HarfBuzz text shaping engine http://harfbuzz.github.io/
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/*
* Copyright © 2011 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
*/
#include "view-cairo.hh"
void
view_cairo_t::init (const font_options_t *font_opts)
{
lines = g_array_new (FALSE, FALSE, sizeof (helper_cairo_line_t));
scale = double (font_size) / hb_face_get_upem (hb_font_get_face (font_opts->get_font ()));
}
void
view_cairo_t::consume_line (hb_buffer_t *buffer,
const char *text,
unsigned int text_len,
hb_bool_t utf8_clusters)
{
direction = hb_buffer_get_direction (buffer);
helper_cairo_line_t l;
helper_cairo_line_from_buffer (&l, buffer, text, text_len, scale, utf8_clusters);
g_array_append_val (lines, l);
}
void
view_cairo_t::finish (const font_options_t *font_opts)
{
render (font_opts);
for (unsigned int i = 0; i < lines->len; i++) {
helper_cairo_line_t &line = g_array_index (lines, helper_cairo_line_t, i);
line.finish ();
}
g_array_unref (lines);
}
void
view_cairo_t::get_surface_size (cairo_scaled_font_t *scaled_font,
double *w, double *h)
{
cairo_font_extents_t font_extents;
cairo_scaled_font_extents (scaled_font, &font_extents);
bool vertical = HB_DIRECTION_IS_VERTICAL (direction);
(vertical ? *w : *h) = (int) lines->len * (font_extents.height + line_space) - line_space;
(vertical ? *h : *w) = 0;
for (unsigned int i = 0; i < lines->len; i++) {
helper_cairo_line_t &line = g_array_index (lines, helper_cairo_line_t, i);
double x_advance, y_advance;
line.get_advance (&x_advance, &y_advance);
if (vertical)
*h = MAX (*h, y_advance);
else
*w = MAX (*w, x_advance);
}
*w += margin.l + margin.r;
*h += margin.t + margin.b;
}
void
view_cairo_t::render (const font_options_t *font_opts)
{
cairo_scaled_font_t *scaled_font = helper_cairo_create_scaled_font (font_opts, font_size);
double w, h;
get_surface_size (scaled_font, &w, &h);
cairo_t *cr = helper_cairo_create_context (w, h, this, this);
cairo_set_scaled_font (cr, scaled_font);
cairo_scaled_font_destroy (scaled_font);
draw (cr);
helper_cairo_destroy_context (cr);
}
void
view_cairo_t::draw (cairo_t *cr)
{
cairo_save (cr);
bool vertical = HB_DIRECTION_IS_VERTICAL (direction);
int v = vertical ? 1 : 0;
int h = vertical ? 0 : 1;
cairo_font_extents_t font_extents;
cairo_font_extents (cr, &font_extents);
cairo_translate (cr, margin.l, margin.t);
double descent;
if (vertical)
descent = font_extents.height * (lines->len + .5);
else
descent = font_extents.height - font_extents.ascent;
cairo_translate (cr, v * descent, h * -descent);
for (unsigned int i = 0; i < lines->len; i++)
{
helper_cairo_line_t &l = g_array_index (lines, helper_cairo_line_t, i);
if (i)
cairo_translate (cr, v * -line_space, h * line_space);
cairo_translate (cr, v * -font_extents.height, h * font_extents.height);
if (annotate) {
cairo_save (cr);
/* Draw actual glyph origins */
cairo_set_source_rgba (cr, 1., 0., 0., .5);
cairo_set_line_width (cr, 5);
cairo_set_line_cap (cr, CAIRO_LINE_CAP_ROUND);
for (unsigned i = 0; i < l.num_glyphs; i++) {
cairo_move_to (cr, l.glyphs[i].x, l.glyphs[i].y);
cairo_rel_line_to (cr, 0, 0);
}
cairo_stroke (cr);
cairo_restore (cr);
}
if (0 && cairo_surface_get_type (cairo_get_target (cr)) == CAIRO_SURFACE_TYPE_IMAGE) {
/* cairo_show_glyphs() doesn't support subpixel positioning */
cairo_glyph_path (cr, l.glyphs, l.num_glyphs);
cairo_fill (cr);
} else if (l.num_clusters)
cairo_show_text_glyphs (cr,
l.utf8, l.utf8_len,
l.glyphs, l.num_glyphs,
l.clusters, l.num_clusters,
l.cluster_flags);
else
cairo_show_glyphs (cr, l.glyphs, l.num_glyphs);
}
cairo_restore (cr);
}