`ComboBox`: add builder method for height (#3001)

Matches the already existing `ComboBox::width()`.

---------

Co-authored-by: Emil Ernerfeldt <emil.ernerfeldt@gmail.com>

crates/egui/src/containers/combo_box.rs

@@ -2,6 +2,9 @@ use epaint::Shape;
 
 use crate::{style::WidgetVisuals, *};
 
+#[allow(unused_imports)] // Documentation
+use crate::style::Spacing;
+
 /// Indicate whether or not a popup will be shown above or below the box.
 #[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
 pub enum AboveOrBelow {
@@ -35,6 +38,7 @@ pub struct ComboBox {
     label: Option<WidgetText>,
     selected_text: WidgetText,
     width: Option<f32>,
+    height: Option<f32>,
     icon: Option<IconPainter>,
     wrap_enabled: bool,
 }
@@ -47,6 +51,7 @@ impl ComboBox {
             label: Some(label.into()),
             selected_text: Default::default(),
             width: None,
+            height: None,
             icon: None,
             wrap_enabled: false,
         }
@@ -60,6 +65,7 @@ impl ComboBox {
             label: Some(label),
             selected_text: Default::default(),
             width: None,
+            height: None,
             icon: None,
             wrap_enabled: false,
         }
@@ -72,18 +78,30 @@ impl ComboBox {
             label: Default::default(),
             selected_text: Default::default(),
             width: None,
+            height: None,
             icon: None,
             wrap_enabled: false,
         }
     }
 
     /// Set the outer width of the button and menu.
+    ///
+    /// Default is [`Spacing::combo_width`].
     #[inline]
     pub fn width(mut self, width: f32) -> Self {
         self.width = Some(width);
         self
     }
 
+    /// Set the maximum outer height of the menu.
+    ///
+    /// Default is [`Spacing::combo_height`].
+    #[inline]
+    pub fn height(mut self, height: f32) -> Self {
+        self.height = Some(height);
+        self
+    }
+
     /// What we show as the currently selected value
     #[inline]
     pub fn selected_text(mut self, selected_text: impl Into<WidgetText>) -> Self {
@@ -158,6 +176,7 @@ impl ComboBox {
             label,
             selected_text,
             width,
+            height,
             icon,
             wrap_enabled,
         } = self;
@@ -172,7 +191,7 @@ impl ComboBox {
                 menu_contents,
                 icon,
                 wrap_enabled,
-                width,
+                (width, height),
             );
             if let Some(label) = label {
                 ir.response
@@ -241,7 +260,7 @@ fn combo_box_dyn<'c, R>(
     menu_contents: Box<dyn FnOnce(&mut Ui) -> R + 'c>,
     icon: Option<IconPainter>,
     wrap_enabled: bool,
-    width: Option<f32>,
+    (width, height): (Option<f32>, Option<f32>),
 ) -> InnerResponse<Option<R>> {
     let popup_id = button_id.with("popup");
 
@@ -335,6 +354,9 @@ fn combo_box_dyn<'c, R>(
     if button_response.clicked() {
         ui.memory_mut(|mem| mem.toggle_popup(popup_id));
     }
+
+    let height = height.unwrap_or_else(|| ui.spacing().combo_height);
+
     let inner = crate::popup::popup_above_or_below_widget(
         ui,
         popup_id,
@@ -342,7 +364,7 @@ fn combo_box_dyn<'c, R>(
         above_or_below,
         |ui| {
             ScrollArea::vertical()
-                .max_height(ui.spacing().combo_height)
+                .max_height(height)
                 .show(ui, menu_contents)
                 .inner
         },