Try our best to convert preedit styling to text-input-v3 cursor range.

text-input-v3 does not have preedit styling, instead, it can only
specify the range of cursor. Try to keep track of any
highlight/selection style range and combine them together. If it matches
the cursor position, use it as the cursor range.

autotests/integration/inputmethod_test.cpp

@@ -57,6 +57,7 @@ private Q_SLOTS:
     void testEnableActive();
     void testHidePanel();
     void testSwitchFocusedSurfaces();
+    void testV3Styling();
 
 private:
     void touchNow() {
@@ -339,6 +340,96 @@ void InputMethodTest::testSwitchFocusedSurfaces()
     }
 }
 
+void InputMethodTest::testV3Styling()
+{
+    // Create an xdg_toplevel surface and wait for the compositor to catch up.
+    QScopedPointer<KWayland::Client::Surface> surface(Test::createSurface());
+    QScopedPointer<Test::XdgToplevel> shellSurface(Test::createXdgToplevelSurface(surface.data()));
+    AbstractClient *client = Test::renderAndWaitForShown(surface.data(), QSize(1280, 1024), Qt::red);
+    QVERIFY(client);
+    QVERIFY(client->isActive());
+    QCOMPARE(client->frameGeometry().size(), QSize(1280, 1024));
+
+    Test::TextInputV3 *textInputV3 = new Test::TextInputV3();
+    textInputV3->init(Test::waylandTextInputManagerV3()->get_text_input(*(Test::waylandSeat())));
+    textInputV3->enable();
+
+    QSignalSpy inputMethodActiveSpy(InputMethod::self(), &InputMethod::activeChanged);
+    QSignalSpy inputMethodActivateSpy(Test::inputMethod(), &Test::MockInputMethod::activate);
+    // just enabling the text-input should not show it but rather on commit
+    QVERIFY(!InputMethod::self()->isActive());
+    textInputV3->commit();
+    QVERIFY(inputMethodActiveSpy.count() || inputMethodActiveSpy.wait());
+    QVERIFY(InputMethod::self()->isActive());
+    QVERIFY(inputMethodActivateSpy.wait());
+    auto context = Test::inputMethod()->context();
+    QSignalSpy textInputPreeditSpy(textInputV3, &Test::TextInputV3::preeditString);
+    zwp_input_method_context_v1_preedit_cursor(context, 0);
+    zwp_input_method_context_v1_preedit_styling(context, 0, 3, 7);
+    zwp_input_method_context_v1_preedit_string(context, 0, "ABCD", "ABCD");
+    QVERIFY(textInputPreeditSpy.wait());
+    QCOMPARE(textInputPreeditSpy.last().at(0), QString("ABCD"));
+    QCOMPARE(textInputPreeditSpy.last().at(1), 0);
+    QCOMPARE(textInputPreeditSpy.last().at(2), 0);
+
+    zwp_input_method_context_v1_preedit_cursor(context, 1);
+    zwp_input_method_context_v1_preedit_styling(context, 0, 3, 7);
+    zwp_input_method_context_v1_preedit_string(context, 0, "ABCDE", "ABCDE");
+    QVERIFY(textInputPreeditSpy.wait());
+    QCOMPARE(textInputPreeditSpy.last().at(0), QString("ABCDE"));
+    QCOMPARE(textInputPreeditSpy.last().at(1), 1);
+    QCOMPARE(textInputPreeditSpy.last().at(2), 1);
+
+    zwp_input_method_context_v1_preedit_cursor(context, 2);
+    // Use selection for [2, 2+2)
+    zwp_input_method_context_v1_preedit_styling(context, 2, 2, 6);
+    // Use high light for [3, 3+3)
+    zwp_input_method_context_v1_preedit_styling(context, 3, 3, 4);
+    zwp_input_method_context_v1_preedit_string(context, 0, "ABCDEF", "ABCDEF");
+    QVERIFY(textInputPreeditSpy.wait());
+    QCOMPARE(textInputPreeditSpy.last().at(0), QString("ABCDEF"));
+    // Merged range should be [2, 6)
+    QCOMPARE(textInputPreeditSpy.last().at(1), 2);
+    QCOMPARE(textInputPreeditSpy.last().at(2), 6);
+
+    zwp_input_method_context_v1_preedit_cursor(context, 2);
+    // Use selection for [0, 0+2)
+    zwp_input_method_context_v1_preedit_styling(context, 0, 2, 6);
+    // Use high light for [3, 3+3)
+    zwp_input_method_context_v1_preedit_styling(context, 3, 3, 4);
+    zwp_input_method_context_v1_preedit_string(context, 0, "ABCDEF", "ABCDEF");
+    QVERIFY(textInputPreeditSpy.wait());
+    QCOMPARE(textInputPreeditSpy.last().at(0), QString("ABCDEF"));
+    // Merged range should be none, because of the disjunction highlight.
+    QCOMPARE(textInputPreeditSpy.last().at(1), 2);
+    QCOMPARE(textInputPreeditSpy.last().at(2), 2);
+
+    zwp_input_method_context_v1_preedit_cursor(context, 1);
+    // Use selection for [0, 0+2)
+    zwp_input_method_context_v1_preedit_styling(context, 0, 2, 6);
+    // Use high light for [2, 2+3)
+    zwp_input_method_context_v1_preedit_styling(context, 2, 3, 4);
+    zwp_input_method_context_v1_preedit_string(context, 0, "ABCDEF", "ABCDEF");
+    QVERIFY(textInputPreeditSpy.wait());
+    QCOMPARE(textInputPreeditSpy.last().at(0), QString("ABCDEF"));
+    // Merged range should be none, starting offset does not match.
+    QCOMPARE(textInputPreeditSpy.last().at(1), 1);
+    QCOMPARE(textInputPreeditSpy.last().at(2), 1);
+
+    // Use different order of styling and cursor
+    // Use high light for [3, 3+3)
+    zwp_input_method_context_v1_preedit_styling(context, 3, 3, 4);
+    zwp_input_method_context_v1_preedit_cursor(context, 1);
+    // Use selection for [1, 1+2)
+    zwp_input_method_context_v1_preedit_styling(context, 1, 2, 6);
+    zwp_input_method_context_v1_preedit_string(context, 0, "ABCDEF", "ABCDEF");
+    QVERIFY(textInputPreeditSpy.wait());
+    QCOMPARE(textInputPreeditSpy.last().at(0), QString("ABCDEF"));
+    // Merged range should be [1,6).
+    QCOMPARE(textInputPreeditSpy.last().at(1), 1);
+    QCOMPARE(textInputPreeditSpy.last().at(2), 6);
+}
+
 WAYLANDTEST_MAIN(InputMethodTest)
 
