diff options
Diffstat (limited to 'gfx/harfbuzz/src/hb-subset-instancer-iup.cc')
| -rw-r--r-- | gfx/harfbuzz/src/hb-subset-instancer-iup.cc | 532 |
1 files changed, 532 insertions, 0 deletions
diff --git a/gfx/harfbuzz/src/hb-subset-instancer-iup.cc b/gfx/harfbuzz/src/hb-subset-instancer-iup.cc new file mode 100644 index 0000000000..35a964d082 --- /dev/null +++ b/gfx/harfbuzz/src/hb-subset-instancer-iup.cc @@ -0,0 +1,532 @@ +/* + * Copyright © 2024 Google, Inc. + * + * 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. + */ + +#include "hb-subset-instancer-iup.hh" + +/* This file is a straight port of the following: + * + * https://github.com/fonttools/fonttools/blob/main/Lib/fontTools/varLib/iup.py + * + * Where that file returns optimzied deltas vector, we return optimized + * referenced point indices. + */ + +constexpr static unsigned MAX_LOOKBACK = 8; + +static void _iup_contour_bound_forced_set (const hb_array_t<const contour_point_t> contour_points, + const hb_array_t<const int> x_deltas, + const hb_array_t<const int> y_deltas, + hb_set_t& forced_set, /* OUT */ + float tolerance = 0.f) +{ + unsigned len = contour_points.length; + unsigned next_i = 0; + for (int i = len - 1; i >= 0; i--) + { + unsigned last_i = (len + i -1) % len; + for (unsigned j = 0; j < 2; j++) + { + float cj, lcj, ncj; + int dj, ldj, ndj; + if (j == 0) + { + cj = contour_points.arrayZ[i].x; + dj = x_deltas.arrayZ[i]; + lcj = contour_points.arrayZ[last_i].x; + ldj = x_deltas.arrayZ[last_i]; + ncj = contour_points.arrayZ[next_i].x; + ndj = x_deltas.arrayZ[next_i]; + } + else + { + cj = contour_points.arrayZ[i].y; + dj = y_deltas.arrayZ[i]; + lcj = contour_points.arrayZ[last_i].y; + ldj = y_deltas.arrayZ[last_i]; + ncj = contour_points.arrayZ[next_i].y; + ndj = y_deltas.arrayZ[next_i]; + } + + float c1, c2; + int d1, d2; + if (lcj <= ncj) + { + c1 = lcj; + c2 = ncj; + d1 = ldj; + d2 = ndj; + } + else + { + c1 = ncj; + c2 = lcj; + d1 = ndj; + d2 = ldj; + } + + bool force = false; + if (c1 == c2) + { + if (abs (d1 - d2) > tolerance && abs (dj) > tolerance) + force = true; + } + else if (c1 <= cj && cj <= c2) + { + if (!(hb_min (d1, d2) - tolerance <= dj && + dj <= hb_max (d1, d2) + tolerance)) + force = true; + } + else + { + if (d1 != d2) + { + if (cj < c1) + { + if (abs (dj) > tolerance && + abs (dj - d1) > tolerance && + ((dj - tolerance < d1) != (d1 < d2))) + force = true; + } + else + { + if (abs (dj) > tolerance && + abs (dj - d2) > tolerance && + ((d2 < dj + tolerance) != (d1 < d2))) + force = true; + } + } + } + + if (force) + { + forced_set.add (i); + break; + } + } + next_i = i; + } +} + +template <typename T, + hb_enable_if (hb_is_trivially_copyable (T))> +static bool rotate_array (const hb_array_t<const T>& org_array, + int k, + hb_vector_t<T>& out) +{ + unsigned n = org_array.length; + if (!n) return true; + if (unlikely (!out.resize (n, false))) + return false; + + unsigned item_size = hb_static_size (T); + if (k < 0) + k = n - (-k) % n; + else + k %= n; + + hb_memcpy ((void *) out.arrayZ, (const void *) (org_array.arrayZ + n - k), k * item_size); + hb_memcpy ((void *) (out.arrayZ + k), (const void *) org_array.arrayZ, (n - k) * item_size); + return true; +} + +static