tests/barf.c

   1 /*
   2  * Compile me with:
   3  * gcc -g -O0 -Wall -pthread -o barf barf.c `pkg-config --cflags --libs gtk+-2.0`
   4  */
   5
   6 #include <gtk/gtk.h>
   7
   8 static gulong pager_handler = 0;
   9 static gulong expose_handler = 0;
  10 static gboolean currently_paging = FALSE;
  11
  12 static gboolean
  13 quit()
  14 {
  15         gtk_main_quit();
  16         return TRUE;
  17 }
  18
  19 static void
  20 barf(GtkButton *button, GtkTextBuffer *buffer)
  21 {
  22         GtkTextIter end;
  23         gtk_text_buffer_get_end_iter(buffer, &end);
  24
  25         gtk_text_buffer_move_mark_by_name(buffer, "pager_position", &end);
  26
  27         gchar *loremipsum;
  28         g_file_get_contents("loremipsum.txt", &loremipsum, NULL, NULL);
  29         gtk_text_buffer_insert(buffer, &end, loremipsum, -1);
  30         g_free(loremipsum);
  31 }
  32
  33 static gint
  34 move_pager_and_get_scroll_distance(GtkTextView *textview)
  35 {
  36         GdkRectangle pagerpos, endpos, visiblerect;
  37         GtkTextIter pager, end;
  38         GtkTextBuffer *buffer = gtk_text_view_get_buffer(textview);
  39
  40         gtk_text_view_get_visible_rect(textview, &visiblerect);
  41         gtk_text_view_get_iter_at_location(textview, &pager, visiblerect.x + visiblerect.width, visiblerect.y + visiblerect.height);
  42         gtk_text_buffer_move_mark_by_name(buffer, "pager_position", &pager);
  43
  44         gtk_text_buffer_get_end_iter(buffer, &end);
  45         gtk_text_view_get_iter_location(textview, &pager, &pagerpos);
  46         gtk_text_view_get_iter_location(textview, &end, &endpos);
  47
  48         g_printerr("View height = %d\n", visiblerect.height);
  49         g_printerr("End - Pager = %d\n", endpos.y - pagerpos.y);
  50
  51         return endpos.y - pagerpos.y;
  52 }
  53
  54 static void
  55 start_paging(GtkTextView *textview)
  56 {
  57         currently_paging = TRUE;
  58         g_signal_handler_unblock(textview, expose_handler);
  59         g_signal_handler_unblock(textview, pager_handler);
  60 }
  61
  62 static void
  63 stop_paging(GtkTextView *textview)
  64 {
  65         currently_paging = FALSE;
  66         g_signal_handler_block(textview, expose_handler);
  67         g_signal_handler_block(textview, pager_handler);
  68 }
  69
  70 static void
  71 after_insert(GtkTextBuffer *buffer, GtkTextIter *location, gchar *text, gint len, GtkTextView *textview)
  72 {
  73         while(gtk_events_pending())
  74                 gtk_main_iteration();
  75
  76         /* Move the pager to the last visible character in the buffer */
  77         gint scroll_distance = move_pager_and_get_scroll_distance(textview);
  78
  79         /* Wait for a keypress to advance the pager */
  80         if(scroll_distance > 0 && !currently_paging)
  81                 start_paging(textview);
  82 }
  83
  84 static gboolean
  85 pager_wait(GtkTextView *textview, GdkEventKey *event, GtkTextBuffer *buffer)
  86 {
  87         GtkTextMark *pagermark = gtk_text_buffer_get_mark(buffer, "pager_position");
  88         gtk_text_view_scroll_to_mark(textview, pagermark, 0.0, TRUE, 0.0, 0.0);
  89
  90         /*** ALTERNATIVE, POSSIBLY BETTER, METHOD OF SCROLLING ***
  91         GtkWidget *scrolledwindow = gtk_widget_get_parent(GTK_WIDGET(textview));
  92         GtkAdjustment *adjustment = gtk_scrolled_window_get_vadjustment(GTK_SCROLLED_WINDOW(scrolledwindow));
  93         gdouble page_size; // SUCKY_DEBIAN: use gtk_adjustment_get_page_size() post 2.12
  94         g_object_get(adjustment, "page-size", &page_size, NULL);
  95         gtk_adjustment_set_value(adjustment, gtk_adjustment_get_value(adjustment) + page_size);