 #include "inputmethod_test.moc"

autotests/integration/kwin_wayland_test.h

@@ -9,18 +9,22 @@
 #ifndef KWIN_WAYLAND_TEST_H
 #define KWIN_WAYLAND_TEST_H
 
+#include "abstract_client.h"
 #include "main.h"
 
 // Qt
 #include <QtTest>
 
+#include <KWayland/Client/surface.h>
+
 #include "qwayland-idle-inhibit-unstable-v1.h"
-#include "qwayland-wlr-layer-shell-unstable-v1.h"
-#include "qwayland-text-input-unstable-v3.h"
-#include "qwayland-xdg-decoration-unstable-v1.h"
-#include "qwayland-xdg-shell.h"
+#include "qwayland-input-method-unstable-v1.h"
 #include "qwayland-kde-output-device-v2.h"
 #include "qwayland-kde-output-management-v2.h"
+#include "qwayland-text-input-unstable-v3.h"
+#include "qwayland-wlr-layer-shell-unstable-v1.h"
+#include "qwayland-xdg-decoration-unstable-v1.h"
+#include "qwayland-xdg-shell.h"
 
 namespace KWayland
 {
@@ -93,9 +97,20 @@ public:
     ~TextInputManagerV3() override { destroy(); }
 };
 
-class TextInputV3 : public QtWayland::zwp_text_input_v3
+class TextInputV3 : public QObject, public QtWayland::zwp_text_input_v3
 {
+    Q_OBJECT
+public:
     ~TextInputV3() override { destroy(); }
+
+Q_SIGNALS:
+    void preeditString(const QString &text, int cursor_begin, int cursor_end);
+
+protected:
+    void zwp_text_input_v3_preedit_string(const QString &text, int32_t cursor_begin, int32_t cursor_end) override
+    {
+        Q_EMIT preeditString(text, cursor_begin, cursor_end);
+    }
 };
 
 class LayerShellV1 : public QtWayland::zwlr_layer_shell_v1
@@ -393,6 +408,40 @@ private:
     uint32_t m_rgbRange;
 };
 
