mirror of
https://gitlab.gnome.org/GNOME/gtk.git
synced 2024-12-25 21:21:21 +00:00
444 lines
14 KiB
C
444 lines
14 KiB
C
/* Pango/Font Rendering
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*
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* Demonstrates various aspects of font rendering,
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* such as hinting, antialiasing and grid alignment.
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*
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* The demo lets you explore font rendering options
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* interactively to get a feeling for they affect the
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* shape and positioning of the glyphs.
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*/
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#include <gtk/gtk.h>
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static GtkWidget *window = NULL;
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static GtkWidget *font_button = NULL;
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static GtkWidget *entry = NULL;
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static GtkWidget *image = NULL;
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static GtkWidget *hinting = NULL;
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static GtkWidget *anti_alias = NULL;
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static GtkWidget *hint_metrics = NULL;
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static GtkWidget *up_button = NULL;
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static GtkWidget *down_button = NULL;
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static GtkWidget *text_radio = NULL;
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static GtkWidget *show_grid = NULL;
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static GtkWidget *show_extents = NULL;
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static GtkWidget *show_pixels = NULL;
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static GtkWidget *show_outlines = NULL;
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static PangoContext *context;
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static int scale = 7;
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static double pixel_alpha = 1.0;
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static double outline_alpha = 0.0;
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static void
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update_image (void)
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{
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const char *text;
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PangoFontDescription *desc;
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PangoLayout *layout;
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PangoRectangle ink, logical;
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int baseline;
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cairo_surface_t *surface;
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cairo_t *cr;
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GdkPixbuf *pixbuf;
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GdkPixbuf *pixbuf2;
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cairo_font_options_t *fopt;
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cairo_hint_style_t hintstyle;
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cairo_hint_metrics_t hintmetrics;
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cairo_antialias_t antialias;
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cairo_path_t *path;
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if (!context)
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context = gtk_widget_create_pango_context (image);
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text = gtk_editable_get_text (GTK_EDITABLE (entry));
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desc = gtk_font_dialog_button_get_font_desc (GTK_FONT_DIALOG_BUTTON (font_button));
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fopt = cairo_font_options_copy (pango_cairo_context_get_font_options (context));
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switch (gtk_drop_down_get_selected (GTK_DROP_DOWN (hinting)))
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{
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case 0:
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hintstyle = CAIRO_HINT_STYLE_NONE;
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break;
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case 1:
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hintstyle = CAIRO_HINT_STYLE_SLIGHT;
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break;
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case 2:
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hintstyle = CAIRO_HINT_STYLE_MEDIUM;
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break;
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case 3:
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hintstyle = CAIRO_HINT_STYLE_FULL;
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break;
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default:
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hintstyle = CAIRO_HINT_STYLE_DEFAULT;
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break;
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}
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cairo_font_options_set_hint_style (fopt, hintstyle);
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if (gtk_check_button_get_active (GTK_CHECK_BUTTON (hint_metrics)))
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hintmetrics = CAIRO_HINT_METRICS_ON;
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else
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hintmetrics = CAIRO_HINT_METRICS_OFF;
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cairo_font_options_set_hint_metrics (fopt, hintmetrics);
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if (gtk_check_button_get_active (GTK_CHECK_BUTTON (anti_alias)))
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antialias = CAIRO_ANTIALIAS_GRAY;
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else
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antialias = CAIRO_ANTIALIAS_NONE;
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cairo_font_options_set_antialias (fopt, antialias);
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pango_context_set_round_glyph_positions (context, hintmetrics == CAIRO_HINT_METRICS_ON);
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pango_cairo_context_set_font_options (context, fopt);
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cairo_font_options_destroy (fopt);
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pango_context_changed (context);
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if (gtk_toggle_button_get_active (GTK_TOGGLE_BUTTON (text_radio)))
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{
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layout = pango_layout_new (context);
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pango_layout_set_font_description (layout, desc);
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pango_layout_set_text (layout, text, -1);
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pango_layout_get_extents (layout, &ink, &logical);
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baseline = pango_layout_get_baseline (layout);
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pango_extents_to_pixels (&ink, NULL);
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surface = cairo_image_surface_create (CAIRO_FORMAT_ARGB32, ink.width + 20, ink.height + 20);
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cr = cairo_create (surface);
