kinda works now...

hui-examples/examples/mom_downloader.rs

@@ -6,7 +6,7 @@ use winit::{
   event_loop::{EventLoopBuilder, ControlFlow}
 };
 use hui::{
-  UiInstance, elements,
+  UiInstance,
   layout::{Alignment, UiDirection, UiSize},
   rectangle::{Corners, Sides},
   element::{
@@ -17,6 +17,12 @@ use hui::{
 };
 use hui_glium::GliumUiRenderer;
 
+fn elements(mut f: impl FnMut(&mut Vec<Box<dyn hui::element::UiElement>>)) -> Vec<Box<dyn hui::element::UiElement>> {
+  let mut e = vec![];
+  f(&mut e);
+  e
+}
+
 fn main() {
   kubi_logging::init();
 
@@ -27,7 +33,7 @@ fn main() {
   let mut hui = UiInstance::new();
   let mut backend = GliumUiRenderer::new(&display);
 
-  let font_handle = hui.add_font_from_bytes(include_bytes!("../assets/roboto/Roboto-Regular.ttf"));
+  let font_handle = hui.add_font(include_bytes!("../assets/roboto/Roboto-Regular.ttf"));
 
   let instant = Instant::now();
 
@@ -59,18 +65,18 @@ fn main() {
             corner_radius: Corners::all(8.),
             elements: elements(|el| {
               if instant.elapsed().as_secs_f32() < 5. {
-                el.add(Text {
+                el.push(Box::new(Text {
                   text: "Downloading your mom...".into(),
                   font: font_handle,
                   text_size: 24,
                   ..Default::default()
-                });
+                }));
-                el.add(ProgressBar {
+                el.push(Box::new(ProgressBar {
                   value: mom_ratio,
                   corner_radius: Corners::all(0.125 * ProgressBar::DEFAULT_HEIGHT),
                   ..Default::default()
-                });
+                }));
-                el.add(Container {
+                el.push(Box::new(Container {
                   direction: UiDirection::Horizontal,
                   align: (Alignment::End, Alignment::Center).into(),
                   size: (UiSize::Fraction(1.), UiSize::Auto),
@@ -81,21 +87,21 @@ fn main() {
                     ..Default::default()
                   })],
                   ..Default::default()
-                });
+                }));
               } else if instant.elapsed().as_secs() < 10 {
-                el.add(Text {
+                el.push(Box::new(Text {
                   text: "Error 413: Request Entity Too Large".into(),
                   font: font_handle,
                   color: vec4(1., 0.125, 0.125, 1.),
                   text_size: 20,
                   ..Default::default()
-                });
+                }));
-                el.add(Text {
+                el.push(Box::new(Text {
                   text: format!("Exiting in {}...", 10 - instant.elapsed().as_secs()).into(),
                   font: font_handle,
                   text_size: 16,
                   ..Default::default()
-                });
+                }));
               } else {
                 window_target.exit();
               }

hui-examples/examples/text_weird.rs

@@ -6,7 +6,7 @@ use winit::{
   event_loop::{EventLoopBuilder, ControlFlow}
 };
 use hui::{
-  UiInstance, elements,
+  UiInstance,
   layout::UiSize,
   element::{
     container::Container,
@@ -15,6 +15,12 @@ use hui::{
 };
 use hui_glium::GliumUiRenderer;
 
+fn elements(mut f: impl FnMut(&mut Vec<Box<dyn hui::element::UiElement>>)) -> Vec<Box<dyn hui::element::UiElement>> {
+  let mut e = vec![];
+  f(&mut e);
+  e
+}
+
 fn main() {
   kubi_logging::init();
 
@@ -25,7 +31,7 @@ fn main() {
   let mut hui = UiInstance::new();
   let mut backend = GliumUiRenderer::new(&display);
 
