[Lcms-user] passing Arrays of fixed sizes to cmsDoTransform

[Roger B. <gr...@vi...>]

I am still having difficulty with calling cmsDoTransform with
variable-length arrays of bytes.
I always get MemoryAccessViolations errors.

Today's preliminary testing suggest I would have better luck using fixed
size arrays.

What will happen if I break down my bitmap image in fixed size chunks?

Suppose image size = 104 bytes 
Suppose I chose Fixed array size = 64 bytes

My new C# pinvoke function signature would look like this :

[DllImport(@lcms2Path, CallingConvention = CallingConvention.Winapi)]
static extern void cmsDoTransform(
            IntPtr xform,
            [MarshalAs(UnmanagedType.LPArray, SizeParamIndex = 64), In]
byte[] inputColors,
            [MarshalAs(UnmanagedType.LPArray, SizeParamIndex = 64), Out]
byte[] outputColors,
            uint Size);

Then, I will iterate cmsDoTransform 2x with 64 bytes each.

Upon return, it will be up to my code to throw away the remainder 2 x 64 =
128 - 104 -> 24 bytes.

I guess I will have to pad these extra 24 bytes with 00.

But, would this work?

At least, this approach has the merit of avoiding MemoryAccessViolations.

Best / Roger