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cairo_set_source_rgb (cr, 1, 1, 1);
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cairo_paint (cr);
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cairo_set_source_rgba (cr, 0, 0, 0, pixel_alpha);
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cairo_move_to (cr, 10, 10);
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pango_cairo_show_layout (cr, layout);
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pango_cairo_layout_path (cr, layout);
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path = cairo_copy_path (cr);
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cairo_destroy (cr);
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g_object_unref (layout);
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pixbuf = gdk_pixbuf_get_from_surface (surface, 0, 0, cairo_image_surface_get_width (surface), cairo_image_surface_get_height (surface));
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pixbuf2 = gdk_pixbuf_scale_simple (pixbuf, gdk_pixbuf_get_width (pixbuf) * scale, gdk_pixbuf_get_height (pixbuf) * scale, GDK_INTERP_NEAREST);
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g_object_unref (pixbuf);
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cairo_surface_destroy (surface);
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surface = cairo_image_surface_create_for_data (gdk_pixbuf_get_pixels (pixbuf2),
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CAIRO_FORMAT_ARGB32,
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gdk_pixbuf_get_width (pixbuf2),
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gdk_pixbuf_get_height (pixbuf2),
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gdk_pixbuf_get_rowstride (pixbuf2));
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cr = cairo_create (surface);
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cairo_set_line_width (cr, 1);
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if (gtk_check_button_get_active (GTK_CHECK_BUTTON (show_grid)))
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{
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int i;
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cairo_set_source_rgba (cr, 0.2, 0, 0, 0.2);
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for (i = 1; i < ink.height + 20; i++)
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{
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cairo_move_to (cr, 0, scale * i - 0.5);
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cairo_line_to (cr, scale * (ink.width + 20), scale * i - 0.5);
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cairo_stroke (cr);
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}
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for (i = 1; i < ink.width + 20; i++)
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{
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cairo_move_to (cr, scale * i - 0.5, 0);
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cairo_line_to (cr, scale * i - 0.5, scale * (ink.height + 20));
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cairo_stroke (cr);
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}
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}
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if (gtk_check_button_get_active (GTK_CHECK_BUTTON (show_extents)))
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{
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cairo_set_source_rgb (cr, 0, 0, 1);
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cairo_rectangle (cr,
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scale * (10 + pango_units_to_double (logical.x)) - 0.5,
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scale * (10 + pango_units_to_double (logical.y)) - 0.5,
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scale * pango_units_to_double (logical.width) + 1,
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scale * pango_units_to_double (logical.height) + 1);
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cairo_stroke (cr);
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cairo_move_to (cr, scale * (10 + pango_units_to_double (logical.x)) - 0.5,
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scale * (10 + pango_units_to_double (baseline)) - 0.5);
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cairo_line_to (cr, scale * (10 + pango_units_to_double (logical.x + logical.width)) + 1,
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scale * (10 + pango_units_to_double (baseline)) - 0.5);
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cairo_stroke (cr);
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cairo_set_source_rgb (cr, 1, 0, 0);
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cairo_rectangle (cr,
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scale * (10 + ink.x) - 0.5,
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scale * (10 + ink.y) - 0.5,
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scale * ink.width + 1,
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scale * ink.height + 1);
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cairo_stroke (cr);
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}
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for (int i = 0; i < path->num_data; i += path->data[i].header.length)
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{
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cairo_path_data_t *data = &path->data[i];
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switch (data->header.type)
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{
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case CAIRO_PATH_CURVE_TO:
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data[3].point.x *= scale; data[3].point.y *= scale;
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data[2].point.x *= scale; data[2].point.y *= scale;
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data[1].point.x *= scale; data[1].point.y *= scale;
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break;
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case CAIRO_PATH_LINE_TO:
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case CAIRO_PATH_MOVE_TO:
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data[1].point.x *= scale; data[1].point.y *= scale;
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break;
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case CAIRO_PATH_CLOSE_PATH:
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break;
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default:
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g_assert_not_reached ();
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}
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}
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cairo_set_source_rgba (cr, 0, 0, 0, outline_alpha);
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cairo_move_to (cr, scale * 20 - 0.5, scale * 20 - 0.5);
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cairo_append_path (cr, path);
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cairo_stroke (cr);
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cairo_surface_destroy (surface);
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cairo_destroy (cr);
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cairo_path_destroy (path);
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}
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else
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{
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PangoLayoutIter *iter;
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PangoLayoutRun *run;
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PangoGlyphInfo *g;
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int i, j;
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GString *str;
