Extract cursor proportion calculations

cove-tui/src/chat/tree/util.rs

@@ -1,7 +1,7 @@
 //! Constants and helper functions.
 
 use crossterm::style::{ContentStyle, Stylize};
-use toss::frame::Frame;
+use toss::frame::{Frame, Size};
 
 pub const TIME_FORMAT: &str = "%H:%M ";
 pub const TIME_EMPTY: &str = "      ";
@@ -42,3 +42,15 @@ pub fn after_indent(indent: usize) -> i32 {
 pub fn after_nick(frame: &mut Frame, indent: usize, nick: &str) -> i32 {
     after_indent(indent) + 1 + frame.width(nick) as i32 + 2
 }
+
+pub fn proportion_to_line(height: u16, proportion: f32) -> i32 {
+    ((height - 1) as f32 * proportion).ceil() as i32
+}
+
+pub fn line_to_proportion(height: u16, line: i32) -> f32 {
+    if height > 1 {
+        line as f32 / (height - 1) as f32
+    } else {
+        0.0
+    }
+}