bool rotate_set (const hb_set_t& org_set, + int k, + unsigned n, + hb_set_t& out) +{ + if (!n) return false; + k %= n; + if (k < 0) + k = n + k; + + if (k == 0) + { + out.set (org_set); + } + else + { + for (auto v : org_set) + out.add ((v + k) % n); + } + return !out.in_error (); +} + +/* Given two reference coordinates (start and end of contour_points array), + * output interpolated deltas for points in between */ +static bool _iup_segment (const hb_array_t<const contour_point_t> contour_points, + const hb_array_t<const int> x_deltas, + const hb_array_t<const int> y_deltas, + const contour_point_t& p1, const contour_point_t& p2, + int p1_dx, int p2_dx, + int p1_dy, int p2_dy, + hb_vector_t<float>& interp_x_deltas, /* OUT */ + hb_vector_t<float>& interp_y_deltas /* OUT */) +{ + unsigned n = contour_points.length; + if (unlikely (!interp_x_deltas.resize (n, false) || + !interp_y_deltas.resize (n, false))) + return false; + + for (unsigned j = 0; j < 2; j++) + { + float x1, x2, d1, d2; + float *out; + if (j == 0) + { + x1 = p1.x; + x2 = p2.x; + d1 = p1_dx; + d2 = p2_dx; + out = interp_x_deltas.arrayZ; + } + else + { + x1 = p1.y; + x2 = p2.y; + d1 = p1_dy; + d2 = p2_dy; + out = interp_y_deltas.arrayZ; + } + + if (x1 == x2) + { + if (d1 == d2) + { + for (unsigned i = 0; i < n; i++) + out[i] = d1; + } + else + { + for (unsigned i = 0; i < n; i++) + out[i] = 0.f; + } + continue; + } + + if (x1 > x2) + { + hb_swap (x1, x2); + hb_swap (d1, d2); + } + + float scale = (d2 - d1) / (x2 - x1); + for (unsigned i = 0; i < n; i++) + { + float x = j == 0 ? contour_points.arrayZ[i].x : contour_points.arrayZ[i].y; + float d; + if (x <= x1) + d = d1; + else if (x >= x2) + d = d2; + else + d = d1 + (x - x1) * scale; + + out[i] = d; + } + } + return true; +} + +static bool _can_iup_in_between (const hb_array_t<const contour_point_t> contour_points, + const hb_array_t<const int> x_deltas, + const hb_array_t<const int> y_deltas, + const contour_point_t& p1, const contour_point_t& p2, + int p1_dx, int p2_dx, + int p1_dy, int p2_dy, + float tolerance) +{ + hb_vector_t<float> interp_x_deltas, interp_y_deltas; + if (!_iup_segment (contour_points, x_deltas, y_deltas, + p1, p2, p1_dx, p2_dx, p1_dy, p2_dy, + interp_x_deltas, interp_y_deltas)) + return false; + + unsigned num = contour_points.length; + + for (unsigned i = 0; i < num; i++) + { + float dx = x_deltas.arrayZ[i] - interp_x_deltas.arrayZ[i]; + float dy = y_deltas.arrayZ[i] - interp_y_deltas.arrayZ[i]; + + if (sqrtf ((float)dx * dx + (float)dy * dy) > tolerance) + return false; + } + return true; +} + +static bool _iup_contour_optimize_dp (const contour_point_vector_t& contour_points, + const hb_vector_t<int>& x_deltas, + const hb_vector_t<int>& y_deltas, + const hb_set_t& forced_set, + float tolerance, + unsigned lookback, + hb_vector_t<unsigned>& costs, /* OUT */ + hb_vector_t<int>& chain /* OUT */) +{ + unsigned n = contour_points.length; + if (unlikely (!costs.resize (n, false) || + !chain.resize (n, false))) + return false; + + lookback = hb_min (lookback, MAX_LOOKBACK); + + for (unsigned i = 0; i < n; i++) + { + unsigned best_cost = (i == 0 ? 