+/*
+ * Compile me with:
+ * gcc -g -O0 -Wall -pthread -o barf barf.c `pkg-config --cflags --libs gtk+-2.0`
+ */
+
#include <gtk/gtk.h>
+#include <gdk/gdkkeysyms.h>
+
+/* Uncomment to try the other paging method */
+/* #define PAGE_ONLY_UNSEEN 1 */
+
+static gulong pager_handler = 0;
+static gulong expose_handler = 0;
+static gboolean currently_paging = FALSE;
+
+static gint promptwidth, promptheight;
+static PangoLayout *prompt;
+static GdkColor red, white;
static gboolean
quit()
return TRUE;
}
+/* Vomit a load of text onto the screen */
static void
-barf(GtkButton *button, GtkTextBuffer *buffer)
+barf(GtkButton *button, GtkTextView *textview)
{
GtkTextIter end;
+ GtkTextBuffer *buffer = gtk_text_view_get_buffer(textview);
gtk_text_buffer_get_end_iter(buffer, &end);
- gtk_text_buffer_move_mark_by_name(buffer, "pager_position", &end);
-
gchar *loremipsum;
g_file_get_contents("loremipsum.txt", &loremipsum, NULL, NULL);
gtk_text_buffer_insert(buffer, &end, loremipsum, -1);
g_free(loremipsum);
+
+ gtk_widget_grab_focus(GTK_WIDGET(textview));
+}
+
+/* Helper function: move the pager to the last visible position in the buffer,
+ and return the distance between the pager and the end of the buffer in buffer
+ coordinates */
+static gint
+move_pager_and_get_scroll_distance(GtkTextView *textview)
+{
+ GdkRectangle pagerpos, endpos, visiblerect;
+ GtkTextIter oldpager, newpager, end;
+ GtkTextBuffer *buffer = gtk_text_view_get_buffer(textview);
+ GtkTextMark *pager = gtk_text_buffer_get_mark(buffer, "pager_position");
+
+ /* Get an iter at the lower right corner of the visible part of the buffer */
+ gtk_text_view_get_visible_rect(textview, &visiblerect);
+ gtk_text_view_get_iter_at_location(textview, &newpager, visiblerect.x + visiblerect.width, visiblerect.y + visiblerect.height);
+ gtk_text_buffer_get_iter_at_mark(buffer, &oldpager, pager);
+
+#ifdef PAGE_ONLY_UNSEEN
+ if(gtk_text_iter_compare(&oldpager, &newpager) < 0)
+ gtk_text_buffer_move_mark(buffer, pager, &newpager);
+#else
+ gtk_text_buffer_move_mark(buffer, pager, &newpager);
+#endif
+
+ /* Get the buffer coordinates of the pager and the end iter */
+ gtk_text_buffer_get_end_iter(buffer, &end);
+ gtk_text_buffer_get_iter_at_mark(buffer, &newpager, pager);
+ gtk_text_view_get_iter_location(textview, &newpager, &pagerpos);
+ gtk_text_view_get_iter_location(textview, &end, &endpos);
+
+ //g_printerr("View height = %d\n", visiblerect.height);
+ //g_printerr("End - Pager = %d\n", endpos.y - pagerpos.y);
+
+ return endpos.y - pagerpos.y;
+}
+
+/* Helper function: turn on paging for this textview */
+static void
+start_paging(GtkTextView *textview)
+{
+ currently_paging = TRUE;
+ g_signal_handler_unblock(textview, expose_handler);
+ g_signal_handler_unblock(textview, pager_handler);
}
+/* Helper function: turn off paging for this textview */
+static void
+stop_paging(GtkTextView *textview)
+{
+ currently_paging = FALSE;
+ g_signal_handler_block(textview, expose_handler);
+ g_signal_handler_block(textview, pager_handler);
+}
+
+/* Update the pager position after new text is inserted in the buffer */
static void