+class MockInputMethod : public QObject, QtWayland::zwp_input_method_v1
+{
+    Q_OBJECT
+public:
+    MockInputMethod(struct wl_registry *registry, int id, int version);
+    ~MockInputMethod();
+
+    AbstractClient *client() const
+    {
+        return m_client;
+    }
+    KWayland::Client::Surface *inputPanelSurface() const
+    {
+        return m_inputSurface;
+    }
+    auto *context() const
+    {
+        return m_context;
+    }
+
+Q_SIGNALS:
+    void activate();
+
+protected:
+    void zwp_input_method_v1_activate(struct ::zwp_input_method_context_v1 *context) override;
+    void zwp_input_method_v1_deactivate(struct ::zwp_input_method_context_v1 *context) override;
+
+private:
+    QPointer<KWayland::Client::Surface> m_inputSurface;
+    QtWayland::zwp_input_panel_surface_v1 *m_inputMethodSurface = nullptr;
+    QPointer<AbstractClient> m_client;
+    struct ::zwp_input_method_context_v1 *m_context = nullptr;
+};
+
 enum class AdditionalWaylandInterface {
     Seat = 1 << 0,
     Decoration = 1 << 1,
@@ -528,6 +577,7 @@ bool unlockScreen();
 void initWaylandWorkspace();
 
 AbstractClient *inputPanelClient();
+MockInputMethod *inputMethod();
 KWayland::Client::Surface *inputPanelSurface();
 
 }

autotests/integration/test_helpers.cpp

@@ -7,11 +7,9 @@
     SPDX-License-Identifier: GPL-2.0-or-later
 */
 #include "kwin_wayland_test.h"
-#include "abstract_client.h"
 #include "screenlockerwatcher.h"
 #include "wayland_server.h"
 #include "workspace.h"
-#include "qwayland-input-method-unstable-v1.h"
 #include "inputmethod.h"
 
 #include <KWayland/Client/compositor.h>
@@ -249,30 +247,16 @@ static struct {
     TextInputManagerV3 *textInputManagerV3 = nullptr;
 } s_waylandConnection;
 
-class MockInputMethod : public QtWayland::zwp_input_method_v1
-{
-public:
-    MockInputMethod(struct wl_registry *registry, int id, int version);
-    ~MockInputMethod();
-
-    AbstractClient *client() const { return m_client; }
-    KWayland::Client::Surface *inputPanelSurface() const { return m_inputSurface; }
-
-protected:
-    void zwp_input_method_v1_activate(struct ::zwp_input_method_context_v1 *context) override;
-    void zwp_input_method_v1_deactivate(struct ::zwp_input_method_context_v1 *context) override;
-
-private:
-    QPointer<KWayland::Client::Surface> m_inputSurface;
-    QtWayland::zwp_input_panel_surface_v1 *m_inputMethodSurface = nullptr;
-    QPointer<AbstractClient> m_client;
-};
-
 AbstractClient *inputPanelClient()
 {
     return s_waylandConnection.inputMethodV1->client();
 }
 
+MockInputMethod *inputMethod()
+{
+    return s_waylandConnection.inputMethodV1;
+}
+
 KWayland::Client::Surface *inputPanelSurface()
 {
     return s_waylandConnection.inputMethodV1->inputPanelSurface();
@@ -295,11 +279,16 @@ void MockInputMethod::zwp_input_method_v1_activate(struct ::zwp_input_method_con
         m_inputMethodSurface = Test::createInputPanelSurfaceV1(m_inputSurface, s_waylandConnection.outputs.first());
     }
     m_client = Test::renderAndWaitForShown(m_inputSurface, QSize(1280, 400), Qt::blue);
+    m_context = context;
+
+    Q_EMIT activate();
 }
 
 void MockInputMethod::zwp_input_method_v1_deactivate(struct ::zwp_input_method_context_v1 *context)
 {
+    QCOMPARE(context, m_context);
     zwp_input_method_context_v1_destroy(context);
+    m_context = nullptr;
 
