diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..1caac49
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,3 @@
+# IDE tool cache
+.idea/*
+.vscode/*
diff --git a/windows.go b/windows.go
index 36e604f..02ed988 100644
--- a/windows.go
+++ b/windows.go
@@ -68,6 +68,9 @@ func Capture(x, y, width, height int) (*image.RGBA, error) {
 	}
 	defer win.SelectObject(memory_device, old)
 
+	if x == width || y == height {
+		return nil, errors.New("size failed (width or height are consistent)")
+	}
 	if !win.BitBlt(memory_device, 0, 0, int32(width), int32(height), hdc, int32(x), int32(y), win.SRCCOPY) {
 		return nil, errors.New("BitBlt failed")
 	}