add QAD::VirtualKeyboard library, vkbd for widgets with JSON-based description

libs/virtual_keyboard/virtual_keyboard.h

@@ -0,0 +1,54 @@
+#ifndef virtual_keyboard_h
+#define virtual_keyboard_h
+
+#include "qad_virtual_keyboard_export.h"
+
+#include <QWidget>
+#include <qad_timers.h>
+
+namespace Ui {
+class VirtualKeyboard;
+};
+class VirtualKeyboardLayout;
+
+
+class QAD_VIRTUAL_KEYBOARD_EXPORT VirtualKeyboard: public QWidget, private IndexedTimer<> {
+	Q_OBJECT
+	Q_PROPERTY(QString layoutPath READ layoutPath WRITE setLayoutPath)
+
+public:
+	VirtualKeyboard(QWidget * parent = nullptr);
+	~VirtualKeyboard();
+
+	const QString & layoutPath() const { return layout_path_; }
+	void setLayoutPath(const QString & path);
+
+	bool isAlwaysVisible() const { return always_visible; }
+	void setAlwaysVisible(bool yes);
+
+	void setEnabled(bool yes);
+	void setDisabled(bool yes);
+
+protected:
+	bool eventFilter(QObject * o, QEvent * e) override;
+	void changeEvent(QEvent * e) override;
+	void resizeEvent(QResizeEvent * e) override;
+	void showEvent(QShowEvent * e) override;
+
+	void init(QString layout_path);
+	void destroy();
+	void adjust();
+	void setKeyboardVisible(bool yes);
+
+private:
+	Ui::VirtualKeyboard * ui       = nullptr;
+	VirtualKeyboardLayout * layout = nullptr;
+	QWidget * watched              = nullptr;
+	QString layout_path_;
+	bool first_show = true, always_visible = false;
+	int prev_width = -1;
+
+private slots:
+};
+
+#endif