Update devcontainer.json

.devcontainer/devcontainer.json

@@ -0,0 +1,16 @@
+{
+  "image": "mcr.microsoft.com/devcontainers/universal:2",
+  "features": {
+    "ghcr.io/devcontainers/features/rust:1": {},
+    "ghcr.io/devcontainers/features/desktop-lite:1": {}
+  },
+  "forwardPorts": [6080, 5901],
+  "portsAttributes": {
+    "6080": {
+      "label": "desktop"
+    },
+    "5901": {
+      "label": "desktop"
+    }
+  }
+}

.markdownlint.jsonc

@@ -0,0 +1,5 @@
+{
+  "MD041": false, //first-line-heading
+  "MD013": false, //line-length
+  "MD033": false  //inline-html
+}

.vscode/settings.json

@@ -1,5 +1,6 @@
 {
   "editor.detectIndentation": false,
   "editor.tabSize": 2,
-  "editor.insertSpaces": true
+  "editor.insertSpaces": true,
+  "editor.wordWrap": "off"
 }

Cargo.toml

@@ -1,3 +1,3 @@
 [workspace]
 resolver = "2"
-members = ["hui", "hui-examples", "hui-glium", "hui-winit"]
+members = ["hui", "hui-derive", "hui-examples", "hui-glium", "hui-winit"]

README.md

@@ -1,5 +1,5 @@
 <p></p><p></p>
-<img src="https://raw.githubusercontent.com/griffi-gh/hui/master/.assets/hui.svg" width="120" align="left">
+<img src="https://raw.githubusercontent.com/griffi-gh/hui/master/.assets/hui.svg" width="120" align="left" alt="logo">
 <h1>hUI</h1>
 <div>
   <span>
@@ -17,22 +17,25 @@
 
 <table align="center">
   <td>
-    <img src="https://raw.githubusercontent.com/griffi-gh/hui/master/.assets/demo0.gif" width="300">
+    <img src="https://raw.githubusercontent.com/griffi-gh/hui/master/.assets/demo0.gif" width="300" alt="example: mom_downloader">
   </td>
   <td>
-    <img src="https://raw.githubusercontent.com/griffi-gh/hui/master/.assets/demo1.gif" width="300">
+    <img src="https://raw.githubusercontent.com/griffi-gh/hui/master/.assets/demo1.gif" width="300" alt="example: align_test">
   </td>
 </table>
 
 <h2>Example</h2>
-<img src="https://raw.githubusercontent.com/griffi-gh/hui/master/.assets/exemplaris.png" height="175" align="right" float="right">
+<img src="https://raw.githubusercontent.com/griffi-gh/hui/master/.assets/exemplaris.png"
+  height="175" align="right" float="right" alt="code result">
 <pre lang="rust">Container::default()
   .with_size(size!(100%, 50%))
   .with_align(Alignment::Center)
   .with_padding(5.)
   .with_gap(10.)
-  .with_corner_radius(10.)
-  .with_background(color::WHITE)
+  .with_background(frame_rect! {
+    color: (0.5, 0.5, 0.5, 1.),
+    corner_radius: 10.,
+  })
   .with_children(|ui| {
     Text::default()
       .with_text("Hello, world")
@@ -41,8 +44,10 @@
       .add_child(ui);
     Container::default()
       .with_padding((10., 20.))
-      .with_corner_radius((2.5, 30., 2.5, 2.5))
-      .with_background(color::DARK_RED)
+      .with_background(frame_rect! {
+        color: color::DARK_RED,
+        corner_radius: (2.5, 30., 2.5, 2.5),
+      })
       .with_children(|ui| {
         Text::default()
           .with_text("Lorem ipsum dolor sit amet, consectetur adipiscing elit.")
@@ -51,7 +56,7 @@
       })
       .add_child(ui);
   })
-  .add_root(&mut hui, resolution);</pre>
+  .add_root(ui, size);</pre>
 
 <h2>Backends</h2>
 <p>
@@ -89,6 +94,20 @@
     </td>
     <td align="center">(support planned)</td>
   </tr>
+  <tr>
+    <td align="center">
+      <code>0.1.0-alpha.4</code>
+    </th>
+    <td>
+      <code>hui-glium = "0.1.0-alpha.4"</code><br>
+      <code>glium = "0.34"</code>
+    </td>
+    <td>
+      <code>hui-winit = "0.1.0-alpha.4"</code><br>
+      <code>winit = "0.29"</code>
+    </td>
+    <td align="center">N/A</td>
+  </tr>
   <tr>
     <td align="center">
       <code>0.1.0-alpha.3</code>
@@ -140,3 +159,6 @@
     <td align="center">-</td>
   </tr> -->
 </table>
+
+<h2>MSRV</h2>
+1.75

hui-derive/Cargo.toml

@@ -0,0 +1,23 @@
+[package]
+name = "hui-derive"
+description = "Derive macros for hUI"
+repository = "https://github.com/griffi-gh/hui"
+readme = "../README.md"
+authors = ["griffi-gh <prasol258@gmail.com>"]
+rust-version = "1.75"
+version = "0.1.0-alpha.5"
+edition = "2021"
+license = "GPL-3.0-or-later"
+publish = true
+include = [
+  "assets/**/*",
+  "src/**/*.rs",
+  "Cargo.toml",
+]
+
+[lib]
+proc-macro = true
+
+[dependencies]
+quote = "1.0"
+syn = "2.0"

hui-derive/src/lib.rs

@@ -0,0 +1,13 @@
+extern crate proc_macro;
+
+use proc_macro::TokenStream;
+use quote::quote;
+use syn::{parse_macro_input, DeriveInput};
+
+/// Implements `Signal` trait for the given type
+#[proc_macro_derive(Signal)]
+pub fn signal(input: TokenStream) -> TokenStream {
+  let input = parse_macro_input!(input as DeriveInput);
+  let name = input.ident;
+  quote!(impl ::hui::signal::Signal for #name {}).into()
+}

hui-examples/Cargo.toml

@@ -14,5 +14,6 @@ glium = "0.34"
 winit = "0.29"
 glam = "0.27"
 log = "0.4"
+image = { version = "0.25", features = ["jpeg", "png"] }
 
 #created as a workaround for rust-analyzer dependency cycle (which should be allowed)

hui-examples/examples/align_test.rs

@@ -62,7 +62,7 @@ fn main() {
           children: ElementList(vec![
             Box::new(ProgressBar {
               value: z,
-              corner_radius: Corners::all(0.25 * ProgressBar::DEFAULT_HEIGHT),
+              // corner_radius: Corners::all(0.25 * ProgressBar::DEFAULT_HEIGHT),
               ..Default::default()
             }),
             Box::new(Container {

hui-examples/examples/mom_downloader.rs

@@ -1,6 +1,6 @@
 use std::time::Instant;
 use hui::{
-  element::{
+  color, element::{
     container::Container,
     progress_bar::ProgressBar,
     text::Text,
@@ -43,7 +43,14 @@ ui_main!{
                 .add_child(ui);
               ProgressBar::default()
                 .with_value(mom_ratio)
-                .with_corner_radius(0.125 * ProgressBar::DEFAULT_HEIGHT)
+                .with_background(frame_rect! {
+                  color: color::BLACK,
+                  corner_radius: 0.125 * ProgressBar::DEFAULT_HEIGHT
+                })
+                .with_foreground(frame_rect! {
+                  color: color::BLUE,
+                  corner_radius: 0.125 * ProgressBar::DEFAULT_HEIGHT
+                })
                 .add_child(ui);
               Container::default()
                 .with_direction(Direction::Horizontal)

hui-examples/examples/ui_test_5_input.rs

@@ -1,7 +1,7 @@
 use hui::{
   color, size,
-  draw::TextureFormat,
   signal::Signal,
+  draw::TextureFormat,
   layout::{Alignment, Direction},
   element::{
     container::Container,
@@ -13,11 +13,11 @@ use hui::{
   },
 };
 
+#[derive(Signal)]
 enum CounterSignal {
   Increment,
   Decrement,
 }
-impl Signal for CounterSignal {}
 
