add offset / scrolling + clipboard support

src/layout/pos.rs

@@ -11,23 +11,20 @@ pub struct UiVec2 {
 }
 
 impl UiVec2 {
+    pub const ZERO: Self = Self {
+        rel: Vec2::ZERO,
+        abs: Vec2::ZERO,
+    };
+
     /// expands this position into a sized region centered at self
     pub fn expand(&self, size: impl Into<Vec2>) -> UiRegion {
         let size = size.into();
         UiRegion {
-            top_left: self.shifted(-size / 2.0),
-            bot_right: self.shifted(size / 2.0),
+            top_left: self.offset(-size / 2.0),
+            bot_right: self.offset(size / 2.0),
         }
     }
 
-    pub const fn anchor(anchor: Vec2) -> Self {
-        Self::rel(anchor)
-    }
-
-    pub const fn offset(offset: Vec2) -> Self {
-        Self::abs(offset)
-    }
-
     pub const fn abs(abs: Vec2) -> Self {
         Self {
             rel: Vec2::ZERO,
@@ -42,11 +39,12 @@ impl UiVec2 {
         }
     }
 
-    pub const fn shift(&mut self, offset: impl const Into<Vec2>) {
-        self.abs += offset.into();
+    pub const fn shift(&mut self, offset: impl const Into<UiVec2>) {
+        let offset = offset.into();
+        *self += offset;
     }
 
-    pub const fn shifted(mut self, offset: Vec2) -> Self {
+    pub const fn offset(mut self, offset: impl const Into<UiVec2>) -> Self {
         self.shift(offset);
         self
     }
@@ -118,7 +116,7 @@ impl_op!(UiVec2 Sub sub; rel abs);
 
 impl const From<Align> for UiVec2 {
     fn from(align: Align) -> Self {
-        Self::anchor(align.anchor())
+        Self::rel(align.rel())
     }
 }
 
@@ -128,6 +126,12 @@ impl Align {
     }
 }
 
+impl const From<Vec2> for UiVec2 {
+    fn from(abs: Vec2) -> Self {
+        Self::abs(abs)
+    }
+}
+
 #[derive(Clone, Copy, Debug, Default)]
 pub struct UiScalar {
     pub rel: f32,
@@ -198,10 +202,10 @@ impl UiRegion {
             bot_right: Align::BotRight.into(),
         }
     }
-    pub fn anchor(anchor: Vec2) -> Self {
+    pub fn rel(anchor: Vec2) -> Self {
         Self {
-            top_left: UiVec2::anchor(anchor),
-            bot_right: UiVec2::anchor(anchor),
+            top_left: UiVec2::rel(anchor),
+            bot_right: UiVec2::rel(anchor),
         }
     }
     pub fn within(&self, parent: &Self) -> Self {
@@ -229,13 +233,13 @@ impl UiRegion {
         std::mem::swap(&mut self.top_left, &mut self.bot_right);
     }
 
-    pub fn shift(&mut self, offset: impl Into<Vec2>) {
+    pub fn shift(&mut self, offset: impl Into<UiVec2>) {
         let offset = offset.into();
         self.top_left.shift(offset);
         self.bot_right.shift(offset);
     }
 
-    pub fn shifted(mut self, offset: impl Into<Vec2>) -> Self {
+    pub fn offset(mut self, offset: impl Into<UiVec2>) -> Self {
         self.shift(offset);
         self
     }
@@ -265,9 +269,9 @@ impl UiRegion {
 
     pub fn from_size_align(size: Vec2, align: Align) -> Self {
         let mut top_left = UiVec2::from(align);
-        top_left.abs -= size * align.anchor();
+        top_left.abs -= size * align.rel();
         let mut bot_right = UiVec2::from(align);
-        bot_right.abs += size * (Vec2::ONE - align.anchor());
+        bot_right.abs += size * (Vec2::ONE - align.rel());
         Self {
             top_left,
             bot_right,
@@ -276,11 +280,11 @@ impl UiRegion {
 
     pub fn from_ui_size_align(size: UiVec2, align: Align) -> Self {
         let mut top_left = UiVec2::from(align);
-        top_left.abs -= size.abs * align.anchor();
-        top_left.rel -= size.rel * align.anchor();
+        top_left.abs -= size.abs * align.rel();
+        top_left.rel -= size.rel * align.rel();
         let mut bot_right = UiVec2::from(align);
-        bot_right.abs += size.abs * (Vec2::ONE - align.anchor());
-        bot_right.rel += size.rel * (Vec2::ONE - align.anchor());
+        bot_right.abs += size.abs * (Vec2::ONE - align.rel());
+        bot_right.rel += size.rel * (Vec2::ONE - align.rel());
         Self {
             top_left,
             bot_right,