perf(terminal): stop the cursor blink while the window lacks the keyboard

qmltermwidget/lib/TerminalView.cpp

@@ -80,7 +80,7 @@ TerminalView::TerminalView()
     updatePointerCursor();
 
     _blinkTimer.onTimeout = [this] { blinkEvent(); };
-    _blinkCursorTimer.onTimeout = [this] { blinkCursorEvent(); };
+    _blinkCursorTimer.onTimeout = [this] { blinkCursorTimeout(); };
     _tripleClickTimer.setSingleShot(true);
     _tripleClickTimer.onTimeout = [this] { _possibleTripleClick = false; };
     _bellTimer.setSingleShot(true);
@@ -270,7 +270,7 @@ void TerminalView::setBlinkingCursor(bool blink)
 {
     _hasBlinkingCursor = blink;
 
-    if (blink && !_blinkCursorTimer.isActive() && hasFocus())
+    if (blink && !_blinkCursorTimer.isActive() && hasKeyboard())
         _blinkCursorTimer.start(std::chrono::milliseconds(CURSOR_BLINK_INTERVAL));
 
     if (!blink && _blinkCursorTimer.isActive()) {
@@ -306,9 +306,28 @@ void TerminalView::blinkCursorEvent()
     requestPaint();
 }
 
+void TerminalView::blinkCursorTimeout()
+{
+    // Without the keyboard the cursor shows in its unfocused state; the next
+    // paint with it starts blinking again.
+    if (!hasKeyboard()) {
+        _blinkCursorTimer.stop();
+        if (_cursorBlinking)
+            blinkCursorEvent();
+        return;
+    }
+    blinkCursorEvent();
+}
+
+bool TerminalView::hasKeyboard() const
+{
+    const ui::Window* window = this->window();
+    return hasFocus() && window->hasKeyboardFocus();
+}
+
 void TerminalView::focusIn(ui::FocusReason)
 {
-    if (_hasBlinkingCursor)
+    if (_hasBlinkingCursor && hasKeyboard())
         _blinkCursorTimer.start(std::chrono::milliseconds(CURSOR_BLINK_INTERVAL));
     requestPaint();
 
@@ -2087,6 +2106,15 @@ static void addOtherLineChar(FramePainter& frame, double left, double top, int w
 // Mirrors TerminalGpuNode::build(), which mirrored TerminalDisplay::paint().
 void TerminalView::paint(ui::Painter& painter)
 {
+    // The window repaints its focus view when the keyboard comes or goes.
+    if (hasKeyboard()) {
+        if (_hasBlinkingCursor && !_blinkCursorTimer.isActive())
+            _blinkCursorTimer.start(std::chrono::milliseconds(CURSOR_BLINK_INTERVAL));
+    } else if (_blinkCursorTimer.isActive()) {
+        _blinkCursorTimer.stop();
+        _cursorBlinking = false;
+    }
+
     if (_image.empty() || geometry().width <= 0 || geometry().height <= 0)
         return;
 

qmltermwidget/lib/TerminalView.h

@@ -100,6 +100,7 @@ public:
 
     void setTerminalFont(const std::string& family, double pointSize);
     void setBlinkingCursor(bool blink);
+    bool isCursorBlinking() const { return _blinkCursorTimer.isActive(); }
     void setTerminalCursorShape(int shape);
     void setBellMode(int mode) { _bellMode = mode; }
     void setConfirmMultilinePaste(bool confirm) { _confirmMultilinePaste = confirm; }
@@ -229,6 +230,8 @@ private:
     int drawnLines() const;
     void blinkEvent();
     void blinkCursorEvent();
+    void blinkCursorTimeout();
+    bool hasKeyboard() const;
     void restartCursorBlink();
     void bell();
     void swapColorTable();

tests/window_test.cpp

@@ -21,6 +21,7 @@
 
 #include "TerminalFont.h"
 #include "TerminalSession.h"
+#include "TerminalView.h"
 #include "tools.h"
 
 #include "terminalpage.h"
@@ -153,6 +154,48 @@ TEST_F(WindowTest, CloseOtherTabsAfterTheKeptTabEnded)
     EXPECT_TRUE(busy->isVisible());
 }
 
+TEST_F(WindowTest, CursorBlinksOnlyWithTheKeyboard)
+{
+    Windows windows(m_settings);
+    TerminalWindow* window = windows.create(shell());
+    ui::Window& surface = window->window();
+    Konsole::TerminalView* terminal = window->currentPage()->terminal();
+    ASSERT_TRUE(terminal->hasFocus());
+
+    ui::TestInput::setKeyboardFocus(surface, true);
+    surface.grab();
+    EXPECT_TRUE(terminal->isCursorBlinking());
+
+    ui::TestInput::setKeyboardFocus(surface, false);
+    surface.grab();
+    EXPECT_FALSE(terminal->isCursorBlinking());
+
+    ui::TestInput::setKeyboardFocus(surface, true);
+    surface.grab();
+    EXPECT_TRUE(terminal->isCursorBlinking());
+
+    // Without a frame drawn, the next blink stops the timer.
+    ui::TestInput::setKeyboardFocus(surface, false);
+    EXPECT_TRUE(waitFor([&] { return !terminal->isCursorBlinking(); }));
+}
+
+TEST_F(WindowTest, CursorWithoutBlinkingNeverStartsTheTimer)
+{
+    m_settings.setBlinkingCursor(false);
+    Windows windows(m_settings);
+    TerminalWindow* window = windows.create(shell());
+    ui::Window& surface = window->window();
+    Konsole::TerminalView* terminal = window->currentPage()->terminal();
+
+    ui::TestInput::setKeyboardFocus(surface, true);
+    surface.grab();
+    EXPECT_FALSE(terminal->isCursorBlinking());
+
+    ui::TestInput::setKeyboardFocus(surface, false);
+    surface.grab();
+    EXPECT_FALSE(terminal->isCursorBlinking());
+}
+
 namespace {
 
 class Canvas : public ui::View