 #[path = "../boilerplate.rs"]
 #[macro_use]

hui-examples/examples/ui_test_6_slider.rs

@@ -8,15 +8,15 @@ use hui::{
     text::Text,
     UiElementExt,
   },
-  layout::{Alignment, Direction},
   signal::Signal,
+  layout::{Alignment, Direction},
   size,
 };
 
+#[derive(Signal)]
 enum CounterSignal {
   ChangeValue(u32)
 }
-impl Signal for CounterSignal {}
 
 #[path = "../boilerplate.rs"]
 #[macro_use]

hui-examples/examples/ui_test_7_9patch.rs

@@ -1,34 +1,92 @@
-use std::time::Instant;
+use glam::vec2;
 use hui::{
-  color, element::{
+  color,
+  element::{
     container::Container,
     fill_rect::FillRect,
+    slider::Slider,
+    text::Text,
     UiElementExt
-  }, frame_rect, layout::{Alignment, Direction}, size
+  },
+  frame::nine_patch::{NinePatchAsset, NinePatchFrame},
+  layout::Alignment,
+  rect::Rect,
+  signal::Signal,
+  size,
 };
 
 #[path = "../boilerplate.rs"]
 #[macro_use]
 mod boilerplate;
 
+#[derive(Signal)]
+struct SetValue(f32);
+
 ui_main!(
   "hUI: 9-Patch demo",
-  init: |_| {
-
+  init: |ui| {
+    (
+      NinePatchAsset {
+        image: ui.add_image_file_path("./hui-examples/assets/ninepatch_button.png").unwrap(),
+        size: (190, 49),
+        scalable_region: Rect {
+          position: vec2(8. / 190., 8. / 49.),
+          size: vec2(1. - 16. / 190., 1. - 18. / 49.),
+        },
+      },
+      0.33,
+    )
   },
-  run: |ui, size, _| {
+  run: |ui, size, (asset, value)| {
     Container::default()
       .with_size(size!(100%))
       .with_align(Alignment::Center)
+      .with_gap(5.)
       .with_background(color::WHITE)
       .with_children(|ui| {
-        FillRect::default()
+        Container::default()
           .with_size(size!(300, 100))
-          .with_frame(frame_rect! {
-            color: color::RED
+          .with_background(NinePatchFrame::from_asset(*asset).with_color(color::RED))
+          .with_padding(10.)
+          .with_children(|ui| {
+            Text::new("Hello, world!\nThis is a 9-patch frame used as a background \nfor Container with a Text element.\nIt's scalable and looks great!\nBelow, there are two FillRects with the same \n9-patch frame used as the background.")
+              .with_text_size(16)
+              .add_child(ui);
           })
           .add_child(ui);
+        FillRect::default()
+          .with_size(size!(600, 75))
+          .with_frame(NinePatchFrame::from_asset(*asset).with_color(color::GREEN))
+          .add_child(ui);
+        Text::new("This one's fancy:")
+          .with_color(color::BLACK)
+          .with_text_size(32)
+          .add_child(ui);
+        FillRect::default()
+          .with_size(size!(700, 50))
+          .with_frame(NinePatchFrame::from_asset(*asset).with_color((
+            (1., 0., 1.),
+            (0., 1., 1.),
+            (1., 1., 0.),
+            (0., 0., 1.),
+          )))
+          .add_child(ui);
+        Text::new("Slider customized with `NinePatchFrame`s:")
+          .with_color(color::BLACK)
+          .with_text_size(32)
+          .add_child(ui);
+        Slider::new(*value)
+          .with_size(size!(50%, 30))
+          .with_track_height(1.)
+          .with_handle_size((20., 1.))
+          .with_handle(NinePatchFrame::from_asset(*asset).with_color(color::CYAN))
+          .with_track(NinePatchFrame::from_asset(*asset))
+          .with_track_active(NinePatchFrame::from_asset(*asset).with_color(color::SKY_BLUE))
+          .on_change(SetValue)
+          .add_child(ui);
       })
       .add_root(ui, size);
+
+    ui.process_signals::<SetValue>(|signal| *value = signal.0);
   }
 );

hui-examples/examples/vscode_layout.rs

@@ -38,7 +38,7 @@ ui_main!(
           .with_size(size!(100%, auto))
           .with_direction(Direction::Horizontal)
           .with_align((Alignment::Begin, Alignment::Center))
-          .with_padding(8.)
+          .with_padding(5.)
           .with_gap(15.)
           .with_background(color::rgb_hex(0x3d3c3e))
           .with_wrap(true) //XXX: not authentic but great for demostration
@@ -51,6 +51,15 @@ ui_main!(
                 .with_text_size(15)
                 .add_child(ui);
             }
+            Container::default()
+              .with_size(size!(100%=, 100%))
+              .with_align((Alignment::End, Alignment::Center))
+              .with_children(|ui| {
+                Text::new("- ×")
+                  .with_text_size(32)
+                  .add_child(ui);
+              })
+              .add_child(ui);
           })
           .add_child(ui);
         FillRect::default()
@@ -58,9 +67,10 @@ ui_main!(
           .with_frame(color::rgb_hex(0x2d2d30))
           .add_child(ui);
         Container::default()
-          .with_size(size!(100%, 100%))
+          .with_size(size!(100%, 100%=))
           .with_direction(Direction::Horizontal)
           .with_children(|ui| {
+            // Sidebar:
             Container::default()
               .with_size(size!(54, 100%))
               .with_background(color::rgb_hex(0x343334))
@@ -69,6 +79,8 @@ ui_main!(
               .with_size(size!(1, 100%))
               .with_frame(color::rgb_hex(0x2d2d30))
               .add_child(ui);
+
+            // Explorer pane:
             Container::default()
               .with_size(size!(200, 100%))
               .with_padding((15., 8.))
@@ -78,20 +90,16 @@ ui_main!(
                   .add_child(ui);
               })
               .add_child(ui);
+
+            // "Code" pane
             Container::default()
-              .with_size(size!(100%, 100%))
+              .with_size(size!(100%=, 100%))
               .with_background(color::rgb_hex(0x1f1e1f))
               .add_child(ui);
           })
           .add_child(ui);
-      })
-      .add_root(ui, size);
 
-      //Bottom bar (yeah, it's basically fake/overlay)
-      Container::default()
-        .with_size(size!(100%))
-        .with_align((Alignment::Begin, Alignment::End))
-        .with_children(|ui| {
+          //Status bar
           Container::default()
             .with_size(size!(100%, auto))
             .with_background(color::rgb_hex(0x0079cc))
@@ -111,8 +119,8 @@ ui_main!(
                 .with_text_size(15)
                 .add_child(ui);
             })
-            .add_child(ui);
-        })
-        .add_root(ui, size);
+          .add_child(ui);
+      })
+      .add_root(ui, size);
   }
 );

hui-glium/Cargo.toml

@@ -4,7 +4,8 @@ description = "glium render backend for `hui`"
 repository = "https://github.com/griffi-gh/hui"
 readme = "../README.md"
 authors = ["griffi-gh <prasol258@gmail.com>"]
-version = "0.1.0-alpha.4"
+version = "0.1.0-alpha.5"
+rust-version = "1.75"
 edition = "2021"
 license = "GPL-3.0-or-later"
 publish = true
@@ -15,7 +16,7 @@ include = [
 ]
 
