新增qwt源码版本

qwtdemo/examples/controls/knobtab.cpp

@@ -0,0 +1,17 @@
+#include "knobtab.h"
+#include "knobbox.h"
+#include <qlayout.h>
+
+KnobTab::KnobTab( QWidget *parent ):
+    QWidget( parent )
+{
+    QGridLayout *layout = new QGridLayout( this );
+
+    const int numRows = 3;
+    for ( int i = 0; i < 2 * numRows; i++ )
+    {
+        KnobBox *knobBox = new KnobBox( this, i );
+        layout->addWidget( knobBox, i / numRows, i % numRows );
+    }
+}
+