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(composing) => Some(composing.text.clone()),
                     })
                     .ok();
                 })));

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

@@ -9,6 +9,7 @@ use crate::shapecache::*;
 use crate::termwindow::render::paint::AllowImage;
 use crate::termwindow::{BorrowedShapeCacheKey, RenderState, ShapedInfo, TermWindowNotif};
 use crate::utilsprites::RenderMetrics;
+use crate::Composing;
 use ::window::bitmaps::{TextureCoord, TextureRect, TextureSize};
 use ::window::{DeadKeyStatus, PointF, RectF, SizeF, WindowOps};
 use anyhow::{anyhow, Context};
@@ -56,7 +57,7 @@ pub struct LineQuadCacheKey {
     pub shape_generation: usize,
     pub quad_generation: usize,
     /// Only set if cursor.y == stable_row
-    pub composing: Option<String>,
+    pub composing: Option<Composing>,
     pub selection: Range<usize>,
     pub shape_hash: [u8; 16],
     pub top_pixel_y: NotNan<f32>,

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

@@ -398,7 +398,7 @@ impl crate::TermWindow {
                             }),
                             match (self.pos.is_active, &self.term_window.dead_key_status) {
                                 (true, DeadKeyStatus::Composing(composing)) => {
-                                    Some(composing.to_string())
+                                    Some(composing.clone())
                                 }
                                 _ => None,
                             },
@@ -430,7 +430,7 @@ impl crate::TermWindow {
                         config_generation: self.term_window.config.generation(),
                         shape_generation: self.term_window.shape_generation,
                         quad_generation: self.term_window.quad_generation,
-                        composing: composing.clone(),
+                        composing,
                         selection: selrange.clone(),
                         cursor,
                         shape_hash,
@@ -477,7 +477,7 @@ impl crate::TermWindow {
                             if let DeadKeyStatus::Composing(composing) =
                                 &self.term_window.dead_key_status
                             {
-                                Some((self.cursor.x, composing.to_string()))
+                                Some((self.cursor.x, composing.text.clone()))
                             } else {
                                 None
                             }

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

@@ -5,6 +5,7 @@ use crate::termwindow::render::{
     RenderScreenLineParams, RenderScreenLineResult,
 };
 use crate::termwindow::LineToElementShapeItem;
+use crate::Composing;
 use ::window::DeadKeyStatus;
 use anyhow::Context;
 use config::{HsbTransform, TextStyle};
@@ -17,6 +18,7 @@ use termwiz::surface::CursorShape;
 use wezterm_bidi::Direction;
 use wezterm_term::color::ColorAttribute;
 use wezterm_term::CellAttributes;
+use window::ComposingAttribute;
 
 impl crate::TermWindow {
     /// "Render" a line of the terminal screen into the vertex buffer.
@@ -64,6 +66,9 @@ impl crate::TermWindow {
         let pos_y = (self.dimensions.pixel_height as f32 / -2.) + params.top_pixel_y;
         let gl_x = self.dimensions.pixel_width as f32 / -2.;
 
+        let (_bidi_enabled, bidi_direction) = params.line.bidi_info();
+        let direction = bidi_direction.direction();
+
         let start = Instant::now();
 
         let cursor_idx = if params.pane.is_some()
@@ -75,25 +80,42 @@ impl crate::TermWindow {
             None
         };
 
+        let mut composing_text_width = 0;
+        let mut composing_selections = vec![];
+
         // 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)
-            } else {
-                None
+        if cursor_idx.is_some() {
+            // Do we need to shape immediately, or can we use the pre-shaped data?
+            if let DeadKeyStatus::Composing(Composing { text, attr }) = &self.dead_key_status {
+                composing_text_width = unicode_column_width(text, None);
+
+                if let Some(attr) = attr {
+                    // convert text and attr to selections
+                    let mut selection = 0usize..0;
+                    // iterate over byte end of each character in text
+                    for (i, end) in text
+                        .char_indices()
+                        .map(|(offset, _)| offset)
+                        .chain([text.len()])
+                        .skip(1)
+                        .take(attr.len())
+                        .enumerate()
+                    {
+                        // update end to unicode width
+                        let end = unicode_column_width(&text[..end], None);
+                        if attr[i].contains(ComposingAttribute::SELECTED) {
+                            selection.end = end;
+                        }
+                        // add non-empty selection and prepare next selection
+                        if i + 1 == attr.len() || !attr[i].contains(ComposingAttribute::SELECTED) {
+                            if !selection.is_empty() {
+                                composing_selections.push(selection);
+                            }
+                            selection = end..end;
+                        }
+                    }
+                }
             }
-        } else {
-            None
-        };
-
-        let mut composition_width = 0;
-
-        let (_bidi_enabled, bidi_direction) = params.line.bidi_info();
-        let direction = bidi_direction.direction();
-
-        // 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);
         }
 
         let cursor_cell = if params.stable_line_idx == Some(params.cursor.y) {
@@ -102,8 +124,8 @@ impl crate::TermWindow {
             None
         };
 