 [dependencies]
-hui = { version = "=0.1.0-alpha.4", path = "../hui", default-features = false }
+hui = { version = "=0.1.0-alpha.5", path = "../hui", default-features = false }
 glium = { version = "0.34", default-features = false }
 glam = "0.27"
 log = "0.4"

hui-glium/shaders/fragment.150.frag

@@ -0,0 +1,13 @@
+#version 150 core
+
+precision highp float;
+precision highp sampler2D;
+
+out vec4 out_color;
+in vec4 vtx_color;
+in vec2 vtx_uv;
+uniform sampler2D tex;
+
+void main() {
+  out_color = texture(tex, vtx_uv) * vtx_color;
+}

hui-glium/shaders/vertex.150.vert

@@ -0,0 +1,17 @@
+#version 150 core
+
+precision highp float;
+
+uniform vec2 resolution;
+in vec2 uv;
+in vec4 color;
+in vec2 position;
+out vec4 vtx_color;
+out vec2 vtx_uv;
+
+void main() {
+  vtx_color = color;
+  vtx_uv = uv;
+  vec2 pos2d = (vec2(2., -2.) * (position / resolution)) + vec2(-1, 1);
+  gl_Position = vec4(pos2d, 0., 1.);
+}

hui-glium/src/lib.rs

@@ -1,19 +1,17 @@
 use std::rc::Rc;
 use glam::Vec2;
 use glium::{
-  Blend, DrawParameters, IndexBuffer, Program, Surface, VertexBuffer,
-  implement_vertex, uniform,
-  backend::{Context, Facade},
-  index::PrimitiveType,
-  texture::{RawImage2d, Texture2d},
-  uniforms::{MagnifySamplerFilter, MinifySamplerFilter, Sampler, SamplerBehavior, SamplerWrapFunction},
+  backend::{Context, Facade}, implement_vertex, index::PrimitiveType, texture::{RawImage2d, Texture2d}, uniform, uniforms::{MagnifySamplerFilter, MinifySamplerFilter, Sampler, SamplerBehavior, SamplerWrapFunction}, Api, Blend, DrawParameters, IndexBuffer, Program, Surface, VertexBuffer
 };
 use hui::{
   draw::{TextureAtlasMeta, UiDrawCall, UiVertex}, UiInstance
 };
 
-const VERTEX_SHADER: &str = include_str!("../shaders/vertex.vert");
-const FRAGMENT_SHADER: &str = include_str!("../shaders/fragment.frag");
+const VERTEX_SHADER_GLES3: &str = include_str!("../shaders/vertex.es.vert");
+const FRAGMENT_SHADER_GLES3: &str = include_str!("../shaders/fragment.es.frag");
+
+const VERTEX_SHADER_150: &str = include_str!("../shaders/vertex.150.vert");
+const FRAGMENT_SHADER_150: &str = include_str!("../shaders/fragment.150.frag");
 
 #[derive(Clone, Copy)]
 #[repr(C)]
@@ -122,7 +120,10 @@ impl GliumUiRenderer {
   pub fn new<F: Facade>(facade: &F) -> Self {
     log::info!("initializing hui-glium");
     Self {
-      program: Program::from_source(facade, VERTEX_SHADER, FRAGMENT_SHADER, None).unwrap(),
+      program: match facade.get_context().get_supported_glsl_version().0 {
+        Api::Gl => Program::from_source(facade, VERTEX_SHADER_150, FRAGMENT_SHADER_150, None).unwrap(),
+        Api::GlEs => Program::from_source(facade, VERTEX_SHADER_GLES3, FRAGMENT_SHADER_GLES3, None).unwrap(),
+      },
       context: Rc::clone(facade.get_context()),
       ui_texture: None,
       buffer_pair: None,
@@ -183,7 +184,7 @@ impl GliumUiRenderer {
           tex: Sampler(self.ui_texture.as_ref().unwrap(), SamplerBehavior {
             max_anisotropy: 1,
             magnify_filter: MagnifySamplerFilter::Nearest,
-            minify_filter: MinifySamplerFilter::NearestMipmapNearest,
+            minify_filter: MinifySamplerFilter::Linear,
             wrap_function: (SamplerWrapFunction::Clamp, SamplerWrapFunction::Clamp, SamplerWrapFunction::Clamp),
             ..Default::default()
           }),

hui-winit/Cargo.toml

@@ -4,7 +4,7 @@ description = "winit platform backend for `hui`"
 repository = "https://github.com/griffi-gh/hui"
 readme = "../README.md"
 authors = ["griffi-gh <prasol258@gmail.com>"]
-version = "0.1.0-alpha.4"
+version = "0.1.0-alpha.5"
 edition = "2021"
 license = "GPL-3.0-or-later"
 publish = true
@@ -14,7 +14,7 @@ include = [
 ]
 
 [dependencies]
-hui = { version = "=0.1.0-alpha.4", path = "../hui", default-features = false }
+hui = { version = "=0.1.0-alpha.5", path = "../hui", default-features = false }
 winit = { version = "0.29", default-features = false }
 glam = "0.27"
 log = "0.4"

hui/Cargo.toml

@@ -5,7 +5,7 @@ repository = "https://github.com/griffi-gh/hui"
 readme = "../README.md"
 authors = ["griffi-gh <prasol258@gmail.com>"]
 rust-version = "1.75"
-version = "0.1.0-alpha.4"
+version = "0.1.0-alpha.5"
 edition = "2021"
 license = "GPL-3.0-or-later"
 publish = true
@@ -16,6 +16,7 @@ include = [
 ]
 
 [dependencies]
+hui-derive = { version = "0.1.0-alpha.5", path = "../hui-derive", optional = true }
 hashbrown = "0.14"
 nohash-hasher = "0.2"
 glam = "0.27"
@@ -29,15 +30,14 @@ tinyset = "0.4"
 image = { version = "0.25", default-features = false, optional = true }
 
 [features]
-default = ["el_all", "image", "builtin_font", "pixel_perfect_text"]
+default = ["el_all", "image", "builtin_font", "pixel_perfect_text", "derive"]
 
-#! Image loading support:
+## Enable derive macros
+derive = ["dep:hui-derive"]
 
 ## Enable image loading support using the `image` crate
 image = ["dep:image"]
 
-#! #### Built-in font:
-
 ## Enable the built-in font (ProggyTiny, adds *35kb* to the executable)
 builtin_font = []
 

hui/src/draw.rs

@@ -1,7 +1,5 @@
 //! draw commands, tesselation and UI rendering.
 
-//TODO: 9-slice draw command
-
 use crate::{
   rect::Corners,
   text::{FontHandle, TextRenderer}
@@ -35,6 +33,8 @@ pub enum UiDrawCommand {
     color: Corners<Vec4>,
     ///Texture
     texture: Option<ImageHandle>,
+    ///Sub-UV coordinates for the texture
+    texture_uv: Option<Corners<Vec2>>,
     ///Rounded corners
     rounded_corners: Option<RoundedCorners>,
   },
@@ -161,10 +161,36 @@ impl UiDrawCall {
             v.position += center;
           }
         },
-        UiDrawCommand::Rectangle { position, size, color, texture, rounded_corners } => {
+        UiDrawCommand::Rectangle { position, size, color, texture, texture_uv, rounded_corners } => {
           let uvs = texture
             .map(|x| atlas.get_uv(x))
             .flatten()
+            .map(|guv| {
+              if let Some(texture_uv) = texture_uv {
+                //XXX: this may not work if the texture is rotated
+                //also is this slow?
+
+                let top = guv.top_left.lerp(guv.top_right, texture_uv.top_left.x);
+                let bottom = guv.bottom_left.lerp(guv.bottom_right, texture_uv.top_left.x);
+                let top_left = top.lerp(bottom, texture_uv.top_left.y);
+
+                let top = guv.top_left.lerp(guv.top_right, texture_uv.top_right.x);
+                let bottom = guv.bottom_left.lerp(guv.bottom_right, texture_uv.top_right.x);
+                let top_right = top.lerp(bottom, texture_uv.top_right.y);
+
+                let top = guv.top_left.lerp(guv.top_right, texture_uv.bottom_left.x);
+                let bottom = guv.bottom_left.lerp(guv.bottom_right, texture_uv.bottom_left.x);
+                let bottom_left = top.lerp(bottom, texture_uv.bottom_left.y);
+
+                let top = guv.top_left.lerp(guv.top_right, texture_uv.bottom_right.x);
+                let bottom = guv.bottom_left.lerp(guv.bottom_right, texture_uv.bottom_right.x);
+                let bottom_right = top.lerp(bottom, texture_uv.bottom_right.y);
+
+                Corners { top_left, top_right, bottom_left, bottom_right }
+              } else {
+                guv
+              }
+            })
             .unwrap_or(Corners::all(Vec2::ZERO));
 
           let vidx = draw_call.vertices.len() as u32;

hui/src/element.rs

@@ -4,7 +4,7 @@ use std::any::Any;
 use crate::{
   draw::{atlas::ImageCtx, UiDrawCommandList},
   input::InputCtx,
-  layout::LayoutInfo,
+  layout::{LayoutInfo, Size2d},
   measure::Response,
   signal::SignalStore,
   state::StateRepo,
@@ -45,6 +45,11 @@ pub trait UiElement {
   /// For example, "button" or "progress_bar"
   fn name(&self) -> &'static str;
 
