gtk2/demos/gtk-demo/hypertext.c
Matthias Clasen 895dc94cc9 gtk-demo: Avoid a missing icon
The hypertext demo was using an icon that we no longer
include in our embedded icon theme. Use a different one.
2021-11-08 14:17:42 -05:00

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/* Text View/Hypertext
* #Keywords: GtkTextView, GtkTextBuffer
*
* Usually, tags modify the appearance of text in the view, e.g. making it
* bold or colored or underlined. But tags are not restricted to appearance.
* They can also affect the behavior of mouse and key presses, as this demo
* shows.
*
* We also demonstrate adding other things to a text view, such as
* clickable icons.
*/
#include <gtk/gtk.h>
#include <gdk/gdkkeysyms.h>
/* Inserts a piece of text into the buffer, giving it the usual
* appearance of a hyperlink in a web browser: blue and underlined.
* Additionally, attaches some data on the tag, to make it recognizable
* as a link.
*/
static void
insert_link (GtkTextBuffer *buffer,
GtkTextIter *iter,
const char *text,
int page)
{
GtkTextTag *tag;
tag = gtk_text_buffer_create_tag (buffer, NULL,
"foreground", "blue",
"underline", PANGO_UNDERLINE_SINGLE,
NULL);
g_object_set_data (G_OBJECT (tag), "page", GINT_TO_POINTER (page));
gtk_text_buffer_insert_with_tags (buffer, iter, text, -1, tag, NULL);
}
/* Quick-and-dirty text-to-speech for a single word. If you don't hear
* anything, you are missing espeak-ng on your system.
*/
static void
say_word (GtkGestureClick *gesture,
guint n_press,
double x,
double y,
const char *word)
{
const char *argv[3];
argv[0] = "espeak-ng";
argv[1] = word;
argv[2] = NULL;
g_spawn_async (NULL, (char **)argv, NULL, G_SPAWN_SEARCH_PATH, NULL, NULL, NULL, NULL);
}
/* Fills the buffer with text and interspersed links. In any real
* hypertext app, this method would parse a file to identify the links.
*/
static void
show_page (GtkTextView *text_view,
int page)
{
GtkTextBuffer *buffer;
GtkTextIter iter, start;
GtkTextMark *mark;
GtkWidget *child;
GtkTextChildAnchor *anchor;
GtkEventController *controller;
GtkTextTag *bold, *mono, *nobreaks;
buffer = gtk_text_view_get_buffer (text_view);
bold = gtk_text_buffer_create_tag (buffer, NULL,
"weight", PANGO_WEIGHT_BOLD,
"scale", PANGO_SCALE_X_LARGE,
NULL);
mono = gtk_text_buffer_create_tag (buffer, NULL,
"family", "monospace",
NULL);
nobreaks = gtk_text_buffer_create_tag (buffer, NULL,
"allow-breaks", FALSE,
NULL);
gtk_text_buffer_set_text (buffer, "", 0);
gtk_text_buffer_get_iter_at_offset (buffer, &iter, 0);
gtk_text_buffer_begin_irreversible_action (buffer);
if (page == 1)
{
GtkIconPaintable *icon;
GtkIconTheme *theme;
gtk_text_buffer_insert (buffer, &iter, "Some text to show that simple ", -1);
insert_link (buffer, &iter, "hypertext", 3);
gtk_text_buffer_insert (buffer, &iter, " can easily be realized with ", -1);
insert_link (buffer, &iter, "tags", 2);
gtk_text_buffer_insert (buffer, &iter, ".\n", -1);
gtk_text_buffer_insert (buffer, &iter, "Of course you can also embed Emoji 😋, ", -1);
gtk_text_buffer_insert (buffer, &iter, "icons ", -1);
theme = gtk_icon_theme_get_for_display (gtk_widget_get_display (GTK_WIDGET (text_view)));
icon = gtk_icon_theme_lookup_icon (theme,
"eye-not-looking-symbolic",
NULL,
16,
1,
GTK_TEXT_DIR_LTR,
0);
gtk_text_buffer_insert_paintable (buffer, &iter, GDK_PAINTABLE (icon));
g_object_unref (icon);
gtk_text_buffer_insert (buffer, &iter, ", or even widgets ", -1);
anchor = gtk_text_buffer_create_child_anchor (buffer, &iter);
child = gtk_level_bar_new_for_interval (0, 100);
gtk_level_bar_set_value (GTK_LEVEL_BAR (child), 50);
gtk_widget_set_size_request (child, 100, -1);
gtk_text_view_add_child_at_anchor (text_view, child, anchor);
gtk_text_buffer_insert (buffer, &iter, ".", -1);
}
else if (page == 2)
{
