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harfbuzz/util/view-cairo.cc

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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"
#ifdef CAIRO_HAS_SVG_SURFACE
# include <cairo-svg.h>
#endif
#ifdef CAIRO_HAS_PDF_SURFACE
# include <cairo-pdf.h>
#endif
#ifdef CAIRO_HAS_PS_SURFACE
# include <cairo-ps.h>
# if CAIRO_VERSION >= CAIRO_VERSION_ENCODE(1,6,0)
# define HAS_EPS 1
static cairo_surface_t *
_cairo_eps_surface_create_for_stream (cairo_write_func_t write_func,
void *closure,
double width,
double height)
{
cairo_surface_t *surface;
surface = cairo_ps_surface_create_for_stream (write_func, closure, width, height);
cairo_ps_surface_set_eps (surface, TRUE);
return surface;
}
# else
# undef HAS_EPS
# endif
#endif
struct line_t {
cairo_glyph_t *glyphs;
unsigned int num_glyphs;
char *utf8;
unsigned int utf8_len;
cairo_text_cluster_t *clusters;
unsigned int num_clusters;
cairo_text_cluster_flags_t cluster_flags;
void finish (void) {
if (glyphs)
cairo_glyph_free (glyphs);
if (clusters)
cairo_text_cluster_free (clusters);
if (utf8)
g_free (utf8);
}
};
void
view_cairo_t::init (const font_options_t *font_opts)
{
lines = g_array_new (FALSE, FALSE, sizeof (line_t));
upem = 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)
{
line_t l = {0};
l.num_glyphs = hb_buffer_get_length (buffer);
hb_glyph_info_t *hb_glyph = hb_buffer_get_glyph_infos (buffer, NULL);
hb_glyph_position_t *hb_position = hb_buffer_get_glyph_positions (buffer, NULL);
l.glyphs = cairo_glyph_allocate (l.num_glyphs + 1);
l.utf8 = g_strndup (text, text_len);
l.utf8_len = text_len;
l.num_clusters = 1;
for (unsigned int i = 1; i < l.num_glyphs; i++)
if (hb_glyph[i].cluster != hb_glyph[i-1].cluster)
l.num_clusters++;
l.clusters = cairo_text_cluster_allocate (l.num_clusters);
if ((l.num_glyphs && !l.glyphs) ||
(l.utf8_len && !l.utf8) ||
(l.num_clusters && !l.clusters))
{
l.finish ();
return;
}
hb_position_t x = 0, y = 0;
int i;
for (i = 0; i < (int) l.num_glyphs; i++)
{
l.glyphs[i].index = hb_glyph[i].codepoint;
l.glyphs[i].x = ( hb_position->x_offset + x) / double (upem);
l.glyphs[i].y = (-hb_position->y_offset + y) / double (upem);
x += hb_position->x_advance;
y += -hb_position->y_advance;
hb_position++;
}
l.glyphs[i].index = 0;
l.glyphs[i].x = x;
l.glyphs[i].y = y;
memset ((void *) l.clusters, 0, l.num_clusters * sizeof (l.clusters[0]));
bool backward = HB_DIRECTION_IS_BACKWARD (hb_buffer_get_direction (buffer));
l.cluster_flags = backward ? CAIRO_TEXT_CLUSTER_FLAG_BACKWARD : (cairo_text_cluster_flags_t) 0;
g_assert (l.num_glyphs);
unsigned int cluster = 0;
l.clusters[cluster].num_glyphs++;
if (backward) {
for (i = l.num_glyphs - 2; i >= 0; i--) {
if (hb_glyph[i].cluster != hb_glyph[i+1].cluster) {
g_assert (hb_glyph[i].cluster > hb_glyph[i+1].cluster);
l.clusters[cluster].num_bytes += hb_glyph[i].cluster - hb_glyph[i+1].cluster;
cluster++;
}
l.clusters[cluster].num_glyphs++;
}
l.clusters[cluster].num_bytes += text_len - hb_glyph[0].cluster;
} else {
for (i = 1; i < (int) l.num_glyphs; i++) {
if (hb_glyph[i].cluster != hb_glyph[i-1].cluster) {
g_assert (hb_glyph[i].cluster > hb_glyph[i-1].cluster);
l.clusters[cluster].num_bytes += hb_glyph[i].cluster - hb_glyph[i-1].cluster;
cluster++;
}
l.clusters[cluster].num_glyphs++;
}
l.clusters[cluster].num_bytes += text_len - hb_glyph[i - 1].cluster;
}
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++) {
line_t &line = g_array_index (lines, line_t, i);
line.finish ();
}
g_array_unref (lines);
}
double
view_cairo_t::line_width (unsigned int i)
{
line_t &line = g_array_index (lines, line_t, i);
return line.glyphs[line.num_glyphs].x / double (upem);
