Behdad Esfahbod
2 years ago
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b5c68c1cf3
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4 changed files with 373 additions and 7 deletions
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/*
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* Copyright © 2023 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_DRAW_EMBOLDEN_HH |
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#define HB_DRAW_EMBOLDEN_HH |
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#include "hb.hh" |
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#include "hb-draw.hh" |
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struct hb_contour_point_t |
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{ |
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enum class type_t |
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{ |
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MOVE_TO, |
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LINE_TO, |
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QUADRATIC_TO, |
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CUBIC_TO, |
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}; |
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hb_contour_point_t (float x, float y, type_t type) : |
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x (x), y (y), type (type) {} |
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float x, y; |
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type_t type; |
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}; |
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using hb_contour_t = hb_vector_t<hb_contour_point_t>; |
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template <typename context_t> |
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struct hb_filter_outline_t |
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{ |
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void replay (hb_draw_funcs_t *pen, void *pen_data) |
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{ |
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hb_draw_state_t st = HB_DRAW_STATE_DEFAULT; |
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unsigned first = 0; |
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for (unsigned contour : contours) |
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{ |
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auto it = points.as_array ().sub_array (first, contour - first); |
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while (it) |
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{ |
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hb_contour_point_t p1 = *it++; |
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switch (p1.type) |
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{ |
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case hb_contour_point_t::type_t::MOVE_TO: |
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{ |
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pen->move_to (pen_data, st, |
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p1.x, p1.y); |
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} |
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break; |
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case hb_contour_point_t::type_t::LINE_TO: |
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{ |
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pen->line_to (pen_data, st, |
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p1.x, p1.y); |
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} |
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break; |
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case hb_contour_point_t::type_t::QUADRATIC_TO: |
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{ |
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hb_contour_point_t p2 = *it++; |
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pen->quadratic_to (pen_data, st, |
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p1.x, p1.y, |
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p2.x, p2.y); |
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} |
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break; |
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case hb_contour_point_t::type_t::CUBIC_TO: |
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{ |
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hb_contour_point_t p2 = *it++; |
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hb_contour_point_t p3 = *it++; |
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pen->cubic_to (pen_data, st, |
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p1.x, p1.y, |
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p2.x, p2.y, |
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p3.x, p3.y); |
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} |
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break; |
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} |
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} |
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pen->close_path (pen_data, st); |
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first = contour; |
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} |
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} |
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hb_vector_t<hb_contour_point_t> points; |
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hb_vector_t<unsigned> contours; |
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}; |
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template <typename context_t> |
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static void |
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hb_filter_outline_move_to (hb_draw_funcs_t *dfuncs HB_UNUSED, |
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void *data, |
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hb_draw_state_t *st, |
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float to_x, float to_y, |
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void *user_data HB_UNUSED) |
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{ |
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context_t *c = (context_t *) data; |
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c->points.push (hb_contour_point_t {to_x, to_y, hb_contour_point_t::type_t::MOVE_TO}); |
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} |
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template <typename context_t> |
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static void |
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hb_filter_outline_line_to (hb_draw_funcs_t *dfuncs HB_UNUSED, |
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void *data, |
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hb_draw_state_t *st, |
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float to_x, float to_y, |
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void *user_data HB_UNUSED) |
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{ |
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context_t *c = (context_t *) data; |
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c->points.push (hb_contour_point_t {to_x, to_y, hb_contour_point_t::type_t::LINE_TO}); |
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} |
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template <typename context_t> |
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static void |
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hb_filter_outline_quadratic_to (hb_draw_funcs_t *dfuncs HB_UNUSED, |
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void *data, |
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hb_draw_state_t *st, |
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float control_x, float control_y, |
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float to_x, float to_y, |
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void *user_data HB_UNUSED) |
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{ |
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context_t *c = (context_t *) data; |
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c->points.push (hb_contour_point_t {control_x, control_y, hb_contour_point_t::type_t::QUADRATIC_TO}); |
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c->points.push (hb_contour_point_t {to_x, to_y, hb_contour_point_t::type_t::QUADRATIC_TO}); |
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} |
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template <typename context_t> |
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static void |
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hb_filter_outline_cubic_to (hb_draw_funcs_t *dfuncs HB_UNUSED, |
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void *data, |
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hb_draw_state_t *st, |
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float control1_x, float control1_y, |
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float control2_x, float control2_y, |
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float to_x, float to_y, |
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void *user_data HB_UNUSED) |
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{ |
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context_t *c = (context_t *) data; |
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c->points.push (hb_contour_point_t {control1_x, control1_y, hb_contour_point_t::type_t::CUBIC_TO}); |
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c->points.push (hb_contour_point_t {control2_x, control2_y, hb_contour_point_t::type_t::CUBIC_TO}); |
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c->points.push (hb_contour_point_t {to_x, to_y, hb_contour_point_t::type_t::CUBIC_TO}); |
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} |
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template <typename context_t> |
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static void |
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hb_filter_outline_close_path (hb_draw_funcs_t *dfuncs HB_UNUSED, |
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void *data, |
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hb_draw_state_t *st, |
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void *user_data HB_UNUSED) |
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{ |
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context_t *c = (context_t *) data; |
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c->contours.push (c->points.length); |
