Fix list bounds

src/elements/direction.rs

@@ -1,5 +1,5 @@
-use super::Align;
-use crate::component_wise::ComponentWise;
+use super::{Align, Icon};
+use crate::{component_wise::ComponentWise, render_util::Rect};
 use serde::{Deserialize, Serialize};
 use strum::{AsRefStr, EnumIter, VariantArray};
 
@@ -61,28 +61,59 @@ impl Direction {
         }
     }
 
+    pub fn list_start_offset(&self, size: [f32; 2], pad: f32, total: usize) -> [f32; 2] {
+        let [width, height] = size;
+        let last = total.saturating_sub(1) as f32;
+        match self {
+            Self::Right | Self::Left | Self::Up | Self::Down => [0.0, 0.0],
+            Self::Horizontal => [-0.5 * last * (width + pad), 0.0],
+            Self::Vertical => [0.0, -0.5 * last * (height + pad)],
+        }
+    }
+
     pub fn list_item_offset(
         &self,
         size: [f32; 2],
         pad: f32,
         element: usize,
         total: usize,
     ) -> [f32; 2] {
-        // TODO: adjust center point of first element?
         let [width, height] = size;
         let i = element as f32;
         let offset_x = i * (width + pad);
         let offset_y = i * (height + pad);
-        let additional = total.saturating_sub(1) as f32;
-        let half = 0.5 * additional;
-        let half_pad = 0.5 * additional * pad;
+        let last = total.saturating_sub(1) as f32;
         match self {
             Self::Right => [offset_x, 0.0],
             Self::Left => [-offset_x, 0.0],
             Self::Up => [0.0, -offset_y],
             Self::Down => [0.0, offset_y],
-            Self::Horizontal => [offset_x - half * width - half_pad, 0.0],
-            Self::Vertical => [0.0, offset_y - half * height - half_pad],
+            Self::Horizontal => [offset_x - 0.5 * last * (width + pad), 0.0],
+            Self::Vertical => [0.0, offset_y - 0.5 * last * (height + pad)],
         }
     }
+
+    pub fn icon_list_bounds(&self, size: [f32; 2], pad: f32, total: usize) -> Rect {
+        let [width, height] = size;
+        let last = total.saturating_sub(1) as f32;
+        let offset_x = last * (width + pad);
+        let offset_y = last * (height + pad);
+        let (min, max) = match self {
+            Self::Right => ([0.0, 0.0], [offset_x, 0.0]),
+            Self::Left => ([-offset_x, 0.0], [0.0, 0.0]),
+            Self::Up => ([0.0, -offset_y], [0.0, 0.0]),
+            Self::Down => ([0.0, 0.0], [0.0, offset_y]),
+            Self::Horizontal => {
+                let start = -0.5 * last * (width + pad);
+                ([start, 0.0], [start + offset_x, 0.0])
+            }
+            Self::Vertical => {
+                let start = -0.5 * last * (height + pad);
+                ([0.0, start], [0.0, start + offset_y])
+            }
+        };
+        let (min, _) = Icon::bounds(min, size);
+        let (_, max) = Icon::bounds(max, size);
+        (min, max)
+    }
 }

src/elements/icon.rs

@@ -40,7 +40,13 @@ impl Icon {
         self.buff.is_active_or_edit(ctx, state)
     }
 
-    pub fn bounds(&self, pos: [f32; 2], size: [f32; 2]) -> Rect {
+    pub fn rel_bounds(size: [f32; 2]) -> Rect {
+        let [half_x, half_y] = size.mul_scalar(0.5);
+
+        ([-half_x, -half_y], [half_x, half_y])
+    }
+
+    pub fn bounds(pos: [f32; 2], size: [f32; 2]) -> Rect {
         let half_size = size.mul_scalar(0.5);
         let start = pos.sub(half_size);
         let end = pos.add(half_size);
@@ -50,7 +56,7 @@ impl Icon {
     pub fn render(&mut self, ui: &Ui, ctx: &Context, state: &RenderState, size: [f32; 2]) {
         let texture = self.source.get_texture();
         if self.source.is_empty() || texture.is_some() {
-            let (start, end) = self.bounds(state.pos, size);
+            let (start, end) = Self::bounds(state.pos, size);
             let color @ [_, _, _, alpha] = self.texture_color(ui);
 
             // render icon

src/elements/icon_element.rs

@@ -28,7 +28,7 @@ impl Render for IconElement {
 
 impl Bounds for IconElement {
     fn bounding_box(&self, _ui: &Ui, _ctx: &Context, pos: [f32; 2]) -> Rect {
-        self.icon.bounds(pos, self.size)
+        Icon::bounds(pos, self.size)
     }
 }
 

src/elements/list.rs

@@ -66,19 +66,10 @@ impl Render for IconList {
 
 impl Bounds for IconList {
     fn bounding_box(&self, _ui: &Ui, _ctx: &Context, pos: [f32; 2]) -> Rect {
-        // we calculate the bounds with all icons visible for now
-        // FIXME: fix & move to direction
-        let len = self.icons.len();
-        if len > 0 {
-            let first = self.direction.list_item_offset(self.size, self.pad, 0, len);
-            let last = self
-                .direction
-                .list_item_offset(self.size, self.pad, len - 1, len);
-            let offset = self.size.mul_scalar(0.5);
-            (pos.add(offset).add(first), pos.sub(offset).add(last))
-        } else {
-            Rect::default()
-        }
+        // calculate with all visible and at least 1 dummy
+        let len = self.icons.len().max(1);
+        let (bound_min, bound_max) = self.direction.icon_list_bounds(self.size, self.pad, len);
+        (pos.add(bound_min), pos.add(bound_max))
     }
 }
 

src/elements/list_icon.rs

@@ -23,7 +23,7 @@ impl ListIcon {
     }
 
     pub fn bounds(&self, pos: [f32; 2], size: [f32; 2]) -> Rect {
-        self.inner.bounds(pos, size)
+        Icon::bounds(pos, size)
     }
 }