}
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);
*h = font_extents.ascent + font_extents.descent + ((int) lines->len - 1) * font_extents.height;
*w = 0;
for (unsigned int i = 0; i < lines->len; i++)
*w = MAX (*w, line_width (i));
*w += margin.l + margin.r;
*h += margin.t + margin.b;
}
cairo_scaled_font_t *
view_cairo_t::create_scaled_font (const font_options_t *font_opts)
{
hb_font_t *font = hb_font_reference (font_opts->get_font ());
cairo_font_face_t *cairo_face = cairo_ft_font_face_create_for_ft_face (hb_ft_font_get_face (font), 0);
cairo_matrix_t ctm, font_matrix;
cairo_font_options_t *font_options;
cairo_matrix_init_identity (&ctm);
cairo_matrix_init_scale (&font_matrix, font_opts->font_size, font_opts->font_size);
font_options = cairo_font_options_create ();
cairo_font_options_set_hint_style (font_options, CAIRO_HINT_STYLE_NONE);
cairo_font_options_set_hint_metrics (font_options, CAIRO_HINT_METRICS_OFF);
cairo_scaled_font_t *scaled_font = cairo_scaled_font_create (cairo_face, &font_matrix, &ctm, font_options);
cairo_font_options_destroy (font_options);
cairo_font_face_destroy (cairo_face);
static cairo_user_data_key_t key;
if (cairo_scaled_font_set_user_data (scaled_font, &key, (void *) font, (cairo_destroy_func_t) hb_font_destroy))
hb_font_destroy (font);
return scaled_font;
}
struct finalize_closure_t {
void (*callback)(finalize_closure_t *);
cairo_surface_t *surface;
cairo_write_func_t write_func;
void *closure;
};
static cairo_user_data_key_t finalize_closure_key;
#ifdef CAIRO_HAS_PNG_FUNCTIONS
static void
finalize_png (finalize_closure_t *closure)
{
cairo_status_t status;
status = cairo_surface_write_to_png_stream (closure->surface,
closure->write_func,
closure->closure);
if (status != CAIRO_STATUS_SUCCESS)
fail (FALSE, "Failed to write output: %s",
cairo_status_to_string (status));
}
static cairo_surface_t *
_cairo_png_surface_create_for_stream (cairo_write_func_t write_func,
void *closure,
double width,
double height,
cairo_content_t content)
{
cairo_surface_t *surface;
int w = ceil (width);
int h = ceil (height);
switch (content) {
case CAIRO_CONTENT_ALPHA:
surface = cairo_image_surface_create (CAIRO_FORMAT_A8, w, h);
break;
default:
case CAIRO_CONTENT_COLOR:
surface = cairo_image_surface_create (CAIRO_FORMAT_RGB24, w, h);
break;
case CAIRO_CONTENT_COLOR_ALPHA:
surface = cairo_image_surface_create (CAIRO_FORMAT_ARGB32, w, h);
break;
}
cairo_status_t status = cairo_surface_status (surface);
if (status != CAIRO_STATUS_SUCCESS)
fail (FALSE, "Failed to create cairo surface: %s",
cairo_status_to_string (status));
finalize_closure_t *png_closure = g_new0 (finalize_closure_t, 1);
png_closure->callback = finalize_png;
png_closure->surface = surface;
png_closure->write_func = write_func;
png_closure->closure = closure;
if (cairo_surface_set_user_data (surface, &finalize_closure_key, (void *) png_closure, (cairo_destroy_func_t) g_free))
g_free ((void *) closure);
return surface;
}
#endif
void
view_cairo_t::render (const font_options_t *font_opts)
{
cairo_scaled_font_t *scaled_font = create_scaled_font (font_opts);
double w, h;
get_surface_size (scaled_font, &w, &h);
cairo_t *cr = create_context (w, h);
cairo_set_scaled_font (cr, scaled_font);
cairo_scaled_font_destroy (scaled_font);
draw (cr);
finalize_closure_t *closure = (finalize_closure_t *)
cairo_surface_get_user_data (cairo_get_target (cr),
&finalize_closure_key);
if (closure)
closure->callback (closure);
cairo_status_t status = cairo_status (cr);
if (status != CAIRO_STATUS_SUCCESS)
fail (FALSE, "Failed: %s",
cairo_status_to_string (status));
cairo_destroy (cr);
}
static cairo_status_t
stdio_write_func (void *closure,
