1 | /* Text View/Hypertext |
2 | * #Keywords: GtkTextView, GtkTextBuffer |
3 | * |
4 | * Usually, tags modify the appearance of text in the view, e.g. making it |
5 | * bold or colored or underlined. But tags are not restricted to appearance. |
6 | * They can also affect the behavior of mouse and key presses, as this demo |
7 | * shows. |
8 | * |
9 | * We also demonstrate adding other things to a text view, such as |
10 | * clickable icons and widgets which can also replace a character |
11 | * (try copying the ghost text). |
12 | */ |
13 | |
14 | #include <gtk/gtk.h> |
15 | #include <gdk/gdkkeysyms.h> |
16 | |
17 | /* Inserts a piece of text into the buffer, giving it the usual |
18 | * appearance of a hyperlink in a web browser: blue and underlined. |
19 | * Additionally, attaches some data on the tag, to make it recognizable |
20 | * as a link. |
21 | */ |
22 | static void |
23 | insert_link (GtkTextBuffer *buffer, |
24 | GtkTextIter *iter, |
25 | const char *text, |
26 | int page) |
27 | { |
28 | GtkTextTag *tag; |
29 | |
30 | tag = gtk_text_buffer_create_tag (buffer, NULL, |
31 | first_property_name: "foreground" , "blue" , |
32 | "underline" , PANGO_UNDERLINE_SINGLE, |
33 | NULL); |
34 | g_object_set_data (G_OBJECT (tag), key: "page" , GINT_TO_POINTER (page)); |
35 | gtk_text_buffer_insert_with_tags (buffer, iter, text, len: -1, first_tag: tag, NULL); |
36 | } |
37 | |
38 | /* Quick-and-dirty text-to-speech for a single word. If you don't hear |
39 | * anything, you are missing espeak-ng on your system. |
40 | */ |
41 | static void |
42 | say_word (GtkGestureClick *gesture, |
43 | guint n_press, |
44 | double x, |
45 | double y, |
46 | const char *word) |
47 | { |
48 | const char *argv[3]; |
49 | |
50 | argv[0] = "espeak-ng" ; |
51 | argv[1] = word; |
52 | argv[2] = NULL; |
53 | |
54 | g_spawn_async (NULL, argv: (char **)argv, NULL, flags: G_SPAWN_SEARCH_PATH, NULL, NULL, NULL, NULL); |
55 | } |
56 | |
57 | /* Fills the buffer with text and interspersed links. In any real |
58 | * hypertext app, this method would parse a file to identify the links. |
59 | */ |
60 | static void |
61 | show_page (GtkTextView *text_view, |
62 | int page) |
63 | { |
64 | GtkTextBuffer *buffer; |
65 | GtkTextIter iter, start; |
66 | GtkTextMark *mark; |
67 | GtkWidget *child; |
68 | GtkTextChildAnchor *anchor; |
69 | GtkEventController *controller; |
70 | GtkTextTag *bold, *mono, *nobreaks; |
71 | |
72 | buffer = gtk_text_view_get_buffer (text_view); |
73 | |
74 | bold = gtk_text_buffer_create_tag (buffer, NULL, |
75 | first_property_name: "weight" , PANGO_WEIGHT_BOLD, |
76 | "scale" , PANGO_SCALE_X_LARGE, |
77 | NULL); |
78 | mono = gtk_text_buffer_create_tag (buffer, NULL, |
79 | first_property_name: "family" , "monospace" , |
80 | NULL); |
81 | nobreaks = gtk_text_buffer_create_tag (buffer, NULL, |
82 | first_property_name: "allow-breaks" , FALSE, |
83 | NULL); |
84 | |
85 | gtk_text_buffer_set_text (buffer, text: "" , len: 0); |
86 | gtk_text_buffer_get_iter_at_offset (buffer, iter: &iter, char_offset: 0); |
87 | gtk_text_buffer_begin_irreversible_action (buffer); |
88 | if (page == 1) |
89 | { |
90 | GtkIconPaintable *icon; |
91 | GtkIconTheme *theme; |
92 | |
93 | gtk_text_buffer_insert (buffer, iter: &iter, text: "Some text to show that simple " , len: -1); |
94 | insert_link (buffer, iter: &iter, text: "hypertext" , page: 3); |
