HarfBuzz text shaping engine http://harfbuzz.github.io/
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/*
* Copyright © 2022 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.
*
* Google Author(s): Behdad Esfahbod
*/
#ifndef HELPER_CAIRO_USER_HH
#define HELPER_CAIRO_USER_HH
#include "font-options.hh"
#include <cairo.h>
#include <hb.h>
#include "hb-blob.hh"
static void
move_to (hb_draw_funcs_t *dfuncs,
cairo_t *cr,
hb_draw_state_t *st,
float to_x, float to_y,
void *)
{
cairo_move_to (cr,
(double) to_x, (double) to_y);
}
static void
line_to (hb_draw_funcs_t *dfuncs,
cairo_t *cr,
hb_draw_state_t *st,
float to_x, float to_y,
void *)
{
cairo_line_to (cr,
(double) to_x, (double) to_y);
}
static void
cubic_to (hb_draw_funcs_t *dfuncs,
cairo_t *cr,
hb_draw_state_t *st,
float control1_x, float control1_y,
float control2_x, float control2_y,
float to_x, float to_y,
void *)
{
cairo_curve_to (cr,
(double) control1_x, (double) control1_y,
(double) control2_x, (double) control2_y,
(double) to_x, (double) to_y);
}
static void
close_path (hb_draw_funcs_t *dfuncs,
cairo_t *cr,
hb_draw_state_t *st,
void *)
{
cairo_close_path (cr);
}
static hb_draw_funcs_t *
get_cairo_draw_funcs ()
{
static hb_draw_funcs_t *funcs;
if (!funcs)
{
funcs = hb_draw_funcs_create ();
hb_draw_funcs_set_move_to_func (funcs, (hb_draw_move_to_func_t) move_to, nullptr, nullptr);
hb_draw_funcs_set_line_to_func (funcs, (hb_draw_line_to_func_t) line_to, nullptr, nullptr);
hb_draw_funcs_set_cubic_to_func (funcs, (hb_draw_cubic_to_func_t) cubic_to, nullptr, nullptr);
hb_draw_funcs_set_close_path_func (funcs, (hb_draw_close_path_func_t) close_path, nullptr, nullptr);
}
return funcs;
}
static const cairo_user_data_key_t _hb_font_cairo_user_data_key = {0};
static cairo_status_t
render_glyph (cairo_scaled_font_t *scaled_font,
unsigned long glyph,
cairo_t *cr,
cairo_text_extents_t *extents)
{
hb_font_t *font = (hb_font_t *) (cairo_font_face_get_user_data (cairo_scaled_font_get_font_face (scaled_font),
&_hb_font_cairo_user_data_key));
hb_position_t x_scale, y_scale;
hb_font_get_scale (font, &x_scale, &y_scale);
cairo_scale (cr, +1./x_scale, -1./y_scale);
hb_font_get_glyph_shape (font, glyph, get_cairo_draw_funcs (), cr);
cairo_fill (cr);
return CAIRO_STATUS_SUCCESS;
}
#ifdef HAVE_CAIRO_USER_FONT_FACE_SET_RENDER_COLOR_GLYPH_FUNC
#ifdef CAIRO_HAS_PNG_FUNCTIONS
static inline cairo_status_t
_hb_bytes_read_func (hb_bytes_t *src,
char *data,
unsigned length)
{
if (unlikely (src->length < length))
return CAIRO_STATUS_READ_ERROR;
memcpy (data, src->arrayZ, length);
*src += length;
return CAIRO_STATUS_SUCCESS;
}
static cairo_status_t
render_color_glyph_png (cairo_scaled_font_t *scaled_font,
unsigned long glyph,
cairo_t *cr,
cairo_text_extents_t *extents)
{
hb_font_t *font = (hb_font_t *) (cairo_font_face_get_user_data (cairo_scaled_font_get_font_face (scaled_font),
&_hb_font_cairo_user_data_key));
hb_blob_t *blob = hb_ot_color_glyph_reference_png (font, glyph);
if (blob == hb_blob_get_empty ())
return CAIRO_STATUS_USER_FONT_NOT_IMPLEMENTED;
hb_position_t x_scale, y_scale;
hb_font_get_scale (font, &x_scale, &y_scale);
cairo_scale (cr, +1./x_scale, -1./y_scale);
/* Draw PNG. */
hb_bytes_t bytes = blob->as_bytes ();
cairo_surface_t *surface = cairo_image_surface_create_from_png_stream ((cairo_read_func_t) _hb_bytes_read_func,
std::addressof (bytes));
hb_blob_destroy (blob);
if (unlikely (cairo_surface_status (surface)) != CAIRO_STATUS_SUCCESS)
{
cairo_surface_destroy (surface);
return CAIRO_STATUS_USER_FONT_NOT_IMPLEMENTED;
}
int width = cairo_image_surface_get_width (surface);
int height = cairo_image_surface_get_width (surface);
hb_glyph_extents_t hb_extents;
if (unlikely (!hb_font_get_glyph_extents (font, glyph, &hb_extents)))
{
cairo_surface_destroy (surface);
