1 files changed, 168 insertions, 0 deletions
diff --git a/graphics/src/widget/tooltip.rs b/graphics/src/widget/tooltip.rs
new file mode 100644
index 00000000..493a6389
--- /dev/null
+++ b/graphics/src/widget/tooltip.rs
@@ -0,0 +1,168 @@
+//! Decorate content and apply alignment.
+use crate::backend::{self, Backend};
+use crate::defaults::{self, Defaults};
+use crate::{Primitive, Renderer, Vector};
+
+use iced_native::container;
+use iced_native::layout::{self, Layout};
+use iced_native::{Element, Padding, Point, Rectangle, Size, Text};
+
+/// An element decorating some content.
+///
+/// This is an alias of an `iced_native` tooltip with a default
+/// `Renderer`.
+pub type Tooltip<'a, Message, Backend> =
+    iced_native::Tooltip<'a, Message, Renderer<Backend>>;
+
+pub use iced_native::tooltip::Position;
+
+impl<B> iced_native::tooltip::Renderer for Renderer<B>
+where
+    B: Backend + backend::Text,
+{
+    const DEFAULT_PADDING: u16 = 5;
+
+    fn draw<Message>(
+        &mut self,
+        defaults: &Defaults,
+        cursor_position: Point,
+        content_layout: Layout<'_>,
+        viewport: &Rectangle,
+        content: &Element<'_, Message, Self>,
+        tooltip: &Text<Self>,
+        position: Position,
+        style_sheet: &<Self as container::Renderer>::Style,
+        gap: u16,
+        padding: u16,
+    ) -> Self::Output {
+        let (content, mouse_interaction) = content.draw(
+            self,
+            &defaults,
+            content_layout,
+            cursor_position,
+            viewport,
+        );
+
+        let bounds = content_layout.bounds();
+
+        if bounds.contains(cursor_position) {
+            use iced_native::Widget;
+
+            let gap = f32::from(gap);
+            let style = style_sheet.style();
+
+            let defaults = Defaults {
+                text: defaults::Text {
+                    color: style.text_color.unwrap_or(defaults.text.color),
+                },
+            };
+
+            let text_layout = Widget::<(), Self>::layout(
+                tooltip,
+                self,
+                &layout::Limits::new(Size::ZERO, viewport.size())
+                    .pad(Padding::new(padding)),
+            );
+
+            let padding = f32::from(padding);
+            let text_bounds = text_layout.bounds();
+            let x_center = bounds.x + (bounds.width - text_bounds.width) / 2.0;
+            let y_center =
+                bounds.y + (bounds.height - text_bounds.height) / 2.0;
+
+            let mut tooltip_bounds = {
+                let offset = match position {
+                    Position::Top => Vector::new(
+                        x_center,
+                        bounds.y - text_bounds.height - gap - padding,
+                    ),
+                    Position::Bottom => Vector::new(
+                        x_center,
+                        bounds.y + bounds.height + gap + padding,
+                    ),
+                    Position::Left => Vector::new(
+                        bounds.x - text_bounds.width - gap - padding,
+                        y_center,
+                    ),
+                    Position::Right => Vector::new(
+                        bounds.x + bounds.width + gap + padding,
+                        y_center,
+                    ),
+                    Position::FollowCursor => Vector::new(
+                        cursor_position.x,
+                        cursor_position.y - text_bounds.height,
+                    ),
+                };
+
+                Rectangle {
+                    x: offset.x - padding,
+                    y: offset.y - padding,
+                    width: text_bounds.width + padding * 2.0,
+                    height: text_bounds.height + padding * 2.0,
+                }
+            };
+
+            if tooltip_bounds.x < viewport.x {
+                tooltip_bounds.x = viewport.x;
+            } else if viewport.x + viewport.width
+                < tooltip_bounds.x + tooltip_bounds.width
+            {
+                tooltip_bounds.x =
+                    viewport.x + viewport.width - tooltip_bounds.width;
+            }
+
+            if tooltip_bounds.y < viewport.y {
+                tooltip_bounds.y = viewport.y;
+            } else if viewport.y + viewport.height
+                < tooltip_bounds.y + tooltip_bounds.height
+            {
+                tooltip_bounds.y =
+                    viewport.y + viewport.height - tooltip_bounds.height;
+            }
+
+            let (tooltip, _) = Widget::<(), Self>::draw(
+                tooltip,
+                self,
+                &defaults,
+                Layout::with_offset(
+                    Vector::new(
+                        tooltip_bounds.x + padding,
+                        tooltip_bounds.y + padding,
+                    ),
+                    &text_layout,
+                ),
+                cursor_position,
+                viewport,
+            );
+
+            (
+                Primitive::Group {
+                    primitives: vec![
+                        content,
+                        Primitive::Clip {
+                            bounds: *viewport,
+                            offset: Vector::new(0, 0),
+                            content: Box::new(
+                                if let Some(background) =
+                                    crate::container::background(
+                                        tooltip_bounds,
+                                        &style,
+                                    )
+                                {
+                                    Primitive::Group {
+                                        primitives: vec![background, tooltip],
+                                    }
+                                } else {
+                                    tooltip
+                                },
+                            ),
+                        },
+                    ],
+                },
+                mouse_interaction,
+            )
+        } else {
+            (content, mouse_interaction)
+        }
+    }
+}