+  /// Get the requested UiElement size
+  ///
+  /// You should implement this function whenever possible, otherwise some features may not work at all, such as the `Remaining` size
+  fn size(&self) -> Option<Size2d> { None }
+
   /// Get the unique id used for internal state management\
   /// This value must be unique for each instance of the element
   ///

hui/src/element/builtin/container.rs

@@ -4,10 +4,10 @@ use derive_setters::Setters;
 use glam::{Vec2, vec2};
 use crate::{
   element::{ElementList, MeasureContext, ProcessContext, UiElement},
-  layout::{Alignment, Alignment2d, Direction, LayoutInfo, Size, Size2d},
   frame::{Frame, FrameRect},
+  layout::{compute_size, Alignment, Alignment2d, Direction, LayoutInfo, Size, Size2d, WrapBehavior},
   measure::{Hints, Response},
-  rect::{Sides, FillColor},
+  rect::Sides,
 };
 
 //XXX: add Order/Direction::Forward/Reverse or sth?
@@ -19,6 +19,7 @@ use crate::{
 struct CudLine {
   start_idx: usize,
   content_size: Vec2,
+  remaining_space: f32,
 }
 
 struct ContainerUserData {
@@ -52,13 +53,9 @@ pub struct Container {
   #[setters(skip)]
   pub background_frame: Box<dyn Frame>,
 
-  /// Set this to `true` to allow the elements wrap automatically
-  ///
-  /// Disabling/enabling this does not affect explicit wrapping\
-  /// (for example, `Br`, or any other element with `should_wrap` set to `true`)
-  ///
-  /// This is an experimental feature and may not work as expected
-  pub wrap: bool,
+  /// Controls if wrapping is enabled
+  #[setters(into)]
+  pub wrap: WrapBehavior,
 
   /// List of children elements
   #[setters(skip)]
@@ -86,7 +83,7 @@ impl Default for Container {
       padding: Sides::all(0.),
       align: Alignment2d::default(),
       background_frame: Box::<FrameRect>::default(),
-      wrap: false,
+      wrap: WrapBehavior::Allow,
       children: ElementList(Vec::new()),
     }
   }
@@ -94,19 +91,24 @@ impl Default for Container {
 
 impl Container {
   pub fn measure_max_inner_size(&self, layout: &LayoutInfo) -> Vec2 {
-    let outer_size_x = match self.size.width {
-      Size::Auto => layout.max_size.x,
-      Size::Relative(p) => layout.max_size.x * p,
-      Size::Absolute(p) => p,
-    };
-    let outer_size_y = match self.size.height {
-      Size::Auto => layout.max_size.y,
-      Size::Relative(p) => layout.max_size.y * p,
-      Size::Absolute(p) => p,
-    };
+    // let outer_size_x = match self.size.width {
+    //   Size::Auto => layout.max_size.x,
+    //   Size::Relative(p) => layout.max_size.x * p,
+    //   Size::Absolute(p) => p,
+    //   Size::Remaining(p) => match layout.direction {
+    //     Direction::Horizontal => layout.remaining_space.unwrap_or(layout.max_size.x) * p,
+    //     Direction::Vertical => layout.max_size.x,
+    //   }
+    // };
+    // let outer_size_y = match self.size.height {
+    //   Size::Auto => layout.max_size.y,
+    //   Size::Relative(p) => layout.max_size.y * p,
+    //   Size::Absolute(p) => p,
+    // };
+    let outer_size = compute_size(layout, self.size, layout.max_size);
     vec2(
-      outer_size_x - (self.padding.left + self.padding.right),
-      outer_size_y - (self.padding.top + self.padding.bottom),
+      outer_size.x - (self.padding.left + self.padding.right),
+      outer_size.y - (self.padding.top + self.padding.bottom),
     )
   }
 }
@@ -116,6 +118,10 @@ impl UiElement for Container {
     "container"
   }
 
+  fn size(&self) -> Option<Size2d> {
+    Some(self.size)
+  }
+
   fn measure(&self, ctx: MeasureContext) -> Response {
     // XXX: If both axes are NOT set to auto, we should be able quickly return the size
     // ... but we can't, because we need to measure the children to get the inner_content_size and user_data values
@@ -130,11 +136,13 @@ impl UiElement for Container {
         Size::Auto => ctx.layout.max_size.x,
         Size::Relative(p) => ctx.layout.max_size.x * p,
         Size::Absolute(p) => p,
+        Size::Remaining(p) => ctx.layout.remaining_space.unwrap_or(ctx.layout.max_size.x) * p,
       },
       Direction::Vertical => match self.size.height {
         Size::Auto => ctx.layout.max_size.y,
         Size::Relative(p) => ctx.layout.max_size.y * p,
         Size::Absolute(p) => p,
+        Size::Remaining(p) => ctx.layout.remaining_space.unwrap_or(ctx.layout.max_size.y) * p,
       }
     };
 
@@ -160,10 +168,25 @@ impl UiElement for Container {
       CudLine {
         start_idx: 0,
         content_size: Vec2::ZERO,
+        remaining_space: 0.,
       }
     ];
 
+    //set to true if in the current line there is an element with Remaining size (line will have to be wrapped)
+    // let mut has_remaining = false;
+
     for (idx, element) in self.children.0.iter().enumerate() {
+      if let Some(esize) = element.size() {
+        let pri_size = match self.direction {
+          Direction::Horizontal => esize.width,
+          Direction::Vertical => esize.height,
+        };
+        if matches!(pri_size, Size::Remaining(_)) {
+          //XXX: kinda a hack?
+          continue;
+        }
+      }
+
       let measure = element.measure(MeasureContext{
         state: ctx.state,
         layout: &LayoutInfo {
@@ -176,6 +199,7 @@ impl UiElement for Container {
           //TODO: subtract size already taken by previous children
           max_size: self.measure_max_inner_size(ctx.layout),
           direction: self.direction,
+          remaining_space: None,
         },
         text_measure: ctx.text_measure,
         current_font: ctx.current_font,
@@ -189,19 +213,30 @@ impl UiElement for Container {
       };
 
       //Wrap the element if it exceeds container's size and is not the first element in the line
-      if ((self.wrap && (end_pos_pri > max_line_pri)) || measure.should_wrap) && (line_element_count > 0) {
+      let should_wrap_overflow = self.wrap.is_enabled() && (end_pos_pri > max_line_pri);
+      if self.wrap.is_allowed() && line_element_count > 0 && (measure.should_wrap || should_wrap_overflow) {
         // >>>>>>> WRAP THAT B*TCH!
 
         //Negate the leftover gap from the previous element
         line_size -= leftover_gap;
 
         //update the previous line metadata
-        lines.last_mut().unwrap().content_size = line_size;
+        {
+          let last_line = lines.last_mut().unwrap();
+          last_line.content_size = line_size;
+          //HACK: why? - self.gap, may be different for the last element or if it's the only element in the line
+          let will_produce_gap = if line_element_count > 1 { self.gap } else { 0. };
+          last_line.remaining_space = max_line_pri - will_produce_gap - match self.direction {
+            Direction::Horizontal => line_size.x + self.padding.left + self.padding.right,
+            Direction::Vertical => line_size.y + self.padding.top + self.padding.bottom,
+          };
+        }
 
         //push the line metadata
         lines.push(CudLine {
           start_idx: idx,
           content_size: Vec2::ZERO,
+          remaining_space: 0.,
         });
 
         //Update the total size accordingly
@@ -252,7 +287,16 @@ impl UiElement for Container {
     line_size -= leftover_gap;
 
     //Update the content size of the last line
-    lines.last_mut().unwrap().content_size = line_size;
+    {
+      //HACK: why? - self.gap, may be different for the last element or if it's the only element in the line
+      let cur_line = lines.last_mut().unwrap();
+      cur_line.content_size = line_size;
+      let will_produce_gap = if line_element_count > 1 { self.gap } else { 0. };
+      cur_line.remaining_space = max_line_pri - will_produce_gap - match self.direction {
+        Direction::Horizontal => line_size.x + self.padding.left + self.padding.right,
+        Direction::Vertical => line_size.y + self.padding.top + self.padding.bottom,
+      };
+    }
 
