static FreeImageEngine()
{
// Check if FreeImage.dll is present and cancel setting the callback function if not
if (!IsAvailable)
{
return;
}
// Create a delegate (function pointer) to 'OnMessage'
outputMessageFunction = new OutputMessageFunction(OnMessage);
// Set the callback
FreeImage.SetOutputMessage(outputMessageFunction);
}
static FreeImageEngine()
{
// Check if FreeImage.dll is present and cancel setting the callbackfuntion if not
if (!IsAvailable)
{
return;
}
// Create a delegate (function pointer) to 'OnMessage'
outputMessageFunction = new OutputMessageFunction(OnMessage);
// Set the callback
FreeImage.SetOutputMessage(outputMessageFunction);
}
/// <summary>
/// Internal callback
/// </summary>
private static void OnMessage(FREE_IMAGE_FORMAT fif, string message)
{
// Get a local copy of the multicast-delegate
OutputMessageFunction m = Message;
// Check the local copy instead of the static instance
// to prevent a second thread from setting the delegate
// to null, which would cause a null reference exception
if (m != null)
{
// Invoke the multicast-delegate
m.Invoke(fif, message);
}
}
private static void InitializeMessage()
{
if (null == outputMessageFunction)
{
lock (outputMessageFunctionLock)
{
if (null == outputMessageFunction)
{
FreeImage.ValidateAvailability();
try
{
// Create a delegate (function pointer) to 'OnMessage'
outputMessageFunction =
delegate(FREE_IMAGE_FORMAT fif, string message)
{
LastErrorMessage = message;
// Get a local copy of the multicast-delegate
OutputMessageFunction m = FreeImageEngine.message;
// Check the local copy instead of the static instance
// to prevent a second thread from setting the delegate
// to null, which would cause a nullreference exception
if (m != null)
{
// Invoke the multicast-delegate
m.Invoke(fif, message);
}
};
// Set the callback
FreeImage.SetOutputMessage(outputMessageFunction);
}
catch
{
outputMessageFunction = null;
throw;
}
}
}
}
}
internal static extern void SetOutputMessage(OutputMessageFunction omf);
internal static extern void SetOutputMessage(OutputMessageFunction outputMessageFunction);
static FreeImage()
{
// Check if FreeImage.dll is present and cancel setting the callbackfuntion if not
if (!IsAvailable())
{
return;
}
// Create a delegate (function pointer) to 'OnMessage'
outputMessageFunction = new OutputMessageFunction(OnMessage);
// Pin the object so the garbage collector does not move it around in memory
outputMessageHandle = GCHandle.Alloc(outputMessageFunction, GCHandleType.Normal);
// Set the callback
SetOutputMessage(outputMessageFunction);
}
