Bug 437533 – Implement draw_shape PangoRenderer method
2009-03-27 Behdad Esfahbod <behdad@gnome.org> Bug 437533 – Implement draw_shape PangoRenderer method * gdk/gdkpango.c (gdk_pango_renderer_draw_shape), (gdk_pango_renderer_class_init): Implement draw_shape * demos/gtk-demo/rotated_text.c (fancy_shape_renderer), (create_fancy_attr_list_for_layout), (rotated_text_expose_event), (do_rotated_text): 1) Port to pangocairo 2) Also show a rotated label 3) Install a custom shape renderer on both. The second one goes through gdkpango and hence tests the patch above. It's working. svn path=/trunk/; revision=22592
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Behdad Esfahbod
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Behdad Esfahbod
Behdad Esfahbod
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@ -1,101 +1,173 @@
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/* Rotated Text
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*
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* This demo shows how to use GDK and Pango to draw rotated and transformed
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* text. The use of GdkPangoRenderer in this example is a somewhat advanced
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* technique; most applications can simply use gdk_draw_layout(). We use
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* it here mostly because that allows us to work in user coordinates - that is,
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* coordinates prior to the application of the transformation matrix, rather
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* than device coordinates.
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* This demo shows how to use PangoCairo to draw rotated and transformed
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* text. The right pane shows a rotated GtkLabel widget.
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*
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* As of GTK+-2.6, the ability to draw transformed and anti-aliased graphics
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* as shown in this example is only present for text. With GTK+-2.8, a new
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* graphics system called "Cairo" will be introduced that provides these
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* capabilities and many more for all types of graphics.
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* In both cases, a custom PangoCairo shape renderer is installed to draw
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* a red heard using cairo drawing operations instead of the Unicode heart
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* character.
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*/
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#include <math.h>
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#include <gtk/gtk.h>
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#include <string.h>
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static GtkWidget *window = NULL;
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#define HEART "♥"
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const char text[] = "I ♥ GTK+";
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static void
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fancy_shape_renderer (cairo_t *cr,
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PangoAttrShape *attr,
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gboolean do_path,
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gpointer data)
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{
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double x, y;
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cairo_get_current_point (cr, &x, &y);
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cairo_translate (cr, x, y);
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cairo_scale (cr,
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(double) attr->ink_rect.width / PANGO_SCALE,
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(double) attr->ink_rect.height / PANGO_SCALE);
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switch (GPOINTER_TO_UINT (attr->data))
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{
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case 0x2665: /* U+2665 BLACK HEART SUIT */
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{
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cairo_move_to (cr, .5, .0);
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cairo_line_to (cr, .9, -.4);
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cairo_curve_to (cr, 1.1, -.8, .5, -.9, .5, -.5);
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cairo_curve_to (cr, .5, -.9, -.1, -.8, .1, -.4);
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cairo_close_path (cr);
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}
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break;
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}
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if (!do_path) {
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cairo_set_source_rgb (cr, 1., 0., 0.);
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cairo_fill (cr);
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}
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}
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PangoAttrList *
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create_fancy_attr_list_for_layout (PangoLayout *layout)
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{
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PangoAttrList *attrs;
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PangoFontMetrics *metrics;
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int ascent;
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PangoRectangle ink_rect, logical_rect;
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const char *p;
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/* Get font metrics and prepare fancy shape size */
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metrics = pango_context_get_metrics (pango_layout_get_context (layout),
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pango_layout_get_font_description (layout),
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NULL);
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ascent = pango_font_metrics_get_ascent (metrics);
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logical_rect.x = 0;
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logical_rect.width = ascent;
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logical_rect.y = -ascent;
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logical_rect.height = ascent;
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ink_rect = logical_rect;
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pango_font_metrics_unref (metrics);
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/* Set fancy shape attributes for all hearts */
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attrs = pango_attr_list_new ();
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for (p = text; (p = strstr (p, HEART)); p += strlen (HEART))
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{
