Pass Image to .dll

Question

Hi,
I found quite a lot of topics on passing images to a .dll, however I didn't quite find an answer to my problem.
I want to pass a reference to an Image to a .dll.
The reference is of Type void* myImage in the LabView configure-dll, and when I create a .c file, it changes to uintptr_t* myImage.
If I pass that reference to the function
     void*  IMAQ_STDCALL imaqImageToArray(const Image* image, Rect rect, int* columns, int* rows);
with the conversion (Image*)myImage, the function will always return a NULL-Pointer.
I know I can call all these function as VIs outside a dll, however I would really prefer calling them inside the .dll.
Some posts sounded as if this weren't possible, however I guess it has to be, as all the Vision-VIdo it.
Thanks for your ideas
Greetings
Solved!
Go to Solution.

Answer 1

Hi,
solved it myself, sorry to have bothered you!
For veryone who might run into the same problem:
Use the Image Datatype to Image Cluster.vi and pass the cluster to the .dll. It is in the folder National Instruments/LabViewX.x/vi.lib/vision/DatatypeCoversion
In the generated c-code, there will be a struct:
typedef struct {
    LStrHandle elt1;
    uint32_t elt2;
    } TD1;
where elt1 is the name of the picture and elt2 the address.
Say you've gt a function
void __declspec(dllexport) MyFunction(TD1 *ImageCluster, otherparameters)
you can now use the address elt2 to call tne imaq functions eg. like this:
Image *testImage;
testImage = (Image*) ImageCluster -> elt2;
uint8_t *ptr;
ptr = (uint8_t*) imaqImageToArray(testImage,imaqMakeRect(0,0,50,50),&x,&y);
Sorry again
Greetings