libchimara/pager.c

   1 #include <gdk/gdkkeysyms.h>
   2
   3 #include "pager.h"
   4
   5 /* Helper function: move the pager to the last visible position in the buffer,
   6  and return the distance between the pager and the end of the buffer in buffer
   7  coordinates */
   8 static gint
   9 move_pager_and_get_scroll_distance(GtkTextView *textview)
  10 {
  11         GdkRectangle pagerpos, endpos, visiblerect;
  12         GtkTextIter oldpager, newpager, end;
  13         GtkTextBuffer *buffer = gtk_text_view_get_buffer(textview);
  14         GtkTextMark *pager = gtk_text_buffer_get_mark(buffer, "pager_position");
  15
  16         /* Get an iter at the lower right corner of the visible part of the buffer */
  17         gtk_text_view_get_visible_rect(textview, &visiblerect);
  18         gtk_text_view_get_iter_at_location(textview, &newpager, visiblerect.x + visiblerect.width, visiblerect.y + visiblerect.height);
  19         gtk_text_buffer_get_iter_at_mark(buffer, &oldpager, pager);
  20
  21         gtk_text_buffer_move_mark(buffer, pager, &newpager);
  22
  23         /* Get the buffer coordinates of the pager and the end iter */
  24         gtk_text_buffer_get_end_iter(buffer, &end);
  25         gtk_text_buffer_get_iter_at_mark(buffer, &newpager, pager);
  26         gtk_text_view_get_iter_location(textview, &newpager, &pagerpos);
  27         gtk_text_view_get_iter_location(textview, &end, &endpos);
  28
  29         //g_printerr("View height = %d\n", visiblerect.height);
  30         //g_printerr("End - Pager = %d\n", endpos.y - pagerpos.y);
  31
  32         return endpos.y - pagerpos.y;
  33 }
  34
  35 /* Helper function: turn on paging for this textview */
  36 static void
  37 start_paging(winid_t win)
  38 {
  39         win->currently_paging = TRUE;
  40         g_signal_handler_unblock(win->widget, win->pager_expose_handler);
  41         g_signal_handler_unblock(win->widget, win->pager_keypress_handler);
  42 }
  43
  44 /* Helper function: turn off paging for this textview */
  45 static void
  46 stop_paging(winid_t win)
  47 {
  48         win->currently_paging = FALSE;
  49         g_signal_handler_block(win->widget, win->pager_expose_handler);
  50         g_signal_handler_block(win->widget, win->pager_keypress_handler);
  51 }
  52
  53 /* Update the pager position after new text is inserted in the buffer */
  54 void
  55 pager_after_insert_text(GtkTextBuffer *buffer, GtkTextIter *location, gchar *text, gint len, winid_t win)
  56 {
  57         while(gtk_events_pending())
  58                 gtk_main_iteration();
  59
  60         /* Move the pager to the last visible character in the buffer */
  61         gint scroll_distance = move_pager_and_get_scroll_distance( GTK_TEXT_VIEW(win->widget) );
  62
  63         if(scroll_distance > 0 && !win->currently_paging)
  64                 start_paging(win);
  65 }
  66
  67 void
  68 pager_after_adjustment_changed(GtkAdjustment *adj, winid_t win)
  69 {
  70         while(gtk_events_pending())
  71                 gtk_main_iteration();
  72
  73         /* Move the pager, etc. */
  74         gint scroll_distance = move_pager_and_get_scroll_distance( GTK_TEXT_VIEW(win->widget) );
  75
  76         if(scroll_distance > 0 && !win->currently_paging)
  77                 start_paging(win);
  78         else if(scroll_distance == 0 && win->currently_paging)
  79                 stop_paging(win);
  80
  81         /* Refresh the widget so that any extra "more" prompts disappear */
  82         gtk_widget_queue_draw(win->widget);
  83 }
  84
  85 /* Handle key press events in the textview while paging is active */
  86 gboolean
  87 pager_on_key_press_event(GtkTextView *textview, GdkEventKey *event, winid_t win)
  88 {
  89         /*** ALTERNATIVE, POSSIBLY INFERIOR, METHOD OF SCROLLING ***
  90         GtkTextMark *pagermark = gtk_text_buffer_get_mark(buffer, "pager_position");
  91         gtk_text_view_scroll_to_mark(textview, pagermark, 0.0, TRUE, 0.0, 0.0);
  92         */
  93
  94         GtkAdjustment *adj = gtk_scrolled_window_get_vadjustment( GTK_SCROLLED_WINDOW(win->frame) );
  95         gdouble step_increment, page_size, upper, lower, value;
  96         g_object_get(adj,
  97                 "page-size", &page_size,
  98                 "step-increment", &step_increment,
  99                 "upper", &upper,
 100                 "lower", &lower,
 101                 "value", &value,
 102                 NULL);
 103
 104         switch (event->keyval) {
 105                 case GDK_space: case GDK_KP_Space: case GDK_Page_Down: case GDK_KP_Page_Down:
 106                         gtk_adjustment_set_value(adj, CLAMP(value + page_size, lower, upper - page_size));
 107                         return TRUE;
 108                 case GDK_Page_Up: case GDK_KP_Page_Up:
 109                         gtk_adjustment_set_value(adj, CLAMP(value - page_size, lower, upper - page_size));
 110                         return TRUE;
 111                 case GDK_Return: case GDK_KP_Enter:
 112                         gtk_adjustment_set_value(adj, CLAMP(value + step_increment, lower, upper - page_size));
 113                         return TRUE;
 114                         /* don't handle "up" and "down", they're used for input history */
 115         }
 116
 117         return FALSE; /* if the key wasn't handled here, pass it to other handlers */
 118 }
 119
 120 /* Draw the "more" prompt on top of the buffer, after the regular expose event has run */
 121 gboolean
 122 pager_on_expose(GtkTextView *textview, GdkEventExpose *event, winid_t win)
 123 {
 124         /* Calculate the position of the 'more' tag */
 125         gint promptwidth, promptheight;
 126         pango_layout_get_pixel_size(win->pager_layout, &promptwidth, &promptheight);
 127
 128         gint winx, winy, winwidth, winheight;
 129         gdk_window_get_position(event->window, &winx, &winy);
 130         gdk_drawable_get_size(GDK_DRAWABLE(event->window), &winwidth, &winheight);
 131
 132         /* Draw the 'more' tag */
 133         GdkGC *context = gdk_gc_new(GDK_DRAWABLE(event->window));
 134         /*
 135         gdk_draw_layout_with_colors(event->window, context,
 136                 winx + winwidth - promptwidth,
 137                 winy + winheight - promptheight,
 138                 prompt, &white, &red);
 139         */
 140         gdk_draw_layout(event->window, context,
 141                 winx + winwidth - promptwidth,
 142                 winy + winheight - promptheight,
 143                 win->pager_layout);
 144
 145         return FALSE; /* Propagate event further */
 146 }