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#include <cairo/cairo.h>
#include <harfbuzz/hb-ft.h>
#include <math.h>
#include "harfbuzz.h"
#include "../entry.h"
#include "../log.h"
#include "../nelem.h"
#include "../xmalloc.h"
/*
* FreeType is normally compiled without error strings, so we have to do this
* funky macro trick to get them. See <freetype/fterrors.h> for more details.
*/
#undef FTERRORS_H_
#define FT_ERRORDEF( e, v, s ) { e, s },
#define FT_ERROR_START_LIST {
#define FT_ERROR_END_LIST { 0, NULL } };
const struct {
int err_code;
const char *err_msg;
} ft_errors[] =
#include <freetype/fterrors.h>
static const char *get_ft_error_string(int err_code)
{
for (size_t i = 0; i < N_ELEM(ft_errors); i++) {
if (ft_errors[i].err_code == err_code) {
return ft_errors[i].err_msg;
}
}
return "Unknown FT error";
}
/*
* Cairo / FreeType use 72 Pts per inch, but Pango uses 96 DPI, so we have to
* rescale for consistency.
*/
#define PT_TO_DPI (96.0 / 72.0)
/*
* hb_buffer_clear_contents also clears some basic script information, so group
* them here for convenience.
*/
static void setup_hb_buffer(hb_buffer_t *buffer)
{
hb_buffer_set_direction(buffer, HB_DIRECTION_LTR);
hb_buffer_set_script(buffer, HB_SCRIPT_LATIN);
hb_buffer_set_language(buffer, hb_language_from_string("en", -1));
}
/*
* Render a hb_buffer with Cairo, and return the width of the rendered area in
* Cairo units.
*/
static uint32_t render_hb_buffer(cairo_t *cr, hb_buffer_t *buffer)
{
cairo_save(cr);
/*
* Cairo uses y-down coordinates, but HarfBuzz uses y-up, so we
* shift the text down by its ascent height to compensate.
*/
cairo_font_extents_t font_extents;
cairo_font_extents(cr, &font_extents);
cairo_translate(cr, 0, font_extents.ascent);
unsigned int glyph_count;
hb_glyph_info_t *glyph_info = hb_buffer_get_glyph_infos(buffer, &glyph_count);
hb_glyph_position_t *glyph_pos = hb_buffer_get_glyph_positions(buffer, &glyph_count);
cairo_glyph_t *cairo_glyphs = xmalloc(sizeof(cairo_glyph_t) * glyph_count);
double x = 0;
double y = 0;
for (unsigned int i=0; i < glyph_count; i++) {
/*
* The coordinates returned by HarfBuzz are in 26.6 fixed-point
* format, so we divide by 64.0 (2^6) to get floats.
*/
cairo_glyphs[i].index = glyph_info[i].codepoint;
cairo_glyphs[i].x = x + glyph_pos[i].x_offset / 64.0;
cairo_glyphs[i].y = y - glyph_pos[i].y_offset / 64.0;
x += glyph_pos[i].x_advance / 64.0;
y -= glyph_pos[i].y_advance / 64.0;
}
cairo_show_glyphs(cr, cairo_glyphs, glyph_count);
free(cairo_glyphs);
cairo_restore(cr);
double width = 0;
for (unsigned int i=0; i < glyph_count; i++) {
width += glyph_pos[i].x_advance / 64.0;
}
return ceil(width);
}
void entry_backend_harfbuzz_init(
struct entry *entry,
uint32_t *width,
uint32_t *height)
{
cairo_t *cr = entry->cairo[0].cr;
/* Setup FreeType. */
log_debug("Creating FreeType library.\n");
int err;
err = FT_Init_FreeType(&entry->harfbuzz.ft_library);
if (err) {
log_error("Error initialising FreeType: %s\n",
get_ft_error_string(err));
exit(EXIT_FAILURE);
}
log_debug("Loading FreeType font.\n");
err = FT_New_Face(
entry->harfbuzz.ft_library, entry->font_name, 0,
&entry->harfbuzz.ft_face);
if (err) {
log_error("Error loading font: %s\n", get_ft_error_string(err));
exit(EXIT_FAILURE);
}
