更换SpkWindow基类为QWidget并修复多个问题

修复mResizable为false时阻止窗口移动的问题
更改About窗口为固定大小

inc/spkdialog.h

@@ -17,6 +17,7 @@ class SpkDialog : public SpkWindow
     void AddWidget(QWidget*);
     void AddLayout(QLayout*);
     void AddSpacing(int);
+    void AddStretch(int a = 0);
     void SetMargin(int);
     void SetMargin(int, int, int, int);
     int  Exec();

inc/spktitlebar.h

@@ -50,7 +50,7 @@ class SpkTitleBar : public QWidget
     void SetTitle(QString t) { mTitle->setText(t); }
     QString GetTitle() { return mTitle->text(); }
     void SetUseIcon(bool t) { mIcon->setVisible(t); }
-    void SetLinkedWindow(QMainWindow *w) { mLinkedWindow = w; }
+    void SetLinkedWindow(SpkWindow *w) { mLinkedWindow = w; }
 
     QHBoxLayout *GetUserSpace() { return mUserSpace; }
   protected:
@@ -59,7 +59,7 @@ class SpkTitleBar : public QWidget
   private:
     QLabel *mIcon;
     QLabel *mTitle;
-    QMainWindow *mLinkedWindow;
+    SpkWindow *mLinkedWindow;
     QHBoxLayout *mMainLayout, *mUserSpace, *mBtnGroup;
     SpkTitleBarDefaultButton *mBtnMin, *mBtnMaxRestore, *mBtnClose;
 

inc/spkwindow.h

@@ -4,16 +4,16 @@
 
 #pragma once
 
-#include <QMainWindow>
 #include <QFrame>
 #include <QHBoxLayout>
 #include <QVBoxLayout>
 #include <QPushButton>
 #include <QLabel>
 #include <QCloseEvent>
-#include "spktitlebar.h"
 
-class SpkWindow : public QMainWindow
+class SpkTitleBar;
+
+class SpkWindow : public QWidget
 {
     Q_OBJECT
   public:
@@ -21,7 +21,7 @@ class SpkWindow : public QMainWindow
     static constexpr int BorderWidth = 7;
 
   private:
-    QWidget *mCentralWidget, *mUserCentralWidget;
+    QWidget *mUserCentralWidget;
     QVBoxLayout *mMainVLayout;
     SpkTitleBar *mTitleBarComponent;
     int mCornerRadius;
@@ -32,7 +32,7 @@ class SpkWindow : public QMainWindow
     bool mUseCustomEvents;
 
   public:
-    SpkWindow(QWidget *parent = nullptr, Qt::WindowFlags flags = Qt::WindowFlags());
+    SpkWindow(QWidget *parent = nullptr);
     ~SpkWindow() override;
     void SetCentralWidget(QWidget *);
     bool GetUseTitleBar();
@@ -62,4 +62,6 @@ class SpkWindow : public QMainWindow
 
   private:
     void PopulateUi();
+
+    void paintWindowBorder();
 };