From 98178e9d691b2db2bf957be5ea9b7a3d417256a5 Mon Sep 17 00:00:00 2001
From: Emil Ernerfeldt <emilernerfeldt@gmail.com>
Date: Mon, 20 Apr 2020 10:01:13 +0200
Subject: [PATCH] Show resize mouse cursor when resizing windows

---
 emigui/src/context.rs     | 18 ++++++++++++++++++
 emigui/src/lib.rs         |  2 +-
 emigui/src/window.rs      |  4 ++++
 example_glium/src/main.rs |  9 ++++++++-
 4 files changed, 31 insertions(+), 2 deletions(-)

diff --git a/emigui/src/context.rs b/emigui/src/context.rs
index 94e0ee93..9c122c8e 100644
--- a/emigui/src/context.rs
+++ b/emigui/src/context.rs
@@ -4,6 +4,18 @@ use parking_lot::Mutex;
 
 use crate::{layout::align_rect, *};
 
+#[derive(Clone, Copy)]
+pub enum CursorIcon {
+    Default,
+    ResizeNorthWestSouthEast,
+}
+
+impl Default for CursorIcon {
+    fn default() -> Self {
+        CursorIcon::Default
+    }
+}
+
 /// Contains the input, style and output of all GUI commands.
 pub struct Context {
     /// The default style for new regions
@@ -13,6 +25,9 @@ pub struct Context {
     pub(crate) memory: Mutex<Memory>,
     pub(crate) graphics: Mutex<GraphicLayers>,
 
+    /// Set each frame to what the mouse cursor should look like.
+    pub cursor_icon: Mutex<CursorIcon>,
+
     /// Used to debug name clashes of e.g. windows
     used_ids: Mutex<HashMap<Id, Pos2>>,
 }
@@ -26,6 +41,7 @@ impl Clone for Context {
             input: self.input,
             memory: Mutex::new(self.memory.lock().clone()),
             graphics: Mutex::new(self.graphics.lock().clone()),
+            cursor_icon: Mutex::new(self.cursor_icon.lock().clone()),
             used_ids: Mutex::new(self.used_ids.lock().clone()),
         }
     }
@@ -39,6 +55,7 @@ impl Context {
             input: Default::default(),
             memory: Default::default(),
             graphics: Default::default(),
+            cursor_icon: Default::default(),
             used_ids: Default::default(),
         }
     }
@@ -59,6 +76,7 @@ impl Context {
     pub fn new_frame(&mut self, gui_input: GuiInput) {
         self.used_ids.lock().clear();
         self.input = gui_input;
+        *self.cursor_icon.lock() = CursorIcon::Default;
         if !gui_input.mouse_down || gui_input.mouse_pos.is_none() {
             self.memory.lock().active_id = None;
         }
diff --git a/emigui/src/lib.rs b/emigui/src/lib.rs
index 2ba8580b..3ca8d878 100644
--- a/emigui/src/lib.rs
+++ b/emigui/src/lib.rs
@@ -28,7 +28,7 @@ mod window;
 pub use {
     crate::emigui::Emigui,
     color::Color,
-    context::Context,
+    context::{Context, CursorIcon},
     fonts::{FontDefinitions, Fonts, TextStyle},
     id::Id,
     layers::*,
diff --git a/emigui/src/window.rs b/emigui/src/window.rs
index 4a37384f..2458dab2 100644
--- a/emigui/src/window.rs
+++ b/emigui/src/window.rs
@@ -170,6 +170,10 @@ impl Window {
             state.rect = state.rect.translate(ctx.input().mouse_move);
         }
 
+        if corner_interact.hovered || corner_interact.active {
+            *ctx.cursor_icon.lock() = CursorIcon::ResizeNorthWestSouthEast;
+        }
+
         let mut memory = ctx.memory.lock();
         if win_interact.active || corner_interact.active {
             memory.move_window_to_top(id);
diff --git a/example_glium/src/main.rs b/example_glium/src/main.rs
index 771fd184..b6d46477 100644
--- a/example_glium/src/main.rs
+++ b/example_glium/src/main.rs
@@ -8,7 +8,7 @@ use {
         label,
         math::*,
         widgets::{Button, Label},
-        Align, Emigui, Window,
+        Align, CursorIcon, Emigui, Window,
     },
     emigui_glium::Painter,
     glium::glutin,
@@ -110,5 +110,12 @@ fn main() {
 
         let mesh = emigui.paint();
         painter.paint(&display, mesh, emigui.texture());
+
+        let cursor = *emigui.ctx.cursor_icon.lock();
+        let cursor = match cursor {
+            CursorIcon::Default => glutin::MouseCursor::Default,
+            CursorIcon::ResizeNorthWestSouthEast => glutin::MouseCursor::NwseResize,
+        };
+        display.gl_window().set_cursor(cursor);
     }
 }