Returning an array or string using C++

[Dargor]

Hi,

I'm trying to write a function in C++ that goes through all pixels in a bitmap and returns the x,y, and RGBA value of all these pixels. The problem is, I don't know what and how to return the result.

I want to use the returned value in Ruby.

Here's what I have right now:

 

extern "C" _declspec (dllexport) BOOL GetMappedPixels(long object){

    RGSSBMINFO *bitmap = ((RGSSBITMAP*) (object<<1)) -> bm -> bminfo;

    DWORD rowsize;

    DWORD width, height;

    LPBYTE row;

 

    // *********************

    // my string or array variable?

 

    long x, y;

 

    if(!bitmap) return false;

    width = bitmap -> infoheader -> biWidth;

    height = bitmap -> infoheader -> biHeight;

    rowsize = width * 4;

 

    row = (LPBYTE) (bitmap -> firstRow);

    for ( y = 0; y < (int) height; y++) {

        LPBYTE thisrow = row;

        for ( x = 0; x < (int) width; x++) {

 

            // *************************

            // add xyrgba values to my string or array?

 

            thisrow += 4;

        }

        row -= rowsize;

    }

    return colors;

}

 

The goal behind this is to create a palette system. The code above would gather all pixels in the bitmap and once I have this information back in Ruby, I want to assign an index to each color and map the index to the x/y values returned by the code above.

So, how can I do that?

Thanks in advance.
- Dargor

 

[Yeyinde]

If my understanding is correct, you will need to return a pointer to the data ('p' as the fourth Win32API argument). You might need to store it in a C string instead of a C array, but it's not too hard to convert a Ruby string to a Ruby array once you have it.