From 3d3b93da8ba91412e11354bb5e015b11d9b36a27 Mon Sep 17 00:00:00 2001
From: Emil Ernerfeldt <emilernerfeldt@gmail.com>
Date: Sat, 29 Aug 2020 15:14:44 +0200
Subject: [PATCH] Force user to explicitly select a max height for a ScrollArea

---
 egui/src/containers/scroll_area.rs | 21 ++++++++++-----------
 egui/src/containers/window.rs      |  6 +-----
 egui/src/demos/app.rs              |  2 +-
 3 files changed, 12 insertions(+), 17 deletions(-)

diff --git a/egui/src/containers/scroll_area.rs b/egui/src/containers/scroll_area.rs
index d8b4b4c3..be783cbb 100644
--- a/egui/src/containers/scroll_area.rs
+++ b/egui/src/containers/scroll_area.rs
@@ -33,22 +33,21 @@ pub struct ScrollArea {
     always_show_scroll: bool,
 }
 
-impl Default for ScrollArea {
-    fn default() -> Self {
+impl ScrollArea {
+    /// Will make the area be as high as it is allowed to be (i.e. fill the ui it is in)
+    pub fn auto_sized() -> Self {
+        Self::from_max_height(f32::INFINITY)
+    }
+
+    /// Use `f32::INFINITY` if you want the scroll area to expand to fit the surrounding Ui
+    pub fn from_max_height(max_height: f32) -> Self {
         Self {
-            max_height: 200.0,
+            max_height,
             always_show_scroll: false,
         }
     }
-}
 
-impl ScrollArea {
-    pub fn max_height(mut self, max_height: f32) -> Self {
-        self.max_height = max_height;
-        self
-    }
-
-    /// If `false` (defualt), the scroll bar will be hidden when not needed/
+    /// If `false` (default), the scroll bar will be hidden when not needed/
     /// If `true`, the scroll bar will always be displayed even if not needed.
     pub fn always_show_scroll(mut self, always_show_scroll: bool) -> Self {
         self.always_show_scroll = always_show_scroll;
diff --git a/egui/src/containers/window.rs b/egui/src/containers/window.rs
index 966d0a56..172a4935 100644
--- a/egui/src/containers/window.rs
+++ b/egui/src/containers/window.rs
@@ -142,11 +142,7 @@ impl<'open> Window<'open> {
     pub fn scroll(mut self, scroll: bool) -> Self {
         if scroll {
             if self.scroll.is_none() {
-                self.scroll = Some(
-                    ScrollArea::default()
-                        .always_show_scroll(false)
-                        .max_height(f32::INFINITY), // As large as we can be
-                );
+                self.scroll = Some(ScrollArea::auto_sized());
             }
             debug_assert!(
                 self.scroll.is_some(),
diff --git a/egui/src/demos/app.rs b/egui/src/demos/app.rs
index 28f468f2..dd927971 100644
--- a/egui/src/demos/app.rs
+++ b/egui/src/demos/app.rs
@@ -360,7 +360,7 @@ impl DemoWindow {
         CollapsingHeader::new("Scroll area")
             .default_open(false)
             .show(ui, |ui| {
-                ScrollArea::default().show(ui, |ui| {
+                ScrollArea::from_max_height(200.0).show(ui, |ui| {
                     ui.label(LOREM_IPSUM_LONG);
                 });
             });