mark = gtk_text_buffer_create_mark (buffer, "mark", &iter, TRUE);
gtk_text_buffer_insert_with_tags (buffer, &iter, "tag", -1, bold, NULL);
gtk_text_buffer_insert (buffer, &iter, " /", -1);
gtk_text_buffer_get_iter_at_mark (buffer, &start, mark);
gtk_text_buffer_apply_tag (buffer, nobreaks, &start, &iter);
gtk_text_buffer_insert (buffer, &iter, " ", -1);
gtk_text_buffer_move_mark (buffer, mark, &iter);
gtk_text_buffer_insert_with_tags (buffer, &iter, "tag", -1, mono, NULL);
gtk_text_buffer_insert (buffer, &iter, " /", -1);
gtk_text_buffer_get_iter_at_mark (buffer, &start, mark);
gtk_text_buffer_apply_tag (buffer, nobreaks, &start, &iter);
gtk_text_buffer_insert (buffer, &iter, " ", -1);
anchor = gtk_text_buffer_create_child_anchor (buffer, &iter);
child = gtk_image_new_from_icon_name ("audio-volume-high-symbolic");
gtk_widget_set_cursor_from_name (child, "pointer");
controller = GTK_EVENT_CONTROLLER (gtk_gesture_click_new ());
g_signal_connect (controller, "pressed", G_CALLBACK (say_word), (gpointer)"tag");
gtk_widget_add_controller (child, controller);
gtk_text_view_add_child_at_anchor (text_view, child, anchor);
gtk_text_buffer_insert (buffer, &iter, "\n"
"An attribute that can be applied to some range of text. For example, "
"a tag might be called “bold” and make the text inside the tag bold.\n"
"However, the tag concept is more general than that; "
"tags don't have to affect appearance. They can instead affect the "
"behavior of mouse and key presses, “lock” a range of text so the "
"user can't edit it, or countless other things.\n", -1);
insert_link (buffer, &iter, "Go back", 1);
gtk_text_buffer_delete_mark (buffer, mark);
}
else if (page == 3)
{
mark = gtk_text_buffer_create_mark (buffer, "mark", &iter, TRUE);
gtk_text_buffer_insert_with_tags (buffer, &iter, "hypertext", -1, bold, NULL);
gtk_text_buffer_insert (buffer, &iter, " /", -1);
gtk_text_buffer_get_iter_at_mark (buffer, &start, mark);
gtk_text_buffer_apply_tag (buffer, nobreaks, &start, &iter);
gtk_text_buffer_insert (buffer, &iter, " ", -1);
gtk_text_buffer_move_mark (buffer, mark, &iter);
gtk_text_buffer_insert_with_tags (buffer, &iter, "ˈhaɪ pərˌtɛkst", -1, mono, NULL);
gtk_text_buffer_insert (buffer, &iter, " /", -1);
gtk_text_buffer_get_iter_at_mark (buffer, &start, mark);
gtk_text_buffer_apply_tag (buffer, nobreaks, &start, &iter);
gtk_text_buffer_insert (buffer, &iter, " ", -1);
anchor = gtk_text_buffer_create_child_anchor (buffer, &iter);
child = gtk_image_new_from_icon_name ("audio-volume-high-symbolic");
gtk_widget_set_cursor_from_name (child, "pointer");
controller = GTK_EVENT_CONTROLLER (gtk_gesture_click_new ());
g_signal_connect (controller, "pressed", G_CALLBACK (say_word), (gpointer)"hypertext");
gtk_widget_add_controller (child, controller);
gtk_text_view_add_child_at_anchor (text_view, child, anchor);
gtk_text_buffer_insert (buffer, &iter, "\n"
"Machine-readable text that is not sequential but is organized "
"so that related items of information are connected.\n", -1);
insert_link (buffer, &iter, "Go back", 1);
gtk_text_buffer_delete_mark (buffer, mark);
}
gtk_text_buffer_end_irreversible_action (buffer);
}
/* Looks at all tags covering the position of iter in the text view,
* and if one of them is a link, follow it by showing the page identified
* by the data attached to it.
*/
static void
follow_if_link (GtkWidget *text_view,
GtkTextIter *iter)
{
GSList *tags = NULL, *tagp = NULL;
tags = gtk_text_iter_get_tags (iter);
for (tagp = tags; tagp != NULL; tagp = tagp->next)
{
GtkTextTag *tag = tagp->data;
int page = GPOINTER_TO_INT (g_object_get_data (G_OBJECT (tag), "page"));
if (page != 0)
{
show_page (GTK_TEXT_VIEW (text_view), page);
break;
}
}
if (tags)
g_slist_free (tags);
}
/* Links can be activated by pressing Enter.