return CAIRO_STATUS_USER_FONT_NOT_IMPLEMENTED;
}
cairo_pattern_t *pattern = cairo_pattern_create_for_surface (surface);
cairo_pattern_set_extend (pattern, CAIRO_EXTEND_PAD);
cairo_matrix_t matrix = {(double) width, 0, 0, (double) height, 0, 0};
cairo_pattern_set_matrix (pattern, &matrix);
cairo_translate (cr, hb_extents.x_bearing, hb_extents.y_bearing);
cairo_scale (cr, hb_extents.width, hb_extents.height);
cairo_set_source (cr, pattern);
cairo_rectangle (cr, 0, 0, 1, 1);
cairo_fill (cr);
cairo_pattern_destroy (pattern);
cairo_surface_destroy (surface);
return CAIRO_STATUS_SUCCESS;
}
#endif
static cairo_status_t
render_color_glyph_layers (cairo_scaled_font_t *scaled_font,
unsigned long glyph,
cairo_t *cr,
cairo_text_extents_t *extents)
{
hb_font_t *font = (hb_font_t *) (cairo_font_face_get_user_data (cairo_scaled_font_get_font_face (scaled_font),
&_hb_font_cairo_user_data_key));
hb_face_t *face = hb_font_get_face (font);
unsigned count = hb_ot_color_glyph_get_layers (face, glyph, 0, nullptr, nullptr);
if (!count)
return CAIRO_STATUS_USER_FONT_NOT_IMPLEMENTED;
hb_ot_color_layer_t layers[16];
unsigned offset = 0, len;
do {
len = ARRAY_LENGTH (layers);
hb_ot_color_glyph_get_layers (face, glyph,
offset,
&len,
layers);
for (unsigned i = 0; i < len; i++)
{
hb_color_t color;
unsigned clen = 1;
unsigned color_index = layers[i].color_index;
bool is_foreground = color_index == 65535;
if (!is_foreground)
{
hb_ot_color_palette_get_colors (face,
0/*palette_index*/,
color_index/*start_offset*/,
&clen/*color_count*/,
&color);
if (clen < 1)
continue;
}
cairo_save (cr);
{
if (!is_foreground)
cairo_set_source_rgba (cr,
hb_color_get_red (color) / 255.,
hb_color_get_green (color) / 255.,
hb_color_get_blue (color) / 255.,
hb_color_get_alpha (color) / 255.);
cairo_status_t ret = render_glyph (scaled_font, layers[i].glyph, cr, extents);
if (ret != CAIRO_STATUS_SUCCESS)
return ret;
}
cairo_restore (cr);
}
}
while (len == ARRAY_LENGTH (layers));
return CAIRO_STATUS_SUCCESS;
}
static cairo_status_t
render_color_glyph (cairo_scaled_font_t *scaled_font,
unsigned long glyph,
cairo_t *cr,
cairo_text_extents_t *extents)
{
cairo_status_t ret = CAIRO_STATUS_USER_FONT_NOT_IMPLEMENTED;
#ifdef CAIRO_HAS_PNG_FUNCTIONS
ret = render_color_glyph_png (scaled_font, glyph, cr, extents);
if (ret != CAIRO_STATUS_USER_FONT_NOT_IMPLEMENTED)
return ret;
#endif
ret = render_color_glyph_layers (scaled_font, glyph, cr, extents);
if (ret != CAIRO_STATUS_USER_FONT_NOT_IMPLEMENTED)
return ret;
return render_glyph (scaled_font, glyph, cr, extents);
}
#endif
static inline cairo_font_face_t *
helper_cairo_create_user_font_face (const font_options_t *font_opts)
{
cairo_font_face_t *cairo_face = cairo_user_font_face_create ();
cairo_font_face_set_user_data (cairo_face,
&_hb_font_cairo_user_data_key,
hb_font_reference (font_opts->font),
(cairo_destroy_func_t) hb_font_destroy);
cairo_user_font_face_set_render_glyph_func (cairo_face, render_glyph);
#ifdef HAVE_CAIRO_USER_FONT_FACE_SET_RENDER_COLOR_GLYPH_FUNC
hb_face_t *face = hb_font_get_face (font_opts->font);
if (hb_ot_color_has_png (face) || hb_ot_color_has_layers (face))
cairo_user_font_face_set_render_color_glyph_func (cairo_face, render_color_glyph);
#endif
return cairo_face;
}
static inline bool
helper_cairo_user_font_face_has_data (cairo_font_face_t *font_face)
{
return cairo_font_face_get_user_data (font_face, &_hb_font_cairo_user_data_key);
}
static inline bool
helper_cairo_user_scaled_font_has_color (cairo_scaled_font_t *scaled_font)
{
/* Ignoring SVG for now, since we cannot render it. */
hb_font_t *font = (hb_font_t *) (cairo_font_face_get_user_data (cairo_scaled_font_get_font_face (scaled_font),
&_hb_font_cairo_user_data_key));
hb_face_t *face = hb_font_get_face (font);
return hb_ot_color_has_png (face) || hb_ot_color_has_layers (face);
}
#endif