app work

src/core/position/pad.rs

@@ -39,6 +39,13 @@ pub struct Padding {
 }
 
 impl Padding {
+    pub const ZERO: Self = Self {
+        left: 0.0,
+        right: 0.0,
+        top: 0.0,
+        bottom: 0.0,
+    };
+
     pub fn uniform(amt: impl UiNum) -> Self {
         let amt = amt.to_f32();
         Self {
@@ -75,6 +82,30 @@ impl Padding {
         }
     }
 
+    pub fn top(amt: impl UiNum) -> Self {
+        let mut s = Self::ZERO;
+        s.top = amt.to_f32();
+        s
+    }
+
+    pub fn bottom(amt: impl UiNum) -> Self {
+        let mut s = Self::ZERO;
+        s.bottom = amt.to_f32();
+        s
+    }
+
+    pub fn left(amt: impl UiNum) -> Self {
+        let mut s = Self::ZERO;
+        s.left = amt.to_f32();
+        s
+    }
+
+    pub fn right(amt: impl UiNum) -> Self {
+        let mut s = Self::ZERO;
+        s.right = amt.to_f32();
+        s
+    }
+
     pub fn with_top(mut self, amt: impl UiNum) -> Self {
         self.top = amt.to_f32();
         self