Perhaps your code got corrupted with copy-and-paste, with a lot of missing underscores and stars. This is my first attempt at a first clean-up:
(*rotate function*)
rotate[inImage_, rot_,
Offset_] := {Offset[[1]] +
Sqrt[(inImage[[1]] - Offset[[1]])^2 + (inImage[[2]] -
Offset[[2]])^2]*
Cos[ArcTan[(inImage[[1]] - Offset[[1]]), (inImage[[2]] -
Offset[[2]])] - rot],
Offset[[2]] +
Sqrt[(inImage[[1]] - Offset[[1]])^2 + (inImage[[2]] -
Offset[[2]])^2]*
Sin[ArcTan[(inImage[[1]] - Offset[[1]]), (inImage[[2]] -
Offset[[2]])] - rot]};
(*Nearest Neighbour Interpolation*)
NearNeigh[NewPoints_,
InImage_] := {InImage[[Round[NewPoints[[1]]],
Round[NewPoints[[2]]]]]};
(*Module to rotate an Image by a specific Angle,InterpMethod is \
unused atm*)
Rotier[InImage_, Rotatio_, InterpMethod_] :=
Module[{OutImage, PunkteNeu, PunkteAlt, ImageHeight, ImageWidth,
Offset, Corners, MinX, MaxX, MinY, MaxY},
{ImageWidth, ImageHeight} = ImageDimensions[InImage];
(*I want to rotate around middle for now*)
Offset = {ImageWidth/2. + 0.5, ImageHeight/2. + 0.5};
(*Here i check the Corners of the DestinationImage*)
Corners = {{1, ImageWidth, 1, ImageWidth}, {1, 1, ImageHeight,
ImageHeight}};
Corners = rotate[Corners, Rotatio, Offset];
MinX = Floor[Min[Corners[[1, All]]]];
MaxX = Ceiling[Max[Corners[[1, All]]]];
MinY = Floor[Min[Corners[[2, All]]]];
MaxY = Ceiling[Max[Corners[[2, All]]]];
(*Here i create a Matrix with the coordinates of the destination \
Image so i can inversewarp the image*)
PunkteAlt = {Table[i, {i, MinX, MaxX}, {j, MinY, MaxY}],
Table[i, {j, MinX, MaxX}, {i, MinY, MaxY}]};
(*I rotate every coordinate of the destination Image to get the \
coresponding souce image coordinates*)
PunkteNeu = rotate[PunkteAlt, Rotatio, Offset];
(*Because i get noninteger values i have to interpolate.but this \
doesn't work atm*) OutImage = NearNeigh[PunkteNeu, InImage];
Return[OutImage];];(*End Module Rotier*)
Still, I can't figure out how you are going to use these functions. In rotate you seem to assume that InImage is a vector, because you make numerical computations with its first and second element. In Rotier you take the ImageDimensions of InImage, which assumes that InImage is an image, which has no first and second element.
A general advice: inside the code it is better to avoid variable names that start with a capital letter, to avoid conflit with built-in functions. For example, Offset, with capitalized initial, is a built-in function.
