Add Harfbuzz backend.

Another source of slow startup is initialising Pango. If the user
supplies a ttf file, we can skip any Pango stuff and use Harfbuzz
directly with Cairo to do our font rendering, providing a large speedup.

4 files changed, 285 insertions, 0 deletions

diff --git a/src/entry_backend/harfbuzz.c b/src/entry_backend/harfbuzz.c
new file mode 100644
index 0000000..d1f54e9
--- /dev/null
+++ b/src/entry_backend/harfbuzz.c
@@ -0,0 +1,148 @@
+#include <assert.h>
+#include <cairo/cairo.h>
+#include <glib.h>
+#include <harfbuzz/hb-ft.h>
+#include <harfbuzz/hb-glib.h>
+#include <math.h>
+#include <pango/pangocairo.h>
+#include <pango/pango.h>
+#include <wchar.h>
+#include "../entry.h"
+#include "../log.h"
+#include "../nelem.h"
+#include "../xmalloc.h"
+
+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));
+}
+
+
+static hb_buffer_t *create_hb_buffer(void)
+{
+	hb_buffer_t *buffer = hb_buffer_create();
+	hb_buffer_set_unicode_funcs(buffer, hb_glib_get_unicode_funcs());
+	setup_hb_buffer(buffer);
+
+	return buffer;
+}
+
+static uint32_t render_hb_buffer(cairo_t *cr, hb_buffer_t *buffer, uint32_t scale)
+{
+	cairo_save(cr);
+
+	cairo_font_extents_t font_extents;
+	cairo_font_extents(cr, &font_extents);
+	cairo_matrix_t font_matrix;
+	cairo_get_font_matrix(cr, &font_matrix);
+	double baseline = (font_matrix.xx - font_extents.height) / 2 + font_extents.ascent;
+	cairo_translate(cr, 0, baseline);
+
+	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);
+
+	unsigned int width = 0;
+	for (unsigned int i=0; i < glyph_count; ++i) {
+		width += ceil(glyph_pos[i].x_advance / 64.0 / scale);
+	}
+
+	int x = 0;
+	int y = 0;
+	for (unsigned int i=0; i < glyph_count; ++i) {
+		cairo_glyphs[i].index = glyph_info[i].codepoint;
+		cairo_glyphs[i].x = x + ceil(glyph_pos[i].x_offset / 64.0 / scale);
+		cairo_glyphs[i].y = y - ceil(glyph_pos[i].y_offset / 64.0 / scale);
+		x += ceil(glyph_pos[i].x_advance / 64.0 / scale);
+		y -= ceil(glyph_pos[i].y_advance / 64.0 / scale);
+	}
+
+	cairo_show_glyphs(cr, cairo_glyphs, glyph_count);
+
+	free(cairo_glyphs);
+
+	cairo_restore(cr);
+
+	return width;
+}
+
+void entry_backend_init(struct entry *entry, uint32_t width, uint32_t height, uint32_t scale)
+{
+	cairo_t *cr = entry->cairo.cr;
+
+	/* Setup FreeType. */
+	log_debug("Creating FreeType library.\n");
+	assert(!FT_Init_FreeType(&entry->backend.ft_library));
+
+	log_debug("Loading FreeType font.\n");
+	assert(!FT_New_Face(entry->backend.ft_library, "font.ttf", 0, &entry->backend.ft_face));
+	assert(!FT_Set_Char_Size(entry->backend.ft_face, entry->font_size * 64, entry->font_size * 64, 0, 0));
+
+	log_debug("Creating Cairo font.\n");
+	entry->backend.cairo_face = cairo_ft_font_face_create_for_ft_face(entry->backend.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->backend.cairo_face);
+	cairo_set_font_size(cr, entry->font_size * (96.0 / 72.0));
+
+	cairo_font_extents_t font_extents;
+	cairo_font_extents(cr, &font_extents);
+
+	log_debug("Creating Harfbuzz font.\n");
+	entry->backend.hb_font = hb_ft_font_create_referenced(entry->backend.ft_face);
+
+	log_debug("Creating Harfbuzz buffer.\n");
