Render IME selected string in different color from other preedit string

wezterm-gui/src/scripting/guiwin.rs

@@ -232,7 +232,7 @@ impl UserData for GuiWin {
                 .notify(TermWindowNotif::Apply(Box::new(move |term_window| {
                     tx.try_send(match term_window.composition_status() {
                         DeadKeyStatus::None => None,
-                        DeadKeyStatus::Composing(s) => Some(s.clone()),
+                        DeadKeyStatus::Composing(s, ..) => Some(s.clone()),
                     })
                     .ok();
                 })));

wezterm-gui/src/termwindow/render/pane.rs

@@ -397,7 +397,7 @@ impl crate::TermWindow {
                                 cursor_is_default_color: self.cursor_is_default_color,
                             }),
                             match (self.pos.is_active, &self.term_window.dead_key_status) {
-                                (true, DeadKeyStatus::Composing(composing)) => {
+                                (true, DeadKeyStatus::Composing(composing, _)) => {
                                     Some(composing.to_string())
                                 }
                                 _ => None,
@@ -474,7 +474,7 @@ impl crate::TermWindow {
                         shape_hash,
                         shape_generation: quad_key.shape_generation,
                         composing: if self.cursor.y == stable_row && self.pos.is_active {
-                            if let DeadKeyStatus::Composing(composing) =
+                            if let DeadKeyStatus::Composing(composing, _) =
                                 &self.term_window.dead_key_status
                             {
                                 Some((self.cursor.x, composing.to_string()))

wezterm-gui/src/termwindow/render/screen_line.rs

@@ -76,16 +76,18 @@ impl crate::TermWindow {
         };
 
         // Referencing the text being composed, but only if it belongs to this pane
-        let composing = if cursor_idx.is_some() {
-            if let DeadKeyStatus::Composing(composing) = &self.dead_key_status {
-                Some(composing)
+        let (composing, selected_range) = if cursor_idx.is_some() {
+            if let DeadKeyStatus::Composing(composing, selected_range) = &self.dead_key_status {
+                (Some(composing), selected_range.as_ref())
             } else {
-                None
+                (None, None)
             }
         } else {
-            None
+            (None, None)
         };
 
+        let mut selected_start = 0;
+        let mut selected_width = 0;
         let mut composition_width = 0;
 
         let (_bidi_enabled, bidi_direction) = params.line.bidi_info();
@@ -94,6 +96,11 @@ impl crate::TermWindow {
         // Do we need to shape immediately, or can we use the pre-shaped data?
         if let Some(composing) = composing {
             composition_width = unicode_column_width(composing, None);
+
+            if let Some(selected_range) = selected_range {
+                selected_start = unicode_column_width(&composing[..selected_range.start], None);
+                selected_width = unicode_column_width(&composing[selected_range.clone()], None);
+            }
         }
 
         let cursor_cell = if params.stable_line_idx == Some(params.cursor.y) {
@@ -110,6 +117,12 @@ impl crate::TermWindow {
             0..0
         };
 
+        let selected_cursor_range = if selected_width > 0 {
+            params.cursor.x + selected_start..params.cursor.x + selected_start + selected_width
+        } else {
+            0..0
+        };
+
         let cursor_range_pixels = params.left_pixel_x + cursor_range.start as f32 * cell_width
             ..params.left_pixel_x + cursor_range.end as f32 * cell_width;
 
@@ -419,6 +432,38 @@ impl crate::TermWindow {
 
                 quad.set_fg_color(cursor_border_color);
                 quad.set_alt_color_and_mix_value(cursor_border_color_alt, cursor_border_mix);
+
+                if !selected_cursor_range.is_empty()
+                    && (cursor_range.start <= selected_cursor_range.start)
+                    && (selected_cursor_range.end <= cursor_range.end)
+                {
+                    let mut quad = layers.allocate(0)?;
+                    quad.set_position(
+                        pos_x
+                            + (selected_cursor_range.start - cursor_range.start) as f32
+                                * cell_width,
+                        pos_y,
+                        pos_x
+                            + (selected_cursor_range.end - cursor_range.start) as f32 * cell_width,
+                        pos_y + cell_height,
+                    );
+                    quad.set_hsv(hsv);
+                    quad.set_has_color(false);
+
+                    quad.set_texture(
+                        gl_state
+                            .glyph_cache
+                            .borrow_mut()
+                            .cursor_sprite(
+                                cursor_shape,
+                                &params.render_metrics,
+                                (selected_cursor_range.end - selected_cursor_range.start) as u8,
+                            )?
+                            .texture_coords(),
+                    );
+
+                    quad.set_fg_color(params.selection_bg);
+                }
             }
         }
 

window/src/lib.rs

@@ -4,6 +4,7 @@ use config::window::WindowLevel;
 use config::{ConfigHandle, Dimension, GeometryOrigin};
 use promise::Future;
 use std::any::Any;
+use std::ops::Range;
 use std::path::PathBuf;
 use std::rc::Rc;
 use thiserror::Error;
@@ -150,7 +151,7 @@ pub enum DeadKeyStatus {
     None,
     /// Holding until composition is done; the string is the uncommitted
     /// composition text to show as a placeholder
-    Composing(String),
+    Composing(String, Option<Range<usize>>),
 }
 
 #[derive(Debug)]

window/src/os/macos/mod.rs

@@ -22,11 +22,16 @@ fn nsstring(s: &str) -> StrongPtr {
     unsafe { StrongPtr::new(NSString::alloc(nil).init_str(s)) }
 }
 