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gunichar ch;
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if (*text == '\0')
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text = " ";
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ch = g_utf8_get_char (text);
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str = g_string_new ("");
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layout = pango_layout_new (context);
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retry:
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for (i = 0; i < 4; i++)
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{
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g_string_append_unichar (str, ch);
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g_string_append_unichar (str, 0x200c);
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}
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pango_layout_set_font_description (layout, desc);
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pango_layout_set_text (layout, str->str, -1);
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pango_layout_get_extents (layout, &ink, &logical);
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pango_extents_to_pixels (&logical, NULL);
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iter = pango_layout_get_iter (layout);
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run = pango_layout_iter_get_run (iter);
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if (run->glyphs->num_glyphs < 8)
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{
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/* not a good char to use */
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g_string_truncate (str, 0);
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ch = 'a';
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goto retry;
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}
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g_string_free (str, TRUE);
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surface = cairo_image_surface_create (CAIRO_FORMAT_ARGB32, logical.width * 3 / 2, 4*logical.height);
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cr = cairo_create (surface);
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cairo_set_source_rgb (cr, 1, 1, 1);
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cairo_paint (cr);
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cairo_set_source_rgb (cr, 0, 0, 0);
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for (i = 0; i < 4; i++)
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{
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g = &(run->glyphs->glyphs[2*i]);
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g->geometry.width = PANGO_UNITS_ROUND (g->geometry.width * 3 / 2);
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}
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for (j = 0; j < 4; j++)
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{
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for (i = 0; i < 4; i++)
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{
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g = &(run->glyphs->glyphs[2*i]);
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g->geometry.x_offset = i * (PANGO_SCALE / 4);
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g->geometry.y_offset = j * (PANGO_SCALE / 4);
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}
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cairo_move_to (cr, 0, j * logical.height);
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pango_cairo_show_layout (cr, layout);
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}
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cairo_destroy (cr);
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pango_layout_iter_free (iter);
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g_object_unref (layout);
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pixbuf = gdk_pixbuf_get_from_surface (surface, 0, 0, cairo_image_surface_get_width (surface), cairo_image_surface_get_height (surface));
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pixbuf2 = gdk_pixbuf_scale_simple (pixbuf, gdk_pixbuf_get_width (pixbuf) * scale, gdk_pixbuf_get_height (pixbuf) * scale, GDK_INTERP_NEAREST);
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g_object_unref (pixbuf);
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cairo_surface_destroy (surface);
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}
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gtk_picture_set_pixbuf (GTK_PICTURE (image), pixbuf2);
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g_object_unref (pixbuf2);
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}
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static gboolean fading = FALSE;
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static double start_pixel_alpha;
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static double end_pixel_alpha;
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static double start_outline_alpha;
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static double end_outline_alpha;
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static gint64 start_time;
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static gint64 end_time;
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static double
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ease_out_cubic (double t)
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{
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double p = t - 1;
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return p * p * p + 1;
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}
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static gboolean
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change_alpha (GtkWidget *widget,
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GdkFrameClock *clock,
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gpointer user_data)
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{
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gint64 now = g_get_monotonic_time ();
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double t;
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t = ease_out_cubic ((now - start_time) / (double) (end_time - start_time));
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pixel_alpha = start_pixel_alpha + (end_pixel_alpha - start_pixel_alpha) * t;
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outline_alpha = start_outline_alpha + (end_outline_alpha - start_outline_alpha) * t;
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update_image ();
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if (now >= end_time)
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{
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fading = FALSE;
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return G_SOURCE_REMOVE;
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}
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return G_SOURCE_CONTINUE;
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}
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static void
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start_alpha_fade (void)
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{
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gboolean pixels;
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gboolean outlines;
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if (fading)
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return;
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pixels = gtk_check_button_get_active (GTK_CHECK_BUTTON (show_pixels));
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outlines = gtk_check_button_get_active (GTK_CHECK_BUTTON (show_outlines));
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start_pixel_alpha = pixel_alpha;