95 | gtk_text_buffer_insert (buffer, iter: &iter, text: " can easily be realized with " , len: -1); |
96 | insert_link (buffer, iter: &iter, text: "tags" , page: 2); |
97 | gtk_text_buffer_insert (buffer, iter: &iter, text: ".\n" , len: -1); |
98 | gtk_text_buffer_insert (buffer, iter: &iter, text: "Of course you can also embed Emoji 😋, " , len: -1); |
99 | gtk_text_buffer_insert (buffer, iter: &iter, text: "icons " , len: -1); |
100 | |
101 | theme = gtk_icon_theme_get_for_display (display: gtk_widget_get_display (GTK_WIDGET (text_view))); |
102 | icon = gtk_icon_theme_lookup_icon (self: theme, |
103 | icon_name: "eye-not-looking-symbolic" , |
104 | NULL, |
105 | size: 16, |
106 | scale: 1, |
107 | direction: GTK_TEXT_DIR_LTR, |
108 | flags: 0); |
109 | gtk_text_buffer_insert_paintable (buffer, iter: &iter, paintable: GDK_PAINTABLE (ptr: icon)); |
110 | g_object_unref (object: icon); |
111 | gtk_text_buffer_insert (buffer, iter: &iter, text: ", or even widgets " , len: -1); |
112 | anchor = gtk_text_buffer_create_child_anchor (buffer, iter: &iter); |
113 | child = gtk_level_bar_new_for_interval (min_value: 0, max_value: 100); |
114 | gtk_level_bar_set_value (GTK_LEVEL_BAR (child), value: 50); |
115 | gtk_widget_set_size_request (widget: child, width: 100, height: -1); |
116 | gtk_text_view_add_child_at_anchor (text_view, child, anchor); |
117 | gtk_text_buffer_insert (buffer, iter: &iter, text: " and labels with " , len: -1); |
118 | anchor = gtk_text_child_anchor_new_with_replacement (character: "👻" ); |
119 | gtk_text_buffer_insert_child_anchor (buffer, iter: &iter, anchor); |
120 | child = gtk_label_new (str: "ghost" ); |
121 | gtk_text_view_add_child_at_anchor (text_view, child, anchor); |
122 | gtk_text_buffer_insert (buffer, iter: &iter, text: " text." , len: -1); |
123 | } |
124 | else if (page == 2) |
125 | { |
126 | mark = gtk_text_buffer_create_mark (buffer, mark_name: "mark" , where: &iter, TRUE); |
127 | |
128 | gtk_text_buffer_insert_with_tags (buffer, iter: &iter, text: "tag" , len: -1, first_tag: bold, NULL); |
129 | gtk_text_buffer_insert (buffer, iter: &iter, text: " /" , len: -1); |
130 | |
131 | gtk_text_buffer_get_iter_at_mark (buffer, iter: &start, mark); |
132 | gtk_text_buffer_apply_tag (buffer, tag: nobreaks, start: &start, end: &iter); |
133 | gtk_text_buffer_insert (buffer, iter: &iter, text: " " , len: -1); |
134 | |
135 | gtk_text_buffer_move_mark (buffer, mark, where: &iter); |
136 | gtk_text_buffer_insert_with_tags (buffer, iter: &iter, text: "tag" , len: -1, first_tag: mono, NULL); |
137 | gtk_text_buffer_insert (buffer, iter: &iter, text: " /" , len: -1); |
138 | |
139 | gtk_text_buffer_get_iter_at_mark (buffer, iter: &start, mark); |
140 | gtk_text_buffer_apply_tag (buffer, tag: nobreaks, start: &start, end: &iter); |
141 | gtk_text_buffer_insert (buffer, iter: &iter, text: " " , len: -1); |
142 | |
143 | anchor = gtk_text_buffer_create_child_anchor (buffer, iter: &iter); |
144 | child = gtk_image_new_from_icon_name (icon_name: "audio-volume-high-symbolic" ); |
145 | gtk_widget_set_cursor_from_name (widget: child, name: "pointer" ); |
146 | controller = GTK_EVENT_CONTROLLER (gtk_gesture_click_new ()); |
147 | g_signal_connect (controller, "pressed" , G_CALLBACK (say_word), (gpointer)"tag" ); |
148 | gtk_widget_add_controller (widget: child, controller); |