-  let font_handle = hui.add_font_from_bytes(include_bytes!("../assets/roboto/Roboto-Regular.ttf"));
+  let font_handle = hui.add_font(include_bytes!("../assets/roboto/Roboto-Regular.ttf"));
   let instant = Instant::now();
 
   event_loop.run(|event, window_target| {
@@ -46,56 +52,56 @@ fn main() {
           size: (UiSize::Fraction(1.), UiSize::Fraction(1.)),
           background: vec4(0.1, 0.1, 0.1, 1.).into(),
           elements: elements(|elem| {
-            elem.add(Text {
+            elem.push(Box::new(Text {
               text: "THIS LINE SHOULD BE SHARP!".into(),
               ..Default::default()
-            });
+            }));
-            elem.add(Text {
+            elem.push(Box::new(Text {
               text: "THIS LINE SHOULD BE SHARP!".into(),
               text_size: 32,
               ..Default::default()
-            });
+            }));
-            elem.add(Text {
+            elem.push(Box::new(Text {
               text: "All lines except 3 and 6 below will be blurry:".into(),
               ..Default::default()
-            });
+            }));
             for size in [9, 12, 16, 18, 24, 32] {
-              elem.add(Text {
+              elem.push(Box::new(Text {
                 text: "Testing default font, Proggy Tiny".into(),
                 text_size: size,
                 ..Default::default()
-              });
+              }));
             }
-            elem.add(Rect {
+            elem.push(Box::new(Rect {
               size: (UiSize::Fraction(1.), UiSize::Static(10.)),
               color: vec4(0., 0., 1., 1.).into(),
-            });
+            }));
-            elem.add(Rect {
+            elem.push(Box::new(Rect {
               size: (UiSize::Fraction(1.), UiSize::Static(10.)),
               color: vec4(1., 1., 0., 1.).into(),
-            });
+            }));
-            elem.add(Text {
+            elem.push(Box::new(Text {
               text: "Hello, world!\nżółty liść. życie nie ma sensu i wszyscy zginemy;\nтест кирилиці їїїїїїїїїїї\njapanese text: テスト".into(),
               font: font_handle,
               text_size: 32,
               ..Default::default()
-            });
+            }));
             if instant.elapsed().as_secs() & 1 != 0 {
-              elem.add(Rect {
+              elem.push(Box::new(Rect {
                 size: (UiSize::Fraction(1.), UiSize::Static(10.)),
                 color: vec4(1., 0., 0., 1.).into(),
-              });
+              }));
-              elem.add(Rect {
+              elem.push(Box::new(Rect {
                 size: (UiSize::Fraction(1.), UiSize::Static(10.)),
                 color: vec4(0., 0., 0., 1.).into(),
-              });
+              }));
-              elem.add(Spacer(100.));
+              elem.push(Box::new(Spacer(100.)));
-              elem.add(Text {
+              elem.push(Box::new(Text {
                 text: "FLAG SHOULD NOT OVERLAP WITH TEXT".into(),
                 text_size: 64,
                 color: vec4(1., 0., 1., 1.),
                 ..Default::default()
-              });
+              }));
             }
           }),
           ..Default::default()

hui-glium/shaders/fragment.frag

@@ -6,7 +6,8 @@ precision highp sampler2D;
 out vec4 out_color;
 in vec4 vtx_color;
 in vec2 vtx_uv;
+uniform sampler2D tex;
 
 void main() {
-  out_color = vtx_color;
+  out_color = texture(tex, vtx_uv) * vtx_color;
 }

hui-glium/shaders/fragment_tex.frag

@@ -1,13 +0,0 @@
-#version 300 es
-
-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/src/lib.rs

@@ -10,14 +10,11 @@ use glium::{
   uniform, uniforms::{Sampler, SamplerBehavior, SamplerWrapFunction},
 };
 use hui::{
-  UiInstance,
+  draw::{TextureAtlasMeta, UiDrawCall, UiVertex}, UiInstance
-  draw::{UiDrawCall, UiVertex, BindTexture},
-  text::FontTextureInfo, IfModified,
 };
 
 const VERTEX_SHADER: &str = include_str!("../shaders/vertex.vert");
 const FRAGMENT_SHADER: &str = include_str!("../shaders/fragment.frag");
-const FRAGMENT_SHADER_TEX: &str = include_str!("../shaders/fragment_tex.frag");
 
