third-party/glyphy/glyphy.h

   1 /*
   2  * Copyright 2012 Google, Inc. All Rights Reserved.
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at
   7  *
   8  *     http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  *
  16  * Google Author(s): Behdad Esfahbod, Maysum Panju
  17  */
  18
  19 #ifndef GLYPHY_H
  20 #define GLYPHY_H
  21
  22 #include <dali/devel-api/text-abstraction/text-abstraction-definitions.h>
  23
  24 #ifdef __cplusplus
  25 extern "C" {
  26 #endif
  27
  28 typedef int glyphy_bool_t;
  29
  30 typedef struct {
  31   double x;
  32   double y;
  33 } glyphy_point_t;
  34
  35 /*
  36  * Geometry extents
  37  */
  38
  39 typedef struct {
  40   double min_x;
  41   double min_y;
  42   double max_x;
  43   double max_y;
  44 } glyphy_extents_t;
  45
  46 void
  47 glyphy_extents_clear (glyphy_extents_t *extents);
  48
  49 glyphy_bool_t
  50 glyphy_extents_is_empty (const glyphy_extents_t *extents);
  51
  52 void
  53 glyphy_extents_add (glyphy_extents_t     *extents,
  54                     const glyphy_point_t *p);
  55
  56 void
  57 glyphy_extents_extend (glyphy_extents_t       *extents,
  58                        const glyphy_extents_t *other);
  59
  60 glyphy_bool_t
  61 glyphy_extents_includes (const glyphy_extents_t *extents,
  62                          const glyphy_point_t   *p);
  63
  64 void
  65 glyphy_extents_scale (glyphy_extents_t *extents,
  66                       double            x_scale,
  67                       double            y_scale);
  68
  69 /*
  70  * Circular arcs
  71  */
  72
  73 typedef struct {
  74   glyphy_point_t p0;
  75   glyphy_point_t p1;
  76   double d;
  77 } glyphy_arc_t;
  78
  79 /*
  80  * Approximate outlines with multiple arcs
  81  */
  82
  83 typedef struct {
  84   glyphy_point_t p;
  85   double d;
  86 } glyphy_arc_endpoint_t;
  87
  88 typedef glyphy_bool_t (*glyphy_arc_endpoint_accumulator_callback_t) (glyphy_arc_endpoint_t *endpoint,
  89                                                                      void                  *user_data);
  90
  91 typedef struct glyphy_arc_accumulator_t glyphy_arc_accumulator_t;
  92
  93 glyphy_arc_accumulator_t *
  94 glyphy_arc_accumulator_create (void);
  95
  96 void
  97 glyphy_arc_accumulator_destroy (glyphy_arc_accumulator_t *acc);
  98
  99 void
 100 glyphy_arc_accumulator_reset (glyphy_arc_accumulator_t *acc);
 101
 102 /* Configure accumulator */
 103
 104 void
 105 glyphy_arc_accumulator_set_tolerance (glyphy_arc_accumulator_t *acc,
 106                                       double                    tolerance);
 107
 108 double
 109 glyphy_arc_accumulator_get_tolerance (glyphy_arc_accumulator_t *acc);
 110
 111 void
 112 glyphy_arc_accumulator_set_callback (glyphy_arc_accumulator_t *acc,
 113                                      glyphy_arc_endpoint_accumulator_callback_t callback,
 114                                      void                     *user_data);
 115
 116 void
 117 glyphy_arc_accumulator_get_callback (glyphy_arc_accumulator_t  *acc,
 118                                      glyphy_arc_endpoint_accumulator_callback_t *callback,
 119                                      void                     **user_data);
 120
 121 /* Accumulation results */
 122
 123 double
 124 glyphy_arc_accumulator_get_error (glyphy_arc_accumulator_t *acc);
 125
 126 glyphy_bool_t
 127 glyphy_arc_accumulator_successful (glyphy_arc_accumulator_t *acc);
 128
 129
 130 /* Accumulate */
 131
 132 void
 133 glyphy_arc_accumulator_move_to (glyphy_arc_accumulator_t *acc,
 134                                 const glyphy_point_t *p0);
 135
 136 void
 137 glyphy_arc_accumulator_line_to (glyphy_arc_accumulator_t *acc,
 138                                 const glyphy_point_t *p1);
 139
 140 void
 141 glyphy_arc_accumulator_conic_to (glyphy_arc_accumulator_t *acc,
 142                                  const glyphy_point_t *p1,
 143                                  const glyphy_point_t *p2);
 144
 145 void
 146 glyphy_arc_accumulator_cubic_to (glyphy_arc_accumulator_t *acc,
 147                                  const glyphy_point_t *p1,
 148                                  const glyphy_point_t *p2,
 149                                  const glyphy_point_t *p3);
 150
 151 void
 152 glyphy_arc_accumulator_arc_to (glyphy_arc_accumulator_t *acc,
 153                                const glyphy_point_t *p1,
 154                                double                d);
 155
 156 void
 157 glyphy_arc_accumulator_close_path (glyphy_arc_accumulator_t *acc);
 158
 159 void
 160 glyphy_arc_list_extents (const glyphy_arc_endpoint_t *endpoints,
 161                          unsigned int                 num_endpoints,
 162                          glyphy_extents_t            *extents);
 163
 164 /*
 165  * Modify outlines for proper consumption
 166  */
 167
 168 void
 169 glyphy_outline_reverse (glyphy_arc_endpoint_t *endpoints,
 170                         unsigned int           num_endpoints);
 171
 172 /* Returns true if outline was modified */
 173 glyphy_bool_t
 174 glyphy_outline_winding_from_even_odd (glyphy_arc_endpoint_t *endpoints,
 175                                       unsigned int           num_endpoints,
 176                                       glyphy_bool_t          inverse);
 177
 178 /*
 179  * Encode an arc outline into binary blob for fast SDF calculation
 180  */
 181
 182 typedef Dali::TextAbstraction::VectorBlob glyphy_rgba_t;
 183
 184 glyphy_bool_t
 185 glyphy_arc_list_encode_blob (const glyphy_arc_endpoint_t *endpoints,
 186                              unsigned int                 num_endpoints,
 187                              glyphy_rgba_t               *blob,
 188                              unsigned int                 blob_size,
 189                              double                       faraway,
 190                              double                       avg_fetch_desired,
 191                              double                      *avg_fetch_achieved,
 192                              unsigned int                *output_len,
 193                              unsigned int                *nominal_width,  /* 6bit */
 194                              unsigned int                *nominal_height, /* 6bit */
 195                              glyphy_extents_t            *extents);
 196
 197 /*
 198  * Calculate signed-distance-field from (encoded) arc list
 199  */
 200
 201 double
 202 glyphy_sdf_from_arc_list (const glyphy_arc_endpoint_t *endpoints,
 203                           unsigned int                 num_endpoints,
 204                           const glyphy_point_t        *p,
 205                           glyphy_point_t              *closest_p /* may be NULL; TBD not implemented yet */);
 206
 207 double
 208 glyphy_sdf_from_blob (const glyphy_rgba_t  *blob,
 209                       unsigned int          nominal_width,
 210                       unsigned int          nominal_height,
 211                       const glyphy_point_t *p,
 212                       glyphy_point_t       *closest_p /* may be NULL; TBD not implemented yet */);
 213
 214 #ifdef __cplusplus
 215 }
 216 #endif
 217
 218 #endif /* GLYPHY_H */