149 | gtk_text_view_add_child_at_anchor (text_view, child, anchor); |
150 | |
151 | gtk_text_buffer_insert (buffer, iter: &iter, text: "\n" |
152 | "An attribute that can be applied to some range of text. For example, " |
153 | "a tag might be called “bold” and make the text inside the tag bold.\n" |
154 | "However, the tag concept is more general than that; " |
155 | "tags don't have to affect appearance. They can instead affect the " |
156 | "behavior of mouse and key presses, “lock” a range of text so the " |
157 | "user can't edit it, or countless other things.\n" , len: -1); |
158 | insert_link (buffer, iter: &iter, text: "Go back" , page: 1); |
159 | |
160 | gtk_text_buffer_delete_mark (buffer, mark); |
161 | } |
162 | else if (page == 3) |
163 | { |
164 | mark = gtk_text_buffer_create_mark (buffer, mark_name: "mark" , where: &iter, TRUE); |
165 | |
166 | gtk_text_buffer_insert_with_tags (buffer, iter: &iter, text: "hypertext" , len: -1, first_tag: bold, NULL); |
167 | gtk_text_buffer_insert (buffer, iter: &iter, text: " /" , len: -1); |
168 | |
169 | gtk_text_buffer_get_iter_at_mark (buffer, iter: &start, mark); |
170 | gtk_text_buffer_apply_tag (buffer, tag: nobreaks, start: &start, end: &iter); |
171 | gtk_text_buffer_insert (buffer, iter: &iter, text: " " , len: -1); |
172 | |
173 | gtk_text_buffer_move_mark (buffer, mark, where: &iter); |
174 | gtk_text_buffer_insert_with_tags (buffer, iter: &iter, text: "ˈhaɪ pərˌtɛkst" , len: -1, first_tag: mono, NULL); |
175 | gtk_text_buffer_insert (buffer, iter: &iter, text: " /" , len: -1); |
176 | gtk_text_buffer_get_iter_at_mark (buffer, iter: &start, mark); |
177 | gtk_text_buffer_apply_tag (buffer, tag: nobreaks, start: &start, end: &iter); |
178 | gtk_text_buffer_insert (buffer, iter: &iter, text: " " , len: -1); |
179 | |
180 | anchor = gtk_text_buffer_create_child_anchor (buffer, iter: &iter); |
181 | child = gtk_image_new_from_icon_name (icon_name: "audio-volume-high-symbolic" ); |
182 | gtk_widget_set_cursor_from_name (widget: child, name: "pointer" ); |
183 | controller = GTK_EVENT_CONTROLLER (gtk_gesture_click_new ()); |
184 | g_signal_connect (controller, "pressed" , G_CALLBACK (say_word), (gpointer)"hypertext" ); |
185 | gtk_widget_add_controller (widget: child, controller); |
186 | gtk_text_view_add_child_at_anchor (text_view, child, anchor); |
187 | |
188 | gtk_text_buffer_insert (buffer, iter: &iter, text: "\n" |
189 | "Machine-readable text that is not sequential but is organized " |
190 | "so that related items of information are connected.\n" , len: -1); |
191 | insert_link (buffer, iter: &iter, text: "Go back" , page: 1); |
192 | |
193 | gtk_text_buffer_delete_mark (buffer, mark); |
194 | } |
195 | gtk_text_buffer_end_irreversible_action (buffer); |
196 | } |
197 | |
198 | /* Looks at all tags covering the position of iter in the text view, |
199 | * and if one of them is a link, follow it by showing the page identified |
200 | * by the data attached to it. |
201 | */ |
202 | static void |
203 | follow_if_link (GtkWidget *text_view, |
204 | GtkTextIter *iter) |
205 | { |
206 | GSList *tags = NULL, *tagp = NULL; |
207 | |
208 | tags = gtk_text_iter_get_tags (iter); |
209 | for (tagp = tags; tagp != NULL; tagp = tagp->next) |
210 | { |
211 | GtkTextTag *tag = tagp->data; |
