/* * Compile me with: * gcc -g -O0 -Wall -pthread -o barf barf.c `pkg-config --cflags --libs gtk+-2.0` */ #include #include /* 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() { gtk_main_quit(); return TRUE; } /* Vomit a load of text onto the screen */ static void barf(GtkButton *button, GtkTextView *textview) { GtkTextIter end; GtkTextBuffer *buffer = gtk_text_view_get_buffer(textview); gtk_text_buffer_get_end_iter(buffer, &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(GtkWidget *eventbox) { currently_paging = TRUE; g_signal_handler_unblock(eventbox, expose_handler); g_signal_handler_unblock(eventbox, pager_handler); } /* Helper function: turn off paging for this textview */ static void stop_paging(GtkWidget *eventbox) { currently_paging = FALSE; g_signal_handler_block(eventbox, expose_handler); g_signal_handler_block(eventbox, 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) { GtkWidget *eventbox = gtk_widget_get_parent( gtk_widget_get_parent(GTK_WIDGET(textview)) ); start_paging(eventbox); } } 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); GtkWidget *eventbox = gtk_widget_get_parent( gtk_widget_get_parent(GTK_WIDGET(textview)) ); if(scroll_distance > 0 && !currently_paging) start_paging(eventbox); else if(scroll_distance == 0 && currently_paging) stop_paging(eventbox); /* Refresh the widget so that any extra "more" prompts disappear */ gtk_widget_queue_draw(GTK_WIDGET(eventbox)); } /* Handle key press events in the textview while paging is active */ static gboolean pager_wait(GtkTextView *eventbox, 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_bin_get_child(GTK_BIN(eventbox)); 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); 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)); return TRUE; case GDK_Page_Up: case GDK_KP_Page_Up: gtk_adjustment_set_value(adj, CLAMP(value - page_size, lower, upper - page_size)); return TRUE; case GDK_Return: case GDK_KP_Enter: gtk_adjustment_set_value(adj, CLAMP(value + step_increment, lower, upper - page_size)); return TRUE; /* don't handle "up" and "down", they're used for input history */ } return FALSE; /* if the key wasn't handled here, pass it to other handlers */ } /* Draw the "more" prompt on top of the buffer, after the regular expose event has run */ static gboolean expose_prompt(GtkEventBox *eventbox, 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, winy - 5, prompt, &white, &red); return FALSE; /* Propagate event further */ } int main(int argc, char **argv) { 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 *eventbox = gtk_event_box_new(); // gtk_event_box_set_above_child( GTK_EVENT_BOX(eventbox), TRUE ); GTK_WIDGET_SET_FLAGS(eventbox, GTK_APP_PAINTABLE); 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_container_add(GTK_CONTAINER(eventbox), scrolledwindow); gtk_box_pack_start(GTK_BOX(vbox), button, FALSE, FALSE, 0); gtk_box_pack_start(GTK_BOX(vbox), eventbox, 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(eventbox), 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(eventbox, "key-press-event", G_CALLBACK(pager_wait), buffer); g_signal_handler_block(eventbox, pager_handler); expose_handler = g_signal_connect(eventbox, "expose-event", G_CALLBACK(expose_prompt), NULL); g_signal_handler_block(eventbox, 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); 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), textview); gtk_main(); g_object_unref(prompt); return 0; }