Improve ergonomics and reduce boilerplate around creating text elemen…

…ts. (bevyengine#5343)

# Objective

Creating UI elements is very boilerplate-y with lots of indentation.
This PR aims to reduce boilerplate around creating text elements.

## Changelog

* Renamed `Text::with_section` to `from_section`.
  It no longer takes a `TextAlignment` as argument, as the vast majority of cases left it `Default::default()`.
* Added `Text::from_sections` which creates a `Text` from a list of `TextSections`.
  Reduces line-count and reduces indentation by one level.
* Added `Text::with_alignment`.
  A builder style method for setting the `TextAlignment` of a `Text`.
* Added `TextSection::new`.
  Does not reduce line count, but reduces character count and made it easier to read. No more `.to_string()` calls!
* Added `TextSection::from_style` which creates an empty `TextSection` with a style.
  No more empty strings! Reduces indentation.
* Added `TextAlignment::CENTER` and friends.
* Added methods to `TextBundle`. `from_section`, `from_sections`, `with_text_alignment` and `with_style`.

## Note for reviewers.
Because of the nature of these changes I recommend setting diff view to 'split'.
~~Look for the book icon~~ cog in the top-left of the Files changed tab.

Have fun reviewing ❤️
<sup> >:D </sup>

## Migration Guide

`Text::with_section` was renamed to `from_section` and no longer takes a `TextAlignment` as argument.
Use `with_alignment` to set the alignment instead.

Co-authored-by: devil-ira <justthecooldude@gmail.com>

crates/bevy_render/src/mesh/mesh/conversions.rs

@@ -522,7 +522,7 @@ mod tests {
             Err(error) => error,
         };
         assert_eq!(
-            format!("{}", error),
+            error.to_string(),
             "cannot convert VertexAttributeValues::Uint32x4 to alloc::vec::Vec<u32>"
         );
         assert_eq!(format!("{:?}", error),

crates/bevy_text/src/text.rs

@@ -14,54 +14,83 @@ pub struct Text {
 }
 
 impl Text {
-    /// Constructs a [`Text`] with (initially) one section.
+    /// Constructs a [`Text`] with a single section.
     ///
     /// ```
-    /// # use bevy_asset::{AssetServer, Handle};
+    /// # use bevy_asset::Handle;
     /// # use bevy_render::color::Color;
     /// # use bevy_text::{Font, Text, TextAlignment, TextStyle, HorizontalAlign, VerticalAlign};
     /// #
     /// # let font_handle: Handle<Font> = Default::default();
     /// #
-    /// // basic usage
-    /// let hello_world = Text::with_section(
-    ///     "hello world!".to_string(),
+    /// // Basic usage.
+    /// let hello_world = Text::from_section(
+    ///     // Accepts a String or any type that converts into a String, such as &str.
+    ///     "hello world!",
     ///     TextStyle {
     ///         font: font_handle.clone(),
     ///         font_size: 60.0,
     ///         color: Color::WHITE,
     ///     },
-    ///     TextAlignment {
-    ///         vertical: VerticalAlign::Center,
-    ///         horizontal: HorizontalAlign::Center,
-    ///     },
     /// );
     ///
-    /// let hello_bevy = Text::with_section(
-    ///     // accepts a String or any type that converts into a String, such as &str
+    /// let hello_bevy = Text::from_section(
     ///     "hello bevy!",
     ///     TextStyle {
     ///         font: font_handle,
     ///         font_size: 60.0,
     ///         color: Color::WHITE,
     ///     },
-    ///     // you can still use Default
-    ///     Default::default(),
-    /// );
+    /// ) // You can still add an alignment.
+    /// .with_alignment(TextAlignment::CENTER);
+    /// ```
+    pub fn from_section(value: impl Into<String>, style: TextStyle) -> Self {
+        Self {
+            sections: vec![TextSection::new(value, style)],
+            alignment: Default::default(),
+        }
+    }
+
+    /// Constructs a [`Text`] from a list of sections.
+    ///
+    /// ```
+    /// # use bevy_asset::Handle;
+    /// # use bevy_render::color::Color;
+    /// # use bevy_text::{Font, Text, TextStyle, TextSection};
+    /// #
+    /// # let font_handle: Handle<Font> = Default::default();
+    /// #
+    /// let hello_world = Text::from_sections([
+    ///     TextSection::new(
+    ///         "Hello, ",
+    ///         TextStyle {
+    ///             font: font_handle.clone(),
+    ///             font_size: 60.0,
+    ///             color: Color::BLUE,
+    ///         },
+    ///     ),
+    ///     TextSection::new(
+    ///         "World!",
+    ///         TextStyle {
+    ///             font: font_handle,
+    ///             font_size: 60.0,
+    ///             color: Color::RED,
+    ///         },
+    ///     ),
+    /// ]);
     /// ```
-    pub fn with_section<S: Into<String>>(
-        value: S,
-        style: TextStyle,
-        alignment: TextAlignment,
-    ) -> Self {
+    pub fn from_sections(sections: impl IntoIterator<Item = TextSection>) -> Self {
         Self {
-            sections: vec![TextSection {
-                value: value.into(),
-                style,
-            }],
-            alignment,
+            sections: sections.into_iter().collect(),
+            alignment: Default::default(),
         }
     }
+
+    /// Returns this [`Text`] with a new [`TextAlignment`].
+    pub const fn with_alignment(mut self, alignment: TextAlignment) -> Self {
+        self.alignment = alignment;
+        self
+    }
 }
 
