feat: port el-ui vessels — rename crates→vessels, add El source + manifests

ui/vessels/el-layout/src/scroll.rs

@@ -0,0 +1,141 @@
+/// ScrollView — scrollable container.
+///
+/// Wraps content that may exceed the available space. Scrolling axis can be
+/// vertical (default), horizontal, or both. On platforms with native scroll
+/// behaviors (iOS, Android), the backend translates this to a native scroll
+/// container — you get momentum, overscroll, pull-to-refresh for free.
+
+use el_style::modifier::{StyleModifier, StyleSet};
+
+/// Which axis (or axes) can scroll.
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum ScrollAxis {
+    /// Vertical scrolling only (default). Most content views.
+    Vertical,
+    /// Horizontal scrolling only. Carousels, horizontal lists.
+    Horizontal,
+    /// Free scrolling in both directions. Maps, canvases.
+    Both,
+}
+
+/// Scroll indicator visibility.
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum ScrollIndicator {
+    /// Show when scrolling, hide otherwise (platform default).
+    Automatic,
+    /// Always show.
+    Always,
+    /// Never show.
+    Never,
+}
+
+/// A scrollable container.
+#[derive(Debug, Clone)]
+pub struct ScrollView {
+    pub axis: ScrollAxis,
+    pub indicator: ScrollIndicator,
+    /// Whether the user can zoom (pinch-to-zoom). Default: false.
+    pub zoomable: bool,
+    /// Minimum zoom scale (only relevant when zoomable = true).
+    pub min_zoom: f32,
+    /// Maximum zoom scale (only relevant when zoomable = true).
+    pub max_zoom: f32,
+    /// Whether to clip content to the scroll view bounds. Default: true.
+    pub clips_to_bounds: bool,
+    pub style: StyleSet,
+}
+
+impl Default for ScrollView {
+    fn default() -> Self {
+        Self {
+            axis: ScrollAxis::Vertical,
+            indicator: ScrollIndicator::Automatic,
+            zoomable: false,
+            min_zoom: 1.0,
+            max_zoom: 3.0,
+            clips_to_bounds: true,
+            style: StyleSet::default(),
+        }
+    }
+}
+
+impl ScrollView {
+    pub fn new() -> Self {
+        Self::default()
+    }
+
+    pub fn horizontal() -> Self {
+        Self {
+            axis: ScrollAxis::Horizontal,
+            ..Self::default()
+        }
+    }
+
+    pub fn both_axes() -> Self {
+        Self {
+            axis: ScrollAxis::Both,
+            ..Self::default()
+        }
+    }
+
+    pub fn indicator(mut self, indicator: ScrollIndicator) -> Self {
+        self.indicator = indicator;
+        self
+    }
+
+    pub fn zoomable(mut self, min: f32, max: f32) -> Self {
+        self.zoomable = true;
+        self.min_zoom = min;
+        self.max_zoom = max;
+        self
+    }
+}
+
+impl StyleModifier for ScrollView {
+    fn style_mut(&mut self) -> &mut StyleSet {
+        &mut self.style
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn scroll_default_is_vertical() {
+        let sv = ScrollView::new();
+        assert_eq!(sv.axis, ScrollAxis::Vertical);
+    }
+
+    #[test]
+    fn scroll_horizontal_constructor() {
+        let sv = ScrollView::horizontal();
+        assert_eq!(sv.axis, ScrollAxis::Horizontal);
+    }
+
+    #[test]
+    fn scroll_both_axes() {
+        let sv = ScrollView::both_axes();
+        assert_eq!(sv.axis, ScrollAxis::Both);
+    }
+
+    #[test]
+    fn scroll_zoomable() {
+        let sv = ScrollView::new().zoomable(0.5, 4.0);
+        assert!(sv.zoomable);
+        assert_eq!(sv.min_zoom, 0.5);
+        assert_eq!(sv.max_zoom, 4.0);
+    }
+
+    #[test]
+    fn scroll_clips_by_default() {
+        let sv = ScrollView::new();
+        assert!(sv.clips_to_bounds);
+    }
+
+    #[test]
+    fn scroll_indicator_setting() {
+        let sv = ScrollView::new().indicator(ScrollIndicator::Never);
+        assert_eq!(sv.indicator, ScrollIndicator::Never);
+    }
+}