add covers_opaque

hui/src/element/builtin/slider.rs

@@ -122,7 +122,6 @@ impl UiElement for Slider {
     // } else {
     //   vec2(15., ctx.measure.size.y)
     // };
-
     let handle_size = vec2(self.handle_width, ctx.measure.size.y);
 
     //Draw the track
@@ -130,37 +129,25 @@ impl UiElement for Slider {
     //However, if the handle is not opaque, we need to draw the background as the active part won't quite reach the end
     //Of corse, if it's fully transparent, we don't need to draw it either
     // if !(self.track_color.is_transparent() || (self.track_active_color.is_opaque() && self.handle_color.is_opaque() && self.value >= 1.)) {
-    //   ctx.draw.add(UiDrawCommand::Rectangle {
-    //     position: ctx.layout.position + ctx.measure.size * vec2(0., 0.5 - self.track_height_ratio / 2.),
-    //     size: ctx.measure.size * vec2(1., self.track_height_ratio),
-    //     color: self.track_color.into(),
-    //     texture: None,
-    //     rounded_corners: None,
-    //   });
-    // }
+    if !(self.track_active.covers_opaque() && self.handle.covers_opaque() && self.value >= 1.) {
       self.track.draw(
         ctx.draw,
         ctx.layout.position + ctx.measure.size * vec2(0., 0.5 - self.track_height_ratio / 2.),
         ctx.measure.size * vec2(1., self.track_height_ratio),
       );
+    }
 
     //"Active" part of the track
     //We can skip drawing it if it's fully transparent or value <= 0.
     //But if the handle is not opaque, it should be visible even if value is zero
     // if !(self.track_active_color.is_transparent() || (self.value <= 0. && self.handle_color.is_opaque())) {
-    //   ctx.draw.add(UiDrawCommand::Rectangle {
-    //     position: ctx.layout.position + ctx.measure.size * vec2(0., 0.5 - self.track_height_ratio / 2.),
-    //     size: (ctx.measure.size - handle_size * Vec2::X) * vec2(self.value, self.track_height_ratio) + handle_size * Vec2::X / 2.,
-    //     color: self.track_active_color.into(),
-    //     texture: None,
-    //     rounded_corners: None,
-    //   });
-    // }
+    if !(self.handle.covers_opaque() && self.value <= 0.) {
       self.track_active.draw(
         ctx.draw,
         ctx.layout.position + ctx.measure.size * vec2(0., 0.5 - self.track_height_ratio / 2.),
         (ctx.measure.size - handle_size * Vec2::X) * vec2(self.value, self.track_height_ratio) + handle_size * Vec2::X / 2.,
       );
+    }
 
     // The handle
     // if handle_size.x != 0. && !self.handle_color.is_transparent() {
@@ -182,7 +169,9 @@ impl UiElement for Slider {
     //handle events
     if let Some(res) = ctx.input.check_active(ctx.measure.rect(ctx.layout.position)) {
       let new_value = match self.follow_mode {
-        SliderFollowMode::Absolute => ((res.position_in_rect.x - handle_size.x / 2.) / (ctx.measure.size.x - handle_size.x)).clamp(0., 1.),
+        SliderFollowMode::Absolute => {
+          ((res.position_in_rect.x - handle_size.x / 2.) / (ctx.measure.size.x - handle_size.x)).clamp(0., 1.)
+        },
         SliderFollowMode::Relative => {
           let delta = res.position_in_rect.x - res.last_position_in_rect.x;
           let delta_ratio = delta / (ctx.measure.size.x - handle_size.x);

hui/src/frame.rs

@@ -9,5 +9,16 @@ mod impls;
 pub use rect::FrameRect;
 
 pub trait Frame {
+  /// Draw the frame at the given position and size
   fn draw(&self, draw: &mut UiDrawCommandList, position: Vec2, parent_size: Vec2);
+
+  /// Check if the frame is guaranteed to be fully opaque and fully cover the parent frame regardless of it's size
+  ///
+  /// Returns true if the frame:
+  /// - Is fully opaque (i.e. `alpha >= 1.0`)
+  /// - Completely covers (or exceeds the size of) the frame
+  ///
+  /// False negatives are acceptable, but false positives ***are not***.\
+  /// May be used for optimization purposes
+  fn covers_opaque(&self) -> bool { false }
 }

hui/src/frame/impls.rs

@@ -16,6 +16,9 @@ impl Frame for ImageHandle {
       rounded_corners: None,
     })
   }
+  fn covers_opaque(&self) -> bool {
+    true
+  }
 }
 
 impl Frame for FillColor {
@@ -28,6 +31,9 @@ impl Frame for FillColor {
       rounded_corners: None,
     })
   }
+  fn covers_opaque(&self) -> bool {
+    self.is_opaque()
+  }
 }
 
 // impl for various types resembling colors
@@ -38,24 +44,36 @@ impl Frame for Corners<Vec4> {
   fn draw(&self, draw: &mut UiDrawCommandList, position: Vec2, parent_size: Vec2) {
     FillColor::from(*self).draw(draw, position, parent_size)
   }
+  fn covers_opaque(&self) -> bool {
+    FillColor::from(*self).is_opaque()
+  }
 }
 
 impl Frame for (Vec4, Vec4, Vec4, Vec4) {
   fn draw(&self, draw: &mut UiDrawCommandList, position: Vec2, parent_size: Vec2) {
     FillColor::from(*self).draw(draw, position, parent_size)
   }
+  fn covers_opaque(&self) -> bool {
+    FillColor::from(*self).is_opaque()
+  }
 }
 
 impl Frame for ((f32, f32, f32, f32), (f32, f32, f32, f32), (f32, f32, f32, f32), (f32, f32, f32, f32)) {
   fn draw(&self, draw: &mut UiDrawCommandList, position: Vec2, parent_size: Vec2) {
     FillColor::from(*self).draw(draw, position, parent_size)
   }
+  fn covers_opaque(&self) -> bool {
+    FillColor::from(*self).is_opaque()
+  }
 }
 
 impl Frame for [[f32; 4]; 4] {
   fn draw(&self, draw: &mut UiDrawCommandList, position: Vec2, parent_size: Vec2) {
     FillColor::from(*self).draw(draw, position, parent_size)
   }
+  fn covers_opaque(&self) -> bool {
+    FillColor::from(*self).is_opaque()
+  }
 }
 
