Barf improvements -- the paging functionality should now be ready to move into the...
authorfliep <fliep@ddfedd41-794f-dd11-ae45-00112f111e67>
Tue, 2 Feb 2010 20:46:19 +0000 (20:46 +0000)
committerfliep <fliep@ddfedd41-794f-dd11-ae45-00112f111e67>
Tue, 2 Feb 2010 20:46:19 +0000 (20:46 +0000)
Both paging behaviors I mentioned are available for testing - see the #define constant at the top of the file.

tests/barf.c

index 0bf2a93f186a2357714f384bc6534769c15df368..36e51514c7c7e70d2f90c3a62c960ea141c5d941 100644 (file)
@@ -4,6 +4,10 @@
  */
 
 #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;
@@ -16,33 +20,49 @@ 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 pager, end;
+       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, &pager, visiblerect.x + visiblerect.width, visiblerect.y + visiblerect.height);
-       gtk_text_buffer_move_mark_by_name(buffer, "pager_position", &pager);
-
+       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_view_get_iter_location(textview, &pager, &pagerpos);
+       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);
@@ -51,6 +71,7 @@ move_pager_and_get_scroll_distance(GtkTextView *textview)
        return endpos.y - pagerpos.y;
 }
 
+/* Helper function: turn on paging for this textview */
 static void
 start_paging(GtkTextView *textview)
 {
@@ -59,6 +80,7 @@ start_paging(GtkTextView *textview)
        g_signal_handler_unblock(textview, pager_handler);
 }
 
+/* Helper function: turn off paging for this textview */
 static void
 stop_paging(GtkTextView *textview)
 {
@@ -67,6 +89,7 @@ stop_paging(GtkTextView *textview)
        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)
 {
@@ -76,41 +99,68 @@ after_insert(GtkTextBuffer *buffer, GtkTextIter *location, gchar *text, gint len
        /* Move the pager to the last visible character in the buffer */
        gint scroll_distance = move_pager_and_get_scroll_distance(textview);
        
-       /* Wait for a keypress to advance the pager */
        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));
+}
+
+/* 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);
-
-       /*** ALTERNATIVE, POSSIBLY BETTER, METHOD OF SCROLLING ***
-       GtkWidget *scrolledwindow = gtk_widget_get_parent(GTK_WIDGET(textview));
-       GtkAdjustment *adjustment = gtk_scrolled_window_get_vadjustment(GTK_SCROLLED_WINDOW(scrolledwindow));
-       gdouble page_size; // SUCKY_DEBIAN: use gtk_adjustment_get_page_size() post 2.12
-       g_object_get(adjustment, "page-size", &page_size, NULL);
-       gtk_adjustment_set_value(adjustment, gtk_adjustment_get_value(adjustment) + page_size);
        */
 
-       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)
-               stop_paging(textview);
-
-       return TRUE; /* block further handlers */
+       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);
+       
+       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(GtkTextView *textview, GdkEventExpose *event)
 {
-       /* Use Cairo? Cairo supported on Iliad? */
        PangoLayout *prompt = gtk_widget_create_pango_layout(GTK_WIDGET(textview), "More");
        gint promptwidth, promptheight;
        pango_layout_get_pixel_size(prompt, &promptwidth, &promptheight);
@@ -137,6 +187,7 @@ 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");
@@ -146,6 +197,7 @@ main(int argc, char **argv)
        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);
@@ -155,20 +207,26 @@ main(int argc, char **argv)
        /* 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);
 
+       /* 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);
        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();
        return 0;