after_insert(GtkTextBuffer *buffer, GtkTextIter *location, gchar *text, gint len, GtkTextView *textview)
{
while(gtk_events_pending())
gtk_main_iteration();
+
+ /* Move the pager to the last visible character in the buffer */
+ gint scroll_distance = move_pager_and_get_scroll_distance(textview);
+
+ if(scroll_distance > 0 && !currently_paging)
+ start_paging(textview);
+}
+
+static void
+adjustment_changed(GtkAdjustment *adjustment, GtkTextView *textview)
+{
+ while(gtk_events_pending())
+ gtk_main_iteration();
+
+ /* Move the pager, etc. */
+ gint scroll_distance = move_pager_and_get_scroll_distance(textview);
+
+ if(scroll_distance > 0 && !currently_paging)
+ start_paging(textview);
+ else if(scroll_distance == 0 && currently_paging)
+ stop_paging(textview);
+
+ /* Refresh the widget so that any extra "more" prompts disappear */
+ gtk_widget_queue_draw(GTK_WIDGET(textview));
+}
- GdkRectangle pagerpos, endpos, visiblerect;
- GtkTextIter pager, end;
- gtk_text_buffer_get_iter_at_mark(buffer, &pager, gtk_text_buffer_get_mark(buffer, "pager_position"));
- gtk_text_buffer_get_end_iter(buffer, &end);
+/* Handle key press events in the textview while paging is active */
+static gboolean
+pager_wait(GtkTextView *textview, GdkEventKey *event, GtkTextBuffer *buffer)
+{
+ /*** ALTERNATIVE, POSSIBLY INFERIOR, METHOD OF SCROLLING ***
+ GtkTextMark *pagermark = gtk_text_buffer_get_mark(buffer, "pager_position");
+ gtk_text_view_scroll_to_mark(textview, pagermark, 0.0, TRUE, 0.0, 0.0);
+ */
+
+ GtkWidget *scrolledwindow = gtk_widget_get_parent(GTK_WIDGET(textview));
+ GtkAdjustment *adj = gtk_scrolled_window_get_vadjustment(GTK_SCROLLED_WINDOW(scrolledwindow));
+ gdouble step_increment, page_size, upper, lower, value;
+ g_object_get(adj,
+ "page-size", &page_size,
+ "step-increment", &step_increment,
+ "upper", &upper,
+ "lower", &lower,
+ "value", &value,
+ NULL);
- gtk_text_view_get_iter_location(textview, &pager, &pagerpos);
- gtk_text_view_get_iter_location(textview, &end, &endpos);
- gtk_text_view_get_visible_rect(textview, &visiblerect);
+ switch (event->keyval) {
+ case GDK_space: case GDK_KP_Space: case GDK_Page_Down: case GDK_KP_Page_Down:
+ gtk_adjustment_set_value(adj, CLAMP(value + page_size, lower, upper - page_size));
+ break;
+ case GDK_Page_Up: case GDK_KP_Page_Up:
+ gtk_adjustment_set_value(adj, CLAMP(value - page_size, lower, upper - page_size));
+ break;
+ case GDK_Return: case GDK_KP_Enter:
+ gtk_adjustment_set_value(adj, CLAMP(value + step_increment, lower, upper - page_size));
+ break;
+ /* don't handle "up" and "down", they're used for input history */
+ default:
+ return FALSE; /* if the key wasn't handled here, pass it to other handlers */
+ }
+
+ gdk_window_process_updates(gtk_widget_get_window(GTK_WIDGET(textview)), TRUE);
+ return TRUE; /* handled it, stop this event now */
+}
+
+/* Draw the "more" prompt on top of the buffer, after the regular expose event has run */
+static gboolean
+expose_prompt(GtkTextView *textview, GdkEventExpose *event)
+{
+ GdkGC *context = gdk_gc_new(GDK_DRAWABLE(event->window));
+
+ gint winx, winy, winwidth, winheight;