1 : costs.arrayZ[i-1] + 1); + + costs.arrayZ[i] = best_cost; + chain.arrayZ[i] = (i == 0 ? -1 : i - 1); + + if (i > 0 && forced_set.has (i - 1)) + continue; + + int lookback_index = hb_max ((int) i - (int) lookback + 1, -1); + for (int j = i - 2; j >= lookback_index; j--) + { + unsigned cost = j == -1 ? 1 : costs.arrayZ[j] + 1; + /* num points between i and j */ + unsigned num_points = i - j - 1; + unsigned p1 = (j == -1 ? n - 1 : j); + if (cost < best_cost && + _can_iup_in_between (contour_points.as_array ().sub_array (j + 1, num_points), + x_deltas.as_array ().sub_array (j + 1, num_points), + y_deltas.as_array ().sub_array (j + 1, num_points), + contour_points.arrayZ[p1], contour_points.arrayZ[i], + x_deltas.arrayZ[p1], x_deltas.arrayZ[i], + y_deltas.arrayZ[p1], y_deltas.arrayZ[i], + tolerance)) + { + best_cost = cost; + costs.arrayZ[i] = best_cost; + chain.arrayZ[i] = j; + } + + if (j > 0 && forced_set.has (j)) + break; + } + } + return true; +} + +static bool _iup_contour_optimize (const hb_array_t<const contour_point_t> contour_points, + const hb_array_t<const int> x_deltas, + const hb_array_t<const int> y_deltas, + hb_array_t<bool> opt_indices, /* OUT */ + float tolerance = 0.f) +{ + unsigned n = contour_points.length; + if (opt_indices.length != n || + x_deltas.length != n || + y_deltas.length != n) + return false; + + bool all_within_tolerance = true; + for (unsigned i = 0; i < n; i++) + { + int dx = x_deltas.arrayZ[i]; + int dy = y_deltas.arrayZ[i]; + if (sqrtf ((float)dx * dx + (float)dy * dy) > tolerance) + { + all_within_tolerance = false; + break; + } + } + + /* If all are within tolerance distance, do nothing, opt_indices is + * initilized to false */ + if (all_within_tolerance) + return true; + + /* If there's exactly one point, return it */ + if (n == 1) + { + opt_indices.arrayZ[0] = true; + return true; + } + + /* If all deltas are exactly the same, return just one (the first one) */ + bool all_deltas_are_equal = true; + for (unsigned i = 1; i < n; i++) + if (x_deltas.arrayZ[i] != x_deltas.arrayZ[0] || + y_deltas.arrayZ[i] != y_deltas.arrayZ[0]) + { + all_deltas_are_equal = false; + break; + } + + if (all_deltas_are_equal) + { + opt_indices.arrayZ[0] = true; + return true; + } + + /* else, solve the general problem using Dynamic Programming */ + hb_set_t forced_set; + _iup_contour_bound_forced_set (contour_points, x_deltas, y_deltas, forced_set, tolerance); + + if (!forced_set.is_empty ()) + { + int k = n - 1 - forced_set.get_max (); + if (k < 0) + return false; + + hb_vector_t<int> rot_x_deltas, rot_y_deltas; + contour_point_vector_t rot_points; + hb_set_t rot_forced_set; + if (!rotate_array (contour_points, k, rot_points) || + !rotate_array (x_deltas, k, rot_x_deltas) || + !rotate_array (y_deltas, k, rot_y_deltas) || + !rotate_set (forced_set, k, n, rot_forced_set)) + return false; + + hb_vector_t<unsigned> costs; + hb_vector_t<int> chain; + + if (!