From 420454cc0f7f73484700a7e5282588dd6d8a0eca Mon Sep 17 00:00:00 2001
From: Alexandre Bury <alexandre.bury@gmail.com>
Date: Sat, 14 Oct 2017 21:34:37 -0700
Subject: [PATCH] Better mouse scroll drag

Now saturates when to the top or left.
---
 examples/list_view.rs    |  6 +++---
 src/views/list_view.rs   | 15 ++++++---------
 src/views/menu_popup.rs  |  9 ++++-----
 src/views/select_view.rs |  5 ++---
 src/views/text_area.rs   |  5 ++---
 src/views/text_view.rs   |  5 ++---
 6 files changed, 19 insertions(+), 26 deletions(-)

diff --git a/examples/list_view.rs b/examples/list_view.rs
index f31ab3c6c..a4e074af6 100644
--- a/examples/list_view.rs
+++ b/examples/list_view.rs
@@ -57,9 +57,9 @@ fn main() {
                     )
                     .with(|list| for i in 0..50 {
                         list.add_child(
-                                &format!("Item {}", i),
-                                EditView::new(),
-                            );
+                            &format!("Item {}", i),
+                            EditView::new(),
+                        );
                     }),
             ),
     );
diff --git a/src/views/list_view.rs b/src/views/list_view.rs
index 08ef85a9c..00feaafbb 100644
--- a/src/views/list_view.rs
+++ b/src/views/list_view.rs
@@ -346,9 +346,8 @@ impl View for ListView {
                 offset,
             } if self.scrollbase.is_dragging() =>
             {
-                position
-                    .checked_sub(offset)
-                    .map(|position| self.scrollbase.drag(position));
+                let position = position.saturating_sub(offset);
+                self.scrollbase.drag(position);
                 return EventResult::Consumed(None);
             }
             Event::Mouse {
@@ -397,12 +396,10 @@ impl View for ListView {
                     direction::Direction::back(),
                 )
             }
-            Event::Key(Key::End) | Event::Ctrl(Key::End) => {
-                self.move_focus(
-                    usize::max_value(),
-                    direction::Direction::front(),
-                )
-            }
+            Event::Key(Key::End) | Event::Ctrl(Key::End) => self.move_focus(
+                usize::max_value(),
+                direction::Direction::front(),
+            ),
             Event::Key(Key::Tab) => {
                 self.move_focus(1, direction::Direction::front())
             }
diff --git a/src/views/menu_popup.rs b/src/views/menu_popup.rs
index d2d963a0a..0b4af2f3c 100644
--- a/src/views/menu_popup.rs
+++ b/src/views/menu_popup.rs
@@ -234,8 +234,8 @@ impl View for MenuPopup {
                         }
                         printer.print_hline((1, 0), printer.size.x - 2, " ");
                         printer.print((2, 0), label);
-                        printer.print((printer.size.x.saturating_sub(4), 0),
-                                      ">>");
+                        let x = printer.size.x.saturating_sub(4);
+                        printer.print((x, 0), ">>");
                     }
                     MenuItem::Leaf(ref label, _) => {
                         if printer.size.x < 2 {
@@ -333,9 +333,8 @@ impl View for MenuPopup {
             } => {
                 // If the mouse is dragged, we always consume the event.
                 fix_scroll = false;
-                position
-                    .checked_sub(offset + (0, 1))
-                    .map(|position| self.scrollbase.drag(position));
+                let position = position.saturating_sub(offset);
+                self.scrollbase.drag(position);
             }
             Event::Mouse {
                 event: MouseEvent::Press(_),
diff --git a/src/views/select_view.rs b/src/views/select_view.rs
index 19424f369..f9f3c3f9e 100644
--- a/src/views/select_view.rs
+++ b/src/views/select_view.rs
@@ -375,9 +375,8 @@ impl<T: 'static> SelectView<T> {
             } => {
                 // If the mouse is dragged, we always consume the event.
                 fix_scroll = false;
-                position
-                    .checked_sub(offset)
-                    .map(|position| self.scrollbase.drag(position));
+                let position = position.saturating_sub(offset);
+                self.scrollbase.drag(position);
             }
             Event::Mouse {
                 event: MouseEvent::Press(_),
diff --git a/src/views/text_area.rs b/src/views/text_area.rs
index 2d3ce05ac..47fd133b8 100644
--- a/src/views/text_area.rs
+++ b/src/views/text_area.rs
@@ -502,9 +502,8 @@ impl View for TextArea {
                 offset,
             } => {
                 fix_scroll = false;
-                position
-                    .checked_sub(offset)
-                    .map(|position| self.scrollbase.drag(position));
+                let position = position.saturating_sub(offset);
+                self.scrollbase.drag(position);
             }
             Event::Mouse {
                 event: MouseEvent::Press(_),
diff --git a/src/views/text_view.rs b/src/views/text_view.rs
index a02e564c5..e76cf4380 100644
--- a/src/views/text_view.rs
+++ b/src/views/text_view.rs
@@ -303,9 +303,8 @@ impl View for TextView {
                 offset,
             } => {
                 // If the mouse is dragged, we always consume the event.
-                position
-                    .checked_sub(offset)
-                    .map(|position| self.scrollbase.drag(position));
+                let position = position.saturating_sub(offset);
+                self.scrollbase.drag(position);
             }
             Event::Mouse {
                 event: MouseEvent::Release(MouseButton::Left),