-unsafe fn nsstring_to_str<'a>(mut ns: *mut Object) -> &'a str {
+unsafe fn unattributed(mut ns: *mut Object) -> *mut Object {
     let is_astring: bool = msg_send![ns, isKindOfClass: class!(NSAttributedString)];
     if is_astring {
         ns = msg_send![ns, string];
     }
+    ns
+}
+
+unsafe fn nsstring_to_str<'a>(mut ns: *mut Object) -> &'a str {
+    ns = unattributed(ns);
     let data = NSString::UTF8String(ns as id) as *const u8;
     let len = NSString::len(ns as id);
     let bytes = std::slice::from_raw_parts(data, len);

window/src/os/macos/window.rs

@@ -2,7 +2,7 @@
 #![allow(clippy::let_unit_value)]
 
 use super::keycodes::*;
-use super::{nsstring, nsstring_to_str};
+use super::{nsstring, nsstring_to_str, unattributed};
 use crate::clipboard::Clipboard as ClipboardContext;
 use crate::connection::ConnectionOps;
 use crate::os::macos::menu::{MenuItem, RepresentedItem};
@@ -45,6 +45,7 @@ use raw_window_handle::{
 use std::any::Any;
 use std::cell::RefCell;
 use std::ffi::c_void;
+use std::ops::Range;
 use std::path::PathBuf;
 use std::rc::Rc;
 use std::str::FromStr;
@@ -501,6 +502,7 @@ impl Window {
                 ime_last_event: None,
                 live_resizing: false,
                 ime_text: String::new(),
+                selected_range: None,
             }));
 
             let window: id = msg_send![get_window_class(), alloc];
@@ -1441,6 +1443,7 @@ struct Inner {
     live_resizing: bool,
 
     ime_text: String,
+    selected_range: Option<Range<usize>>,
 }
 
 #[repr(C)]
@@ -1906,6 +1909,7 @@ impl WindowView {
         if let Some(myself) = Self::get_this(this) {
             let mut inner = myself.inner.borrow_mut();
             inner.ime_text = s.to_string();
+            inner.selected_range = calc_str_selected_range(astring, selected_range, s.len());
 
             /*
             let key_is_down = inner.key_is_down.take().unwrap_or(true);
@@ -2432,7 +2436,7 @@ impl WindowView {
                     Ok(TranslateStatus::Composing(composing)) => {
                         // Next key press in dead key sequence is pending.
                         inner.events.dispatch(WindowEvent::AdviseDeadKeyStatus(
-                            DeadKeyStatus::Composing(composing),
+                            DeadKeyStatus::Composing(composing, None),
                         ));
 
                         return;
@@ -2541,7 +2545,10 @@ impl WindowView {
                             // If it didn't generate an event, then a composition
                             // is pending.
                             let status = if inner.ime_last_event.is_none() {
-                                DeadKeyStatus::Composing(inner.ime_text.clone())
+                                DeadKeyStatus::Composing(
+                                    inner.ime_text.clone(),
+                                    inner.selected_range.clone(),
+                                )
                             } else {
                                 DeadKeyStatus::None
                             };
@@ -2571,7 +2578,10 @@ impl WindowView {
                             let status = if inner.ime_text.is_empty() {
                                 DeadKeyStatus::None
                             } else {
-                                DeadKeyStatus::Composing(inner.ime_text.clone())
+                                DeadKeyStatus::Composing(
+                                    inner.ime_text.clone(),
+                                    inner.selected_range.clone(),
+                                )
                             };
                             inner
                                 .events
@@ -3300,3 +3310,48 @@ impl WindowView {
         cls.register()
     }
 }
+
+fn calc_str_selected_range(
+    astring: *mut Object,
+    selected_range: NSRange,
+    max: usize,
+) -> Option<Range<usize>> {
+    unsafe fn sub_tostr_len(ns: *mut Object, range: NSRange, max: usize) -> usize {
+        let sub = msg_send![ns, substringWithRange: range];
+        let len = nsstring_to_str(sub).len();
+        std::cmp::min(len, max)
+    }
+
+    let ns;
+    let ns_length: u64;
+    unsafe {
+        ns = unattributed(astring);
+        ns_length = msg_send![ns, length];
+    }
+
+    let a_start = selected_range.0.location;
+    let a_end = a_start + selected_range.0.length;
+    if ns_length < a_end {
+        return None;
+    }
+
+    let s_start;
+    let s_end;
+    unsafe {
+        s_start = if 0 < a_start {
+            sub_tostr_len(ns, NSRange::new(0, a_start), max)
+        } else {
+            0
+        };
+        s_end = if a_end < ns_length {
+            s_start + sub_tostr_len(ns, NSRange::new(a_start, a_end - a_start), max)
+        } else {
+            max
+        };
+    }
+    if s_end <= s_start {
+        return None;
+    }
+
+    Some(s_start..s_end)
+}

window/src/os/wayland/inputhandler.rs

@@ -190,7 +190,7 @@ impl Dispatch<ZwpTextInputV3, TextInputData, WaylandState> for TextInputState {
                     }));
                 }
                 let status = if let Some(text) = pending_state.pre_edit.take() {
-                    DeadKeyStatus::Composing(text)
+                    DeadKeyStatus::Composing(text, None)
                 } else {
                     DeadKeyStatus::None
                 };