     if (m_inputSurface) {
         m_inputSurface->release();

src/inputmethod.cpp

@@ -300,9 +300,7 @@ void InputMethod::textInputInterfaceV3EnabledChanged()
     setActive(t3->isEnabled());
     if (!t3->isEnabled()) {
         // reset value of preedit when textinput is disabled
-        preedit.text = QString();
-        preedit.begin = 0;
-        preedit.end = 0;
+        resetPendingPreedit();
     }
     auto context = waylandServer()->inputMethod()->context();
     if (context) {
@@ -479,8 +477,7 @@ void InputMethod::setPreeditCursor(qint32 index)
     }
     auto t3 = waylandServer()->seat()->textInputV3();
     if (t3 && t3->isEnabled()) {
-        preedit.begin = index;
-        preedit.end = index;
+        preedit.cursor = index;
     }
 }
 
@@ -490,6 +487,13 @@ void InputMethod::setPreeditStyling(quint32 index, quint32 length, quint32 style
     if (t2 && t2->isEnabled()) {
         t2->preEditStyling(index, length, style);
     }
+    auto t3 = waylandServer()->seat()->textInputV3();
+    if (t3 && t3->isEnabled()) {
+        // preedit style: highlight(4) or selection(6)
+        if (style == 4 || style == 6) {
+            preedit.highlightRanges.emplace_back(index, index + length);
+        }
+    }
 }
 
 void InputMethod::setPreeditString(uint32_t serial, const QString &text, const QString &commit)
@@ -503,10 +507,36 @@ void InputMethod::setPreeditString(uint32_t serial, const QString &text, const Q
     if (t3 && t3->isEnabled()) {
         preedit.text = text;
         if (!preedit.text.isEmpty()) {
-            t3->sendPreEditString(preedit.text, preedit.begin, preedit.end);
+            quint32 cursor = 0, cursorEnd = 0;
+            if (preedit.cursor > 0) {
+                cursor = cursorEnd = preedit.cursor;
+            }
+            // Check if we can convert highlight style to a range of selection.
+            if (!preedit.highlightRanges.empty()) {
+                std::sort(preedit.highlightRanges.begin(), preedit.highlightRanges.end());
+                // Check if starting point matches.
+                if (preedit.highlightRanges.front().first == cursor) {
+                    quint32 end = preedit.highlightRanges.front().second;
+                    bool nonContinousHighlight = false;
+                    for (size_t i = 1 ; i < preedit.highlightRanges.size(); i ++) {
+                        if (end >= preedit.highlightRanges[i].first) {
+                            end = std::max(end, preedit.highlightRanges[i].second);
+                        } else {
+                            nonContinousHighlight = true;
+                            break;
+                        }
+                    }
+                    if (!nonContinousHighlight) {
+                        cursorEnd = end;
+                    }
+                }
+            }
+
+            t3->sendPreEditString(preedit.text, cursor, cursorEnd);
         }
         t3->done();
     }
+    resetPendingPreedit();
 }
 
 void InputMethod::key(quint32 /*serial*/, quint32 /*time*/, quint32 keyCode, bool pressed)
@@ -712,4 +742,10 @@ bool InputMethod::isAvailable() const
     return !m_inputMethodCommand.isEmpty();
 }
 
+void InputMethod::resetPendingPreedit() {
+    preedit.text = QString();
+    preedit.cursor = 0;
+    preedit.highlightRanges.clear();
+}
+
 }

src/inputmethod.h

@@ -9,6 +9,9 @@
 #ifndef KWIN_VIRTUAL_KEYBOARD_H
 #define KWIN_VIRTUAL_KEYBOARD_H
 
+#include <vector>
+#include <utility>
+
 #include <QObject>
 
 #include <kwinglobals.h>
@@ -99,11 +102,12 @@ private:
 
     bool touchEventTriggered() const;
     void forwardModifiers();
+    void resetPendingPreedit();
 
     struct {
         QString text = QString();
-        quint32 begin = 0;
-        quint32 end = 0;
+        qint32 cursor = 0;
+        std::vector<std::pair<quint32, quint32>> highlightRanges;
     } preedit;
 
     bool m_enabled = true;