Core: Explicitly provide image for minisplitter cursors

On Linux we fail to get the system cursor for resizing splitters
on several platforms which makes it hard to grab them to move
their position.
Provide a setting which enables the user to use some cursors
explicitly provided by QC instead.

Task-number: QTBUG-119875
Fixes: QTCREATORBUG-29980
Change-Id: I02f031883ddd5cfd33075868ae6766ff78ee6882
Reviewed-by: Eike Ziller <eike.ziller@qt.io>
Reviewed-by: <github-actions-qt-creator@cristianadam.eu>
Reviewed-by: Leena Miettinen <riitta-leena.miettinen@qt.io>

3 files changed, 84 insertions, 0 deletions

diff --git a/src/plugins/coreplugin/generalsettings.cpp b/src/plugins/coreplugin/generalsettings.cpp
index 4b75c15a7e..0689adea52 100644
--- a/src/plugins/coreplugin/generalsettings.cpp
+++ b/src/plugins/coreplugin/generalsettings.cpp
@@ -61,6 +61,14 @@ GeneralSettings::GeneralSettings()
         Tr::tr("Show keyboard shortcuts in context menus (default: %1)")
             .arg(defaultShowShortcutsInContextMenu() ? Tr::tr("on") : Tr::tr("off")));
 
+    provideSplitterCursors.setSettingsKey("General/OverrideSplitterCursors");
+    provideSplitterCursors.setDefaultValue(false);
+    provideSplitterCursors.setLabelText(Tr::tr("Override cursors for views"));
+    provideSplitterCursors.setToolTip(
+        Tr::tr("Provide cursors for resizing views.\nIf the system cursors for resizing views are "
+               "not displayed properly, you can use the cursors provided by %1.")
+            .arg(QGuiApplication::applicationDisplayName()));
+
     connect(&showShortcutsInContextMenus, &BaseAspect::changed, this, [this] {
         QCoreApplication::setAttribute(Qt::AA_DontShowShortcutsInContextMenus,
                                        !showShortcutsInContextMenus());
@@ -179,6 +187,7 @@ GeneralSettingsWidget::GeneralSettingsWidget()
     }
 
     form.addRow({empty, generalSettings().showShortcutsInContextMenus});
+    form.addRow({empty, generalSettings().provideSplitterCursors});
     form.addRow({Row{m_resetWarningsButton, st}});
     form.addRow({Tr::tr("Text codec for tools:"), m_codecBox, st});
     Column{Group{title(Tr::tr("User Interface")), form}}.attachTo(this);
@@ -241,8 +250,12 @@ void GeneralSettingsWidget::fillLanguageBox() const
 
 void GeneralSettingsWidget::apply()
 {
+    bool showRestart = generalSettings().provideSplitterCursors.volatileValue()
+            != generalSettings().provideSplitterCursors.value();
     generalSettings().apply();
     generalSettings().writeSettings();
+    if (showRestart)
+        ICore::askForRestart(Tr::tr("The cursors for resizing views will change after restart."));
 
     int currentIndex = m_languageBox->currentIndex();
     setLanguage(m_languageBox->itemData(currentIndex, Qt::UserRole).toString());
diff --git a/src/plugins/coreplugin/generalsettings.h b/src/plugins/coreplugin/generalsettings.h
index 498e243b2a..202bed4595 100644
--- a/src/plugins/coreplugin/generalsettings.h
+++ b/src/plugins/coreplugin/generalsettings.h
@@ -13,6 +13,7 @@ public:
     GeneralSettings();
 
     Utils::BoolAspect showShortcutsInContextMenus{this};
+    Utils::BoolAspect provideSplitterCursors{this};
 
     static void applyToolbarStyleFromSettings();
 };
diff --git a/src/plugins/coreplugin/minisplitter.cpp b/src/plugins/coreplugin/minisplitter.cpp
index e4e9db129b..8fdec456b0 100644
--- a/src/plugins/coreplugin/minisplitter.cpp
+++ b/src/plugins/coreplugin/minisplitter.cpp
@@ -3,6 +3,8 @@
 
 #include "minisplitter.h"
 
+#include "generalsettings.h"
+
 #include <utils/stylehelper.h>
 #include <utils/theme/theme.h>
 