-        let cursor_range = if composition_width > 0 {
-            params.cursor.x..params.cursor.x + composition_width
+        let cursor_range = if composing_text_width > 0 {
+            params.cursor.x..params.cursor.x + composing_text_width
         } else if params.stable_line_idx == Some(params.cursor.y) {
             params.cursor.x..params.cursor.x + cursor_cell.as_ref().map(|c| c.width()).unwrap_or(1)
         } else {
@@ -419,6 +441,36 @@ impl crate::TermWindow {
 
                 quad.set_fg_color(cursor_border_color);
                 quad.set_alt_color_and_mix_value(cursor_border_color_alt, cursor_border_mix);
+
+                for selection in &composing_selections {
+                    let selection = params.cursor.x + selection.start - cursor_range.start
+                        ..params.cursor.x + selection.end - cursor_range.start;
+                    if !selection.is_empty() {
+                        let mut quad = layers.allocate(0)?;
+                        quad.set_position(
+                            pos_x + selection.start as f32 * cell_width,
+                            pos_y,
+                            pos_x + selection.end 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,
+                                    (selection.end - selection.start) as u8,
+                                )?
+                                .texture_coords(),
+                        );
+
+                        quad.set_fg_color(params.selection_bg);
+                    }
+                }
             }
         }
 

window/src/lib.rs

@@ -151,7 +151,23 @@ pub enum DeadKeyStatus {
     None,
     /// Holding until composition is done; the string is the uncommitted
     /// composition text to show as a placeholder
-    Composing(String),
+    Composing(Composing),
+}
+
+#[derive(Debug, Clone, PartialEq, Eq, Hash, Default)]
+pub struct Composing {
+    /// Holding composing text
+    pub text: String,
+    /// Holding composing attribute of each unicode character in composing text
+    pub attr: Option<Vec<ComposingAttribute>>,
+}
+
+bitflags! {
+    #[derive(Default)]
+    pub struct ComposingAttribute: u8 {
+        const NONE = 0;
+        const SELECTED = 1;
+    }
 }
 
 #[derive(Debug)]

window/src/os/macos/window.rs

@@ -8,10 +8,11 @@ use crate::connection::ConnectionOps;
 use crate::os::macos::menu::{MenuItem, RepresentedItem};
 use crate::parameters::{Border, Parameters, TitleBar};
 use crate::{
-    Clipboard, Connection, DeadKeyStatus, Dimensions, Handled, KeyCode, KeyEvent, Modifiers,
-    MouseButtons, MouseCursor, MouseEvent, MouseEventKind, MousePress, Point, RawKeyEvent, Rect,
-    RequestedWindowGeometry, ResizeIncrement, ResolvedGeometry, ScreenPoint, Size, ULength,
-    WindowDecorations, WindowEvent, WindowEventSender, WindowOps, WindowState,
+    Clipboard, Composing, ComposingAttribute, Connection, DeadKeyStatus, Dimensions, Handled,
+    KeyCode, KeyEvent, Modifiers, MouseButtons, MouseCursor, MouseEvent, MouseEventKind,
+    MousePress, Point, RawKeyEvent, Rect, RequestedWindowGeometry, ResizeIncrement,
+    ResolvedGeometry, ScreenPoint, Size, ULength, WindowDecorations, WindowEvent,
+    WindowEventSender, WindowOps, WindowState,
 };
 use anyhow::{anyhow, bail, ensure};
 use async_trait::async_trait;
@@ -500,7 +501,7 @@ impl Window {
                 ime_state: ImeDisposition::None,
                 ime_last_event: None,
                 live_resizing: false,
-                ime_text: String::new(),
+                ime_composing: Default::default(),
             }));
 
             let window: id = msg_send![get_window_class(), alloc];
@@ -1440,7 +1441,7 @@ struct Inner {
     /// Whether we're in live resize
     live_resizing: bool,
 
