fix(qt): no accent in old version

Author: Berrysoft

src/ui/qt/canvas.cpp

@@ -93,9 +93,14 @@ void painter_draw_text(QPainter &p, QRectF rect, rust::Str text) {
 
 void color_transparent(QColor &c) { new (&c) QColor{Qt::transparent}; }
 
-void color_accent(QColor &c) {
+bool color_accent(QColor &c) {
+#if QT_VERSION >= QT_VERSION_CHECK(6, 6, 0)
     auto accent = QApplication::palette().color(QPalette::Accent);
     new (&c) QColor{accent};
+    return true;
+#else
+    return false;
+#endif
 }
 
 std::unique_ptr<QBrush> new_brush(QColor const &c) {

src/ui/qt/canvas.hpp

@@ -51,7 +51,7 @@ QSizeF painter_measure_text(QPainter &p, QRectF rect, rust::Str text);
 void painter_draw_text(QPainter &p, QRectF rect, rust::Str text);
 
 void color_transparent(QColor &c);
-void color_accent(QColor &c);
+bool color_accent(QColor &c);
 std::unique_ptr<QBrush> new_brush(QColor const &c);
 std::unique_ptr<QPen> new_pen(QBrush const &b, double width);
 

src/ui/qt/canvas.rs

@@ -470,7 +470,7 @@ impl DrawingImage {
 
 /// Get the accent color.
 pub fn accent_color() -> Option<Color> {
-    Some(QColor::accent().into())
+    QColor::accent().map(From::from)
 }
 
 #[repr(i32)]
@@ -570,13 +570,16 @@ impl QColor {
         c
     }
 
-    pub fn accent() -> Self {
+    pub fn accent() -> Option<Self> {
         let mut c = Self {
             cspec: Spec::Invalid,
             ct: [0; 5],
         };
-        ffi::color_accent(Pin::new(&mut c));
-        c
+        if ffi::color_accent(Pin::new(&mut c)) {
+            Some(c)
+        } else {
+            None
+        }
     }
 }
 
@@ -709,7 +712,7 @@ mod ffi {
         fn setPen(self: Pin<&mut QPainter>, color: &QColor);
 
         fn color_transparent(c: Pin<&mut QColor>);
-        fn color_accent(c: Pin<&mut QColor>);
+        fn color_accent(c: Pin<&mut QColor>) -> bool;
         fn new_brush(c: &QColor) -> UniquePtr<QBrush>;
         fn new_pen(b: &QBrush, width: f64) -> UniquePtr<QPen>;