@@ -13,6 +15,72 @@
 namespace Core {
 namespace Internal {
 
+// cursor images / masks taken from qplatformcursor.cpp
+static QCursor hsplitCursor()
+{
+    static const uchar hsplit_bits[] = {
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x40, 0x02, 0x00, 0x00, 0x40, 0x02, 0x00,
+        0x00, 0x40, 0x02, 0x00, 0x00, 0x40, 0x02, 0x00, 0x00, 0x40, 0x02, 0x00,
+        0x00, 0x41, 0x82, 0x00, 0x80, 0x41, 0x82, 0x01, 0xc0, 0x7f, 0xfe, 0x03,
+        0x80, 0x41, 0x82, 0x01, 0x00, 0x41, 0x82, 0x00, 0x00, 0x40, 0x02, 0x00,
+        0x00, 0x40, 0x02, 0x00, 0x00, 0x40, 0x02, 0x00, 0x00, 0x40, 0x02, 0x00,
+        0x00, 0x40, 0x02, 0x00, 0x00, 0x40, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
+    static const uchar hsplitm_bits[] = {
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0xe0, 0x07, 0x00, 0x00, 0xe0, 0x07, 0x00, 0x00, 0xe0, 0x07, 0x00,
+        0x00, 0xe0, 0x07, 0x00, 0x00, 0xe2, 0x47, 0x00, 0x00, 0xe3, 0xc7, 0x00,
+        0x80, 0xe3, 0xc7, 0x01, 0xc0, 0xff, 0xff, 0x03, 0xe0, 0xff, 0xff, 0x07,
+        0xc0, 0xff, 0xff, 0x03, 0x80, 0xe3, 0xc7, 0x01, 0x00, 0xe3, 0xc7, 0x00,
+        0x00, 0xe2, 0x47, 0x00, 0x00, 0xe0, 0x07, 0x00, 0x00, 0xe0, 0x07, 0x00,
+        0x00, 0xe0, 0x07, 0x00, 0x00, 0xe0, 0x07, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
+
+    static QBitmap cursorImg = QBitmap::fromData({32, 32}, hsplit_bits);
+    static QBitmap mask = QBitmap::fromData({32, 32}, hsplitm_bits);
+    static QCursor cursor(cursorImg, mask, 15, 15);
+    return cursor;
+}
+
+static QCursor vsplitCursor()
+{
+    static const uchar vsplit_bits[] = {
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x80, 0x00, 0x00, 0x00, 0xc0, 0x01, 0x00, 0x00, 0xe0, 0x03, 0x00,
+        0x00, 0x80, 0x00, 0x00, 0x00, 0x80, 0x00, 0x00, 0x00, 0x80, 0x00, 0x00,
+        0x00, 0x80, 0x00, 0x00, 0x00, 0x80, 0x00, 0x00, 0x00, 0xff, 0x7f, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xff, 0x7f, 0x00,
+        0x00, 0x80, 0x00, 0x00, 0x00, 0x80, 0x00, 0x00, 0x00, 0x80, 0x00, 0x00,
+        0x00, 0x80, 0x00, 0x00, 0x00, 0x80, 0x00, 0x00, 0x00, 0xe0, 0x03, 0x00,
+        0x00, 0xc0, 0x01, 0x00, 0x00, 0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
+    static const uchar vsplitm_bits[] = {
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x80, 0x00, 0x00,
+        0x00, 0xc0, 0x01, 0x00, 0x00, 0xe0, 0x03, 0x00, 0x00, 0xf0, 0x07, 0x00,
+        0x00, 0xf8, 0x0f, 0x00, 0x00, 0xc0, 0x01, 0x00, 0x00, 0xc0, 0x01, 0x00,
+        0x00, 0xc0, 0x01, 0x00, 0x80, 0xff, 0xff, 0x00, 0x80, 0xff, 0xff, 0x00,
+        0x80, 0xff, 0xff, 0x00, 0x80, 0xff, 0xff, 0x00, 0x80, 0xff, 0xff, 0x00,
+        0x80, 0xff, 0xff, 0x00, 0x00, 0xc0, 0x01, 0x00, 0x00, 0xc0, 0x01, 0x00,
+        0x00, 0xc0, 0x01, 0x00, 0x00, 0xf8, 0x0f, 0x00, 0x00, 0xf0, 0x07, 0x00,
+        0x00, 0xe0, 0x03, 0x00, 0x00, 0xc0, 0x01, 0x00, 0x00, 0x80, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
+    static QBitmap cursorImg = QBitmap::fromData({32, 32}, vsplit_bits);
+    static QBitmap mask = QBitmap::fromData({32, 32}, vsplitm_bits);
+    static QCursor cursor(cursorImg, mask, 15, 15);
+    return cursor;
+}
+
 class MiniSplitterHandle : public QSplitterHandle
 {
 public:
@@ -22,6 +90,8 @@ public:
     {
         setMask(QRegion(contentsRect()));
         setAttribute(Qt::WA_MouseNoMask, true);
+        if (generalSettings().provideSplitterCursors())
+            setCursor(orientation == Qt::Horizontal ? hsplitCursor() : vsplitCursor());
     }
 protected:
     void resizeEvent(QResizeEvent *event) override;