reference: low-level Drag & Drop examples

git-svn-id: svn://ultimatepp.org/upp/trunk@4025 f0d560ea-af0d-0410-9eb7-867de7ffcac7

reference/DragAndDrop2/main.cpp

@@ -0,0 +1,97 @@
+#include <CtrlLib/CtrlLib.h>
+
+using namespace Upp;
+
+struct MyAppData {
+	String text;
+	Color  color;
+};
+
+struct MyApp : TopWindow {
+	Point     pos;
+	MyAppData data;
+	Point     dragpos;
+	
+	virtual void CancelMode();
+	virtual void Paint(Draw& w);
+	virtual void DragAndDrop(Point p, PasteClip& clip);
+	virtual void DragLeave();
+	virtual void LeftDrag(Point p, dword keyflags);
+	virtual String GetSelectionData(const String& fmt) const;
+
+	MyApp();
+};
+
+void MyApp::CancelMode()
+{
+	dragpos = Null;
+	Refresh();
+}
+
+void MyApp::DragAndDrop(Point p, PasteClip& clip)
+{
+	if(clip.Accept("MyAppData")) {
+		String bin = clip;
+		if(bin.GetLength() > sizeof(Color)) { // prudent check
+			pos = p;
+			memcpy(&data.color, ~bin, sizeof(Color));
+			data.text = bin.Mid(sizeof(Color));
+		}
+		Refresh();
+	}
+	if(AcceptText(clip)) {
+		pos = p;
+		data.text = GetString(clip);
+	}
+	dragpos = clip.IsAccepted() ? p : Null;
+	Refresh();
+}
+
+void MyApp::DragLeave()
+{
+	dragpos = Null;
+	Refresh();
+}
+
+String MyApp::GetSelectionData(const String& fmt) const
+{
+	if(fmt == "MyAppData") {
+		String bin;
+		bin.Cat((byte *)&data.color, sizeof(data.color));
+		bin.Cat(data.text);
+		return bin;
+	}
+	return GetTextClip(data.text, fmt);
+}
+
+void MyApp::LeftDrag(Point p, dword keyflags)
+{
+	Size sz(128, 64);
+	ImageDraw iw(sz);
+	iw.DrawRect(sz, Black());
+	iw.Alpha().DrawRect(sz, Black());
+	iw.Alpha().DrawText(0, 0, data.text, Courier(14), White());
+	DoDragAndDrop(String("MyAppData;") + ClipFmtsText(), iw);
+}
+
+void MyApp::Paint(Draw& w)
+{
+	w.DrawRect(GetSize(), SColorPaper());
+	w.DrawText(pos.x, pos.y, data.text, StdFont(), data.color);
+	if(!IsNull(dragpos))
+		w.DrawRect(RectC(dragpos.x - 1, dragpos.y - 1, 3, 3), LtBlue);
+}
+
+MyApp::MyApp()
+{
+	data.text = FormatIntRoman(Random(2000));
+	data.color = Color(Random() & 127, Random() & 127, Random() & 127);
+	pos = Point(10, 10);
+	SetRect(0, 0, 500, 100);
+	dragpos = Null;
+}
+
+GUI_APP_MAIN
+{
+	MyApp().Run();
+}