 #[derive(Clone, Copy)]
 #[repr(C)]
@@ -119,7 +116,6 @@ impl BufferPair {
 pub struct GliumUiRenderer {
   context: Rc<Context>,
   program: glium::Program,
-  program_tex: glium::Program,
   ui_texture: Option<Rc<SrgbTexture2d>>,
   buffer_pair: Option<BufferPair>,
 }
@@ -129,7 +125,6 @@ impl GliumUiRenderer {
     log::info!("initializing hui glium backend");
     Self {
       program: Program::from_source(facade, VERTEX_SHADER, FRAGMENT_SHADER, None).unwrap(),
-      program_tex: Program::from_source(facade, VERTEX_SHADER, FRAGMENT_SHADER_TEX, None).unwrap(),
       context: Rc::clone(facade.get_context()),
       ui_texture: None,
       buffer_pair: None,
@@ -144,34 +139,25 @@ impl GliumUiRenderer {
     } else if !call.indices.is_empty() {
       self.buffer_pair = Some(BufferPair::new_with_data(&self.context, data_vtx, data_idx));
     }
-
-    // self.plan[0].bind_texture = match call.bind_texture {
-    //   Some(BindTexture::FontTexture) => {
-    //     const NO_FNT_TEX: &str = "Font texture exists in draw plan but not yet inited. Make sure to call update_font_texture() *before* update_draw_plan()";
-    //     Some(Rc::clone(self.font_texture.as_ref().expect(NO_FNT_TEX)))
-    //   },
-    //   Some(BindTexture::UserDefined(_)) => todo!("user defined textures are not implemented yet"),
-    //   None => None,
-    // }
   }
 
-  pub fn update_ui_texture(&mut self, font_texture: &FontTextureInfo) {
+  pub fn update_texture_atlas(&mut self, atlas: &TextureAtlasMeta) {
-    log::debug!("updating font texture");
+    log::trace!("updating ui atlas texture");
     self.ui_texture = Some(Rc::new(SrgbTexture2d::new(
       &self.context,
       RawImage2d::from_raw_rgba(
-        font_texture.data.to_owned(),
+        atlas.data.to_owned(),
-        (font_texture.size.x, font_texture.size.y)
+        (atlas.size.x, atlas.size.y)
       )
     ).unwrap()));
   }
 
   pub fn update(&mut self, hui: &UiInstance) {
-    if let Some(texture) = hui.font_texture().if_modified() {
+    if hui.atlas().modified {
-      self.update_ui_texture(texture);
+      self.update_texture_atlas(&hui.atlas());
     }
-    if let Some(plan) = hui.draw_call().if_modified() {
+    if hui.draw_call().0 {
-      self.update_draw_plan(plan);
+      self.update_draw_plan(hui.draw_call().1);
     }
   }
 
@@ -192,7 +178,7 @@ impl GliumUiRenderer {
       frame.draw(
         vtx_buffer,
         idx_buffer,
-        &self.program_tex,
+        &self.program,
         &uniform! {
           resolution: resolution.to_array(),
           tex: Sampler(self.ui_texture.as_ref().unwrap().as_ref(), SamplerBehavior {
@@ -202,20 +188,6 @@ impl GliumUiRenderer {
         },
         &params,
       ).unwrap();
-
-      // if let Some(bind_texture) = call.bind_texture.as_ref() {
-
-      // } else {
-      //   frame.draw(
-      //     vtx_buffer,
-      //     idx_buffer,
-      //     &self.program,
-      //     &uniform! {
-      //       resolution: resolution.to_array(),
-      //     },
-      //     &params,
-      //   ).unwrap();
-      // }
     }
   }
 }

hui/src/draw.rs

@@ -2,13 +2,12 @@
 
 use crate::{
   rectangle::Corners,
-  text::{FontHandle, TextRenderer},
+  text::{FontHandle, TextRenderer}
-  IfModified
 };
 
 pub(crate) mod atlas;
-//pub(crate) use atlas::{TextureAllocation, TextureAtlasManager};
+use atlas::TextureAtlasManager;
-//pub use atlas::TextureHandle;
+pub use atlas::{TextureHandle, TextureAtlasMeta};
 
 mod corner_radius;
 pub use corner_radius::RoundedCorners;
@@ -48,7 +47,7 @@ pub enum UiDrawCommand {
     ///Position in pixels
     position: Vec2,
     ///Font size
-    size: u8,
+    size: u16,
     ///Color (RGBA)
     color: Vec4,
     ///Text to draw
@@ -78,19 +77,6 @@ impl UiDrawCommandList {
 //   }
 // }
 
