2 files changed, 133 insertions, 0 deletions

diff --git a/src/main.rs b/src/main.rs
index 9c186c9..304f6fc 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -6,11 +6,13 @@ mod command;
 mod consts;
 mod dither;
 mod error;
+mod guide;
 mod lisp;
 mod message;
 mod symmetry;
 mod undo;
 mod utils;
+mod widget;
 
 use {
     app::AppState,
diff --git a/src/widget.rs b/src/widget.rs
new file mode 100644
index 0000000..5749ae2
--- /dev/null
+++ b/src/widget.rs
@@ -0,0 +1,131 @@
+use crate::rect;
+
+use sdl2::{rect::Rect, render::Canvas, video::Window};
+
+#[derive(Debug, Clone)]
+pub struct Container {
+    pub start: (i32, i32),
+    pub width: u32,
+    pub height: u32,
+}
+
+pub enum Size {
+    Max,
+    Absolute(u32),
+}
+
+#[derive(Debug, Copy, PartialEq, Clone)]
+pub enum Offset {
+    Top(u32),
+    Left(u32),
+    Bottom(u32),
+    Right(u32),
+}
+
+#[derive(Debug, Copy, PartialEq, Clone)]
+pub enum HorAlign {
+    Left,
+    Center,
+    Right,
+}
+
+#[derive(Debug, Copy, PartialEq, Clone)]
+pub enum VertAlign {
+    Top,
+    Center,
+    Bottom,
+}
+
+impl Offset {
+    fn apply(self, size: u32) -> u32 {
+        match self {
+            Self::Top(t) => t,
+            Self::Left(l) => l,
+            Self::Bottom(b) => size - b,
+            Self::Right(r) => size - r,
+        }
+    }
+}
+
+impl Container {
+    pub fn uninit() -> Self {
+        Self {
+            start: (0, 0),
+            width: 0,
+            height: 0,
+        }
+    }
+
+    pub fn new(start_x: Offset, start_y: Offset, canvas: &Canvas<Window>) -> Self {
+        let (winsize_x, winsize_y) = canvas.window().size();
+        Self {
+            start: (
+                start_x.apply(winsize_x) as i32,
+                start_y.apply(winsize_y) as i32,
+            ),
+            width: 0,
+            height: 0,
+        }
+    }
+
+    pub fn width(mut self, size: Size, canvas: &Canvas<Window>) -> Self {
+        match size {
+            Size::Max => {
+                let (winsize_x, _) = canvas.window().size();
+                self.width = winsize_x;
+            }
+            Size::Absolute(x) => {
+                self.width = x;
+            }
+        }
+        self
+    }
+
+    pub fn height(mut self, size: Size, canvas: &Canvas<Window>) -> Self {
+        match size {
+            Size::Max => {
+                let (_, winsize_y) = canvas.window().size();
+                self.height = winsize_y;
+            }
+            Size::Absolute(y) => {
+                self.height = y;
+            }
+        }
+        self
+    }
+
+    pub fn place(&self, widget: &mut Container, hor_align: HorAlign, vert_align: VertAlign) {
+        let x = self.start.0
+            + match hor_align {
+                HorAlign::Left => 0,
+                HorAlign::Center => ((self.width / 2).saturating_sub(widget.width / 2)) as i32,
+                HorAlign::Right => (self.width - widget.width) as i32,
+            };
+        let y = self.start.1
+            + match vert_align {
+                VertAlign::Top => 0,
+                VertAlign::Center => ((self.height / 2).saturating_sub(widget.height / 2)) as i32,
+                VertAlign::Bottom => (self.height - widget.height) as i32,
+            };
+        widget.start = (x, y);
+    }
+
+    pub fn area(&self) -> Rect {
+        rect!(self.start.0, self.start.1, self.width, self.height)
+    }
+}
+
+#[derive(Debug, Copy, Clone)]
+pub struct Widget {
+    width: u32,
+    height: u32,
+}
+
+impl Widget {
+    pub fn linear_layout(widgets: &[Widget], padding: u32) -> Widget {
+        Widget {
+            width: widgets.iter().fold(0, |acc, x| acc + x.width + padding),
+            height: widgets.iter().map(|x| x.height).max().unwrap_or(0),
+        }
+    }
+}