     //Update the total size according to the size of the last line
     match self.direction {
@@ -278,17 +322,27 @@ impl UiElement for Container {
       self.padding.top + self.padding.bottom,
     );
 
+    let computed_size = compute_size(ctx.layout, self.size, total_size);
     match self.size.width {
       Size::Auto => (),
-      Size::Relative(percentage) => total_size.x = ctx.layout.max_size.x * percentage,
-      Size::Absolute(pixels) => total_size.x = pixels,
+      _ => total_size.x = computed_size.x,
     }
     match self.size.height {
       Size::Auto => (),
-      Size::Relative(percentage) => total_size.y = ctx.layout.max_size.y * percentage,
-      Size::Absolute(pixels) => total_size.y = pixels,
+      _ => total_size.y = computed_size.y,
     }
 
+    // match self.size.width {
+    //   Size::Auto => (),
+    //   Size::Relative(percentage) => total_size.x = ctx.layout.max_size.x * percentage,
+    //   Size::Absolute(pixels) => total_size.x = pixels,
+    // }
+    // match self.size.height {
+    //   Size::Auto => (),
+    //   Size::Relative(percentage) => total_size.y = ctx.layout.max_size.y * percentage,
+    //   Size::Absolute(pixels) => total_size.y = pixels,
+    // }
+
     Response {
       size: total_size,
       hints: Hints {
@@ -385,6 +439,7 @@ impl UiElement for Container {
           position: local_position,
           max_size: self.measure_max_inner_size(ctx.layout),
           direction: self.direction,
+          remaining_space: Some(cur_line.remaining_space),
         };
 
         //measure

hui/src/element/builtin/fill_rect.rs

@@ -6,7 +6,7 @@ use crate::{
   draw::{RoundedCorners, UiDrawCommand},
   element::{MeasureContext, ProcessContext, UiElement},
   frame::{Frame, FrameRect},
-  layout::{Size, Size2d},
+  layout::{compute_size, Size, Size2d},
   measure::Response,
   size
 };
@@ -45,20 +45,13 @@ impl UiElement for FillRect {
     "fill_rect"
   }
 
+  fn size(&self) -> Option<Size2d> {
+    Some(self.size)
+  }
+
   fn measure(&self, ctx: MeasureContext) -> Response {
     Response {
-      size: vec2(
-        match self.size.width {
-          Size::Auto => ctx.layout.max_size.x,
-          Size::Relative(percentage) => ctx.layout.max_size.x * percentage,
-          Size::Absolute(pixels) => pixels,
-        },
-        match self.size.height {
-          Size::Auto => ctx.layout.max_size.y,
-          Size::Relative(percentage) => ctx.layout.max_size.y * percentage,
-          Size::Absolute(pixels) => pixels,
-        },
-      ),
+      size: compute_size(ctx.layout, self.size, ctx.layout.max_size),
       ..Default::default()
     }
   }

hui/src/element/builtin/image.rs

@@ -54,6 +54,10 @@ impl UiElement for Image {
     "image"
   }
 
+  fn size(&self) -> Option<Size2d> {
+    Some(self.size)
+  }
+
   fn measure(&self, ctx: MeasureContext) -> Response {
     let dim = ctx.images.get_size(self.image).expect("invalid image handle");
     let pre_size = compute_size(ctx.layout, self.size, dim.as_vec2());
@@ -79,6 +83,7 @@ impl UiElement for Image {
         size: ctx.measure.size,
         color: self.color.corners(),
         texture: Some(self.image),
+        texture_uv: None,
         rounded_corners: (self.corner_radius.max_f32() > 0.).then_some({
           RoundedCorners::from_radius(self.corner_radius)
         }),

hui/src/element/builtin/interactable.rs

@@ -48,6 +48,10 @@ impl UiElement for Interactable {
     "interactable"
   }
 
+  fn size(&self) -> Option<crate::layout::Size2d> {
+    self.element.size()
+  }
+
   fn measure(&self, ctx: MeasureContext) -> crate::measure::Response {
     self.element.measure(ctx)
   }

hui/src/element/builtin/progress_bar.rs

@@ -1,14 +1,15 @@
 use derive_setters::Setters;
-use glam::{vec2, vec4};
+use glam::vec2;
 use crate::{
-  draw::{RoundedCorners, UiDrawCommand},
   element::{MeasureContext, ProcessContext, UiElement},
+  frame::{Frame, FrameRect},
   layout::{compute_size, Size, Size2d},
   measure::Response,
-  rect::{Corners, FillColor}
 };
 
-#[derive(Debug, Clone, Copy, Setters)]
+//TODO: Use Frames here instead of FillColor
+
+#[derive(Setters)]
 #[setters(prefix = "with_")]
 pub struct ProgressBar {
   /// Current progress, should be in the range 0.0..=1.0
@@ -19,20 +20,26 @@ pub struct ProgressBar {
   pub size: Size2d,
 
   /// Foreground (bar) color
-  #[setters(into)]
-  pub foreground: FillColor,
+  #[setters(skip)]
+  pub foreground: Box<dyn Frame>,
 
   /// Background color
-  #[setters(into)]
-  pub background: FillColor,
-
-  /// Corner radius of the progress bar
-  #[setters(into)]
-  pub corner_radius: Corners<f32>,
+  #[setters(skip)]
+  pub background: Box<dyn Frame>,
 }
 
 impl ProgressBar {
   pub const DEFAULT_HEIGHT: f32 = 20.0;
+
+  pub fn with_background(mut self, frame: impl Frame + 'static) -> Self {
+    self.background = Box::new(frame);
+    self
+  }
+
+  pub fn with_foreground(mut self, frame: impl Frame + 'static) -> Self {
+    self.foreground = Box::new(frame);
+    self
+  }
 }
 
 impl Default for ProgressBar {
@@ -40,9 +47,8 @@ impl Default for ProgressBar {
     Self {
       value: 0.,
       size: Size::Auto.into(),
-      foreground: vec4(0.0, 0.0, 1.0, 1.0).into(),
-      background: vec4(0.0, 0.0, 0.0, 1.0).into(),
-      corner_radius: Corners::all(0.),
+      foreground: Box::new(FrameRect::color((0.0, 0.0, 1.0, 1.0))),
+      background: Box::new(FrameRect::color((0.0, 0.0, 0.0, 1.0))),
     }
   }
 }
@@ -55,7 +61,7 @@ impl UiElement for ProgressBar {
   fn measure(&self, ctx: MeasureContext) -> Response {
     Response {
       size: compute_size(ctx.layout, self.size, vec2(
-        ctx.layout.max_size.x.max(300.),
+        ctx.layout.max_size.x.max(300.), //XXX: remove .max(300)?
         Self::DEFAULT_HEIGHT,
       )),
       hints: Default::default(),
@@ -66,38 +72,49 @@ impl UiElement for ProgressBar {
 