-
-/// Texture to bind for a draw call
-///
-/// - FontTexture: The internally managed font texture
-/// - UserDefined: User-defined texture, value is user-defined and usually depends on the render backend
-#[derive(Clone, Copy, Debug, PartialEq, Eq)]
-pub enum BindTexture {
-  /// The internally managed font texture
-  FontTexture,
-  /// User-defined texture, value is user-defined and usually depends on the render backend
-  UserDefined(usize),
-}
-
 /// A vertex for UI rendering
 #[derive(Clone, Copy, Debug, PartialEq, Default)]
 pub struct UiVertex {
@@ -108,7 +94,7 @@ pub struct UiDrawCall {
 
 impl UiDrawCall {
   /// Tesselate the UI and build a complete draw plan from a list of draw commands
-  pub fn build(draw_commands: &UiDrawCommandList, tr: &mut TextRenderer) -> Self {
+  pub(crate) fn build(draw_commands: &UiDrawCommandList, atlas: &mut TextureAtlasManager, text_renderer: &mut TextRenderer) -> Self {
     let mut draw_call = UiDrawCall::default();
     for command in &draw_commands.commands {
       match command {
@@ -209,17 +195,17 @@ impl UiDrawCall {
               UiVertex {
                 position: *position + vec2(size.x, 0.0),
                 color: color.top_right,
-                uv: vec2(1.0, 0.0),
+                uv: vec2(0.0, 0.0), // vec2(1.0, 0.0),
               },
               UiVertex {
                 position: *position + *size,
                 color: color.bottom_right,
-                uv: vec2(1.0, 1.0),
+                uv: vec2(0.0, 0.0), // vec2(1.0, 1.0),
               },
               UiVertex {
                 position: *position + vec2(0.0, size.y),
                 color: color.bottom_left,
-                uv: vec2(0.0, 1.0),
+                uv: vec2(0.0, 0.0), // vec2(0.0, 1.0),
               },
             ]);
           }
@@ -227,7 +213,7 @@ impl UiDrawCall {
         UiDrawCommand::Circle { .. } => {
           todo!("circle draw command not implemented yet")
         },
-        UiDrawCommand::Text { position, size, color, text, font } => {
+        UiDrawCommand::Text { position, size, color, text, font: font_handle } => {
           if text.is_empty() {
             continue
           }
@@ -235,7 +221,7 @@ impl UiDrawCall {
           //XXX: should we be doing this every time?
           let mut layout = Layout::new(CoordinateSystem::PositiveYDown);
           layout.append(
-            &[tr.internal_font(*font)],
+            &[text_renderer.internal_font(*font_handle)],
             &TextStyle::new(text, *size as f32, 0)
           );
           let glyphs = layout.glyphs();
@@ -245,38 +231,32 @@ impl UiDrawCall {
             if !layout_glyph.char_data.rasterize() {
               continue
             }
-            let font_texture_size = (
+            let atlas_size = atlas.meta().size.as_vec2();
-              tr.font_texture().size.x as f32,
-              tr.font_texture().size.y as f32
-            );
             let vidx = draw_call.vertices.len() as u32;
-            let glyph = tr.glyph(*font, layout_glyph.parent, layout_glyph.key.px as u8);
+            let glyph = text_renderer.glyph(atlas, *font_handle, layout_glyph.parent, layout_glyph.key.px as u8);
+            let uv = atlas.get_uv(glyph.texture);
             //rpos_x += glyph.metrics.advance_width;//glyph.metrics.advance_width;
             draw_call.indices.extend([vidx, vidx + 1, vidx + 2, vidx, vidx + 2, vidx + 3]);
-            let p0x = glyph.position.x as f32 / font_texture_size.0;
-            let p1x = (glyph.position.x + glyph.size.x as i32) as f32 / font_texture_size.0;
-            let p0y = glyph.position.y as f32 / font_texture_size.1;
-            let p1y = (glyph.position.y + glyph.size.y as i32) as f32 / font_texture_size.1;
             draw_call.vertices.extend([
               UiVertex {
                 position: *position + vec2(layout_glyph.x, layout_glyph.y),
                 color: *color,
-                uv: vec2(p0x, p0y),
+                uv: uv.top_left,
               },
               UiVertex {
                 position: *position + vec2(layout_glyph.x + glyph.metrics.width as f32, layout_glyph.y),
                 color: *color,
-                uv: vec2(p1x, p0y),
+                uv: uv.top_right,
               },
               UiVertex {
                 position: *position + vec2(layout_glyph.x + glyph.metrics.width as f32, layout_glyph.y + glyph.metrics.height as f32),
                 color: *color,
-                uv: vec2(p1x, p1y),
+                uv: uv.bottom_right,
               },
               UiVertex {
                 position: *position + vec2(layout_glyph.x, layout_glyph.y + glyph.metrics.height as f32),
                 color: *color,
-                uv: vec2(p0x, p1y),
+                uv: uv.bottom_left,
               },
             ]);
             #[cfg(all(
@@ -298,13 +278,3 @@ impl UiDrawCall {
     draw_call
   }
 }
-
-#[allow(deprecated)]
-impl IfModified<UiDrawCall> for (bool, &UiDrawCall) {
-  fn if_modified(&self) -> Option<&UiDrawCall> {
-    match self.0 {
-      true => Some(self.1),
-      false => None,
-    }
-  }
-}