+	entry->backend.hb_buffer = create_hb_buffer();
+
+	/* Draw the prompt now, as this only needs to be done once */
+	log_debug("Drawing prompt.\n");
+	hb_buffer_add_utf8(entry->backend.hb_buffer, "run: ", -1, 0, -1);
+	hb_shape(entry->backend.hb_font, entry->backend.hb_buffer, NULL, 0);
+
+	/* Move and clip so we don't draw over the prompt */
+	uint32_t prompt_width = render_hb_buffer(cr, entry->backend.hb_buffer, scale);
+	cairo_translate(cr, prompt_width, 0);
+	width -= prompt_width;
+	cairo_rectangle(cr, 0, 0, width, height);
+	cairo_clip(cr);
+}
+
+void entry_backend_destroy(struct entry *entry)
+{
+	hb_buffer_destroy(entry->backend.hb_buffer);
+	hb_font_destroy(entry->backend.hb_font);
+	FT_Done_Face(entry->backend.ft_face);
+	FT_Done_FreeType(entry->backend.ft_library);
+}
+
+void entry_backend_update(struct entry *entry)
+{
+	cairo_t *cr = entry->cairo.cr;
+
+	hb_buffer_clear_contents(entry->backend.hb_buffer);
+	setup_hb_buffer(entry->backend.hb_buffer);
+	hb_buffer_add_utf8(entry->backend.hb_buffer, entry->input_mb, -1, 0, -1);
+	hb_shape(entry->backend.hb_font, entry->backend.hb_buffer, NULL, 0);
+	render_hb_buffer(cr, entry->backend.hb_buffer, entry->image.scale);
+
+	cairo_font_extents_t font_extents;
+	cairo_font_extents(cr, &font_extents);
+
+	for (size_t i = 0; i < 5; i++) {
+		cairo_translate(cr, 0, font_extents.height);
+
+		hb_buffer_t *buffer = entry->backend.hb_buffer;
+
+		hb_buffer_clear_contents(buffer);
+		setup_hb_buffer(buffer);
+		if (i < entry->results.count) {
+			hb_buffer_add_utf8(buffer, entry->results.buf[i], -1, 0, -1);
+			hb_shape(entry->backend.hb_font, buffer, NULL, 0);
+			render_hb_buffer(cr, buffer, entry->image.scale);
+		}
+	}
+}
diff --git a/src/entry_backend/harfbuzz.h b/src/entry_backend/harfbuzz.h
new file mode 100644
index 0000000..0b07538
--- /dev/null
+++ b/src/entry_backend/harfbuzz.h
@@ -0,0 +1,26 @@
+#ifndef ENTRY_BACKEND_HARFBUZZ_H
+#define ENTRY_BACKEND_HARFBUZZ_H
+
+#include <cairo/cairo-ft.h>
+#include <ft2build.h>
+#include FT_FREETYPE_H
+#include <harfbuzz/hb.h>
+#include <pango/pangocairo.h>
+
+struct entry;
+
+struct entry_backend {
+	FT_Library ft_library;
+	FT_Face ft_face;
+
+	cairo_font_face_t *cairo_face;
+
+	hb_font_t *hb_font;
+	hb_buffer_t *hb_buffer;
+};
+
+void entry_backend_init(struct entry *entry, uint32_t width, uint32_t height, uint32_t scale);
+void entry_backend_destroy(struct entry *entry);
+void entry_backend_update(struct entry *entry);
+
+#endif /* ENTRY_BACKEND_HARFBUZZ_H */
diff --git a/src/entry_backend/pango.c b/src/entry_backend/pango.c
new file mode 100644
index 0000000..569a706
--- /dev/null
+++ b/src/entry_backend/pango.c
@@ -0,0 +1,92 @@
+#include <cairo/cairo.h>
+#include <glib.h>
+#include <pango/pangocairo.h>
+#include <pango/pango.h>
+#include <wchar.h>
+#include "../entry.h"
+#include "../log.h"
+#include "../nelem.h"
+
+void entry_backend_init(struct entry *entry, uint32_t width, uint32_t height, uint32_t scale)
+{
+	cairo_t *cr = entry->cairo.cr;
+
+	/* Setup Pango. */
+	log_debug("Creating Pango context.\n");
+	PangoContext *context = pango_cairo_create_context(cr);
+
+	log_debug("Creating Pango font description.\n");