   fn process(&self, ctx: ProcessContext) {
     let value = self.value.clamp(0., 1.);
-    let rounded_corners =
-      (self.corner_radius.max_f32() > 0.).then_some({
-        //HACK: fix clipping issues; //todo: get rid of this
-        let mut radii = self.corner_radius;
-        let width = ctx.measure.size.x * value;
-        if width <= radii.max_f32() * 2. {
-          radii.bottom_right = 0.;
-          radii.top_right = 0.;
-        }
-        if width <= radii.max_f32() {
-          radii.bottom_left = 0.;
-          radii.top_left = 0.;
-        }
-        RoundedCorners::from_radius(radii)
-      });
-    if value < 1. {
-      ctx.draw.add(UiDrawCommand::Rectangle {
-        position: ctx.layout.position,
-        size: ctx.measure.size,
-        color: self.background.corners(),
-        texture: None,
-        rounded_corners
-      });
+
+    //FIXME: these optimizations may not be valid
+    if value < 1. || !self.foreground.covers_opaque() {
+      self.background.draw(ctx.draw, ctx.layout.position, ctx.measure.size);
     }
     if value > 0. {
-      ctx.draw.add(UiDrawCommand::Rectangle {
-        position: ctx.layout.position,
-        size: ctx.measure.size * vec2(value, 1.0),
-        color: self.foreground.corners(),
-        texture: None,
-        rounded_corners,
-      });
+      self.foreground.draw(ctx.draw, ctx.layout.position, ctx.measure.size * vec2(value, 1.));
     }
+
+    // let rounded_corners =
+    //   (self.corner_radius.max_f32() > 0.).then_some({
+    //     //HACK: fix clipping issues; //todo: get rid of this
+    //     let mut radii = self.corner_radius;
+    //     let width = ctx.measure.size.x * value;
+    //     if width <= radii.max_f32() * 2. {
+    //       radii.bottom_right = 0.;
+    //       radii.top_right = 0.;
+    //     }
+    //     if width <= radii.max_f32() {
+    //       radii.bottom_left = 0.;
+    //       radii.top_left = 0.;
+    //     }
+    //     RoundedCorners::from_radius(radii)
+    //   });
+    // if value < 1. {
+    //   ctx.draw.add(UiDrawCommand::Rectangle {
+    //     position: ctx.layout.position,
+    //     size: ctx.measure.size,
+    //     color: self.background.corners(),
+    //     texture: None,
+    //     texture_uv: None,
+    //     rounded_corners
+    //   });
+    // }
+    // if value > 0. {
+    //   ctx.draw.add(UiDrawCommand::Rectangle {
+    //     position: ctx.layout.position,
+    //     size: ctx.measure.size * vec2(value, 1.0),
+    //     color: self.foreground.corners(),
+    //     texture: None,
+    //     texture_uv: None,
+    //     rounded_corners,
+    //   });
+    // }
   }
 }

hui/src/element/builtin/text.rs

@@ -6,7 +6,7 @@ use glam::{vec2, Vec4};
 use crate::{
   draw::UiDrawCommand,
   element::{MeasureContext, ProcessContext, UiElement},
-  layout::{Size, Size2d},
+  layout::{compute_size, Size, Size2d},
   measure::Response,
   text::FontHandle,
 };
@@ -74,6 +74,10 @@ impl UiElement for Text {
     "text"
   }
 
+  fn size(&self) -> Option<Size2d> {
+    Some(self.size)
+  }
+
   fn measure(&self, ctx: MeasureContext) -> Response {
     let mut size = (0., 0.);
     if matches!(self.size.width, Size::Auto) || matches!(self.size.height, Size::Auto) {
@@ -83,18 +87,7 @@ impl UiElement for Text {
       size.1 = res.height;
     }
     Response {
-      size: vec2(
-        match self.size.width {
-          Size::Auto => size.0,
-          Size::Relative(percentage) => ctx.layout.max_size.x * percentage,
-          Size::Absolute(pixels) => pixels,
-        },
-        match self.size.height {
-          Size::Auto => size.1,
-          Size::Relative(percentage) => ctx.layout.max_size.y * percentage,
-          Size::Absolute(pixels) => pixels,
-        },
-      ),
+      size: compute_size(ctx.layout, self.size, size.into()),
       ..Default::default()
     }
   }

hui/src/frame.rs

@@ -1,13 +1,17 @@
+//! modular procedural background system
+
 use glam::Vec2;
 use crate::draw::UiDrawCommandList;
 
 pub mod point;
 mod rect;
 pub mod stack;
+pub mod nine_patch;
 mod impls;
 
 pub use rect::FrameRect;
 
+/// Trait for a drawable frame
 pub trait Frame {
   /// Draw the frame at the given position and size
   fn draw(&self, draw: &mut UiDrawCommandList, position: Vec2, parent_size: Vec2);

hui/src/frame/impls.rs

@@ -13,6 +13,7 @@ impl Frame for ImageHandle {
       size: parent_size,
       color: color::WHITE.into(),
       texture: Some(*self),
+      texture_uv: None,
       rounded_corners: None,
     })
   }
@@ -29,6 +30,7 @@ impl Frame for FillColor {
       size: parent_size,
       color: self.corners(),
       texture: None,
+      texture_uv: None,
       rounded_corners: None,
     })
   }