_iup_contour_optimize_dp (rot_points, rot_x_deltas, rot_y_deltas, + rot_forced_set, tolerance, n, + costs, chain)) + return false; + + hb_set_t solution; + int index = n - 1; + while (index != -1) + { + solution.add (index); + index = chain.arrayZ[index]; + } + + if (solution.is_empty () || + forced_set.get_population () > solution.get_population ()) + return false; + + for (unsigned i : solution) + opt_indices.arrayZ[i] = true; + + hb_vector_t<bool> rot_indices; + const hb_array_t<const bool> opt_indices_array (opt_indices.arrayZ, opt_indices.length); + rotate_array (opt_indices_array, -k, rot_indices); + + for (unsigned i = 0; i < n; i++) + opt_indices.arrayZ[i] = rot_indices.arrayZ[i]; + } + else + { + hb_vector_t<int> repeat_x_deltas, repeat_y_deltas; + contour_point_vector_t repeat_points; + + if (unlikely (!repeat_x_deltas.resize (n * 2, false) || + !repeat_y_deltas.resize (n * 2, false) || + !repeat_points.resize (n * 2, false))) + return false; + + unsigned contour_point_size = hb_static_size (contour_point_t); + for (unsigned i = 0; i < n; i++) + { + hb_memcpy ((void *) repeat_x_deltas.arrayZ, (const void *) x_deltas.arrayZ, n * sizeof (float)); + hb_memcpy ((void *) (repeat_x_deltas.arrayZ + n), (const void *) x_deltas.arrayZ, n * sizeof (float)); + + hb_memcpy ((void *) repeat_y_deltas.arrayZ, (const void *) y_deltas.arrayZ, n * sizeof (float)); + hb_memcpy ((void *) (repeat_y_deltas.arrayZ + n), (const void *) y_deltas.arrayZ, n * sizeof (float)); + + hb_memcpy ((void *) repeat_points.arrayZ, (const void *) contour_points.arrayZ, n * contour_point_size); + hb_memcpy ((void *) (repeat_points.arrayZ + n), (const void *) contour_points.arrayZ, n * contour_point_size); + } + + hb_vector_t<unsigned> costs; + hb_vector_t<int> chain; + if (!_iup_contour_optimize_dp (repeat_points, repeat_x_deltas, repeat_y_deltas, + forced_set, tolerance, n, + costs, chain)) + return false; + + unsigned best_cost = n + 1; + int len = costs.length; + hb_set_t best_sol; + for (int start = n - 1; start < len; start++) + { + hb_set_t solution; + int i = start; + int lookback = start - (int) n; + while (i > lookback) + { + solution.add (i % n); + i = chain.arrayZ[i]; + } + if (i == lookback) + { + unsigned cost_i = i < 0 ? 0 : costs.arrayZ[i]; + unsigned cost = costs.arrayZ[start] - cost_i; + if (cost <= best_cost) + { + best_sol.set (solution); + best_cost = cost; + } + } + } + + for (unsigned i = 0; i < n; i++) + if (best_sol.has (i)) + opt_indices.arrayZ[i] = true; + } + return true; +} + +bool iup_delta_optimize (const contour_point_vector_t& contour_points, + const hb_vector_t<int>& x_deltas, + const hb_vector_t<int>& y_deltas, + hb_vector_t<bool>& opt_indices, /* OUT */ + float tolerance) +{ + if (!opt_indices.resize (contour_points.length)) + return false; + + hb_vector_t<unsigned> end_points; + unsigned count = contour_points.length; + if (unlikely (!end_points.alloc (count))) + return false; + + for (unsigned i = 0; i < count - 4; i++) + if (contour_points.arrayZ[i].is_end_point) + end_points.push (i); + + /* phantom points */ + for (unsigned i = count - 4; i < count; i++) + end_points.push (i); + + if (end_points.in_error ()) return false; + + unsigned start = 0; + for (unsigned end : end_points) + { + unsigned len = end - start + 1; + if (!_iup_contour_optimize (contour_points.as_array ().sub_array (start, len), + x_deltas.as_array ().sub_array (start, len), + y_deltas.as_array ().sub_array (start, len), + opt_indices.as_array ().sub_array (start, len), + tolerance)) + return false; + start = end + 1; + } + return true; +} |