GDAL warp in C++

Question

What is the equivalent to the following GDAL terminal command in C++? I looked into GDAL C++ API, but could not figure it out.

gdalwarp -te xmin ymin xmax ymax -ts 1 1 -r max input.vrt output.vrt

for now I have the following:

GDALDataset  *poDataset = (GDALDataset *) GDALOpen(inputFilename, GA_ReadOnly);
string count_name = num_str1 + num_str2 + num_str3 + num_str4;
const char* args[] = { "-te", num_str1+" "+num_str2+" "+num_str3+" "+num_str4 , NULL };
const char* args[] = { "-ts" , "1 1" , NULL };
const char* args[] = {  "-r" , "max" , NULL };
GDALWarpAppOptions* psOptions = GDALWarpAppOptionsNew((char**)args, NULL);
GDALDatasetH pooDataset = GDALWarp("/", NULL, 1, &poDataset, psOptions, NULL);

https://gdal.org/tutorials/warp_tut.html#overview has a simple reprojection tutorial but it does not show how to use -te,-ts,-r options.

Answer 1

(This should be a comment, but too long and too formatted.)

NB: This is using a Swift wrapper for GDAL, so not actual C++, but hopefully it will give you some idea of how I use GDALWarp(). In particular, my use case DOES use the -r option.

(Note the opts, here, is the Swift array, and cOpts is the equivalent C array.)

I hope this helps.

In brief, I just generate each element of each option as an element of the array. So in the case of the -r option, both the -r flag and the cubic value are consecutive elements of the options arrary.

        guard let destSRSWKT = srs.wkt() else { return (false, nil) }
        let opts = ["-t_srs", destSRSWKT, "-r", "cubic", "-dstalpha", "-of", driver.nameShort()]

        return withMutableArrayOfMutableCStrings(opts) { (cOpts) in
            var optionalSourceDSRef: GDALDatasetH? = _ds
            return withUnsafeMutablePointer(to: &optionalSourceDSRef) { (dsPointer) in
                let warpOpts = GDALWarpAppOptionsNew(cOpts, nil)
                if let _ = reprojectDelegate {
                    //  Not possible to pass a closure as a C function parameter if the closure contains any context
                    //  so have to convert anything required in the closure to pointer to pass in
                    //  and then within the closure convert back to object
                    let selfPtrOuter = UnsafeMutableRawPointer(Unmanaged.passUnretained(self).toOpaque())
                    GDALWarpAppOptionsSetProgress(warpOpts, { (progress, message, selfPtrInner) in
                        if let selfPtrInner = selfPtrInner {
                            let mySelf = Unmanaged<RasterDataset>.fromOpaque(selfPtrInner).takeUnretainedValue()
                            if let repDel = mySelf.reprojectDelegate {
                                return repDel.reprojectProgressShouldContinue(progress)
                            }
                        }
                        return 1
                    }, selfPtrOuter)
                }
                var err: Int32 = 0
                let destDSRef = GDALWarp(url.path, nil, 1, dsPointer, warpOpts, &err)
                GDALWarpAppOptionsFree(warpOpts)