Merge pull request #1952 from H3rnand3zzz/fix/alt-underscroll

Fix underscrolling issue for alternative scrolling

src/ui/window.c

@@ -694,7 +694,7 @@ win_page_down(ProfWin* window, int scroll_size)
  *page_start += scroll_size;
 
  // Scrolled down after reaching the bottom of the page
- if ((*page_start == total_rows || (*page_start == page_space && *page_start >= total_rows)) && window->type == WIN_CHAT) {
+ if ((*page_start > total_rows - page_space || (*page_start == page_space && *page_start >= total_rows)) && window->type == WIN_CHAT) {
  int bf_size = buffer_size(window->layout->buffer);
  if (bf_size > 0) {
  ProfBuffEntry* last_entry = buffer_get_entry(window->layout->buffer, bf_size - 1);
@@ -708,19 +708,19 @@ win_page_down(ProfWin* window, int scroll_size)
  g_date_time_unref(now);
 
  int offset = last_entry->y_end_pos - 1;
- *page_start = offset;
+ *page_start = offset - page_space + scroll_size;
  }
  }
 
  total_rows = getcury(window->layout->win);
 
- // only got half a screen, show full screen
- if ((total_rows - (*page_start)) < page_space)
+ // near the end, but will display only part of the page space, move a bit back to show full page
+ if ((total_rows - *page_start) < page_space) {
  *page_start = total_rows - page_space;
-
- // went past end, show full screen
- else if (*page_start >= total_rows)
+ // went past end, show last page
+ } else if (*page_start >= total_rows) {
  *page_start = total_rows - page_space - 1;
+ }
 
  window->layout->paged = 1;
 
@@ -730,7 +730,7 @@ win_page_down(ProfWin* window, int scroll_size)
  }
 
  // switch off page if last line and space line visible
- if ((total_rows) - *page_start == page_space) {
+ if (total_rows - *page_start == page_space) {
  window->layout->paged = 0;
  }
 }