hui/src/draw/atlas.rs

@@ -1,14 +1,19 @@
-use glam::{uvec2, UVec2};
+use glam::{uvec2, vec2, UVec2, Vec2};
 use hashbrown::HashMap;
 use nohash_hasher::BuildNoHashHasher;
 use rect_packer::DensePacker;
-
+use crate::rectangle::Corners;
-use crate::IfModified;
 
 const CHANNEL_COUNT: u32 = 4;
 //TODO: make this work
 const ALLOW_ROTATION: bool = false;
 
+pub struct TextureAtlasMeta<'a> {
+  pub data: &'a [u8],
+  pub size: UVec2,
+  pub modified: bool,
+}
+
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 pub struct TextureHandle {
   //TODO automatic cleanup when handle is dropped
@@ -22,13 +27,13 @@ pub(crate) struct TextureAllocation {
   pub index: u32,
 
   /// Position in the texture atlas
-  pub position: UVec2,
+  pub(crate) position: UVec2,
 
   /// Requested texture size
   pub size: UVec2,
 
   /// True if the texture was rotated by 90 degrees
-  pub rotated: bool,
+  pub(crate) rotated: bool,
 }
 
 /// Manages a texture atlas and the allocation of space within it\
@@ -39,25 +44,35 @@ pub(crate) struct TextureAtlasManager {
   size: UVec2,
   data: Vec<u8>,
   allocations: HashMap<u32, TextureAllocation, BuildNoHashHasher<u32>>,
+  /// True if the atlas has been modified in a way which requires a texture reupload
+  /// since the beginning of the current frame
   modified: bool,
 }
 
 impl TextureAtlasManager {
   /// Create a new texture atlas with the specified size\
   /// 512x512 is a good default size for most applications, and the texture atlas can grow dynamically as needed
+  /// By default, the texture atlas gets initialized with a single white pixel texture
   pub fn new(size: UVec2) -> Self {
-    Self {
+    let mut tmp = Self {
       packer: DensePacker::new(size.x as i32, size.y as i32),
       count: 0,
-      size: UVec2::new(0, 0),
+      size,
       data: vec![0; (size.x * size.y * CHANNEL_COUNT) as usize],
       allocations: HashMap::default(),
       modified: true,
-    }
+    };
+    tmp.add(1, &[255,255,255,255]);
+    tmp
   }
 
   /// Resize the texture atlas to the new size in-place, preserving the existing data
   pub fn resize(&mut self, new_size: UVec2) {
+    log::trace!("resizing texture atlas to {:?}", new_size);
+    if self.size == new_size {
+      log::warn!("Texture atlas is already the requested size");
+      return
+    }
     if new_size.x > self.size.x && new_size.y > self.size.y{
       self.packer.resize(new_size.x as i32, new_size.y as i32);
       //Resize the data array in-place
@@ -84,6 +99,7 @@ impl TextureAtlasManager {
   /// Use `allocate` to allocate a texture and resize the atlas if necessary\
   /// Does not modify the texture data
   fn try_allocate(&mut self, size: UVec2) -> Option<TextureHandle> {
+    log::trace!("Allocating texture of size {:?}", size);
     let result = self.packer.pack(size.x as i32, size.y as i32, ALLOW_ROTATION)?;
     let index = self.count;
     self.count += 1;
@@ -107,7 +123,9 @@ impl TextureAtlasManager {
       new_size *= 2;
       self.packer.resize(new_size.x as i32, new_size.y as i32);
     }
-    self.resize(new_size);
+    if new_size != self.size {
+      self.resize(new_size);
+    }
     self.try_allocate(size).unwrap()
   }
 
