Shrink handwriting when not focused [wip]

src/handwriting/mod.rs

@@ -76,6 +76,9 @@ pub struct Handwriting {
 struct Ephemeral {
     id: Id,
 
+    /// Whether the handwriting element is being interacted with.
+    is_focused: bool,
+
     /// The stroke that is currently being drawed.
     current_stroke: Vec<Pos2>,
 
@@ -163,6 +166,7 @@ impl Default for Ephemeral {
     fn default() -> Self {
         Self {
             id: random_id(),
+            is_focused: false,
             current_stroke: Default::default(),
             tessellator: None,
             mesh: Default::default(),
@@ -246,9 +250,16 @@ impl Handwriting {
         // Was the user in the process of drawing a stroke last frame?
         let was_drawing = !self.e.current_stroke.is_empty();
 
-        // Is the user in the process of drawing a stroke now?
+        // Is the user in the process of drawing a stroke now?;
         let is_drawing = response.interact_pointer_pos().is_some();
 
+        if is_drawing {
+            self.e.is_focused = true;
+        } else if ui.ctx().input(|i| i.pointer.any_down()) {
+            // if the user starts interactive with something else, unfocus the handwriting area.
+            self.e.is_focused = false;
+        }
+
         if !is_drawing {
             if was_drawing {
                 // commit current line
@@ -256,12 +267,18 @@ impl Handwriting {
                 response.mark_changed();
             }
 
+            let padding = if self.e.is_focused {
+                HANDWRITING_BOTTOM_PADDING
+            } else {
+                0.0
+            };
+
             // recalculate how tall the widget should be
             let lines_max_y = self
                 .strokes
                 .iter()
                 .flatten()
-                .map(|p| p.y + HANDWRITING_BOTTOM_PADDING)
+                .map(|p| p.y + padding)
                 .fold(HANDWRITING_MIN_HEIGHT, |max, y| max.max(y));
 
             // Change the height of the handwriting item.