relayer arranger view and extract button_2 and button_3 to top level

tek/src/view_sizes.rs

@@ -0,0 +1,33 @@
+use crate::*;
+impl Tek {
+    /// Spacing between tracks.
+    pub(crate) const TRACK_SPACING: usize = 0;
+    /// Default scene height.
+    pub(crate) const H_SCENE: usize = 2;
+    /// Default editor height.
+    pub(crate) const H_EDITOR: usize = 15;
+    /// Width taken by all tracks.
+    pub(crate) fn w_tracks (&self) -> u16 {
+        self.tracks_sizes().last().map(|(_, _, _, x)|x as u16).unwrap_or(0)
+    }
+    /// Width available to display tracks.
+    pub(crate) fn w_tracks_area (&self) -> u16 {
+        self.w().saturating_sub(2 * self.w_sidebar())
+    }
+    /// Height available to display tracks.
+    pub(crate) fn h_tracks_area (&self) -> u16 {
+        self.h().saturating_sub(self.h_inputs() + self.h_outputs() + 10)
+    }
+    /// Height taken by all inputs.
+    pub(crate) fn h_inputs (&self) -> u16 {
+        1 + self.inputs_sizes().last().map(|(_, _, _, _, y)|y as u16).unwrap_or(0)
+    }
+    /// Height taken by all outputs.
+    pub(crate) fn h_outputs (&self) -> u16 {
+        1 + self.outputs_sizes().last().map(|(_, _, _, _, y)|y as u16).unwrap_or(0)
+    }
+    /// Height taken by all scenes.
+    pub(crate) fn h_scenes (&self) -> u16 {
+        self.scenes_sizes(self.is_editing(), Self::H_SCENE, Self::H_EDITOR).last().map(|(_, _, _, y)|y as u16).unwrap_or(0)
+    }
+}