diff --git a/README.md b/README.md
index 0030aef..ea28a0e 100644
--- a/README.md
+++ b/README.md
@@ -13,6 +13,7 @@ DFL is a Win32 windowing library for the D language.
 ![screen shot](./examples/tooltip/image/screenshot.png "screen shot")
 ![screen shot](./examples/progressbar/image/screenshot3.png "screen shot")
 ![screen shot](./examples/clipboard/image/screenshot.png "screen shot")
+![screen shot](./examples/clippingform/image/screenshot.png "screen shot")
 
 ## Recent major features
 - DUB is available for DFL.
diff --git a/examples/clippingform/.gitignore b/examples/clippingform/.gitignore
new file mode 100644
index 0000000..60a5f2a
--- /dev/null
+++ b/examples/clippingform/.gitignore
@@ -0,0 +1,16 @@
+.dub
+docs.json
+__dummy.html
+docs/
+/hello_dfl
+hello_dfl.so
+hello_dfl.dylib
+hello_dfl.dll
+hello_dfl.a
+hello_dfl.lib
+hello_dfl-test-*
+*.exe
+*.pdb
+*.o
+*.obj
+*.lst
diff --git a/examples/clippingform/.vscode/launch.json b/examples/clippingform/.vscode/launch.json
new file mode 100644
index 0000000..6ccc1fa
--- /dev/null
+++ b/examples/clippingform/.vscode/launch.json
@@ -0,0 +1,13 @@
+{
+    "version": "0.2.0",
+    "configurations": [
+        {
+            "name": "C++ Launch (Windows) clippingform",
+            "type": "cppvsdbg",
+            "request": "launch",
+            "cwd": "${workspaceRoot}",
+            "program": "./bin/clippingform_sample.exe",
+            "console": "internalConsole"
+        }
+    ]
+}
\ No newline at end of file
diff --git a/examples/clippingform/.vscode/tasks.json b/examples/clippingform/.vscode/tasks.json
new file mode 100644
index 0000000..b7eda52
--- /dev/null
+++ b/examples/clippingform/.vscode/tasks.json
@@ -0,0 +1,20 @@
+{
+	"version": "2.0.0",
+	"tasks": [
+		{
+			"type": "dub",
+			"run": false,
+			"cwd": ".",
+			"compiler": "$current",
+			"archType": "$current",
+			"buildType": "$current",
+			"configuration": "$current",
+			"problemMatcher": [
+				"$dmd"
+			],
+			"group": "build",
+			"label": "dub: Build clippingform_sample",
+			"detail": "dub build --compiler=dmd.EXE -a=x86_64 -b=debug -c=application"
+		}
+	]
+}
\ No newline at end of file
diff --git a/examples/clippingform/README.md b/examples/clippingform/README.md
new file mode 100644
index 0000000..b1a86ca
--- /dev/null
+++ b/examples/clippingform/README.md
@@ -0,0 +1,2 @@
+# Screen Shot
+![screen shot](./image/screenshot.png "screen shot")
diff --git a/examples/clippingform/clippingform.code-workspace b/examples/clippingform/clippingform.code-workspace
new file mode 100644
index 0000000..7e696bc
--- /dev/null
+++ b/examples/clippingform/clippingform.code-workspace
@@ -0,0 +1,12 @@
+{
+	"folders": [
+		{
+			"path": "."
+		}
+	],
+	"settings": {
+		"d.projectImportPaths": [
+			"..\\..\\..\\dfl\\source"
+		]
+	}
+}
\ No newline at end of file
diff --git a/examples/clippingform/dub.json b/examples/clippingform/dub.json
new file mode 100644
index 0000000..95d8658
--- /dev/null
+++ b/examples/clippingform/dub.json
@@ -0,0 +1,16 @@
+{
+	"authors": ["haru-s"],
+	"copyright": "Copyright (C) 2023 haru-s",
+	"description": "DFL sample code.",
+	"name": "clippingform_sample",
+	"targetType": "executable",
+	"targetPath": "bin",
+	"dependencies": {
+		"dfl": {
+			"path": "../../../dfl"
+		}
+	},
+	"lflags-windows-x86_omf-dmd":    ["/exet:nt/su:windows:6.0"],
+	"lflags-windows-x86_mscoff-dmd": ["/SUBSYSTEM:WINDOWS", "/ENTRY:mainCRTStartup"],
+	"lflags-windows-x86_64-dmd":     ["/SUBSYSTEM:WINDOWS", "/ENTRY:mainCRTStartup"]
+}
\ No newline at end of file
diff --git a/examples/clippingform/image/clipping.bmp b/examples/clippingform/image/clipping.bmp
new file mode 100644
index 0000000..6a0c7ed
Binary files /dev/null and b/examples/clippingform/image/clipping.bmp differ
diff --git a/examples/clippingform/image/screenshot.png b/examples/clippingform/image/screenshot.png
new file mode 100644
index 0000000..3c92cdf
Binary files /dev/null and b/examples/clippingform/image/screenshot.png differ
diff --git a/examples/clippingform/shell.bat b/examples/clippingform/shell.bat
new file mode 100644
index 0000000..49ab56b
--- /dev/null
+++ b/examples/clippingform/shell.bat
@@ -0,0 +1,3 @@
+set dmd_path=c:\d\dmd2\windows
+set dmc_path=c:\dmc\dm
+cmd
diff --git a/examples/clippingform/source/clippingform_sample.d b/examples/clippingform/source/clippingform_sample.d
new file mode 100644
index 0000000..c733f6a
--- /dev/null
+++ b/examples/clippingform/source/clippingform_sample.d
@@ -0,0 +1,34 @@
+import dfl;
+
+version(Have_dfl) // For DUB.
+{
+}
+else
+{
+	pragma(lib, "dfl.lib");
+}
+
+class MainForm : ClippingForm
+{
+	private Image _image;
+
+	public this()
+	{
+		this.text = "Clipping Form example";
+		this.size = Size(300, 200);
+		this.clipping = new Bitmap(r".\image\clipping.bmp"); // White is transparent.
+		this.click ~= (Control c, EventArgs e) {
+			this.close();
+		};
+	}
+}
+
+static this()
+{
+	Application.enableVisualStyles();
+}
+
+void main()
+{
+	Application.run(new MainForm());
+}
diff --git a/source/dfl/clippingform.d b/source/dfl/clippingform.d
index ea766e2..e371d56 100644
--- a/source/dfl/clippingform.d
+++ b/source/dfl/clippingform.d
@@ -1,44 +1,9 @@
 module dfl.clippingform;
 
