/* Pango/Font Rendering * * Demonstrates various aspects of font rendering, * such as hinting, antialiasing and grid alignment. * * The demo lets you explore font rendering options * interactively to get a feeling for they affect the * shape and positioning of the glyphs. */ #include static GtkWidget *window = NULL; static GtkWidget *font_button = NULL; static GtkWidget *entry = NULL; static GtkWidget *image = NULL; static GtkWidget *hinting = NULL; static GtkWidget *anti_alias = NULL; static GtkWidget *hint_metrics = NULL; static GtkWidget *up_button = NULL; static GtkWidget *down_button = NULL; static GtkWidget *text_radio = NULL; static GtkWidget *show_grid = NULL; static GtkWidget *show_extents = NULL; static GtkWidget *show_pixels = NULL; static GtkWidget *show_outlines = NULL; static PangoContext *context; static int scale = 7; static double pixel_alpha = 1.0; static double outline_alpha = 0.0; static void update_image (void) { const char *text; PangoFontDescription *desc; PangoLayout *layout; PangoRectangle ink, logical; int baseline; cairo_surface_t *surface; cairo_t *cr; GdkPixbuf *pixbuf; GdkPixbuf *pixbuf2; cairo_font_options_t *fopt; cairo_hint_style_t hintstyle; cairo_hint_metrics_t hintmetrics; cairo_antialias_t antialias; cairo_path_t *path; if (!context) context = gtk_widget_create_pango_context (image); text = gtk_editable_get_text (GTK_EDITABLE (entry)); desc = gtk_font_dialog_button_get_font_desc (GTK_FONT_DIALOG_BUTTON (font_button)); fopt = cairo_font_options_copy (pango_cairo_context_get_font_options (context)); switch (gtk_drop_down_get_selected (GTK_DROP_DOWN (hinting))) { case 0: hintstyle = CAIRO_HINT_STYLE_NONE; break; case 1: hintstyle = CAIRO_HINT_STYLE_SLIGHT; break; case 2: hintstyle = CAIRO_HINT_STYLE_MEDIUM; break; case 3: hintstyle = CAIRO_HINT_STYLE_FULL; break; default: hintstyle = CAIRO_HINT_STYLE_DEFAULT; break; } cairo_font_options_set_hint_style (fopt, hintstyle); if (gtk_check_button_get_active (GTK_CHECK_BUTTON (hint_metrics))) hintmetrics = CAIRO_HINT_METRICS_ON; else hintmetrics = CAIRO_HINT_METRICS_OFF; cairo_font_options_set_hint_metrics (fopt, hintmetrics); if (gtk_check_button_get_active (GTK_CHECK_BUTTON (anti_alias))) antialias = CAIRO_ANTIALIAS_GRAY; else antialias = CAIRO_ANTIALIAS_NONE; cairo_font_options_set_antialias (fopt, antialias); pango_context_set_round_glyph_positions (context, hintmetrics == CAIRO_HINT_METRICS_ON); pango_cairo_context_set_font_options (context, fopt); cairo_font_options_destroy (fopt); pango_context_changed (context); if (gtk_toggle_button_get_active (GTK_TOGGLE_BUTTON (text_radio))) { layout = pango_layout_new (context); pango_layout_set_font_description (layout, desc); pango_layout_set_text (layout, text, -1); pango_layout_get_extents (layout, &ink, &logical); baseline = pango_layout_get_baseline (layout); pango_extents_to_pixels (&ink, NULL); surface = cairo_image_surface_create (CAIRO_FORMAT_ARGB32, ink.width + 20, ink.height + 20); cr = cairo_create (surface); cairo_set_source_rgb (cr, 1, 1, 1); cairo_paint (cr); cairo_set_source_rgba (cr, 0, 0, 0, pixel_alpha); cairo_move_to (cr, 10, 10); pango_cairo_show_layout (cr, layout); pango_cairo_layout_path (cr, layout); path = cairo_copy_path (cr); cairo_destroy (cr); g_object_unref (layout); pixbuf = gdk_pixbuf_get_from_surface (surface, 0, 0, cairo_image_surface_get_width (surface), cairo_image_surface_get_height (surface)); pixbuf2 = gdk_pixbuf_scale_simple (pixbuf, gdk_pixbuf_get_width (pixbuf) * scale, gdk_pixbuf_get_height (pixbuf) * scale, GDK_INTERP_NEAREST); g_object_unref (pixbuf); cairo_surface_destroy (surface); surface = cairo_image_surface_create_for_data (gdk_pixbuf_get_pixels (pixbuf2), CAIRO_FORMAT_ARGB32, gdk_pixbuf_get_width (pixbuf2), gdk_pixbuf_get_height (pixbuf2), gdk_pixbuf_get_rowstride (pixbuf2)); cr = cairo_create (surface); cairo_set_line_width (cr, 1); if (gtk_check_button_get_active (GTK_CHECK_BUTTON (show_grid))) { int i; cairo_set_source_rgba (cr, 0.2, 0, 0, 0.2); for (i = 1; i < ink.height + 20; i++) { cairo_move_to (cr, 0, scale * i - 0.5); cairo_line_to (cr, scale * (ink.width + 20), scale * i - 0.5); cairo_stroke (cr); } for (i = 1; i < ink.width + 20; i++) { cairo_move_to (cr, scale * i - 0.5, 0); cairo_line_to (cr, scale * i - 0.5, scale * (ink.height + 20)); cairo_stroke (cr); } } if (gtk_check_button_get_active (GTK_CHECK_BUTTON (show_extents))) { cairo_set_source_rgb (cr, 0, 0, 1); cairo_rectangle (cr, scale * (10 + pango_units_to_double (logical.x)) - 0.5, scale * (10 + pango_units_to_double (logical.y)) - 0.5, scale * pango_units_to_double (logical.width) + 1, scale * pango_units_to_double (logical.height) + 1); cairo_stroke (cr); cairo_move_to (cr, scale * (10 + pango_units_to_double (logical.x)) - 0.5, scale * (10 + pango_units_to_double (baseline)) - 0.5); cairo_line_to (cr, scale * (10 + pango_units_to_double (logical.x + logical.width)) + 1, scale * (10 + pango_units_to_double (baseline)) - 0.5); cairo_stroke (cr); cairo_set_source_rgb (cr, 1, 0, 0); cairo_rectangle (cr, scale * (10 + ink.x) - 0.5, scale * (10 + ink.y) - 0.5, scale * ink.width + 1, scale * ink.height + 1); cairo_stroke (cr); } for (int i = 0; i < path->num_data; i += path->data[i].header.length) { cairo_path_data_t *data = &path->data[i]; switch (data->header.type) { case CAIRO_PATH_CURVE_TO: data[3].point.x *= scale; data[3].point.y *= scale; data[2].point.x *= scale; data[2].point.y *= scale; data[1].point.x *= scale; data[1].point.y *= scale; break; case CAIRO_PATH_LINE_TO: case CAIRO_PATH_MOVE_TO: data[1].point.x *= scale; data[1].point.y *= scale; break; case CAIRO_PATH_CLOSE_PATH: break; default: g_assert_not_reached (); } } cairo_set_source_rgba (cr, 0, 0, 0, outline_alpha); cairo_move_to (cr, scale * 20 - 0.5, scale * 20 - 0.5); cairo_append_path (cr, path); cairo_stroke (cr); cairo_surface_destroy (surface); cairo_destroy (cr); cairo_path_destroy (path); } else { PangoLayoutIter *iter; PangoLayoutRun *run; PangoGlyphInfo *g; int i, j; GString *str; gunichar ch; if (*text == '\0') text = " "; ch = g_utf8_get_char (text); str = g_string_new (""); layout = pango_layout_new (context); retry: for (i = 0; i < 4; i++) { g_string_append_unichar (str, ch); g_string_append_unichar (str, 0x200c); } pango_layout_set_font_description (layout, desc); pango_layout_set_text (layout, str->str, -1); pango_layout_get_extents (layout, &ink, &logical); pango_extents_to_pixels (&logical, NULL); iter = pango_layout_get_iter (layout); run = pango_layout_iter_get_run (iter); if (run->glyphs->num_glyphs < 8) { /* not a good char to use */ g_string_truncate (str, 0); ch = 'a'; goto retry; } g_string_free (str, TRUE); surface = cairo_image_surface_create (CAIRO_FORMAT_ARGB32, logical.width * 3 / 2, 4*logical.height); cr = cairo_create (surface); cairo_set_source_rgb (cr, 1, 1, 1); cairo_paint (cr); cairo_set_source_rgb (cr, 0, 0, 0); for (i = 0; i < 4; i++) { g = &(run->glyphs->glyphs[2*i]); g->geometry.width = PANGO_UNITS_ROUND (g->geometry.width * 3 / 2); } for (j = 0; j < 4; j++) { for (i = 0; i < 4; i++) { g = &(run->glyphs->glyphs[2*i]); g->geometry.x_offset = i * (PANGO_SCALE / 4); g->geometry.y_offset = j * (PANGO_SCALE / 4); } cairo_move_to (cr, 0, j * logical.height); pango_cairo_show_layout (cr, layout); } cairo_destroy (cr); pango_layout_iter_free (iter); g_object_unref (layout); pixbuf = gdk_pixbuf_get_from_surface (surface, 0, 0, cairo_image_surface_get_width (surface), cairo_image_surface_get_height (surface)); pixbuf2 = gdk_pixbuf_scale_simple (pixbuf, gdk_pixbuf_get_width (pixbuf) * scale, gdk_pixbuf_get_height (pixbuf) * scale, GDK_INTERP_NEAREST); g_object_unref (pixbuf); cairo_surface_destroy (surface); } gtk_picture_set_pixbuf (GTK_PICTURE (image), pixbuf2); g_object_unref (pixbuf2); } static gboolean fading = FALSE; static double start_pixel_alpha; static double end_pixel_alpha; static double start_outline_alpha; static double end_outline_alpha; static gint64 start_time; static gint64 end_time; static double ease_out_cubic (double t) { double p = t - 1; return p * p * p + 1; } static gboolean change_alpha (GtkWidget *widget, GdkFrameClock *clock, gpointer user_data) { gint64 now = g_get_monotonic_time (); double t; t = ease_out_cubic ((now - start_time) / (double) (end_time - start_time)); pixel_alpha = start_pixel_alpha + (end_pixel_alpha - start_pixel_alpha) * t; outline_alpha = start_outline_alpha + (end_outline_alpha - start_outline_alpha) * t; update_image (); if (now >= end_time) { fading = FALSE; return G_SOURCE_REMOVE; } return G_SOURCE_CONTINUE; } static void start_alpha_fade (void) { gboolean pixels; gboolean outlines; if (fading) return; pixels = gtk_check_button_get_active (GTK_CHECK_BUTTON (show_pixels)); outlines = gtk_check_button_get_active (GTK_CHECK_BUTTON (show_outlines)); start_pixel_alpha = pixel_alpha; if (pixels && outlines) end_pixel_alpha = 0.5; else if (pixels) end_pixel_alpha = 1; else end_pixel_alpha = 0; start_outline_alpha = outline_alpha; if (outlines) end_outline_alpha = 1.0; else end_outline_alpha = 0.0; start_time = g_get_monotonic_time (); end_time = start_time + G_TIME_SPAN_SECOND / 2; fading = TRUE; gtk_widget_add_tick_callback (window, change_alpha, NULL, NULL); } static void update_buttons (void) { gtk_widget_set_sensitive (up_button, scale < 32); gtk_widget_set_sensitive (down_button, scale > 1); } static gboolean scale_up (GtkWidget *widget, GVariant *args, gpointer user_data) { scale += 1; update_buttons (); update_image (); return TRUE; } static gboolean scale_down (GtkWidget *widget, GVariant *args, gpointer user_data) { scale -= 1; update_buttons (); update_image (); return TRUE; } GtkWidget * do_fontrendering (GtkWidget *do_widget) { if (!window) { GtkBuilder *builder; builder = gtk_builder_new_from_resource ("/fontrendering/fontrendering.ui"); window = GTK_WIDGET (gtk_builder_get_object (builder, "window")); gtk_window_set_display (GTK_WINDOW (window), gtk_widget_get_display (do_widget)); g_object_add_weak_pointer (G_OBJECT (window), (gpointer *)&window); font_button = GTK_WIDGET (gtk_builder_get_object (builder, "font_button")); up_button = GTK_WIDGET (gtk_builder_get_object (builder, "up_button")); down_button = GTK_WIDGET (gtk_builder_get_object (builder, "down_button")); entry = GTK_WIDGET (gtk_builder_get_object (builder, "entry")); image = GTK_WIDGET (gtk_builder_get_object (builder, "image")); hinting = GTK_WIDGET (gtk_builder_get_object (builder, "hinting")); anti_alias = GTK_WIDGET (gtk_builder_get_object (builder, "antialias")); hint_metrics = GTK_WIDGET (gtk_builder_get_object (builder, "hint_metrics")); text_radio = GTK_WIDGET (gtk_builder_get_object (builder, "text_radio")); show_grid = GTK_WIDGET (gtk_builder_get_object (builder, "show_grid")); show_extents = GTK_WIDGET (gtk_builder_get_object (builder, "show_extents")); show_pixels = GTK_WIDGET (gtk_builder_get_object (builder, "show_pixels")); show_outlines = GTK_WIDGET (gtk_builder_get_object (builder, "show_outlines")); g_signal_connect (up_button, "clicked", G_CALLBACK (scale_up), NULL); g_signal_connect (down_button, "clicked", G_CALLBACK (scale_down), NULL); g_signal_connect (entry, "notify::text", G_CALLBACK (update_image), NULL); g_signal_connect (font_button, "notify::font-desc", G_CALLBACK (update_image), NULL); g_signal_connect (hinting, "notify::selected", G_CALLBACK (update_image), NULL); g_signal_connect (anti_alias, "notify::active", G_CALLBACK (update_image), NULL); g_signal_connect (hint_metrics, "notify::active", G_CALLBACK (update_image), NULL); g_signal_connect (text_radio, "notify::active", G_CALLBACK (update_image), NULL); g_signal_connect (show_grid, "notify::active", G_CALLBACK (update_image), NULL); g_signal_connect (show_extents, "notify::active", G_CALLBACK (update_image), NULL); g_signal_connect (show_pixels, "notify::active", G_CALLBACK (start_alpha_fade), NULL); g_signal_connect (show_outlines, "notify::active", G_CALLBACK (start_alpha_fade), NULL); update_image (); g_object_unref (builder); } if (!gtk_widget_get_visible (window)) gtk_widget_set_visible (window, TRUE); else gtk_window_destroy (GTK_WINDOW (window)); return window; }