Add scrollback hotkeys

This offers a few additional hotkeys that can be used in combination
with scrollback. None of these are used by default yet.

This implements the following bindings:
 - ScrollPageUp: Scroll exactly one screen height up
 - ScrollPageDown: Scroll exactly one screen height down
 - ScrollToTop: Scroll as far up as possible
 - ScrollToBottom: Scroll as far down as possible

This fixes #1151.

1 files changed, 20 insertions, 0 deletions

diff --git a/src/grid/mod.rs b/src/grid/mod.rs
index a52c27c5..ac761adc 100644
--- a/src/grid/mod.rs
+++ b/src/grid/mod.rs
@@ -176,6 +176,26 @@ impl<T: Copy + Clone> Grid<T> {
         self.display_offset = 0;
     }
 
+    pub fn scroll_to_top(&mut self) {
+        self.display_offset = self.scroll_limit;
+    }
+
+    pub fn scroll_page_up(&mut self) {
+        if self.display_offset + self.lines.0 >= self.scroll_limit {
+            self.display_offset = self.scroll_limit;
+        } else {
+            self.display_offset += self.lines.0;
+        }
+    }
+
+    pub fn scroll_page_down(&mut self) {
+        if self.display_offset <= self.lines.0 {
+            self.display_offset = 0;
+        } else {
+            self.display_offset -= self.lines.0;
+        }
+    }
+
     pub fn resize(&mut self, lines: index::Line, cols: index::Column) {
         // Check that there's actually work to do and return early if not
         if lines == self.lines && cols == self.cols {