 // Corners (RGB):
@@ -64,24 +82,36 @@ impl Frame for Corners<Vec3> {
   fn draw(&self, draw: &mut UiDrawCommandList, position: Vec2, parent_size: Vec2) {
     FillColor::from(*self).draw(draw, position, parent_size)
   }
+  fn covers_opaque(&self) -> bool {
+    FillColor::from(*self).is_opaque()
+  }
 }
 
 impl Frame for (Vec3, Vec3, Vec3, Vec3) {
   fn draw(&self, draw: &mut UiDrawCommandList, position: Vec2, parent_size: Vec2) {
     FillColor::from(*self).draw(draw, position, parent_size)
   }
+  fn covers_opaque(&self) -> bool {
+    FillColor::from(*self).is_opaque()
+  }
 }
 
 impl Frame for ((f32, f32, f32), (f32, f32, f32), (f32, f32, f32), (f32, f32, f32)) {
   fn draw(&self, draw: &mut UiDrawCommandList, position: Vec2, parent_size: Vec2) {
     FillColor::from(*self).draw(draw, position, parent_size)
   }
+  fn covers_opaque(&self) -> bool {
+    FillColor::from(*self).is_opaque()
+  }
 }
 
 impl Frame for [[f32; 3]; 4] {
   fn draw(&self, draw: &mut UiDrawCommandList, position: Vec2, parent_size: Vec2) {
     FillColor::from(*self).draw(draw, position, parent_size)
   }
+  fn covers_opaque(&self) -> bool {
+    FillColor::from(*self).is_opaque()
+  }
 }
 
 // RGBA:
@@ -90,18 +120,27 @@ impl Frame for Vec4 {
   fn draw(&self, draw: &mut UiDrawCommandList, position: Vec2, parent_size: Vec2) {
     FillColor::from(*self).draw(draw, position, parent_size)
   }
+  fn covers_opaque(&self) -> bool {
+    FillColor::from(*self).is_opaque()
+  }
 }
 
 impl Frame for (f32, f32, f32, f32) {
   fn draw(&self, draw: &mut UiDrawCommandList, position: Vec2, parent_size: Vec2) {
     FillColor::from(*self).draw(draw, position, parent_size)
   }
+  fn covers_opaque(&self) -> bool {
+    FillColor::from(*self).is_opaque()
+  }
 }
 
 impl Frame for [f32; 4] {
   fn draw(&self, draw: &mut UiDrawCommandList, position: Vec2, parent_size: Vec2) {
     FillColor::from(*self).draw(draw, position, parent_size)
   }
+  fn covers_opaque(&self) -> bool {
+    FillColor::from(*self).is_opaque()
+  }
 }
 
 // RGB:
@@ -110,16 +149,25 @@ impl Frame for Vec3 {
   fn draw(&self, draw: &mut UiDrawCommandList, position: Vec2, parent_size: Vec2) {
     FillColor::from(*self).draw(draw, position, parent_size)
   }
+  fn covers_opaque(&self) -> bool {
+    FillColor::from(*self).is_opaque()
+  }
 }
 
 impl Frame for (f32, f32, f32) {
   fn draw(&self, draw: &mut UiDrawCommandList, position: Vec2, parent_size: Vec2) {
     FillColor::from(*self).draw(draw, position, parent_size)
   }
+  fn covers_opaque(&self) -> bool {
+    FillColor::from(*self).is_opaque()
+  }
 }
 
 impl Frame for [f32; 3] {
   fn draw(&self, draw: &mut UiDrawCommandList, position: Vec2, parent_size: Vec2) {
     FillColor::from(*self).draw(draw, position, parent_size)
   }
+  fn covers_opaque(&self) -> bool {
+    FillColor::from(*self).is_opaque()
+  }
 }

hui/src/frame/rect.rs

@@ -6,6 +6,9 @@ use crate::{
 };
 use super::{Frame, point::FramePoint2d};
 
+/// A rectangular frame
+///
+/// Can optionally be tinted, textured, and have rounded corners
 #[derive(Clone, Copy)]
 pub struct FrameRect {
   /// Background color of the frame\
@@ -126,4 +129,16 @@ impl Frame for FrameRect {
       ),
     });
   }
+
+  fn covers_opaque(&self) -> bool {
+    self.top_left.x.absolute <= 0. &&
+    self.top_left.x.relative <= 0. &&
+    self.top_left.y.absolute <= 0. &&
+    self.top_left.y.relative <= 0. &&
+    self.bottom_right.x.absolute >= 0. &&
+    self.bottom_right.x.relative >= 1. &&
+    self.bottom_right.y.absolute >= 0. &&
+    self.bottom_right.y.relative >= 1. &&
+    self.color.is_opaque()
+  }
 }

hui/src/frame/stack.rs

@@ -9,6 +9,11 @@ impl Frame for FrameStack {
     self.0.draw(draw, position, parent_size);
     self.1.draw(draw, position, parent_size);
   }
+
+  fn covers_opaque(&self) -> bool {
+    self.0.covers_opaque() ||
+    self.1.covers_opaque()
+  }
 }
 
 pub trait FrameStackExt: Frame {