@@ -115,8 +133,8 @@ impl TextureAtlasManager {
   /// This function may resize the atlas as needed, and should never fail under normal circumstances.
   pub fn add(&mut self, width: usize, data: &[u8]) -> TextureHandle {
     let size = uvec2(width as u32, (data.len() / (width * CHANNEL_COUNT as usize)) as u32);
-    let handle = self.allocate(size);
+    let handle: TextureHandle = self.allocate(size);
-    let allocation = self.allocations.get_mut(&handle.index).unwrap();
+    let allocation = self.allocations.get(&handle.index).unwrap();
     assert!(!allocation.rotated, "Rotated textures are not implemented yet");
     for y in 0..size.y {
       for x in 0..size.x {
@@ -127,6 +145,26 @@ impl TextureAtlasManager {
         }
       }
     }
+    self.modified = true;
+    handle
+  }
+
+  /// Works the same way as [`TextureAtlasManager::add`], but the input data is assumed to be grayscale (1 channel per pixel)\
+  /// The data is copied into the alpha channel of the texture, while all the other channels are set to 255\
+  /// May resize the atlas as needed, and should never fail under normal circumstances.
+  pub fn add_grayscale(&mut self, width: usize, data: &[u8]) -> TextureHandle {
+    let size = uvec2(width as u32, (data.len() / width) as u32);
+    let handle = self.allocate(size);
+    let allocation = self.allocations.get(&handle.index).unwrap();
+    assert!(!allocation.rotated, "Rotated textures are not implemented yet");
+    for y in 0..size.y {
+      for x in 0..size.x {
+        let src_idx = (y * size.x + x) as usize;
+        let dst_idx = (((allocation.position.y + y) * self.size.x + allocation.position.x + x) * CHANNEL_COUNT) as usize;
+        self.data[dst_idx..(dst_idx + CHANNEL_COUNT as usize)].copy_from_slice(&[255, 255, 255, data[src_idx]]);
+      }
+    }
+    self.modified = true;
     handle
   }
 
@@ -138,25 +176,43 @@ impl TextureAtlasManager {
     todo!()
   }
 
-  pub fn atlas_size(&self) -> UVec2 {
-    self.size
-  }
-
   pub fn get(&self, handle: TextureHandle) -> Option<&TextureAllocation> {
     self.allocations.get(&handle.index)
   }
 
+  pub(crate) fn get_uv(&self, handle: TextureHandle) -> Corners<Vec2> {
+    let info = self.get(handle).unwrap();
+    let atlas_size = self.meta().size.as_vec2();
+    let p0x = info.position.x as f32 / atlas_size.x;
+    let p1x = (info.position.x as f32 + info.size.x as f32) / atlas_size.x;
+    let p0y = info.position.y as f32 / atlas_size.y;
+    let p1y = (info.position.y as f32 + info.size.y as f32) / atlas_size.y;
+    Corners {
+      top_left: vec2(p0x, p0y),
+      top_right: vec2(p1x, p0y),
+      bottom_left: vec2(p0x, p1y),
+      bottom_right: vec2(p1x, p1y),
+    }
+  }
+
   /// Reset the `is_modified` flag
-  pub fn reset_modified(&mut self) {
+  pub(crate) fn reset_modified(&mut self) {
     self.modified = false;
   }
 
