feat(vqt6): QCheckBox 改自绘子类(矢量框+对勾,按QPalette配色)

vqt6/_bridge_widgets.cpp

@@ -16,6 +16,9 @@
 #include <QPlainTextEdit>
 #include <QCheckBox>
 #include <QRadioButton>
+#include <QPainter>
+#include <QPainterPath>
+#include <QStyleOptionButton>
 #include <QComboBox>
 #include <QListWidget>
 #include <QProgressBar>
@@ -847,18 +850,74 @@ extern "C" VQT6_API int vqt6_qplaintextedit_line_count(void* pte) {
 // ============================================================
 // QCheckBox / QRadioButton
 // ============================================================
+
+// 自绘 QCheckBox：边框+矢量对勾都按 QPalette 绘制，
+// 避免浅色/深色主题切换时原生对勾或边框丢失
+class vqt6_CheckBox : public QCheckBox {
+public:
+    vqt6_CheckBox(QWidget* parent = nullptr) : QCheckBox(parent) {}
+    vqt6_CheckBox(const QString& text, QWidget* parent = nullptr) : QCheckBox(text, parent) {}
+
+protected:
+    void paintEvent(QPaintEvent*) override {
+        QPainter p(this);
+        p.setRenderHint(QPainter::Antialiasing, true);
+        const QPalette& pal = palette();
+        QStyleOptionButton opt;
+        initStyleOption(&opt);
+        QRect r = style()->subElementRect(QStyle::SE_CheckBoxIndicator, &opt, this);
+        if (r.isEmpty() || r.isNull()) {
+            r = QRect(0, 0, 16, 16);
+            r.moveCenter(QPoint(rect().left() + 12, rect().center().y()));
+        }
+        QRectF box(r.left() + 1.0, r.top() + 1.0, r.width() - 2.0, r.height() - 2.0);
+        if (box.width() < 10.0 || box.height() < 10.0) {
+            box = QRectF(0, 0, 16, 16);
+            box.moveCenter(QPointF(r.center().x(), r.center().y()));
+        }
+        QPainterPath path;
+        path.addRoundedRect(box, 3.0, 3.0);
+        const bool on = isChecked();
+        const bool en = isEnabled();
+        QColor border = en ? pal.text().color() : pal.placeholderText().color();
+        if (on) {
+            p.fillPath(path, en ? pal.highlight() : pal.button());
+            border = en ? pal.highlight().color() : pal.buttonText().color();
+        } else {
+            p.fillPath(path, en ? pal.base() : pal.window());
+        }
+        QPen bpen(border, 1.4);
+        p.setPen(bpen);
+        p.drawPath(path);
+        if (on && en) {
+            QPen cpen(pal.highlightedText(), 2.2);
+            cpen.setCapStyle(Qt::RoundCap);
+            p.setPen(cpen);
+            const qreal x0 = box.left(), y0 = box.top(), w = box.width(), h = box.height();
+            p.drawLine(QPointF(x0 + w * 0.24, y0 + h * 0.54), QPointF(x0 + w * 0.43, y0 + h * 0.73));
+            p.drawLine(QPointF(x0 + w * 0.43, y0 + h * 0.73), QPointF(x0 + w * 0.78, y0 + h * 0.28));
+        }
+        // 文本
+        QRect lr = style()->subElementRect(QStyle::SE_CheckBoxContents, &opt, this);
+        if (!lr.isEmpty() && !lr.isNull()) {
+            p.setPen(QPen(en ? pal.text() : pal.placeholderText(), 1.0));
+            p.drawText(lr, Qt::AlignLeft | Qt::AlignVCenter, text());
+        }
+    }
+};
+
 extern "C" VQT6_API void* vqt6_qcheckbox_create(void) {
-    return new QCheckBox();
+    return new vqt6_CheckBox();
 }
 
 extern "C" VQT6_API void* vqt6_qcheckbox_create_with_text(void* text) {
     if (text == nullptr) return nullptr;
-    return new QCheckBox(*static_cast<QString*>(text));
+    return new vqt6_CheckBox(*static_cast<QString*>(text));
 }
 
 extern "C" VQT6_API void* vqt6_qcheckbox_create_with_text_parent(void* text, void* parent) {
     if (text == nullptr || parent == nullptr) return nullptr;
-    return new QCheckBox(*static_cast<QString*>(text), static_cast<QWidget*>(parent));
+    return new vqt6_CheckBox(*static_cast<QString*>(text), static_cast<QWidget*>(parent));
 }
 
 extern "C" VQT6_API void vqt6_qcheckbox_set_checked(void* cb, int checked) {