212 | int page = GPOINTER_TO_INT (g_object_get_data (G_OBJECT (tag), "page" )); |
213 | |
214 | if (page != 0) |
215 | { |
216 | show_page (GTK_TEXT_VIEW (text_view), page); |
217 | break; |
218 | } |
219 | } |
220 | |
221 | if (tags) |
222 | g_slist_free (list: tags); |
223 | } |
224 | |
225 | /* Links can be activated by pressing Enter. |
226 | */ |
227 | static gboolean |
228 | key_pressed (GtkEventController *controller, |
229 | guint keyval, |
230 | guint keycode, |
231 | GdkModifierType modifiers, |
232 | GtkWidget *text_view) |
233 | { |
234 | GtkTextIter iter; |
235 | GtkTextBuffer *buffer; |
236 | |
237 | switch (keyval) |
238 | { |
239 | case GDK_KEY_Return: |
240 | case GDK_KEY_KP_Enter: |
241 | buffer = gtk_text_view_get_buffer (GTK_TEXT_VIEW (text_view)); |
242 | gtk_text_buffer_get_iter_at_mark (buffer, iter: &iter, |
243 | mark: gtk_text_buffer_get_insert (buffer)); |
244 | follow_if_link (text_view, iter: &iter); |
245 | break; |
246 | |
247 | default: |
248 | break; |
249 | } |
250 | |
251 | return GDK_EVENT_PROPAGATE; |
252 | } |
253 | |
254 | static void set_cursor_if_appropriate (GtkTextView *text_view, |
255 | int x, |
256 | int y); |
257 | |
258 | static void |
259 | released_cb (GtkGestureClick *gesture, |
260 | guint n_press, |
261 | double x, |
262 | double y, |
263 | GtkWidget *text_view) |
264 | { |
265 | GtkTextIter start, end, iter; |
266 | GtkTextBuffer *buffer; |
267 | int tx, ty; |
268 | |
269 | if (gtk_gesture_single_get_button (GTK_GESTURE_SINGLE (gesture)) > 1) |
270 | return; |
271 | |
272 | gtk_text_view_window_to_buffer_coords (GTK_TEXT_VIEW (text_view), |
273 | win: GTK_TEXT_WINDOW_WIDGET, |
274 | window_x: x, window_y: y, buffer_x: &tx, buffer_y: &ty); |
275 | |
276 | buffer = gtk_text_view_get_buffer (GTK_TEXT_VIEW (text_view)); |
277 | |
278 | /* we shouldn't follow a link if the user has selected something */ |
279 | gtk_text_buffer_get_selection_bounds (buffer, start: &start, end: &end); |
280 | if (gtk_text_iter_get_offset (iter: &start) != gtk_text_iter_get_offset (iter: &end)) |
281 | return; |
282 | |
283 | if (gtk_text_view_get_iter_at_location (GTK_TEXT_VIEW (text_view), iter: &iter, x: tx, y: ty)) |
284 | follow_if_link (text_view, iter: &iter); |
285 | } |
286 | |
287 | static void |
288 | motion_cb (GtkEventControllerMotion *controller, |
289 | double x, |
290 | double y, |
291 | GtkTextView *text_view) |
292 | { |
293 | int tx, ty; |
294 | |
295 | gtk_text_view_window_to_buffer_coords (text_view, |
296 | win: GTK_TEXT_WINDOW_WIDGET, |
297 | window_x: x, window_y: y, buffer_x: &tx, buffer_y: &ty); |
298 | |
299 | set_cursor_if_appropriate (text_view, x: tx, y: ty); |
300 | } |
301 | |
302 | static gboolean hovering_over_link = FALSE; |
303 | |
304 | /* Looks at all tags covering the position (x, y) in the text view, |
305 | * and if one of them is a link, change the cursor to the "hands" cursor |
306 | * typically used by web browsers. |
307 | */ |
308 | static void |
309 | set_cursor_if_appropriate (GtkTextView *text_view, |
310 | int x, |
311 | int y) |
312 | { |
313 | GSList *tags = NULL, *tagp = NULL; |
314 | GtkTextIter iter; |
315 | gboolean hovering = FALSE; |
316 | |
317 | if (gtk_text_view_get_iter_at_location (text_view, iter: &iter, x, y)) |
318 | { |
319 | tags = gtk_text_iter_get_tags (iter: &iter); |
320 | for (tagp = tags; tagp != NULL; tagp = tagp->next) |
