The action menu item Release View will dispose off the current image.

This article generalizes from there and presents a testbed for loading, capturing, and saving images in various graphical formats including conversion of an image to a usable icon.

A GDI (Graphical Device Interface) window is specified by a window handle.

To operate on a GDI object (basically a.NET control) using a GDI method, we need to use its GDI window handle.

To simplify access, a namespace called Dll is defined whose class names are the same as the DLLs to be accessed.

Each class then defines the desired interop DLL entry points and equivalent C methods.

This method captures an image within a specified rectangle within a specified window.

Second, using the window device context, a compatible capture device context is created, and a GDI bitmap is created and associated with this capture device context.

Third, the specified rectangle in the window device context is copied to the capture device context thus populating the GDI bitmap.

Finally, the GDI bitmap is converted to a GDI bitmap and returned to the caller.

It picks up the width and height of the desktop, a window handle for the desktop and then uses capture method Window to return a bitmap of the desktop.

This information can also be attained using the method System.Windows.Forms.Screen.PrimaryScreen.Bounds.

It picks up the bounds of the desktop working area based on a specified control in that working area and then uses capture method Window to return a bitmap of the desktop.

The second method Control captures a specified portion of the control or whats underneath the control.

To perform this capture and procure the desired bitmap, the control must be hidden prior to capture.

It handles one image at a time and does not as yet include image editing functions.

Load and save support a number of image formats allowing image format conversion.

The form was used for testing, and has very elemental error checking and recovery capabilities.

Desktop or desktop area image capture is accomplished by clicking the appropriate action menu item, Capture Desktop or Capture Desktop Work Area respectively.

Opening the viewport causes the forms transparency key to be set to the background color of the form.

This makes the area underneath the client area of the form visible to the user.

The user moves the form over and sizes the form to encompass the desired selection.

Capture of the image is accomplished by clicking action menu item Capture View.

This causes the view to be captured and the viewport to be closed.

Image Capture By Handle Failed. Uopilot