/* * Copyright 2012 Google, Inc. All Rights Reserved. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. * * Google Author(s): Behdad Esfahbod, Maysum Panju */ #ifndef GLYPHY_H #define GLYPHY_H #ifdef __cplusplus extern "C" { #endif #define GLYPHY_PASTE_ARGS(prefix, name) prefix ## name #define GLYPHY_PASTE(prefix, name) GLYPHY_PASTE_ARGS (prefix, name) typedef int glyphy_bool_t; typedef struct { double x; double y; } glyphy_point_t; /* * Geometry extents */ typedef struct { double min_x; double min_y; double max_x; double max_y; } glyphy_extents_t; void glyphy_extents_clear (glyphy_extents_t *extents); glyphy_bool_t glyphy_extents_is_empty (const glyphy_extents_t *extents); void glyphy_extents_add (glyphy_extents_t *extents, const glyphy_point_t *p); void glyphy_extents_extend (glyphy_extents_t *extents, const glyphy_extents_t *other); glyphy_bool_t glyphy_extents_includes (const glyphy_extents_t *extents, const glyphy_point_t *p); void glyphy_extents_scale (glyphy_extents_t *extents, double x_scale, double y_scale); /* * Circular arcs */ typedef struct { glyphy_point_t p0; glyphy_point_t p1; double d; } glyphy_arc_t; /* Build from a conventional arc representation */ void glyphy_arc_from_conventional (const glyphy_point_t *center, double radius, double angle0, double angle1, glyphy_bool_t negative, glyphy_arc_t *arc); /* Convert to a conventional arc representation */ void glyphy_arc_to_conventional (glyphy_arc_t arc, glyphy_point_t *center /* may be NULL */, double *radius /* may be NULL */, double *angle0 /* may be NULL */, double *angle1 /* may be NULL */, glyphy_bool_t *negative /* may be NULL */); glyphy_bool_t glyphy_arc_is_a_line (glyphy_arc_t arc); void glyphy_arc_extents (glyphy_arc_t arc, glyphy_extents_t *extents); /* * Approximate single pieces of geometry to/from one arc */ void glyphy_arc_from_line (const glyphy_point_t *p0, const glyphy_point_t *p1, glyphy_arc_t *arc); void glyphy_arc_from_conic (const glyphy_point_t *p0, const glyphy_point_t *p1, const glyphy_point_t *p2, glyphy_arc_t *arc, double *error); void glyphy_arc_from_cubic (const glyphy_point_t *p0, const glyphy_point_t *p1, const glyphy_point_t *p2, const glyphy_point_t *p3, glyphy_arc_t *arc, double *error); void glyphy_arc_to_cubic (const glyphy_arc_t *arc, glyphy_point_t *p0, glyphy_point_t *p1, glyphy_point_t *p2, glyphy_point_t *p3, double *error); /* * Approximate outlines with multiple arcs */ typedef struct { glyphy_point_t p; double d; } glyphy_arc_endpoint_t; typedef glyphy_bool_t (*glyphy_arc_endpoint_accumulator_callback_t) (glyphy_arc_endpoint_t *endpoint, void *user_data); typedef struct glyphy_arc_accumulator_t glyphy_arc_accumulator_t; glyphy_arc_accumulator_t * glyphy_arc_accumulator_create (void); void glyphy_arc_accumulator_destroy (glyphy_arc_accumulator_t *acc); glyphy_arc_accumulator_t * glyphy_arc_accumulator_reference (glyphy_arc_accumulator_t *acc); void glyphy_arc_accumulator_reset (glyphy_arc_accumulator_t *acc); /* Configure accumulator */ void glyphy_arc_accumulator_set_tolerance (glyphy_arc_accumulator_t *acc, double tolerance); double glyphy_arc_accumulator_get_tolerance (glyphy_arc_accumulator_t *acc); void glyphy_arc_accumulator_set_callback (glyphy_arc_accumulator_t *acc, glyphy_arc_endpoint_accumulator_callback_t callback, void *user_data); void glyphy_arc_accumulator_get_callback (glyphy_arc_accumulator_t *acc, glyphy_arc_endpoint_accumulator_callback_t *callback, void **user_data); void glyphy_arc_accumulator_set_d_metrics (glyphy_arc_accumulator_t *acc, double max_d, double d_bits); void glyphy_arc_accumulator_get_d_metrics (glyphy_arc_accumulator_t *acc, double *max_d, double *d_bits); /* Accumulation results */ unsigned int glyphy_arc_accumulator_get_num_endpoints (glyphy_arc_accumulator_t *acc); double glyphy_arc_accumulator_get_error (glyphy_arc_accumulator_t *acc); glyphy_bool_t glyphy_arc_accumulator_successful (glyphy_arc_accumulator_t *acc); /* Accumulate */ void glyphy_arc_accumulator_move_to (glyphy_arc_accumulator_t *acc, const glyphy_point_t *p0); void glyphy_arc_accumulator_line_to (glyphy_arc_accumulator_t *acc, const glyphy_point_t *p1); void glyphy_arc_accumulator_conic_to (glyphy_arc_accumulator_t *acc, const glyphy_point_t *p1, const glyphy_point_t *p2); void glyphy_arc_accumulator_cubic_to (glyphy_arc_accumulator_t *acc, const glyphy_point_t *p1, const glyphy_point_t *p2, const glyphy_point_t *p3); void glyphy_arc_accumulator_arc_to (glyphy_arc_accumulator_t *acc, const glyphy_point_t *p1, double d); void glyphy_arc_accumulator_close_path (glyphy_arc_accumulator_t *acc); void glyphy_arc_list_extents (const glyphy_arc_endpoint_t *endpoints, unsigned int num_endpoints, glyphy_extents_t *extents); /* * Modify outlines for proper consumption */ void glyphy_outline_reverse (glyphy_arc_endpoint_t *endpoints, unsigned int num_endpoints); /* Returns true if outline was modified */ glyphy_bool_t glyphy_outline_winding_from_even_odd (glyphy_arc_endpoint_t *endpoints, unsigned int num_endpoints, glyphy_bool_t inverse); /* * Encode an arc outline into binary blob for fast SDF calculation */ typedef struct { unsigned char r; unsigned char g; unsigned char b; unsigned char a; } glyphy_rgba_t; /* TODO make this callback-based also? */ /* TODO rename to glyphy_blob_encode? */ glyphy_bool_t glyphy_arc_list_encode_blob (const glyphy_arc_endpoint_t *endpoints, unsigned int num_endpoints, glyphy_rgba_t *blob, unsigned int blob_size, double faraway, double avg_fetch_desired, double *avg_fetch_achieved, unsigned int *output_len, unsigned int *nominal_width, /* 6bit */ unsigned int *nominal_height, /* 6bit */ glyphy_extents_t *extents); /* TBD _decode_blob */ /* * Calculate signed-distance-field from (encoded) arc list */ double glyphy_sdf_from_arc_list (const glyphy_arc_endpoint_t *endpoints, unsigned int num_endpoints, const glyphy_point_t *p, glyphy_point_t *closest_p /* may be NULL; TBD not implemented yet */); /* TBD */ double glyphy_sdf_from_blob (const glyphy_rgba_t *blob, unsigned int nominal_width, unsigned int nominal_height, const glyphy_point_t *p, glyphy_point_t *closest_p /* may be NULL; TBD not implemented yet */); /* * Shader source code */ /* TODO make this enum-based? */ const char * glyphy_common_shader_source (void); const char * glyphy_common_shader_source_path (void); const char * glyphy_sdf_shader_source (void); const char * glyphy_sdf_shader_source_path (void); #ifdef __cplusplus } #endif #endif /* GLYPHY_H */