From a764b0d23f9be3f938a37bbf7d7e6ee496d92cb8 Mon Sep 17 00:00:00 2001
From: Emil Ernerfeldt <emilernerfeldt@gmail.com>
Date: Wed, 26 Aug 2020 20:40:25 +0200
Subject: [PATCH] [window] visually indicate which windows can be resized

---
 egui/src/containers/resize.rs | 21 ++++++++++++---------
 egui/src/containers/window.rs | 16 ++++++++++++++++
 egui/src/style.rs             |  3 +++
 3 files changed, 31 insertions(+), 9 deletions(-)

diff --git a/egui/src/containers/resize.rs b/egui/src/containers/resize.rs
index e82537af..9a7a71a1 100644
--- a/egui/src/containers/resize.rs
+++ b/egui/src/containers/resize.rs
@@ -151,7 +151,7 @@ impl Resize {
 
         let corner_interact = if self.resizable {
             // Resize-corner:
-            let corner_size = Vec2::splat(16.0); // TODO: style
+            let corner_size = Vec2::splat(ui.style().resize_corner_size);
             let corner_rect = Rect::from_min_size(
                 position + state.desired_size + self.handle_offset - corner_size,
                 corner_size,
@@ -274,21 +274,24 @@ impl Resize {
     }
 }
 
-fn paint_resize_corner(ui: &mut Ui, interact: &InteractInfo) {
+use crate::paint::LineStyle;
+
+pub fn paint_resize_corner(ui: &mut Ui, interact: &InteractInfo) {
     let color = ui.style().interact(interact).stroke_color;
     let width = ui.style().interact(interact).stroke_width;
+    paint_resize_corner_with_style(ui, &interact.rect, LineStyle::new(width, color));
+}
 
+pub fn paint_resize_corner_with_style(ui: &mut Ui, rect: &Rect, style: LineStyle) {
     let painter = ui.painter();
-
-    let corner = painter.round_pos_to_pixels(interact.rect.right_bottom());
+    let corner = painter.round_pos_to_pixels(rect.right_bottom());
     let mut w = 2.0;
 
     while w < 12.0 {
-        painter.add(paint::PaintCmd::line_segment(
-            [pos2(corner.x - w, corner.y), pos2(corner.x, corner.y - w)],
-            color,
-            width,
-        ));
+        painter.add(paint::PaintCmd::LineSegment {
+            points: [pos2(corner.x - w, corner.y), pos2(corner.x, corner.y - w)],
+            style,
+        });
         w += 4.0;
     }
 }
diff --git a/egui/src/containers/window.rs b/egui/src/containers/window.rs
index bedfce38..e1c22d45 100644
--- a/egui/src/containers/window.rs
+++ b/egui/src/containers/window.rs
@@ -235,6 +235,7 @@ impl<'open> Window<'open> {
 
         {
             // BEGIN FRAME --------------------------------
+            let frame_outline = frame.outline;
             let mut frame = frame.begin(&mut area_content_ui);
 
             let default_expanded = true;
@@ -269,6 +270,12 @@ impl<'open> Window<'open> {
                 .map(|ri| ri.1);
 
             let outer_rect = frame.end(&mut area_content_ui);
+
+            if possible.resizable {
+                // TODO: draw BEHIND contents ?
+                paint_resize_corner(&mut area_content_ui, outer_rect, frame_outline);
+            }
+
             // END FRAME --------------------------------
 
             title_bar.ui(
@@ -307,6 +314,15 @@ impl<'open> Window<'open> {
     }
 }
 
+fn paint_resize_corner(ui: &mut Ui, outer_rect: Rect, frame_outline: Option<LineStyle>) {
+    let corner_size = Vec2::splat(ui.style().resize_corner_size);
+    let handle_offset = -Vec2::splat(2.0);
+    let corner_rect =
+        Rect::from_min_size(outer_rect.max - corner_size + handle_offset, corner_size);
+    let outline = frame_outline.unwrap_or_else(|| LineStyle::new(1.0, color::GRAY));
+    crate::resize::paint_resize_corner_with_style(ui, &corner_rect, outline);
+}
+
 // ----------------------------------------------------------------------------
 
 #[derive(Clone, Copy, Debug)]
diff --git a/egui/src/style.rs b/egui/src/style.rs
index 6876c208..942b029c 100644
--- a/egui/src/style.rs
+++ b/egui/src/style.rs
@@ -32,6 +32,8 @@ pub struct Style {
     /// Mouse must be the close to the corner of a window to resize
     pub resize_interact_radius_corner: f32,
 
+    pub resize_corner_size: f32,
+
     // -----------------------------------------------
     // Purely visual:
     pub interact: Interact,
@@ -82,6 +84,7 @@ impl Default for Style {
             start_icon_width: 14.0,
             resize_interact_radius_side: 5.0,
             resize_interact_radius_corner: 10.0,
+            resize_corner_size: 16.0,
             interact: Default::default(),
             text_color: gray(160, 255),
             line_width: 1.0,