+	PangoFontDescription *font_description =
+		pango_font_description_from_string(entry->font_name);
+	pango_font_description_set_size(
+			font_description,
+			entry->font_size * PANGO_SCALE);
+	pango_context_set_font_description(context, font_description);
+	pango_font_description_free(font_description);
+
+	entry->backend.prompt_layout = pango_layout_new(context);
+	log_debug("Setting Pango text.\n");
+	pango_layout_set_text(entry->backend.prompt_layout, "run: ", -1);
+	int prompt_width;
+	int prompt_height;
+	log_debug("Get Pango pixel size.\n");
+	pango_layout_get_pixel_size(entry->backend.prompt_layout, &prompt_width, &prompt_height);
+	log_debug("First Pango draw.\n");
+	pango_cairo_update_layout(cr, entry->backend.prompt_layout);
+
+	/* Draw the prompt now, as this only needs to be done once */
+	struct color color = entry->foreground_color;
+	cairo_set_source_rgba(cr, color.r, color.g, color.b, color.a);
+	pango_cairo_show_layout(cr, entry->backend.prompt_layout);
+
+	/* Move and clip so we don't draw over the prompt */
+	cairo_translate(cr, prompt_width, 0);
+	width -= prompt_width;
+	cairo_rectangle(cr, 0, 0, width, height);
+	cairo_clip(cr);
+
+	log_debug("Creating Pango layout.\n");
+	entry->backend.entry_layout = pango_layout_new(context);
+	pango_layout_set_text(entry->backend.entry_layout, "", -1);
+
+	for (size_t i = 0; i < 5; i++) {
+		PangoLayout *layout = pango_layout_new(context);
+		pango_layout_set_text(layout, "", -1);
+		entry->backend.result_layouts[i] = layout;
+	}
+
+	entry->backend.context = context;
+}
+
+void entry_backend_destroy(struct entry *entry)
+{
+	for (size_t i = 0; i < 5; i++) {
+		g_object_unref(entry->backend.result_layouts[i]);
+	}
+	g_object_unref(entry->backend.entry_layout);
+	g_object_unref(entry->backend.prompt_layout);
+	g_object_unref(entry->backend.context);
+}
+
+void entry_backend_update(struct entry *entry)
+{
+	cairo_t *cr = entry->cairo.cr;
+
+	pango_layout_set_text(entry->backend.entry_layout, entry->input_mb, -1);
+	pango_cairo_update_layout(cr, entry->backend.entry_layout);
+	pango_cairo_show_layout(cr, entry->backend.entry_layout);
+
+	for (size_t i = 0; i < 5; i++) {
+		cairo_translate(cr, 0, 50);
+		PangoLayout *layout = entry->backend.result_layouts[i];
+		const char *str;
+		if (i < entry->results.count) {
+			str = entry->results.buf[i];
+		} else {
+			str = "";
+		}
+		pango_layout_set_text(layout, str, -1);
+		pango_cairo_update_layout(cr, layout);
+		pango_cairo_show_layout(cr, layout);
+	}
+}
diff --git a/src/entry_backend/pango.h b/src/entry_backend/pango.h
new file mode 100644
index 0000000..08572ae
--- /dev/null
+++ b/src/entry_backend/pango.h
@@ -0,0 +1,19 @@
+#ifndef ENTRY_BACKEND_PANGO_H
+#define ENTRY_BACKEND_PANGO_H
+
+#include <pango/pangocairo.h>
+
+struct entry;
+
+struct entry_backend {
+	PangoContext *context;
+	PangoLayout *prompt_layout;
+	PangoLayout *entry_layout;
+	PangoLayout *result_layouts[5];
+};
+
+void entry_backend_init(struct entry *entry, uint32_t width, uint32_t height, uint32_t scale);
+void entry_backend_destroy(struct entry *entry);
+void entry_backend_update(struct entry *entry);
+
+#endif /* ENTRY_BACKEND_PANGO_H */