-private import dfl.all, dfl.internal.winapi;
+private import dfl.all;
 private import dfl.internal.dlib : toI32;
 private import core.memory;
-
-private extern (Windows)
-{
-	struct RGNDATAHEADER
-	{
-		DWORD dwSize;
-		DWORD iType;
-		DWORD nCount;
-		DWORD nRgnSize;
-		RECT rcBound;
-	}
-	
-	struct RGNDATA
-	{
-		RGNDATAHEADER rdh;
-		ubyte[1] Buffer;
-	}
-	
-	struct XFORM
-	{
-		FLOAT eM11;
-		FLOAT eM12;
-		FLOAT eM21;
-		FLOAT eM22;
-		FLOAT eDx;
-		FLOAT eDy;
-	}
-	
-	enum {RDH_RECTANGLES = 1}
-	enum {BI_RGB = 0}
-	enum {DIB_RGB_COLORS = 0}
-	
-	HRGN ExtCreateRegion(void*, DWORD, RGNDATA*);
-	int GetDIBits(HDC, HBITMAP, UINT, UINT, PVOID, LPBITMAPINFO, UINT);
-}
-
+private import core.sys.windows.windows;
 
 ///
 struct RegionRects
@@ -48,19 +13,16 @@ private:
 	size_t _capacity = 0;
 	size_t _width = 0;
 	size_t _height = 0;
+
 public:
-	
-	
-	const @property
-	size_t width()
+	@property size_t width() const
 	{
 		return _width;
 	}
 	
 	
 	///
-	const @property
-	size_t height()
+	@property size_t height() const
 	{
 		return _height;
 	}
@@ -115,8 +77,7 @@ public:
 	
 	
 	///
-	@property
-	Region region()
+	@property Region region()
 	{
 		if (_rgn is null) return null;
 		with (_rgn.rdh)
@@ -167,6 +128,7 @@ public:
 				add(sx, y-1, x-1, y);
 			}
 		}
+		DeleteDC(hDC);
 		return region;
 	}
 	
@@ -199,40 +161,40 @@ public:
 
 
 ///
-class ClippingForm: Form
+class ClippingForm : Form
 {
 private:
-	Image m_Image;
-	RegionRects m_RegionRects;
+	Image _image;
+	RegionRects _regionRects;
+
 protected:
 	override void createParams(ref CreateParams cp)
 	{
 		super.createParams(cp);
 		cp.style = WS_EX_TOPMOST | WS_EX_TOOLWINDOW;
 	}
+
 public:
-	
-	
 	///
 	@property Image clipping()
 	{
-		return m_Image;
+		return _image;
 	}
 	
 	
 	/// ditto
 	@property void clipping(Image img)
 	{
-		m_Image = img;
+		_image = img;
 	}
 	
 	
 	///
 	override void onHandleCreated(EventArgs ea)
 	{
-		if (m_Image)
+		if (_image)
 		{
-			region = m_RegionRects.create(m_Image);
+			region = _regionRects.create(_image);
 		}
 		super.onHandleCreated(ea);
 	}
@@ -241,9 +203,9 @@ public:
 	///
 	override void onPaint(PaintEventArgs pea)
 	{
-		if (m_Image)
+		if (_image)
 		{
-			m_Image.draw(pea.graphics, Point(0,0));
+			_image.draw(pea.graphics, Point(0,0));
 		}
 		else
 		{
diff --git a/source/dfl/package.d b/source/dfl/package.d
index 3f46054..2e87027 100644
--- a/source/dfl/package.d
+++ b/source/dfl/package.d
@@ -6,7 +6,7 @@
 module dfl;
 
 public import dfl.base, dfl.menu, dfl.control, dfl.usercontrol,
-	dfl.form, dfl.drawing, dfl.panel, dfl.event,
+	dfl.form, dfl.drawing, dfl.panel, dfl.event, dfl.clippingform,
 	dfl.application, dfl.button, dfl.socket,
 	dfl.timer, dfl.environment, dfl.label, dfl.textboxbase, dfl.textbox,
 	dfl.listbox, dfl.splitter, dfl.groupbox, dfl.messagebox,