wip: bidi and affinity

examples/vello_editor/src/text.rs

@@ -175,9 +175,11 @@ impl Editor {
  // Send that rectangle to the platform to suggest placement for the IME
  // candidate box.
  let mut union_rect = None;
+
+ debug_assert!(!text_range.is_empty());
  let preedit_selection = Selection::from_cursors(
  Cursor::from_index(&self.layout, text_range.start, Affinity::Downstream),
- Cursor::from_index(&self.layout, text_range.end, Affinity::Downstream),
+ Cursor::from_index(&self.layout, text_range.end - 1, Affinity::Upstream),
  );
 
  preedit_selection.geometry_with(&self.layout, |rect| {
@@ -385,11 +387,21 @@ impl Editor {
  };
 
  self.update_layout(self.width, 1.0);
- self.selection = Selection::from_index(
- &self.layout,
- commit_start + text.len(),
- Affinity::Downstream,
- );
+
+ if text.is_empty() {
+ // is this case ever hit?
+ self.selection = Selection::from_index(
+ &self.layout,
+ commit_start,
+ Affinity::Downstream,
+ );
+ } else {
+ self.selection = Selection::from_index(
+ &self.layout,
+ commit_start + text.len() - 1,
+ Affinity::Upstream,
+ );
+ }
  }
  Ime::Preedit(text, compose_cursor) => {
  let preedit_start = if let Some(text_range) = self.preedit_range.take() {
@@ -404,35 +416,56 @@ impl Editor {
  };
 
  if text.is_empty() {
- self.preedit_range = None;
- } else {
- self.preedit_range = Some(preedit_start..preedit_start + text.len());
- }
-
- self.update_layout(self.width, 1.0);
+ self.update_layout(self.width, 1.0);
 
- if let Some(compose_cursor) = compose_cursor {
- // Select the location indicated by the IME.
- self.selection = Selection::from_cursors(
- Cursor::from_index(
+ if preedit_start > 0 {
+ self.selection = Selection::from_index(
  &self.layout,
- preedit_start + compose_cursor.0,
- Affinity::Downstream,
- ),
- Cursor::from_index(
+ preedit_start - 1,
+ Affinity::Upstream,
+ );
+ } else {
+ self.selection = Selection::from_index(
  &self.layout,
- preedit_start + compose_cursor.1,
+ preedit_start,
  Affinity::Downstream,
- ),
- );
+ );
+ }
  } else {
- // IME indicates nothing is to be selected: collapse the selection to a
- // caret just in front of the preedit.
- self.selection = Selection::from_index(
- &self.layout,
- preedit_start,
- Affinity::Downstream,
- );
+ self.preedit_range = Some(preedit_start..preedit_start + text.len());
+ self.update_layout(self.width, 1.0);
+
+ if let Some(compose_cursor) = compose_cursor {
+ // Select the location indicated by the IME.
+ if compose_cursor.0 == compose_cursor.1 {
+ self.selection = Selection::from_index(
+ &self.layout,
+ preedit_start + compose_cursor.0,
+ Affinity::Downstream,
+ )
+ } else {
+ self.selection = Selection::from_cursors(
+ Cursor::from_index(
+ &self.layout,
+ preedit_start + compose_cursor.0,
+ Affinity::Downstream,
+ ),
+ Cursor::from_index(
+ &self.layout,
+ preedit_start + compose_cursor.1 - 1,
+ Affinity::Upstream,
+ ),
+ );
+ }
+ } else {
+ // IME indicates nothing is to be selected: collapse the selection to a
+ // caret just in front of the preedit.
+ self.selection = Selection::from_index(
+ &self.layout,
+ preedit_start,
+ Affinity::Downstream,
+ );
+ }
  }
 
  self.set_ime_cursor_area(window);