  96         */
  97
  98         while(gtk_events_pending())
  99                 gtk_main_iteration();
 100
 101         /* Move the pager to the last visible character in the buffer */
 102         gint scroll_distance = move_pager_and_get_scroll_distance(textview);
 103
 104         if(scroll_distance == 0)
 105                 stop_paging(textview);
 106
 107         return TRUE; /* block further handlers */
 108 }
 109
 110 static gboolean
 111 expose_prompt(GtkTextView *textview, GdkEventExpose *event)
 112 {
 113         /* Use Cairo? Cairo supported on Iliad? */
 114         PangoLayout *prompt = gtk_widget_create_pango_layout(GTK_WIDGET(textview), "More");
 115         gint promptwidth, promptheight;
 116         pango_layout_get_pixel_size(prompt, &promptwidth, &promptheight);
 117
 118         GdkGC *context = gdk_gc_new(GDK_DRAWABLE(event->window));
 119         GdkColor red, white;
 120         gdk_color_parse("red", &red);
 121         gdk_color_parse("white", &white);
 122
 123         gint winx, winy, winwidth, winheight;
 124         gdk_window_get_position(event->window, &winx, &winy);
 125         gdk_drawable_get_size(GDK_DRAWABLE(event->window), &winwidth, &winheight);
 126
 127         gdk_draw_layout_with_colors(event->window, context,
 128                 winx + winwidth - promptwidth,
 129                 winy + winheight - promptheight,
 130                 prompt, &white, &red);
 131
 132         return FALSE; /* Propagate event further */
 133 }
 134
 135 int
 136 main(int argc, char **argv)
 137 {
 138         gtk_init(&argc, &argv);
 139
 140         GtkWidget *window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
 141         gtk_widget_set_size_request(window, 400, 400);
 142         GtkWidget *button = gtk_button_new_with_label("Barf");
 143         GtkWidget *scrolledwindow = gtk_scrolled_window_new(NULL, NULL);
 144         GtkWidget *textview = gtk_text_view_new();
 145         gtk_text_view_set_wrap_mode(GTK_TEXT_VIEW(textview), GTK_WRAP_WORD_CHAR);
 146         gtk_text_view_set_editable(GTK_TEXT_VIEW(textview), FALSE);
 147         GtkWidget *vbox = gtk_vbox_new(FALSE, 6);
 148
 149         gtk_container_add(GTK_CONTAINER(scrolledwindow), textview);
 150         gtk_box_pack_start(GTK_BOX(vbox), button, FALSE, FALSE, 0);
 151         gtk_box_pack_start(GTK_BOX(vbox), scrolledwindow, TRUE, TRUE, 0);
 152         gtk_container_add(GTK_CONTAINER(window), vbox);
 153         gtk_widget_show_all(window);
 154
 155         /* Set up the textview widget to receive exposure events, must be done after widget has been shown */
 156         gdk_window_set_events(gtk_widget_get_window(textview), GDK_EXPOSURE_MASK);
 157
 158         GtkTextBuffer *buffer = gtk_text_view_get_buffer(GTK_TEXT_VIEW(textview));
 159         g_signal_connect_after(buffer, "insert-text", G_CALLBACK(after_insert), textview);
 160         pager_handler = g_signal_connect(textview, "key-press-event", G_CALLBACK(pager_wait), buffer);
 161         g_signal_handler_block(textview, pager_handler);
 162         expose_handler = g_signal_connect_after(textview, "expose-event", G_CALLBACK(expose_prompt), NULL);
 163         g_signal_handler_block(textview, expose_handler);
 164
 165         GtkTextIter end;
 166         gtk_text_buffer_get_end_iter(buffer, &end);
 167         GtkTextMark *pagermark = gtk_text_buffer_create_mark(buffer, "pager_position", &end, TRUE);
 168         gtk_text_mark_set_visible(pagermark, TRUE);
 169
 170         g_signal_connect(window, "delete-event", G_CALLBACK(quit), NULL);
 171         g_signal_connect(button, "clicked", G_CALLBACK(barf), buffer);
 172
 173         gtk_main();
 174         return 0;
 175 }