various fixes

1 files changed, 18 insertions, 23 deletions

diff --git a/helix-view/src/commands.rs b/helix-view/src/commands.rs
index 0b985dc6..b2223d48 100644
--- a/helix-view/src/commands.rs
+++ b/helix-view/src/commands.rs
@@ -13,6 +13,8 @@ use crate::view::View;
 /// state (usually by creating and applying a transaction).
 pub type Command = fn(view: &mut View, count: usize);
 
+const PADDING: u16 = 10;
+
 pub fn move_char_left(view: &mut View, count: usize) {
     // TODO: use a transaction
     let selection = view
@@ -127,7 +129,7 @@ pub fn move_file_start(view: &mut View, _count: usize) {
 pub fn move_file_end(view: &mut View, _count: usize) {
     // TODO: use a transaction
     let text = &view.state.doc;
-    let last_line = text.line_to_char(text.len_lines().checked_sub(2).unwrap());
+    let last_line = text.line_to_char(text.len_lines().saturating_sub(2));
     view.state.selection = Selection::single(last_line, last_line);
 
     view.state.mode = Mode::Normal;
@@ -136,7 +138,7 @@ pub fn move_file_end(view: &mut View, _count: usize) {
 pub fn check_cursor_in_view(view: &mut View) -> bool {
     let cursor = view.state.selection().cursor();
     let line = view.state.doc().char_to_line(cursor) as u16;
-    let document_end = view.first_line + view.size.1.saturating_sub(1) - 1;
+    let document_end = view.first_line + view.size.1.saturating_sub(2);
     let padding = 5u16;
 
     if (line > document_end.saturating_sub(padding)) | (line < view.first_line + padding) {
@@ -148,44 +150,37 @@ pub fn check_cursor_in_view(view: &mut View) -> bool {
 pub fn page_up(view: &mut View, _count: usize) {
     let text = &view.state.doc;
     view.first_line = view.first_line.saturating_sub(view.size.1);
+    let pos = text.line_to_char(view.first_line as usize);
 
-    view.state.selection = Selection::single(
-        text.line_to_char(view.first_line as usize),
-        text.line_to_char(view.first_line as usize),
-    );
+    view.state.selection = Selection::single(pos, pos);
 }
 
 pub fn page_down(view: &mut View, _count: usize) {
     let text = &view.state.doc;
-    view.first_line += view.size.1;
-
-    view.state.selection = Selection::single(
-        text.line_to_char(view.first_line as usize),
-        text.line_to_char(view.first_line as usize),
-    );
+    view.first_line += view.size.1 + PADDING;
+    if view.first_line < view.state.doc().len_lines() as u16 {
+        let pos = text.line_to_char(view.first_line as usize);
+        view.state.selection = Selection::single(pos, pos);
+    }
 }
 
 pub fn half_page_up(view: &mut View, _count: usize) {
     view.first_line = view.first_line.saturating_sub(view.size.1 / 2);
-
     if !check_cursor_in_view(view) {
         let text = &view.state.doc;
-        view.state.selection = Selection::single(
-            text.line_to_char(view.first_line as usize),
-            text.line_to_char(view.first_line as usize),
-        );
+        let pos = text.line_to_char(view.first_line as usize);
+        view.state.selection = Selection::single(pos, pos);
     }
 }
 
 pub fn half_page_down(view: &mut View, _count: usize) {
-    view.first_line += view.size.1 / 2;
-
+    if view.first_line < view.state.doc().len_lines() as u16 - view.size.1 {
+        view.first_line += view.size.1 / 2;
+    }
     if !check_cursor_in_view(view) {
         let text = &view.state.doc;
-        view.state.selection = Selection::single(
-            text.line_to_char(view.first_line as usize),
-            text.line_to_char(view.first_line as usize),
-        );
+        let pos = text.line_to_char(view.first_line as usize);
+        view.state.selection = Selection::single(pos, pos);
     }
 }
 // avoid select by default by having a visual mode switch that makes movements into selects