hui/src/frame/nine_patch.rs

@@ -0,0 +1,234 @@
+//! nine-patch frame implementation
+//!
+//! A 9-patch image is an image that can be scaled in a way that preserves the corners and edges of the image while scaling the center.
+//! This is useful for creating scalable UI elements like buttons, windows, etc.
+
+use glam::{vec2, UVec2, Vec2};
+use crate::{color, draw::{ImageHandle, UiDrawCommand}, rect::{Corners, FillColor, Rect}};
+use super::Frame;
+
+/// Represents a 9-patch image asset
+#[derive(Clone, Copy, Debug)]
+pub struct NinePatchAsset {
+  pub image: ImageHandle,
+  //TODO: remove this:
+  pub size: (u32, u32),
+  pub scalable_region: Rect,
+}
+
+//TODO allow scaling/moving corners
+
+/// A 9-patch frame
+///
+/// Can optionally be tinted with a color (works well with grayscale assets)
+#[derive(Clone, Copy, Debug)]
+pub struct NinePatchFrame {
+  pub asset: NinePatchAsset,
+  pub color: FillColor,
+}
+
+impl NinePatchFrame {
+  pub fn from_asset(asset: NinePatchAsset) -> Self {
+    Self { asset, ..Default::default() }
+  }
+
+  pub fn with_color(mut self, color: impl Into<FillColor>) -> Self {
+    self.color = color.into();
+    self
+  }
+}
+
+impl Default for NinePatchFrame {
+  fn default() -> Self {
+    Self {
+      //This is not supposed to be left out as the default, so just set it to whatever :p
+      asset: NinePatchAsset { image: ImageHandle::default(), size: (0, 0), scalable_region: Rect::default() },
+      color: color::WHITE.into(),
+    }
+  }
+}
+
+impl Frame for NinePatchFrame {
+  fn draw(&self, draw: &mut crate::draw::UiDrawCommandList, position: glam::Vec2, parent_size: glam::Vec2) {
+    // without this, shїt gets messed up when the position is not a whole number
+    //XXX: should we round the size as well?
+    let position = position.round();
+
+    let img_sz = UVec2::from(self.asset.size).as_vec2();
+
+    //Color stuff
+    let interpolate_color_rect = |uvs: Corners<Vec2>| {
+      Corners {
+        top_left: self.color.interpolate(uvs.top_left),
+        top_right: self.color.interpolate(uvs.top_right),
+        bottom_left: self.color.interpolate(uvs.bottom_left),
+        bottom_right: self.color.interpolate(uvs.bottom_right),
+      }
+    };
+
+    // Inset coords, in UV space
+    let region_uv = self.asset.scalable_region.corners();
+
+    // Inset coords, in image (px) space
+    let corners_image_px = Corners {
+      top_left: img_sz * region_uv.top_left,
+      top_right: img_sz * region_uv.top_right,
+      bottom_left: img_sz * region_uv.bottom_left,
+      bottom_right: img_sz * region_uv.bottom_right,
+    };
+
+    let size_h = (
+      corners_image_px.top_left.x,
+      parent_size.x - corners_image_px.top_left.x - (img_sz.x - corners_image_px.top_right.x),
+      img_sz.x - corners_image_px.top_right.x,
+    );
+
+    let size_v = (
+      corners_image_px.top_left.y,
+      parent_size.y - corners_image_px.top_left.y - (img_sz.y - corners_image_px.bottom_left.y),
+      img_sz.y - corners_image_px.bottom_left.y,
+    );
+
+    //Top-left patch
+    let top_left_patch_uv = Corners {
+      top_left: vec2(0., 0.),
+      top_right: vec2(region_uv.top_left.x, 0.),
+      bottom_left: vec2(0., region_uv.top_left.y),
+      bottom_right: region_uv.top_left,
+    };
+    draw.add(UiDrawCommand::Rectangle {
+      position,
+      size: vec2(size_h.0, size_v.0),
+      color: interpolate_color_rect(top_left_patch_uv),
+      texture: Some(self.asset.image),
+      texture_uv: Some(top_left_patch_uv),
+      rounded_corners: None
+    });
+
+    //Top patch
+    let top_patch_uv = Corners {
+      top_left: vec2(region_uv.top_left.x, 0.),
+      top_right: vec2(region_uv.top_right.x, 0.),
+      bottom_left: region_uv.top_left,
+      bottom_right: region_uv.top_right,
+    };
+    draw.add(UiDrawCommand::Rectangle {
+      position: position + vec2(size_h.0, 0.),
+      size: vec2(size_h.1, size_v.0),
+      color: interpolate_color_rect(top_patch_uv),
+      texture: Some(self.asset.image),
+      texture_uv: Some(top_patch_uv),
+      rounded_corners: None
+    });
+
+    //Top-right patch
+    let top_right_patch_uv = Corners {
+      top_left: vec2(region_uv.top_right.x, 0.),
+      top_right: vec2(1., 0.),
+      bottom_left: region_uv.top_right,
+      bottom_right: vec2(1., region_uv.top_right.y),
+    };
+    draw.add(UiDrawCommand::Rectangle {
+      position: position + vec2(size_h.0 + size_h.1, 0.),
+      size: vec2(size_h.2, size_v.0),
+      color: interpolate_color_rect(top_right_patch_uv),
+      texture: Some(self.asset.image),
+      texture_uv: Some(top_right_patch_uv),
+      rounded_corners: None
+    });
+
+    //Left patch
+    let left_patch_uv = Corners {
+      top_left: vec2(0., region_uv.top_left.y),
+      top_right: region_uv.top_left,
+      bottom_left: vec2(0., region_uv.bottom_left.y),
+      bottom_right: region_uv.bottom_left,
+    };
+    draw.add(UiDrawCommand::Rectangle {
+      position: position + vec2(0., size_v.0),
+      size: vec2(size_h.0, size_v.1),
+      color: interpolate_color_rect(left_patch_uv),
+      texture: Some(self.asset.image),
+      texture_uv: Some(left_patch_uv),
+      rounded_corners: None
+    });
+
+    // Center patch
+    draw.add(UiDrawCommand::Rectangle {
+      position: position + vec2(size_h.0, size_v.0),
+      size: vec2(size_h.1, size_v.1),
+      color: interpolate_color_rect(region_uv),
+      texture: Some(self.asset.image),
+      texture_uv: Some(region_uv),
+      rounded_corners: None
+    });
+
+    //Right patch
+    let right_patch_uv = Corners {
+      top_left: region_uv.top_right,
+      top_right: vec2(1., region_uv.top_right.y),
+      bottom_left: region_uv.bottom_right,
+      bottom_right: vec2(1., region_uv.bottom_right.y),
+    };
+    draw.add(UiDrawCommand::Rectangle {
+      position: position + vec2(size_h.0 + size_h.1, size_v.0),
+      size: vec2(size_h.2, size_v.1),
+      color: interpolate_color_rect(right_patch_uv),
+      texture: Some(self.asset.image),
+      texture_uv: Some(right_patch_uv),
+      rounded_corners: None
+    });
+
+    //Bottom-left patch
+    let bottom_left_patch_uv = Corners {
+      top_left: vec2(0., region_uv.bottom_left.y),
+      top_right: region_uv.bottom_left,
+      bottom_left: vec2(0., 1.),
+      bottom_right: vec2(region_uv.bottom_left.x, 1.),
+    };
+    draw.add(UiDrawCommand::Rectangle {
+      position: position + vec2(0., size_v.0 + size_v.1),
+      size: vec2(size_h.0, size_v.2),
+      color: interpolate_color_rect(bottom_left_patch_uv),
+      texture: Some(self.asset.image),
+      texture_uv: Some(bottom_left_patch_uv),
+      rounded_corners: None
+    });
+
+    //Bottom patch
+    let bottom_patch_uv = Corners {
+      top_left: region_uv.bottom_left,
+      top_right: region_uv.bottom_right,
+      bottom_left: vec2(region_uv.bottom_left.x, 1.),
+      bottom_right: vec2(region_uv.bottom_right.x, 1.),
+    };
+    draw.add(UiDrawCommand::Rectangle {
+      position: position + vec2(size_h.0, size_v.0 + size_v.1),
+      size: vec2(size_h.1, size_v.2),
+      color: interpolate_color_rect(bottom_patch_uv),
+      texture: Some(self.asset.image),
+      texture_uv: Some(bottom_patch_uv),
+      rounded_corners: None
+    });
+
+    //Bottom-right patch
+    let bottom_right_patch_uv = Corners {
+      top_left: region_uv.bottom_right,
+      top_right: vec2(1., region_uv.bottom_right.y),
+      bottom_left: vec2(region_uv.bottom_right.x, 1.),
+      bottom_right: vec2(1., 1.),
+    };
+    draw.add(UiDrawCommand::Rectangle {
+      position: position + vec2(size_h.0 + size_h.1, size_v.0 + size_v.1),
+      size: vec2(size_h.2, size_v.2),
+      color: interpolate_color_rect(bottom_right_patch_uv),
+      texture: Some(self.asset.image),
+      texture_uv: Some(bottom_right_patch_uv),
+      rounded_corners: None
+    });
+  }
+
+  fn covers_opaque(&self) -> bool {
+    false
+  }
+}

hui/src/frame/point.rs

@@ -1,3 +1,5 @@
+//! frame-relative positioning/size
+
 use glam::{Vec2, vec2};
 use derive_more::{Add, AddAssign, Sub, SubAssign};
 use crate::layout::{Size, Size2d};
@@ -24,11 +26,13 @@ impl From<f32> for FramePoint {
 impl From<Size> for FramePoint {
   /// Convert a `Size` into a `FramePoint`
   ///
-  /// This function behaves just as you would expect, but `Auto` is always treated as `BEGIN`
+  /// This function behaves just as you would expect, but:
+  /// - `Auto` is always treated as `BEGIN`
+  /// - `Remaining` is treated as `Relative`
   fn from(size: Size) -> Self {
     match size {
       Size::Auto => Self::BEGIN,
-      Size::Relative(value) => Self::relative(value),
+      Size::Relative(value) | Size::Remaining(value) => Self::relative(value),
       Size::Absolute(value) => Self::absolute(value),
     }
   }

hui/src/frame/rect.rs

@@ -124,6 +124,7 @@ impl Frame for FrameRect {
       size: bottom_right - top_left,
       color: self.color.corners(),
       texture: self.image,
+      texture_uv: None,
       rounded_corners: (self.corner_radius.max_f32() > 0.).then_some(
         RoundedCorners::from_radius(self.corner_radius)
       ),
@@ -140,6 +141,7 @@ impl Frame for FrameRect {
     self.bottom_right.y.absolute >= 0. &&
     self.bottom_right.y.relative >= 1. &&
     self.color.is_opaque() &&
-    self.image.is_none()
+    self.image.is_none() &&
+    self.corner_radius.max_f32() == 0.
   }
 }

hui/src/frame/stack.rs

@@ -1,7 +1,10 @@
+//! allows stacking two frames on top of each other
+
 use glam::Vec2;
 use crate::draw::UiDrawCommandList;
 use super::Frame;
 
+/// A frame that draws two frames on top of each other
 pub struct FrameStack(pub Box<dyn Frame>, pub Box<dyn Frame>);
 
 impl Frame for FrameStack {
@@ -17,6 +20,7 @@ impl Frame for FrameStack {
 }
 
 pub trait FrameStackExt: Frame {
+  /// Stack another frame on top of this one
   fn stack(self, other: impl Frame + 'static) -> FrameStack;
 }
 

hui/src/input.rs

@@ -101,6 +101,8 @@ pub enum KeyboardKey {
 macro_rules! impl_fits64_for_keyboard_key {
   ($($i:ident = $v:literal),*) => {
     impl Fits64 for KeyboardKey {
+      // SAFETY: not actually doing anything unsafe
+      #[allow(unsafe_code)]
       unsafe fn from_u64(x: u64) -> Self {
         match x {
           $( $v => KeyboardKey::$i, )*

hui/src/instance.rs

@@ -95,7 +95,7 @@ impl UiInstance {
   ///   (this will change to a soft error in the future)
   #[cfg(feature = "image")]
   pub fn add_image_file_path(&mut self, path: impl AsRef<std::path::Path>) -> Result<ImageHandle, std::io::Error> {
-    use std::io::Read;
+    use std::io::{Read, Seek};
 