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} |
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struct hb_draw_embolden_context_t : hb_filter_outline_t<hb_draw_embolden_context_t> |
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{ |
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void operator () (float x_strength, float y_strength) |
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{ |
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if (!x_strength && !y_strength) return; |
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if (!points) return; |
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x_strength /= 2.f; |
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y_strength /= 2.f; |
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bool orientation_negative = false; |
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struct vector_t |
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{ |
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float normalize_len () |
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{ |
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float len = hypotf (x, y); |
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if (len) |
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{ |
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x /= len; |
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y /= len; |
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} |
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return len; |
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} |
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float x, y; |
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}; |
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signed first = 0; |
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for (unsigned c = 0; c < contours.length; c++) |
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{ |
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vector_t in, out, anchor, shift; |
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float l_in, l_out, l_anchor = 0, l, q, d; |
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l_in = 0; |
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signed last = (int) contours[c] - 1; |
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/* pacify compiler */ |
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in.x = in.y = anchor.x = anchor.y = 0; |
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/* Counter j cycles though the points; counter i advances only */ |
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/* when points are moved; anchor k marks the first moved point. */ |
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for ( signed i = last, j = first, k = -1; |
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j != i && i != k; |
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j = j < last ? j + 1 : first ) |
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{ |
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if ( j != k ) |
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{ |
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out.x = points[j].x - points[i].x; |
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out.y = points[j].y - points[i].y; |
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l_out = out.normalize_len (); |
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if ( l_out == 0 ) |
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continue; |
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} |
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else |
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{ |
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out = anchor; |
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l_out = l_anchor; |
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} |
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if ( l_in != 0 ) |
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{ |
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if ( k < 0 ) |
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{ |
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k = i; |
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anchor = in; |
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l_anchor = l_in; |
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} |
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d = in.x * out.x + in.y * out.y; |
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/* shift only if turn is less than ~160 degrees */ |
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if ( d > -15.f/16.f ) |
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{ |
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d = d + 1.f; |
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/* shift components along lateral bisector in proper orientation */ |
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shift.x = in.y + out.y; |
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shift.y = in.x + out.x; |
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if ( orientation_negative ) |
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shift.x = -shift.x; |
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else |
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shift.y = -shift.y; |
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/* restrict shift magnitude to better handle collapsing segments */ |
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q = out.x * in.y - out.y * in.x; |
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if ( orientation_negative ) |
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q = -q; |
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l = hb_min (l_in, l_out); |
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/* non-strict inequalities avoid divide-by-zero when q == l == 0 */ |
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if (x_strength * q <= l * d) |
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shift.x = shift.x * x_strength / d; |
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else |
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shift.x = shift.x * l / q; |
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if (y_strength * q <= l * d) |
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shift.y = shift.y * y_strength / d; |
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else |
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shift.y = shift.y * l / q; |
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} |
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else |
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shift.x = shift.y = 0; |
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for ( ; |
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i != j; |
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i = i < last ? i + 1 : first ) |
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{ |
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points[i].x += x_strength + shift.x; |
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points[i].y += y_strength + shift.y; |
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} |
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} |
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else |
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i = j; |
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in = out; |
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l_in = l_out; |
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} |
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first = last + 1; |
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} |
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} |
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hb_draw_funcs_t *pen; |
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void *pen_data; |
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float x_strength, y_strength; |
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}; |
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static inline void free_static_draw_embolden_funcs (); |
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static struct hb_draw_embolden_funcs_lazy_loader_t : hb_draw_funcs_lazy_loader_t<hb_draw_embolden_funcs_lazy_loader_t> |
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{ |
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static hb_draw_funcs_t *create () |
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{ |
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hb_draw_funcs_t *funcs = hb_draw_funcs_create (); |
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using t = hb_draw_embolden_context_t; |
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hb_draw_funcs_set_move_to_func (funcs, hb_filter_outline_move_to<t>, nullptr, nullptr); |
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hb_draw_funcs_set_line_to_func (funcs, hb_filter_outline_line_to<t>, nullptr, nullptr); |
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hb_draw_funcs_set_quadratic_to_func (funcs, hb_filter_outline_quadratic_to<t>, nullptr, nullptr); |
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hb_draw_funcs_set_cubic_to_func (funcs, hb_filter_outline_cubic_to<t>, nullptr, nullptr); |
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hb_draw_funcs_set_close_path_func (funcs, hb_filter_outline_close_path<t>, nullptr, nullptr); |
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hb_draw_funcs_make_immutable (funcs); |
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hb_atexit (free_static_draw_embolden_funcs); |
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return funcs; |
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} |
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} static_draw_embolden_funcs; |
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static inline |
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void free_static_draw_embolden_funcs () |
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{ |
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static_draw_embolden_funcs.free_instance (); |
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} |
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static hb_draw_funcs_t * |
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hb_draw_embolden_get_funcs () |
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{ |
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return static_draw_embolden_funcs.get_unconst (); |
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} |
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#endif /* HB_DRAW_EMBOLDEN_HH */ |
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