err = FT_Set_Char_Size(
entry->harfbuzz.ft_face,
entry->font_size * 64,
entry->font_size * 64,
96,
96);
if (err) {
log_error("Error setting font size: %s\n",
get_ft_error_string(err));
}
log_debug("Creating Cairo font.\n");
entry->harfbuzz.cairo_face =
cairo_ft_font_face_create_for_ft_face(entry->harfbuzz.ft_face, 0);
struct color color = entry->foreground_color;
cairo_set_source_rgba(cr, color.r, color.g, color.b, color.a);
cairo_set_font_face(cr, entry->harfbuzz.cairo_face);
cairo_set_font_size(cr, entry->font_size * PT_TO_DPI);
cairo_font_options_t *opts = cairo_font_options_create();
//cairo_font_options_set_hint_style(opts, CAIRO_HINT_STYLE_NONE);
cairo_set_font_options(cr, opts);
/* We also need to set up the font for our other Cairo context. */
cairo_set_font_face(entry->cairo[1].cr, entry->harfbuzz.cairo_face);
cairo_set_font_size(entry->cairo[1].cr, entry->font_size * PT_TO_DPI);
cairo_set_font_options(entry->cairo[1].cr, opts);
cairo_font_options_destroy(opts);
log_debug("Creating Harfbuzz font.\n");
entry->harfbuzz.hb_font =
hb_ft_font_create_referenced(entry->harfbuzz.ft_face);
log_debug("Creating Harfbuzz buffer.\n");
hb_buffer_t *buffer = hb_buffer_create();
entry->harfbuzz.hb_buffer = buffer;
setup_hb_buffer(buffer);
/* Draw the prompt now, as this only needs to be done once */
log_debug("Drawing prompt.\n");
hb_buffer_add_utf8(entry->harfbuzz.hb_buffer, entry->prompt_text, -1, 0, -1);
hb_shape(entry->harfbuzz.hb_font, entry->harfbuzz.hb_buffer, NULL, 0);
uint32_t prompt_width = render_hb_buffer(cr, buffer);
/* Move and clip so we don't draw over the prompt later */
cairo_translate(cr, prompt_width, 0);
*width -= prompt_width;
cairo_rectangle(cr, 0, 0, *width, *height);
cairo_clip(cr);
}
void entry_backend_harfbuzz_destroy(struct entry *entry)
{
hb_buffer_destroy(entry->harfbuzz.hb_buffer);
hb_font_destroy(entry->harfbuzz.hb_font);
cairo_font_face_destroy(entry->harfbuzz.cairo_face);
FT_Done_Face(entry->harfbuzz.ft_face);
FT_Done_FreeType(entry->harfbuzz.ft_library);
}
void entry_backend_harfbuzz_update(struct entry *entry)
{
cairo_t *cr = entry->cairo[entry->index].cr;
hb_buffer_t *buffer = entry->harfbuzz.hb_buffer;
uint32_t width;
/* Render the entry text */
hb_buffer_clear_contents(buffer);
setup_hb_buffer(buffer);
hb_buffer_add_utf8(buffer, entry->input_mb, -1, 0, -1);
hb_shape(entry->harfbuzz.hb_font, buffer, NULL, 0);
width = render_hb_buffer(cr, buffer);
cairo_font_extents_t font_extents;
cairo_font_extents(cr, &font_extents);
/* Render our results entry text */
for (size_t i = 0; i < entry->num_results && i < entry->results.count; i++) {
if (entry->horizontal) {
cairo_translate(cr, width + entry->result_padding, 0);
} else {
cairo_translate(cr, 0, font_extents.height + entry->result_padding);
}
hb_buffer_clear_contents(buffer);
setup_hb_buffer(buffer);
hb_buffer_add_utf8(buffer, entry->results.buf[i], -1, 0, -1);
hb_shape(entry->harfbuzz.hb_font, buffer, NULL, 0);
if (i == entry->selection) {
cairo_save(cr);
struct color color = entry->selection_color;
cairo_set_source_rgba(cr, color.r, color.g, color.b, color.a);
}
width = render_hb_buffer(cr, buffer);
if (i == entry->selection) {
cairo_restore(cr);
}
}
}
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