     // Open the file (and wrap it in a bufreader)
     let mut file = std::io::BufReader::new(std::fs::File::open(path)?);
@@ -106,6 +106,7 @@ impl UiInstance {
     let mut magic = [0; 64];
     file.read_exact(&mut magic)?;
     let format = image::guess_format(&magic).expect("Invalid image data (FORMAT)");
+    file.seek(std::io::SeekFrom::Start(0))?;
 
     //Parse the image and read the raw uncompressed rgba data
     let image = image::load(file, format).expect("Invalid image data");
@@ -156,6 +157,7 @@ impl UiInstance {
       position: Vec2::ZERO,
       max_size,
       direction: Direction::Vertical,
+      remaining_space: None,
     };
     let measure = element.measure(MeasureContext {
       state: &self.stateful_state,

hui/src/layout.rs

@@ -2,6 +2,46 @@
 
 use glam::{vec2, Vec2};
 
+/// Controls wrapping behavior of elements
+#[derive(Clone, Copy, PartialEq, Eq, Debug, PartialOrd, Ord, Default)]
+pub enum WrapBehavior {
+  /// No wrapping is allowed, even if explicit line breaks is requested by the element
+  Disable = 0,
+
+  /// Allow wrapping if the element explicitly requests it (default behavior)
+  #[default]
+  Allow = 1,
+
+  /// Elements will be wrapped automatically when they reach the maximum width/height of the container
+  Enable = 2,
+}
+
+impl From<bool> for WrapBehavior {
+  #[inline]
+  fn from(value: bool) -> Self {
+    match value {
+      true => Self::Enable,
+      false => Self::Disable,
+    }
+  }
+}
+
+impl WrapBehavior {
+  /// Check if wrapping is allowed for the element
+  #[inline]
+  pub fn is_allowed(&self) -> bool {
+    *self != Self::Disable
+  }
+
+  /// Check if wrapping is enabled for the element
+  ///
+  /// (Wrapping will be done automatically when the element reaches the maximum width/height)
+  #[inline]
+  pub fn is_enabled(&self) -> bool {
+    *self == Self::Enable
+  }
+}
+
 /// Alignment along a single axis
 #[derive(Clone, Copy, PartialEq, Eq, Debug, Default, PartialOrd, Ord)]
 pub enum Alignment {
@@ -86,17 +126,24 @@ pub enum Size {
   #[default]
   Auto,
 
-  /// Size as a ratio of parent size\
-  /// Valid range: 0.0-1.0 (0-100%)
-  ///
-  /// Out of range values are allowed, but are not guaranteed to work as expected\
-  /// (especially with negative values)
-  Relative(f32),
-
-  //TODO FractionRemaining(f32),
-
   /// Static size in pixels
   Absolute(f32),
+
+  /// Size as a ratio of parent element size
+  ///
+  /// Expected range: `0.0..=1.0`
+  Relative(f32),
+
+  /// Size as a ratio of remaining space after all other elements have been laid out
+  ///
+  /// Expected range: `0.0..=1.0`
+  ///
+  /// - This feature is experimental and may not work as expected;\
+  ///   Current `Container` implementation:
+  ///     - Assumes that he line is fully filled if any element uses `Remaining` size, even if sum of remaining sizes is less than 1.0
+  ///     - Does not support `Remaining` size in the secondary axis, it will be treated as `Relative`
+  /// - In cases where it's not applicable or not supported, it's defined to behave as `Relative`
+  Remaining(f32),
 }
 
 impl From<f32> for Size {
@@ -159,6 +206,13 @@ pub struct LayoutInfo {
   /// Current direction of the layout\
   /// (Usually matches direction of the parent container)
   pub direction: Direction,
+
+  /// Remaining space in the primary axis\
+  ///
+  /// This value is only available during the layout step and is only likely to be present if the element uses `Size::Remaining`
+  ///
+  /// (Make sure that LayoutInfo::direction is set to the correct direction!)
+  pub remaining_space: Option<f32>,
 }
 
 /// Helper function to calculate the size of an element based on its layout and size information\
@@ -168,11 +222,19 @@ pub fn compute_size(layout: &LayoutInfo, size: Size2d, comfy_size: Vec2) -> Vec2
     Size::Auto => comfy_size.x,
     Size::Relative(fraction) => layout.max_size.x * fraction,
     Size::Absolute(size) => size,
+    Size::Remaining(fraction) => match layout.direction {
+      Direction::Horizontal => layout.remaining_space.unwrap_or(layout.max_size.x) * fraction,
+      Direction::Vertical => layout.max_size.x * fraction,
+    }
   };
   let height = match size.height {
     Size::Auto => comfy_size.y,
     Size::Relative(fraction) => layout.max_size.y * fraction,
     Size::Absolute(size) => size,
+    Size::Remaining(fraction) => match layout.direction {
+      Direction::Horizontal => layout.max_size.y * fraction,
+      Direction::Vertical => layout.remaining_space.unwrap_or(layout.max_size.y) * fraction,
+    }
   };
   vec2(width, height)
 }

hui/src/lib.rs

@@ -5,9 +5,11 @@
 //! # Features
 #![doc = document_features::document_features!()]
 
-#![allow(unused_parens)]
-//#![forbid(unsafe_code)]
+#![cfg_attr(docsrs, feature(doc_auto_cfg))]
+
+#![deny(unsafe_code)]
 #![forbid(unsafe_op_in_unsafe_fn)]
+#![allow(unused_parens)]
 
 mod instance;
 mod macros;

hui/src/macros.rs

@@ -6,6 +6,8 @@
 /// - `x` - `Size::Absolute(x)`
 /// - `x%` - `Size::Relative(x / 100.)` *(literal only)*
 /// - `x/` - `Size::Relative(x)`
+/// - `x%=` - `Size::Remaining(x / 100.)` *(literal only)*
+/// - `x/=` - `Size::Remaining(x)`
 ///
 /// ...where `x` is a literal, identifier or an expression wrapped in parentheses
 ///
@@ -32,6 +34,12 @@ macro_rules! size {
   ($x:literal /) => {
     $crate::layout::Size::Relative($x as f32)
   };
+  ($x:literal %=) => {
+    $crate::layout::Size::Remaining($x as f32 / 100.)
+  };
+  ($x:literal /=) => {
+    $crate::layout::Size::Remaining($x as f32)
+  };
 
   ($x:ident) => {
     $crate::layout::Size::Absolute($x as f32)
@@ -39,6 +47,9 @@ macro_rules! size {
   ($x:ident /) => {
     $crate::layout::Size::Relative($x as f32)
   };
+  ($x:ident /=) => {
+    $crate::layout::Size::Remaining($x as f32)
+  };
 
   (($x:expr)) => {
     $crate::layout::Size::Absolute(($x) as f32)
@@ -46,6 +57,9 @@ macro_rules! size {
   (($x:expr) /) => {
     $crate::layout::Size::Relative(($x) as f32)
   };
+  (($x:expr) /=) => {
+    $crate::layout::Size::Remaining(($x) as f32)
+  };
 
   ($x:tt , $y:tt $($ys:tt)?) => {
     $crate::layout::Size2d {

hui/src/rect/color.rs

@@ -1,5 +1,5 @@
 use super::Corners;
-use glam::{Vec3, Vec4, vec4};
+use glam::{Vec2, Vec3, Vec4, vec4};
 
 /// Represents the fill color of a rectangle
 ///
@@ -69,6 +69,14 @@ impl FillColor {
   pub const fn corners(&self) -> Corners<Vec4> {
     self.0
   }
+
+  /// Interpolate color on position, assuming a linear gradient
+  pub fn interpolate(&self, uv: Vec2) -> Vec4 {
+    let c = self.corners();
+    let top = c.top_left.lerp(c.top_right, uv.x);
+    let bottom = c.bottom_left.lerp(c.bottom_right, uv.x);
+    top.lerp(bottom, uv.y)
+  }
 }
 
 impl Default for FillColor {

hui/src/signal.rs

@@ -6,6 +6,9 @@ use nohash_hasher::BuildNoHashHasher;
 
 pub mod trigger;
 
+#[cfg(feature = "derive")]
+pub use hui_derive::Signal;
+
 /// A marker trait for UI Signals
 pub trait Signal: Any {}