*/
static gboolean
key_pressed (GtkEventController *controller,
guint keyval,
guint keycode,
GdkModifierType modifiers,
GtkWidget *text_view)
{
GtkTextIter iter;
GtkTextBuffer *buffer;
switch (keyval)
{
case GDK_KEY_Return:
case GDK_KEY_KP_Enter:
buffer = gtk_text_view_get_buffer (GTK_TEXT_VIEW (text_view));
gtk_text_buffer_get_iter_at_mark (buffer, &iter,
gtk_text_buffer_get_insert (buffer));
follow_if_link (text_view, &iter);
break;
default:
break;
}
return GDK_EVENT_PROPAGATE;
}
static void set_cursor_if_appropriate (GtkTextView *text_view,
int x,
int y);
static void
released_cb (GtkGestureClick *gesture,
guint n_press,
double x,
double y,
GtkWidget *text_view)
{
GtkTextIter start, end, iter;
GtkTextBuffer *buffer;
int tx, ty;
if (gtk_gesture_single_get_button (GTK_GESTURE_SINGLE (gesture)) > 1)
return;
gtk_text_view_window_to_buffer_coords (GTK_TEXT_VIEW (text_view),
GTK_TEXT_WINDOW_WIDGET,
x, y, &tx, &ty);
buffer = gtk_text_view_get_buffer (GTK_TEXT_VIEW (text_view));
/* we shouldn't follow a link if the user has selected something */
gtk_text_buffer_get_selection_bounds (buffer, &start, &end);
if (gtk_text_iter_get_offset (&start) != gtk_text_iter_get_offset (&end))
return;
if (gtk_text_view_get_iter_at_location (GTK_TEXT_VIEW (text_view), &iter, tx, ty))
follow_if_link (text_view, &iter);
}
static void
motion_cb (GtkEventControllerMotion *controller,
double x,
double y,
GtkTextView *text_view)
{
int tx, ty;
gtk_text_view_window_to_buffer_coords (text_view,
GTK_TEXT_WINDOW_WIDGET,
x, y, &tx, &ty);
set_cursor_if_appropriate (text_view, tx, ty);
}
static gboolean hovering_over_link = FALSE;
/* Looks at all tags covering the position (x, y) in the text view,
* and if one of them is a link, change the cursor to the "hands" cursor
* typically used by web browsers.
*/
static void
set_cursor_if_appropriate (GtkTextView *text_view,
int x,
int y)
{
GSList *tags = NULL, *tagp = NULL;
GtkTextIter iter;
gboolean hovering = FALSE;
if (gtk_text_view_get_iter_at_location (text_view, &iter, x, y))
{
tags = gtk_text_iter_get_tags (&iter);
for (tagp = tags; tagp != NULL; tagp = tagp->next)
{
GtkTextTag *tag = tagp->data;
int page = GPOINTER_TO_INT (g_object_get_data (G_OBJECT (tag), "page"));
if (page != 0)
{
hovering = TRUE;
break;
}
}
}
if (hovering != hovering_over_link)
{
hovering_over_link = hovering;
if (hovering_over_link)
gtk_widget_set_cursor_from_name (GTK_WIDGET (text_view), "pointer");
else
gtk_widget_set_cursor_from_name (GTK_WIDGET (text_view), "text");
}
if (tags)
g_slist_free (tags);
}
GtkWidget *
do_hypertext (GtkWidget *do_widget)
{
static GtkWidget *window = NULL;
if (!window)
{
GtkWidget *view;
GtkWidget *sw;
GtkTextBuffer *buffer;
GtkEventController *controller;
window = gtk_window_new ();
gtk_window_set_title (GTK_WINDOW (window), "Hypertext");
gtk_window_set_display (GTK_WINDOW (window),
gtk_widget_get_display (do_widget));
gtk_window_set_default_size (GTK_WINDOW (window), 330, 330);
gtk_window_set_resizable (GTK_WINDOW (window), FALSE);
g_object_add_weak_pointer (G_OBJECT (window), (gpointer *)&window);
view = gtk_text_view_new ();
gtk_text_view_set_wrap_mode (GTK_TEXT_VIEW (view), GTK_WRAP_WORD);
gtk_text_view_set_top_margin (GTK_TEXT_VIEW (view), 20);
gtk_text_view_set_bottom_margin (GTK_TEXT_VIEW (view), 20);
gtk_text_view_set_left_margin (GTK_TEXT_VIEW (view), 20);
gtk_text_view_set_right_margin (GTK_TEXT_VIEW (view), 20);
gtk_text_view_set_pixels_below_lines (GTK_TEXT_VIEW (view), 10);
controller = gtk_event_controller_key_new ();
g_signal_connect (controller, "key-pressed", G_CALLBACK (key_pressed), view);
gtk_widget_add_controller (view, controller);
controller = GTK_EVENT_CONTROLLER (gtk_gesture_click_new ());
g_signal_connect (controller, "released",
G_CALLBACK (released_cb), view);
gtk_widget_add_controller (view, controller);
controller = gtk_event_controller_motion_new ();
g_signal_connect (controller, "motion",
G_CALLBACK (motion_cb), view);
gtk_widget_add_controller (view, controller);
buffer = gtk_text_view_get_buffer (GTK_TEXT_VIEW (view));
gtk_text_buffer_set_enable_undo (buffer, TRUE);
sw = gtk_scrolled_window_new ();
gtk_scrolled_window_set_policy (GTK_SCROLLED_WINDOW (sw),
GTK_POLICY_NEVER,
GTK_POLICY_AUTOMATIC);
gtk_window_set_child (GTK_WINDOW (window), sw);
gtk_scrolled_window_set_child (GTK_SCROLLED_WINDOW (sw), view);
show_page (GTK_TEXT_VIEW (view), 1);
}
if (!gtk_widget_get_visible (window))
gtk_widget_show (window);
else
gtk_window_destroy (GTK_WINDOW (window));
return window;
}