-  /// Returns true if the atlas has been modified since the last call to `reset_modified`\
+  /// Returns true if the atlas has been modified since the beginning of the current frame\
-  /// If this function returns true, the texture atlas should be re-uploaded to the GPU\
+  /// If this function returns true, the texture atlas should be re-uploaded to the GPU before rendering\
-  /// This function is mostly useful for developers of graphics backends
   pub fn is_modified(&self) -> bool {
     self.modified
   }
+
+  pub fn meta(&self) -> TextureAtlasMeta {
+    TextureAtlasMeta {
+      data: &self.data,
+      size: self.size,
+      modified: self.modified,
+    }
+  }
 }
 
 impl Default for TextureAtlasManager {
@@ -165,13 +221,3 @@ impl Default for TextureAtlasManager {
     Self::new(UVec2::new(512, 512))
   }
 }
-
-#[allow(deprecated)]
-impl<'a> IfModified<TextureAtlasManager> for TextureAtlasManager {
-  fn if_modified(&self) -> Option<&Self> {
-    match self.modified {
-      true => Some(self),
-      false => None,
-    }
-  }
-}

hui/src/element/builtin/text.rs

@@ -17,7 +17,7 @@ pub struct Text {
   pub size: (UiSize, UiSize),
   pub color: Vec4,
   pub font: FontHandle,
-  pub text_size: u8,
+  pub text_size: u16,
 }
 
 impl Default for Text {

hui/src/instance.rs

@@ -1,12 +1,15 @@
 use std::collections::VecDeque;
 use glam::Vec2;
-use crate:: {
+use crate::{
-  layout::{UiDirection, LayoutInfo},
+  draw::{
+    atlas::{TextureAtlasManager, TextureAtlasMeta},
+    UiDrawCall, UiDrawCommandList,
+  },
   element::{MeasureContext, ProcessContext, UiElement},
   event::UiEvent,
+  layout::{LayoutInfo, UiDirection},
   state::StateRepo,
-  draw::{UiDrawCommandList, UiDrawCall},
+  text::{FontHandle, TextRenderer}
-  text::{TextRenderer, FontTextureInfo, FontHandle},
 };
 
 /// The main instance of the UI system.\
@@ -20,6 +23,7 @@ pub struct UiInstance {
   draw_call: UiDrawCall,
   draw_call_modified: bool,
   text_renderer: TextRenderer,
+  atlas: TextureAtlasManager,
   events: VecDeque<UiEvent>,
 }
 
@@ -39,13 +43,19 @@ impl UiInstance {
       draw_call_modified: false,
       // ftm: FontTextureManager::default(),
       text_renderer: TextRenderer::new(),
+      atlas: {
+        let mut atlas = TextureAtlasManager::default();
+        //HACK: Ensure that vec(0, 0) uv is white square
+        atlas.add_grayscale(1, &[255]);
+        atlas
+      },
       events: VecDeque::new(),
     }
   }
 
   /// Parse and add a font from a raw byte slice to the UI\
   /// Returns a font handle.
-  pub fn add_font_from_bytes(&mut self, font: &[u8]) -> FontHandle {
+  pub fn add_font(&mut self, font: &[u8]) -> FontHandle {
     self.text_renderer.add_font_from_bytes(font)
   }
 
@@ -80,7 +90,7 @@ impl UiInstance {
     std::mem::swap(&mut self.prev_draw_commands, &mut self.draw_commands);
     self.draw_call_modified = false;
     self.draw_commands.commands.clear();
-    self.text_renderer.reset_frame();
+    self.atlas.reset_modified();
   }
 
   /// End the frame and prepare the UI for rendering
@@ -90,29 +100,29 @@ impl UiInstance {
     if self.draw_commands.commands == self.prev_draw_commands.commands {
       return
     }
-    self.draw_call = UiDrawCall::build(&self.draw_commands, &mut self.text_renderer);
+    self.draw_call = UiDrawCall::build(&self.draw_commands, &mut self.atlas, &mut self.text_renderer);
     self.draw_call_modified = true;
   }
 
-  /// Get the draw call for the current frame
+  /// Get the draw call information for the current frame
   ///
   /// This function should only be used by the render backend.\
   /// You should not call this directly unless you're implementing a custom render backend
   ///
-  /// Returns a tuple with a boolean indicating if the draw plan was modified since the last frame
+  /// Returns a tuple with a boolean indicating if the buffers have been modified since the last frame
   pub fn draw_call(&self) -> (bool, &UiDrawCall) {
     (self.draw_call_modified, &self.draw_call)
   }
 