+ gdk_window_get_position(event->window, &winx, &winy);
+ gdk_drawable_get_size(GDK_DRAWABLE(event->window), &winwidth, &winheight);
+
+ gdk_draw_layout_with_colors(event->window, context,
+ winx + winwidth - promptwidth,
+ winy + winheight - promptheight,
+ prompt, &white, &red);
- g_printerr("View height = %d\n", visiblerect.height);
- g_printerr("End - Pager = %d\n", endpos.y - pagerpos.y);
+ return FALSE; /* Propagate event further */
}
int
{
gtk_init(&argc, &argv);
+ /* Construct the widgets */
GtkWidget *window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
gtk_widget_set_size_request(window, 400, 400);
GtkWidget *button = gtk_button_new_with_label("Barf");
GtkWidget *scrolledwindow = gtk_scrolled_window_new(NULL, NULL);
GtkWidget *textview = gtk_text_view_new();
gtk_text_view_set_wrap_mode(GTK_TEXT_VIEW(textview), GTK_WRAP_WORD_CHAR);
+ gtk_text_view_set_editable(GTK_TEXT_VIEW(textview), FALSE);
GtkWidget *vbox = gtk_vbox_new(FALSE, 6);
+ /* Pack all the widgets into their containers */
gtk_container_add(GTK_CONTAINER(scrolledwindow), textview);
gtk_box_pack_start(GTK_BOX(vbox), button, FALSE, FALSE, 0);
gtk_box_pack_start(GTK_BOX(vbox), scrolledwindow, TRUE, TRUE, 0);
gtk_container_add(GTK_CONTAINER(window), vbox);
gtk_widget_show_all(window);
+
+ /* Set up the textview widget to receive exposure events, must be done after widget has been shown */
+ gdk_window_set_events(gtk_widget_get_window(textview), GDK_EXPOSURE_MASK);
+ /* Create the 'more' prompt */
+ prompt = gtk_widget_create_pango_layout(GTK_WIDGET(textview), "More");
+ pango_layout_get_pixel_size(prompt, &promptwidth, &promptheight);
+ gdk_color_parse("red", &red);
+ gdk_color_parse("white", &white);
+
+ /* Connect paging signals */
GtkTextBuffer *buffer = gtk_text_view_get_buffer(GTK_TEXT_VIEW(textview));
g_signal_connect_after(buffer, "insert-text", G_CALLBACK(after_insert), textview);
+ GtkAdjustment *adj = gtk_scrolled_window_get_vadjustment(GTK_SCROLLED_WINDOW(scrolledwindow));
+ g_signal_connect_after(adj, "value-changed", G_CALLBACK(adjustment_changed), textview);
+ pager_handler = g_signal_connect(textview, "key-press-event", G_CALLBACK(pager_wait), buffer);
+ g_signal_handler_block(textview, pager_handler);
+ expose_handler = g_signal_connect_after(textview, "expose-event", G_CALLBACK(expose_prompt), NULL);
+ g_signal_handler_block(textview, expose_handler);
+ /* Create the pager position mark; it stands for the last character in the buffer
+ that has been on-screen */
GtkTextIter end;
gtk_text_buffer_get_end_iter(buffer, &end);
- gtk_text_buffer_create_mark(buffer, "pager_position", &end, TRUE);
+ GtkTextMark *pagermark = gtk_text_buffer_create_mark(buffer, "pager_position", &end, TRUE);
+ gtk_text_mark_set_visible(pagermark, TRUE);
+ /* Connect "regular program" signals */
g_signal_connect(window, "delete-event", G_CALLBACK(quit), NULL);
- g_signal_connect(button, "clicked", G_CALLBACK(barf), buffer);
-
+ g_signal_connect(button, "clicked", G_CALLBACK(barf), textview);
gtk_main();
+
+ g_object_unref(prompt);
return 0;
}
projects / rodin / chimara.git / blobdiff