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PangoAttribute *attr;
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attr = pango_attr_shape_new_with_data (&ink_rect,
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&logical_rect,
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GUINT_TO_POINTER (g_utf8_get_char (p)),
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NULL, NULL);
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attr->start_index = p - text;
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attr->end_index = attr->start_index + strlen (HEART);
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pango_attr_list_insert (attrs, attr);
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}
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return attrs;
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}
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static gboolean
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rotated_text_expose_event (GtkWidget *widget,
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GdkEventExpose *event,
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gpointer data)
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{
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#define RADIUS 150
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#define N_WORDS 10
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#define FONT "Sans Bold 27"
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PangoRenderer *renderer;
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PangoMatrix matrix = PANGO_MATRIX_INIT;
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#define N_WORDS 5
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#define FONT "Serif 18"
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PangoContext *context;
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PangoLayout *layout;
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PangoFontDescription *desc;
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cairo_t *cr;
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cairo_pattern_t *pattern;
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PangoAttrList *attrs;
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int width = widget->allocation.width;
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int height = widget->allocation.height;
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double device_radius;
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int i;
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/* Get the default renderer for the screen, and set it up for drawing */
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renderer = gdk_pango_renderer_get_default (gtk_widget_get_screen (widget));
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gdk_pango_renderer_set_drawable (GDK_PANGO_RENDERER (renderer), widget->window);
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gdk_pango_renderer_set_gc (GDK_PANGO_RENDERER (renderer), widget->style->black_gc);
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/* Set up a transformation matrix so that the user space coordinates for
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* the centered square where we draw are [-RADIUS, RADIUS], [-RADIUS, RADIUS]
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* We first center, then change the scale */
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/* Create a cairo context and set up a transformation matrix so that the user
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* space coordinates for the centered square where we draw are [-RADIUS, RADIUS],
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* [-RADIUS, RADIUS].
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* We first center, then change the scale. */
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cr = gdk_cairo_create (widget->window);
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device_radius = MIN (width, height) / 2.;
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pango_matrix_translate (&matrix,
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device_radius + (width - 2 * device_radius) / 2,
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device_radius + (height - 2 * device_radius) / 2);
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pango_matrix_scale (&matrix, device_radius / RADIUS, device_radius / RADIUS);
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cairo_translate (cr,
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device_radius + (width - 2 * device_radius) / 2,
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device_radius + (height - 2 * device_radius) / 2);
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cairo_scale (cr, device_radius / RADIUS, device_radius / RADIUS);
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/* Create a PangoLayout, set the font and text */
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/* Create and a subtle gradient source and use it. */
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pattern = cairo_pattern_create_linear (-RADIUS, -RADIUS, RADIUS, RADIUS);
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cairo_pattern_add_color_stop_rgb (pattern, 0., .5, .0, .0);
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cairo_pattern_add_color_stop_rgb (pattern, 1., .0, .0, .5);
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cairo_set_source (cr, pattern);
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/* Create a PangoContext and set up our shape renderer */
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context = gtk_widget_create_pango_context (widget);
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pango_cairo_context_set_shape_renderer (context,
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fancy_shape_renderer,
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NULL, NULL);
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/* Create a PangoLayout, set the text, font, and attributes */
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layout = pango_layout_new (context);
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pango_layout_set_text (layout, "Text", -1);
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pango_layout_set_text (layout, text, -1);
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desc = pango_font_description_from_string (FONT);
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pango_layout_set_font_description (layout, desc);
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pango_font_description_free (desc);
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attrs = create_fancy_attr_list_for_layout (layout);
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pango_layout_set_attributes (layout, attrs);
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pango_attr_list_unref (attrs);
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/* Draw the layout N_WORDS times in a circle */
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for (i = 0; i < N_WORDS; i++)
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{
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GdkColor color;
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PangoMatrix rotated_matrix = matrix;
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int width, height;