 #[derive(Debug, Default, Clone, FromReflect, Reflect)]
@@ -70,18 +99,89 @@ pub struct TextSection {
     pub style: TextStyle,
 }
 
+impl TextSection {
+    /// Create a new [`TextSection`].
+    pub fn new(value: impl Into<String>, style: TextStyle) -> Self {
+        Self {
+            value: value.into(),
+            style,
+        }
+    }
+
+    /// Create an empty [`TextSection`] from a style. Useful when the value will be set dynamically.
+    pub const fn from_style(style: TextStyle) -> Self {
+        Self {
+            value: String::new(),
+            style,
+        }
+    }
+}
+
 #[derive(Debug, Clone, Copy, Reflect)]
 pub struct TextAlignment {
     pub vertical: VerticalAlign,
     pub horizontal: HorizontalAlign,
 }
 
+impl TextAlignment {
+    /// A [`TextAlignment`] set to the top-left.
+    pub const TOP_LEFT: Self = TextAlignment {
+        vertical: VerticalAlign::Top,
+        horizontal: HorizontalAlign::Left,
+    };
+
+    /// A [`TextAlignment`] set to the top-center.
+    pub const TOP_CENTER: Self = TextAlignment {
+        vertical: VerticalAlign::Top,
+        horizontal: HorizontalAlign::Center,
+    };
+
+    /// A [`TextAlignment`] set to the the top-right.
+    pub const TOP_RIGHT: Self = TextAlignment {
+        vertical: VerticalAlign::Top,
+        horizontal: HorizontalAlign::Right,
+    };
+
+    /// A [`TextAlignment`] set to center the center-left.
+    pub const CENTER_LEFT: Self = TextAlignment {
+        vertical: VerticalAlign::Center,
+        horizontal: HorizontalAlign::Left,
+    };
+
+    /// A [`TextAlignment`] set to center on both axes.
+    pub const CENTER: Self = TextAlignment {
+        vertical: VerticalAlign::Center,
+        horizontal: HorizontalAlign::Center,
+    };
+
+    /// A [`TextAlignment`] set to the center-right.
+    pub const CENTER_RIGHT: Self = TextAlignment {
+        vertical: VerticalAlign::Center,
+        horizontal: HorizontalAlign::Right,
+    };
+
+    /// A [`TextAlignment`] set to the bottom-left.
+    pub const BOTTOM_LEFT: Self = TextAlignment {
+        vertical: VerticalAlign::Bottom,
+        horizontal: HorizontalAlign::Left,
+    };
+
+    /// A [`TextAlignment`] set to the bottom-center.
+    pub const BOTTOM_CENTER: Self = TextAlignment {
+        vertical: VerticalAlign::Bottom,
+        horizontal: HorizontalAlign::Center,
+    };
+
+    /// A [`TextAlignment`] set to the bottom-right.
+    pub const BOTTOM_RIGHT: Self = TextAlignment {
+        vertical: VerticalAlign::Bottom,
+        horizontal: HorizontalAlign::Right,
+    };
+}
+
 impl Default for TextAlignment {
     fn default() -> Self {
-        TextAlignment {
-            vertical: VerticalAlign::Top,
-            horizontal: HorizontalAlign::Left,
-        }
+        TextAlignment::TOP_LEFT
     }
 }
 

crates/bevy_ui/src/entity.rs

@@ -13,7 +13,7 @@ use bevy_render::{
     camera::Camera, extract_component::ExtractComponent, prelude::ComputedVisibility,
     view::Visibility,
 };
-use bevy_text::Text;
+use bevy_text::{Text, TextAlignment, TextSection, TextStyle};
 use bevy_transform::prelude::{GlobalTransform, Transform};
 
 /// The basic UI node
@@ -89,6 +89,40 @@ pub struct TextBundle {
     pub computed_visibility: ComputedVisibility,
 }
 
