 0; // in degrees, counter-clockwise
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float tCenterX = 0;
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float tCenterY = 0;
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operator bool () const
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{
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return translateX || translateY ||
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rotation ||
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scaleX != 1 || scaleY != 1 ||
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skewX || skewY ||
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tCenterX || tCenterY;
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}
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hb_transform_t to_transform () const
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{
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hb_transform_t t;
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t.translate (translateX + tCenterX, translateY + tCenterY);
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t.rotate (rotation);
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t.scale (scaleX, scaleY);
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t.skew (-skewX, skewY);
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t.translate (-tCenterX, -tCenterY);
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return t;
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}
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};
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#endif /* HB_GEOMETRY_HH */
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