SEXP
RGDAL_GenCMap(SEXP input1, SEXP input2, SEXP input3, SEXP output, SEXP nColors, SEXP setCMap) {
GDALRasterBand* band1 = getGDALRasterPtr(input1);
GDALRasterBand* band2 = getGDALRasterPtr(input2);
GDALRasterBand* band3 = getGDALRasterPtr(input3);
GDALColorTable ctab;
int ncol = asInteger(nColors);
if (ncol < 2 || ncol > 256)
error("Number of colors should range from 2 to 256");
installErrorHandler();
int err = GDALComputeMedianCutPCT(band1, band2, band3, NULL,
ncol, &ctab, NULL, NULL);
if (err == CE_Failure) {
uninstallErrorHandlerAndTriggerError();
error("Error generating color table");
}
uninstallErrorHandlerAndTriggerError();
if (output != R_NilValue) {
GDALRasterBand* target = getGDALRasterPtr(output);
installErrorHandler();
err = GDALDitherRGB2PCT(band1, band2, band3, target, &ctab, NULL, NULL);
if (err == CE_Failure) {
uninstallErrorHandlerAndTriggerError();
error("Image dithering failed");
}
uninstallErrorHandlerAndTriggerError();
if (asLogical(setCMap)) {
installErrorHandler();
err = GDALSetRasterColorTable(target, &ctab);
if (err == CE_Failure) {
uninstallErrorHandlerAndTriggerError();
warning("Unable to set color table");
}
uninstallErrorHandlerAndTriggerError();
}
}
return(GDALColorTable2Matrix(&ctab));
}
SEXP
RGDAL_GetColorTable(SEXP rasterObj) {
GDALRasterBandH rasterBand = getGDALRasterPtr(rasterObj);
GDALColorTableH ctab = GDALGetRasterColorTable(rasterBand);
if (ctab == NULL) return(R_NilValue);
return(GDALColorTable2Matrix(ctab));
}
SEXP
RGDAL_GetColorTable(SEXP rasterObj) {
GDALRasterBandH rasterBand = getGDALRasterPtr(rasterObj);
installErrorHandler();
GDALColorTableH ctab = GDALGetRasterColorTable(rasterBand);
uninstallErrorHandlerAndTriggerError();
if (ctab == NULL) return(R_NilValue);
return(GDALColorTable2Matrix(ctab));
}