+impl TextBundle {
+    /// Create a [`TextBundle`] from a single section.
+    ///
+    /// See [`Text::from_section`] for usage.
+    pub fn from_section(value: impl Into<String>, style: TextStyle) -> Self {
+        Self {
+            text: Text::from_section(value, style),
+            ..Default::default()
+        }
+    }
+
+    /// Create a [`TextBundle`] from a list of sections.
+    ///
+    /// See [`Text::from_sections`] for usage.
+    pub fn from_sections(sections: impl IntoIterator<Item = TextSection>) -> Self {
+        Self {
+            text: Text::from_sections(sections),
+            ..Default::default()
+        }
+    }
+
+    /// Returns this [`TextBundle`] with a new [`TextAlignment`] on [`Text`].
+    pub const fn with_text_alignment(mut self, alignment: TextAlignment) -> Self {
+        self.text.alignment = alignment;
+        self
+    }
+
+    /// Returns this [`TextBundle`] with a new [`Style`].
+    pub const fn with_style(mut self, style: Style) -> Self {
+        self.style = style;
+        self
+    }
+}
+
 impl Default for TextBundle {
     fn default() -> Self {
         TextBundle {

examples/2d/text2d.rs

@@ -31,30 +31,28 @@ fn setup(mut commands: Commands, asset_server: Res<AssetServer>) {
         font_size: 60.0,
         color: Color::WHITE,
     };
-    let text_alignment = TextAlignment {
-        vertical: VerticalAlign::Center,
-        horizontal: HorizontalAlign::Center,
-    };
+    let text_alignment = TextAlignment::CENTER;
     // 2d camera
     commands.spawn_bundle(Camera2dBundle::default());
     // Demonstrate changing translation
     commands
         .spawn_bundle(Text2dBundle {
-            text: Text::with_section("translation", text_style.clone(), text_alignment),
+            text: Text::from_section("translation", text_style.clone())
+                .with_alignment(text_alignment),
             ..default()
         })
         .insert(AnimateTranslation);
     // Demonstrate changing rotation
     commands
         .spawn_bundle(Text2dBundle {
-            text: Text::with_section("rotation", text_style.clone(), text_alignment),
+            text: Text::from_section("rotation", text_style.clone()).with_alignment(text_alignment),
             ..default()
         })
         .insert(AnimateRotation);
     // Demonstrate changing scale
     commands
         .spawn_bundle(Text2dBundle {
-            text: Text::with_section("scale", text_style.clone(), text_alignment),
+            text: Text::from_section("scale", text_style.clone()).with_alignment(text_alignment),
             ..default()
         })
         .insert(AnimateScale);
@@ -70,16 +68,8 @@ fn setup(mut commands: Commands, asset_server: Res<AssetServer>) {
         transform: Transform::from_translation(box_position.extend(0.0)),
         ..default()
     });
-    let text_alignment_topleft = TextAlignment {
-        vertical: VerticalAlign::Top,
-        horizontal: HorizontalAlign::Left,
-    };
     commands.spawn_bundle(Text2dBundle {
-        text: Text::with_section(
-            "this text wraps in the box",
-            text_style,
-            text_alignment_topleft,
-        ),
+        text: Text::from_section("this text wraps in the box", text_style),
         text_2d_bounds: Text2dBounds {
             // Wrap text in the rectangle
             size: box_size,

examples/async_tasks/external_source_external_thread.rs

@@ -62,13 +62,11 @@ fn spawn_text(
         font_size: 20.0,
         color: Color::WHITE,
     };
-    let text_alignment = TextAlignment {
-        vertical: VerticalAlign::Center,
-        horizontal: HorizontalAlign::Center,
-    };
+
     for (per_frame, event) in reader.iter().enumerate() {
         commands.spawn_bundle(Text2dBundle {
-            text: Text::with_section(format!("{}", event.0), text_style.clone(), text_alignment),
+            text: Text::from_section(event.0.to_string(), text_style.clone())
+                .with_alignment(TextAlignment::CENTER),
             transform: Transform::from_xyz(
                 per_frame as f32 * 100.0 + rand::thread_rng().gen_range(-40.0..40.0),
                 300.0,

examples/ecs/state.rs

@@ -55,18 +55,14 @@ fn setup_menu(mut commands: Commands, asset_server: Res<AssetServer>) {
             ..default()
         })
         .with_children(|parent| {
-            parent.spawn_bundle(TextBundle {
-                text: Text::with_section(
-                    "Play",
-                    TextStyle {
-                        font: asset_server.load("fonts/FiraSans-Bold.ttf"),
-                        font_size: 40.0,
-                        color: Color::rgb(0.9, 0.9, 0.9),
-                    },
-                    Default::default(),
-                ),
-                ..default()
-            });
+            parent.spawn_bundle(TextBundle::from_section(
+                "Play",
+                TextStyle {
+                    font: asset_server.load("fonts/FiraSans-Bold.ttf"),
+                    font_size: 40.0,
+                    color: Color::rgb(0.9, 0.9, 0.9),
+                },
+            ));
         })
         .id();
     commands.insert_resource(MenuData { button_entity });