-  /// Get the font texture for the current frame
+  /// Get the texture atlas size and data for the current frame
   ///
   /// This function should only be used by the render backend.\
   /// You should not call this directly unless you're implementing a custom render backend
   ///
-  /// Make sure to check `FontTextureInfo::modified` to see if the texture was modified
+  /// Make sure to check [`TextureAtlasMeta::modified`] to see if the texture has been modified
-  /// since the last frame before uploading it to the GPU
+  /// since the beginning of the current frame before uploading it to the GPU
-  pub fn font_texture(&self) -> FontTextureInfo {
+  pub fn atlas(&self) -> TextureAtlasMeta {
-    self.text_renderer.font_texture()
+    self.atlas.meta()
   }
 
   /// Push a platform event to the UI event queue

hui/src/lib.rs

@@ -22,9 +22,3 @@ pub mod state;
 pub mod text;
 
 pub use instance::UiInstance;
-
-#[deprecated(since = "0.1.0-alpha.4", note = "will be removed in the next release")]
-pub trait IfModified<T> {
-  #[deprecated(since = "0.1.0-alpha.4", note = "will be removed in the next release")]
-  fn if_modified(&self) -> Option<&T>;
-}

hui/src/text.rs

@@ -10,7 +10,7 @@ pub use font::BUILTIN_FONT;
 pub(crate) use font::DEFAULT_FONT;
 use fontdue::{Font, FontSettings};
 use ftm::FontTextureManager;
-pub use ftm::{FontTextureInfo, GlyphCacheEntry};
+pub use ftm::GlyphCacheEntry;
 
 use crate::draw::atlas::TextureAtlasManager;
 
@@ -32,7 +32,7 @@ impl TextRenderer {
   }
 
   pub fn glyph(&mut self, atlas: &mut TextureAtlasManager, font_handle: FontHandle, character: char, size: u8) -> Arc<GlyphCacheEntry> {
-    self.ftm.glyph(&self.fm, atlas, font_handle, character, size)
+    self.ftm.glyph(atlas, &self.fm, font_handle, character, size)
   }
 
   pub(crate) fn internal_font(&self, handle: FontHandle) -> &Font {
@@ -55,7 +55,7 @@ pub struct TextMeasureResponse {
 pub struct TextMeasure<'a>(&'a TextRenderer);
 
 impl<'a> TextMeasure<'a> {
-  pub fn measure(&self, font: FontHandle, size: u8, text: &str) -> TextMeasureResponse {
+  pub fn measure(&self, font: FontHandle, size: u16, text: &str) -> TextMeasureResponse {
     use fontdue::layout::{Layout, CoordinateSystem, TextStyle};
     let mut layout = Layout::new(CoordinateSystem::PositiveYDown);
     layout.append(
@@ -79,7 +79,7 @@ impl TextRenderer {
     TextMeasure(self)
   }
 
-  pub fn measure(&self, font: FontHandle, size: u8, text: &str) -> TextMeasureResponse {
+  pub fn measure(&self, font: FontHandle, size: u16, text: &str) -> TextMeasureResponse {
     TextMeasure(self).measure(font, size, text)
   }
 }

hui/src/text/ftm.rs

@@ -1,11 +1,7 @@
 use std::sync::Arc;
 use fontdue::Metrics;
-use glam::UVec2;
 use hashbrown::HashMap;
-use crate::{
+use crate::draw::atlas::{TextureAtlasManager, TextureHandle};
-  draw::atlas::{TextureAtlasManager, TextureHandle},
-  IfModified
-};
 
 use super::font::{FontHandle, FontManager};
 
@@ -51,8 +47,8 @@ impl FontTextureManager {
     }
     let font = font_manager.get(font_handle).unwrap();
     let (metrics, bitmap) = font.rasterize(character, size as f32);
-    log::debug!("rasterized glyph: {}, {:?}, {:?}", character, metrics, bitmap);
+    log::trace!("rasterized glyph: {}, {:?}, {:?}", character, metrics, bitmap);
-    let texture = atlas.add(metrics.width, &bitmap);
+    let texture = atlas.add_grayscale(metrics.width, &bitmap);
     let entry = Arc::new(GlyphCacheEntry {
       metrics,
       texture