-    ime_text: String,
+    ime_composing: Composing,
 }
 
 #[repr(C)]
@@ -1822,7 +1823,7 @@ impl WindowView {
     extern "C" fn has_marked_text(this: &mut Object, _sel: Sel) -> BOOL {
         if let Some(myself) = Self::get_this(this) {
             let inner = myself.inner.borrow();
-            if inner.ime_text.is_empty() {
+            if inner.ime_composing.text.is_empty() {
                 NO
             } else {
                 YES
@@ -1835,11 +1836,11 @@ impl WindowView {
     extern "C" fn marked_range(this: &mut Object, _sel: Sel) -> NSRange {
         if let Some(myself) = Self::get_this(this) {
             let inner = myself.inner.borrow();
-            log::trace!("marked_range {:?}", inner.ime_text);
-            if inner.ime_text.is_empty() {
+            log::trace!("marked_range {:?}", inner.ime_composing);
+            if inner.ime_composing.text.is_empty() {
                 NSRange::new(NSNotFound as _, 0)
             } else {
-                NSRange::new(0, inner.ime_text.len() as u64)
+                NSRange::new(0, inner.ime_composing.text.len() as u64)
             }
         } else {
             NSRange::new(NSNotFound as _, 0)
@@ -1879,7 +1880,7 @@ impl WindowView {
                 raw: None,
             };
 
-            inner.ime_text.clear();
+            inner.ime_composing = Default::default();
             inner
                 .events
                 .dispatch(WindowEvent::AdviseDeadKeyStatus(DeadKeyStatus::None));
@@ -1905,7 +1906,23 @@ impl WindowView {
         );
         if let Some(myself) = Self::get_this(this) {
             let mut inner = myself.inner.borrow_mut();
-            inner.ime_text = s.to_string();
+
+            let text = s.to_string();
+            let attr = Some(
+                text.chars()
+                    .scan(0, |i, c| (Some(*i), *i += c.len_utf16()).0)
+                    .map(|i| {
+                        let mut attr = ComposingAttribute::NONE;
+                        if selected_range.0.location <= (i as u64)
+                            && (i as u64) < selected_range.0.location + selected_range.0.length
+                        {
+                            attr |= ComposingAttribute::SELECTED;
+                        }
+                        attr
+                    })
+                    .collect(),
+            );
+            inner.ime_composing = Composing { text, attr };
 
             /*
             let key_is_down = inner.key_is_down.take().unwrap_or(true);
@@ -1935,7 +1952,7 @@ impl WindowView {
             // FIXME: docs say to insert the text here,
             // but iterm doesn't... and we've never seen
             // this get called so far?
-            inner.ime_text.clear();
+            inner.ime_composing = Default::default();
             inner.ime_last_event.take();
             inner.ime_state = ImeDisposition::Acted;
         }
@@ -2432,7 +2449,10 @@ 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 {
+                                text: composing,
+                                attr: None,
+                            }),
                         ));
 
                         return;
@@ -2513,7 +2533,7 @@ impl WindowView {
                 let mut inner = myself.inner.borrow_mut();
                 inner.key_is_down.replace(key_is_down);
                 inner.ime_state = ImeDisposition::None;
-                inner.ime_text.clear();
+                inner.ime_composing = Default::default();
             }
 
             unsafe {
@@ -2541,7 +2561,7 @@ 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_composing.clone())
                             } else {
                                 DeadKeyStatus::None
                             };
@@ -2568,10 +2588,10 @@ impl WindowView {
                                     return;
                                 }
                             }
-                            let status = if inner.ime_text.is_empty() {
+                            let status = if inner.ime_composing.text.is_empty() {
                                 DeadKeyStatus::None
                             } else {
-                                DeadKeyStatus::Composing(inner.ime_text.clone())
+                                DeadKeyStatus::Composing(inner.ime_composing.clone())
                             };
                             inner
                                 .events

window/src/os/wayland/inputhandler.rs

@@ -16,7 +16,7 @@ use wayland_protocols::wp::text_input::zv3::client::zwp_text_input_v3::{
 };
 use wezterm_input_types::{KeyCode, KeyEvent, KeyboardLedStatus, Modifiers};
 
-use crate::{DeadKeyStatus, WindowEvent};
+use crate::{Composing, DeadKeyStatus, WindowEvent};
 
 use super::state::WaylandState;
 
@@ -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(Composing { text, attr: None })
                 } else {
                     DeadKeyStatus::None
                 };