321 | { |
322 | GtkTextTag *tag = tagp->data; |
323 | int page = GPOINTER_TO_INT (g_object_get_data (G_OBJECT (tag), "page" )); |
324 | |
325 | if (page != 0) |
326 | { |
327 | hovering = TRUE; |
328 | break; |
329 | } |
330 | } |
331 | } |
332 | |
333 | if (hovering != hovering_over_link) |
334 | { |
335 | hovering_over_link = hovering; |
336 | |
337 | if (hovering_over_link) |
338 | gtk_widget_set_cursor_from_name (GTK_WIDGET (text_view), name: "pointer" ); |
339 | else |
340 | gtk_widget_set_cursor_from_name (GTK_WIDGET (text_view), name: "text" ); |
341 | } |
342 | |
343 | if (tags) |
344 | g_slist_free (list: tags); |
345 | } |
346 | |
347 | GtkWidget * |
348 | do_hypertext (GtkWidget *do_widget) |
349 | { |
350 | static GtkWidget *window = NULL; |
351 | |
352 | if (!window) |
353 | { |
354 | GtkWidget *view; |
355 | GtkWidget *sw; |
356 | GtkTextBuffer *buffer; |
357 | GtkEventController *controller; |
358 | |
359 | window = gtk_window_new (); |
360 | gtk_window_set_title (GTK_WINDOW (window), title: "Hypertext" ); |
361 | gtk_window_set_display (GTK_WINDOW (window), |
362 | display: gtk_widget_get_display (widget: do_widget)); |
363 | gtk_window_set_default_size (GTK_WINDOW (window), width: 330, height: 330); |
364 | gtk_window_set_resizable (GTK_WINDOW (window), FALSE); |
365 | g_object_add_weak_pointer (G_OBJECT (window), weak_pointer_location: (gpointer *)&window); |
366 | |
367 | view = gtk_text_view_new (); |
368 | gtk_text_view_set_wrap_mode (GTK_TEXT_VIEW (view), wrap_mode: GTK_WRAP_WORD); |
369 | gtk_text_view_set_top_margin (GTK_TEXT_VIEW (view), top_margin: 20); |
370 | gtk_text_view_set_bottom_margin (GTK_TEXT_VIEW (view), bottom_margin: 20); |
371 | gtk_text_view_set_left_margin (GTK_TEXT_VIEW (view), left_margin: 20); |
372 | gtk_text_view_set_right_margin (GTK_TEXT_VIEW (view), right_margin: 20); |
373 | gtk_text_view_set_pixels_below_lines (GTK_TEXT_VIEW (view), pixels_below_lines: 10); |
374 | controller = gtk_event_controller_key_new (); |
375 | g_signal_connect (controller, "key-pressed" , G_CALLBACK (key_pressed), view); |
376 | gtk_widget_add_controller (widget: view, controller); |
377 | |
378 | controller = GTK_EVENT_CONTROLLER (gtk_gesture_click_new ()); |
379 | g_signal_connect (controller, "released" , |
380 | G_CALLBACK (released_cb), view); |
381 | gtk_widget_add_controller (widget: view, controller); |
382 | |
383 | controller = gtk_event_controller_motion_new (); |
384 | g_signal_connect (controller, "motion" , |
385 | G_CALLBACK (motion_cb), view); |
386 | gtk_widget_add_controller (widget: view, controller); |
387 | |
388 | buffer = gtk_text_view_get_buffer (GTK_TEXT_VIEW (view)); |
389 | gtk_text_buffer_set_enable_undo (buffer, TRUE); |
390 | |
391 | sw = gtk_scrolled_window_new (); |
392 | gtk_scrolled_window_set_policy (GTK_SCROLLED_WINDOW (sw), |
393 | hscrollbar_policy: GTK_POLICY_NEVER, |
394 | vscrollbar_policy: GTK_POLICY_AUTOMATIC); |
395 | gtk_window_set_child (GTK_WINDOW (window), child: sw); |
396 | gtk_scrolled_window_set_child (GTK_SCROLLED_WINDOW (sw), child: view); |
397 | |
398 | show_page (GTK_TEXT_VIEW (view), page: 1); |
399 | } |
400 | |
401 | if (!gtk_widget_get_visible (widget: window)) |
402 | gtk_widget_show (widget: window); |
403 | else |
404 | gtk_window_destroy (GTK_WINDOW (window)); |
405 | |
406 | return window; |
407 | } |
408 | |