const unsigned char *data,
unsigned int size)
{
FILE *fp = (FILE *) closure;
while (size) {
size_t ret = fwrite (data, 1, size, fp);
size -= ret;
data += ret;
if (size && ferror (fp))
fail (FALSE, "Failed to write output: %s", strerror (errno));
}
return CAIRO_STATUS_SUCCESS;
}
cairo_t *
view_cairo_t::create_context (double w, double h)
{
cairo_surface_t *(*constructor) (cairo_write_func_t write_func,
void *closure,
double width,
double height) = NULL;
cairo_surface_t *(*constructor2) (cairo_write_func_t write_func,
void *closure,
double width,
double height,
cairo_content_t content) = NULL;
const char *extension = output_format;
if (!extension)
extension = "png";
if (0)
;
#ifdef CAIRO_HAS_PNG_FUNCTIONS
else if (0 == strcasecmp (extension, "png"))
constructor2 = _cairo_png_surface_create_for_stream;
#endif
#ifdef CAIRO_HAS_SVG_SURFACE
else if (0 == strcasecmp (extension, "svg"))
constructor = cairo_svg_surface_create_for_stream;
#endif
#ifdef CAIRO_HAS_PDF_SURFACE
else if (0 == strcasecmp (extension, "pdf"))
constructor = cairo_pdf_surface_create_for_stream;
#endif
#ifdef CAIRO_HAS_PS_SURFACE
else if (0 == strcasecmp (extension, "ps"))
constructor = cairo_ps_surface_create_for_stream;
#ifdef HAS_EPS
else if (0 == strcasecmp (extension, "eps"))
constructor = _cairo_eps_surface_create_for_stream;
#endif
#endif
unsigned int fr, fg, fb, fa, br, bg, bb, ba;
br = bg = bb = ba = 255;
sscanf (back + (*back=='#'), "%2x%2x%2x%2x", &br, &bg, &bb, &ba);
fr = fg = fb = 0; fa = 255;
sscanf (fore + (*fore=='#'), "%2x%2x%2x%2x", &fr, &fg, &fb, &fa);
cairo_content_t content;
if (!annotate && ba == 255 && br == bg && bg == bb && fr == fg && fg == fb)
content = CAIRO_CONTENT_ALPHA;
else if (ba == 255)
content = CAIRO_CONTENT_COLOR;
else
content = CAIRO_CONTENT_COLOR_ALPHA;
cairo_surface_t *surface;
FILE *f = get_file_handle ();
if (constructor)
surface = constructor (stdio_write_func, f, w, h);
else if (constructor2)
surface = constructor2 (stdio_write_func, f, w, h, content);
else
fail (FALSE, "Unknown output format `%s'", extension);
cairo_t *cr = cairo_create (surface);
content = cairo_surface_get_content (surface);
switch (content) {
case CAIRO_CONTENT_ALPHA:
cairo_set_operator (cr, CAIRO_OPERATOR_SOURCE);
cairo_set_source_rgba (cr, 1., 1., 1., br / 255.);
cairo_paint (cr);
cairo_set_source_rgba (cr, 1., 1., 1., (fr / 255.) * (fa / 255.) + (br / 255) * (1 - (fa / 255.)));
break;
default:
case CAIRO_CONTENT_COLOR:
case CAIRO_CONTENT_COLOR_ALPHA:
cairo_set_operator (cr, CAIRO_OPERATOR_SOURCE);
cairo_set_source_rgba (cr, br / 255., bg / 255., bb / 255., ba / 255.);
cairo_paint (cr);
cairo_set_operator (cr, CAIRO_OPERATOR_OVER);
cairo_set_source_rgba (cr, fr / 255., fg / 255., fb / 255., fa / 255.);
break;
}
cairo_surface_destroy (surface);
return cr;
}
void
view_cairo_t::draw (cairo_t *cr)
{
cairo_save (cr);
cairo_font_extents_t font_extents;
cairo_font_extents (cr, &font_extents);
cairo_translate (cr, margin.l, margin.t);
for (unsigned int i = 0; i < lines->len; i++)
{
line_t &l = g_array_index (lines, line_t, i);
if (i)
cairo_translate (cr, 0, line_space);
cairo_translate (cr, 0, font_extents.ascent);
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 (cairo_surface_get_type (cairo_get_target (cr)) == CAIRO_SURFACE_TYPE_IMAGE) {
/* cairo_show_glyphs() doesn't support subpixel positioining */
cairo_glyph_path (cr, l.glyphs, l.num_glyphs);
cairo_fill (cr);
} else
cairo_show_text_glyphs (cr,
l.utf8, l.utf8_len,
l.glyphs, l.num_glyphs,
l.clusters, l.num_clusters,
l.cluster_flags);
cairo_translate (cr, 0, font_extents.height - font_extents.ascent);
}
cairo_restore (cr);
}
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