wip3 (33e): ermh...

crates/tek.old/src/app_focus.rs

@@ -0,0 +1,37 @@
+use crate::*;
+
+/// Different sections of the UI that may be focused.
+#[derive(PartialEq, Clone, Copy)]
+pub enum AppFocus {
+    /// The transport is selected.
+    Transport,
+    /// The arranger is selected.
+    Arranger,
+    /// The sequencer is selected.
+    Sequencer,
+    /// The device chain is selected.
+    Chain,
+}
+
+impl Default for AppFocus {
+    fn default () -> Self { Self::Arranger }
+}
+
+impl AppFocus {
+    pub fn prev (&mut self) {
+        *self = match self {
+            Self::Transport => Self::Chain,
+            Self::Arranger  => Self::Transport,
+            Self::Sequencer => Self::Arranger,
+            Self::Chain     => Self::Sequencer,
+        }
+    }
+    pub fn next (&mut self) {
+        *self = match self {
+            Self::Transport => Self::Arranger,
+            Self::Arranger  => Self::Sequencer,
+            Self::Sequencer => Self::Chain,
+            Self::Chain     => Self::Transport,
+        }
+    }
+}