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if (pixels && outlines)
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end_pixel_alpha = 0.5;
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else if (pixels)
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end_pixel_alpha = 1;
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else
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end_pixel_alpha = 0;
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start_outline_alpha = outline_alpha;
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if (outlines)
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end_outline_alpha = 1.0;
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else
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end_outline_alpha = 0.0;
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start_time = g_get_monotonic_time ();
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end_time = start_time + G_TIME_SPAN_SECOND / 2;
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fading = TRUE;
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gtk_widget_add_tick_callback (window, change_alpha, NULL, NULL);
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}
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static void
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update_buttons (void)
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{
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gtk_widget_set_sensitive (up_button, scale < 32);
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gtk_widget_set_sensitive (down_button, scale > 1);
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}
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static gboolean
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scale_up (GtkWidget *widget,
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GVariant *args,
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gpointer user_data)
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{
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scale += 1;
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update_buttons ();
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update_image ();
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return TRUE;
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}
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static gboolean
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scale_down (GtkWidget *widget,
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GVariant *args,
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gpointer user_data)
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{
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scale -= 1;
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update_buttons ();
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update_image ();
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return TRUE;
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}
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GtkWidget *
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do_fontrendering (GtkWidget *do_widget)
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{
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if (!window)
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{
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GtkBuilder *builder;
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builder = gtk_builder_new_from_resource ("/fontrendering/fontrendering.ui");
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window = GTK_WIDGET (gtk_builder_get_object (builder, "window"));
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gtk_window_set_display (GTK_WINDOW (window),
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gtk_widget_get_display (do_widget));
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g_object_add_weak_pointer (G_OBJECT (window), (gpointer *)&window);
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font_button = GTK_WIDGET (gtk_builder_get_object (builder, "font_button"));
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up_button = GTK_WIDGET (gtk_builder_get_object (builder, "up_button"));
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down_button = GTK_WIDGET (gtk_builder_get_object (builder, "down_button"));
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entry = GTK_WIDGET (gtk_builder_get_object (builder, "entry"));
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image = GTK_WIDGET (gtk_builder_get_object (builder, "image"));
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hinting = GTK_WIDGET (gtk_builder_get_object (builder, "hinting"));
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anti_alias = GTK_WIDGET (gtk_builder_get_object (builder, "antialias"));
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hint_metrics = GTK_WIDGET (gtk_builder_get_object (builder, "hint_metrics"));
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text_radio = GTK_WIDGET (gtk_builder_get_object (builder, "text_radio"));
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show_grid = GTK_WIDGET (gtk_builder_get_object (builder, "show_grid"));
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show_extents = GTK_WIDGET (gtk_builder_get_object (builder, "show_extents"));
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show_pixels = GTK_WIDGET (gtk_builder_get_object (builder, "show_pixels"));
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show_outlines = GTK_WIDGET (gtk_builder_get_object (builder, "show_outlines"));
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g_signal_connect (up_button, "clicked", G_CALLBACK (scale_up), NULL);
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g_signal_connect (down_button, "clicked", G_CALLBACK (scale_down), NULL);
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g_signal_connect (entry, "notify::text", G_CALLBACK (update_image), NULL);
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g_signal_connect (font_button, "notify::font-desc", G_CALLBACK (update_image), NULL);
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g_signal_connect (hinting, "notify::selected", G_CALLBACK (update_image), NULL);
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g_signal_connect (anti_alias, "notify::active", G_CALLBACK (update_image), NULL);
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g_signal_connect (hint_metrics, "notify::active", G_CALLBACK (update_image), NULL);
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g_signal_connect (text_radio, "notify::active", G_CALLBACK (update_image), NULL);
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g_signal_connect (show_grid, "notify::active", G_CALLBACK (update_image), NULL);
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g_signal_connect (show_extents, "notify::active", G_CALLBACK (update_image), NULL);
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g_signal_connect (show_pixels, "notify::active", G_CALLBACK (start_alpha_fade), NULL);
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g_signal_connect (show_outlines, "notify::active", G_CALLBACK (start_alpha_fade), NULL);
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update_image ();
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g_object_unref (builder);
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}
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if (!gtk_widget_get_visible (window))
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gtk_widget_set_visible (window, TRUE);
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else
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gtk_window_destroy (GTK_WINDOW (window));
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return window;
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}
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