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double angle = (360. * i) / N_WORDS;
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/* Gradient from red at angle == 60 to blue at angle == 300 */
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color.red = 65535 * (1 + cos ((angle - 60) * G_PI / 180.)) / 2;
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color.green = 0;
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color.blue = 65535 - color.red;
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gdk_pango_renderer_set_override_color (GDK_PANGO_RENDERER (renderer),
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PANGO_RENDER_PART_FOREGROUND, &color);
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pango_matrix_rotate (&rotated_matrix, angle);
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pango_context_set_matrix (context, &rotated_matrix);
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/* Inform Pango to re-layout the text with the new transformation matrix */
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pango_layout_context_changed (layout);
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pango_cairo_update_layout (cr, layout);
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pango_layout_get_size (layout, &width, &height);
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pango_renderer_draw_layout (renderer, layout,
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- width / 2, - RADIUS * PANGO_SCALE);
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pango_layout_get_pixel_size (layout, &width, &height);
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cairo_move_to (cr, - width / 2, - RADIUS * .9);
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pango_cairo_show_layout (cr, layout);
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/* Rotate for the next turn */
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cairo_rotate (cr, G_PI*2 / N_WORDS);
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}
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/* Clean up default renderer, since it is shared */
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gdk_pango_renderer_set_override_color (GDK_PANGO_RENDERER (renderer),
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PANGO_RENDER_PART_FOREGROUND, NULL);
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gdk_pango_renderer_set_drawable (GDK_PANGO_RENDERER (renderer), NULL);
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gdk_pango_renderer_set_gc (GDK_PANGO_RENDERER (renderer), NULL);
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/* free the objects we created */
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pango_font_description_free (desc);
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g_object_unref (layout);
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g_object_unref (context);
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cairo_pattern_destroy (pattern);
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cairo_destroy (cr);
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return FALSE;
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}
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@ -103,21 +175,30 @@ rotated_text_expose_event (GtkWidget *widget,
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GtkWidget *
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do_rotated_text (GtkWidget *do_widget)
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{
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GtkWidget *drawing_area;
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if (!window)
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{
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GtkWidget *box;
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GtkWidget *drawing_area;
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GtkWidget *label;
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PangoLayout *layout;
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PangoAttrList *attrs;
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const GdkColor white = { 0, 0xffff, 0xffff, 0xffff };
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window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
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gtk_window_set_screen (GTK_WINDOW (window),
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gtk_widget_get_screen (do_widget));
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gtk_window_set_title (GTK_WINDOW (window), "Rotated Text");
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gtk_window_set_default_size (GTK_WINDOW (window), 4 * RADIUS, 2 * RADIUS);
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g_signal_connect (window, "destroy", G_CALLBACK (gtk_widget_destroyed), &window);
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box = gtk_hbox_new (TRUE, 0);
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gtk_container_add (GTK_CONTAINER (window), box);
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/* Add a drawing area */
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drawing_area = gtk_drawing_area_new ();
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gtk_container_add (GTK_CONTAINER (window), drawing_area);
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gtk_container_add (GTK_CONTAINER (box), drawing_area);
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/* This overrides the background color from the theme */
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gtk_widget_modify_bg (drawing_area, GTK_STATE_NORMAL, &white);
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@ -125,7 +206,21 @@ do_rotated_text (GtkWidget *do_widget)
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g_signal_connect (drawing_area, "expose-event",
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G_CALLBACK (rotated_text_expose_event), NULL);
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gtk_window_set_default_size (GTK_WINDOW (window), 2 * RADIUS, 2 * RADIUS);
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/* And a label */
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label = gtk_label_new (text);
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gtk_container_add (GTK_CONTAINER (box), label);
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gtk_label_set_angle (label, 45);
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/* Set up fancy stuff on the label */
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layout = gtk_label_get_layout (label);
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pango_cairo_context_set_shape_renderer (pango_layout_get_context (layout),
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fancy_shape_renderer,
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NULL, NULL);
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attrs = create_fancy_attr_list_for_layout (layout);
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gtk_label_set_attributes (label, attrs);
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pango_attr_list_unref (attrs);
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}
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if (!GTK_WIDGET_VISIBLE (window))
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