Add the MakeCompexPixelFunc that make a complex out of a real and ima…

…g bands

README.txt

@@ -26,6 +26,8 @@ List of pixel functions
 :"imag":
     extract imaginary part from a single raster band (0 for
     non-complex)
+:"makecomplex":
+    make a complex band merging two bands used as real and imag values
 :"mod":
     extract module from a single raster band (real or complex)
 :"phase":

autotest/gcore/data/pixfun_makecomplex.vrt

@@ -0,0 +1,19 @@
+<VRTDataset rasterXSize="20" rasterYSize="20">
+  <VRTRasterBand dataType="CFloat32" band="1" subClass="VRTDerivedRasterBand">
+    <Description>Make complex</Description>
+    <PixelFunctionType>makecomplex</PixelFunctionType>
+    <SourceTransferType>CFloat32</SourceTransferType>
+    <SimpleSource>
+      <SourceFilename relativeToVRT="1">int32.tif</SourceFilename>
+      <SourceBand>1</SourceBand>
+      <SrcRect xOff="0" yOff="0" xSize="20" ySize="20"/>
+      <DstRect xOff="0" yOff="0" xSize="20" ySize="20"/>
+    </SimpleSource>
+    <SimpleSource>
+      <SourceFilename relativeToVRT="1">int32.tif</SourceFilename>
+      <SourceBand>1</SourceBand>
+      <SrcRect xOff="0" yOff="0" xSize="20" ySize="20"/>
+      <DstRect xOff="0" yOff="0" xSize="20" ySize="20"/>
+    </SimpleSource>
+  </VRTRasterBand>
+</VRTDataset>

autotest/gcore/pixfun.py

@@ -135,6 +135,31 @@ def pixfun_imag_r():
     return 'success'
 
 
+###############################################################################
+# Verify imaginary part extraction from a real dataset.
+
+def pixfun_makecomplex():
+
+    filename = 'data/pixfun_makecomplex.vrt'
+    ds = gdal.OpenShared(filename, gdal.GA_ReadOnly)
+    if ds is None:
+        gdaltest.post_reason('Unable to open "%s" dataset.' % filename)
+        return 'fail'
+    data = ds.GetRasterBand(1).ReadAsArray()
+
+    reffilename = 'data/int32.tif'
+    refds = gdal.Open(reffilename)
+    if refds is None:
+        gdaltest.post_reason('Unable to open "%s" dataset.' % reffilename)
+        return 'fail'
+    refdata = refds.GetRasterBand(1).ReadAsArray()
+
+    if not numpy.allclose(data, refdata + 1j * refdata):
+        return 'fail'
+
+    return 'success'
+
+
 ###############################################################################
 # Verify modulus extraction from a complex (float) dataset.
 
@@ -731,6 +756,7 @@ def pixfun_dB2pow():
     pixfun_real_r,
     pixfun_imag_c,
     pixfun_imag_r,
+    pixfun_makecomplex,
     pixfun_mod_c,
     pixfun_mod_r,
     pixfun_phase_c,

pixelfunctions.c

@@ -99,6 +99,39 @@ CPLErr ImagPixelFunc(void **papoSources, int nSources, void *pData,
 } /* ImagPixelFunc */
 
 
+CPLErr MakeComplexPixelFunc(void **papoSources, int nSources, void *pData,
+                       int nXSize, int nYSize,
+                       GDALDataType eSrcType, GDALDataType eBufType,
+                       int nPixelSpace, int nLineSpace)
+{
+    int ii, iLine, iCol;
+    double adfPixVal[2];
+
+    void *pReal = papoSources[0];
+    void *pImag = papoSources[1];
+
+    /* ---- Init ---- */
+    if (nSources != 2) return CE_Failure;
+
+    /* ---- Set pixels ---- */
+    for( iLine = 0, ii= 0; iLine < nYSize; ++iLine ) {
+        for( iCol = 0; iCol < nXSize; ++iCol, ++ii ) {
+
+            /* Source raster pixels may be obtained with SRCVAL macro */
+            adfPixVal[0] = SRCVAL(pReal, eSrcType, ii); /* re */
+            adfPixVal[1] = SRCVAL(pImag, eSrcType, ii); /* im */
+
+            GDALCopyWords(adfPixVal, GDT_CFloat64, 0,
+                          ((GByte *)pData) + nLineSpace * iLine +
+                          iCol * nPixelSpace, eBufType, nPixelSpace, 1);
+        }
+    }
+
+    /* ---- Return success ---- */
+    return CE_None;
+} /* MakeComplexPixelFunc */
+
+
 CPLErr ModulePixelFunc(void **papoSources, int nSources, void *pData,
                        int nXSize, int nYSize,
                        GDALDataType eSrcType, GDALDataType eBufType,
@@ -800,6 +833,7 @@ CPLErr CPL_STDCALL GDALRegisterDefaultPixelFunc()
 {
     GDALAddDerivedBandPixelFunc("real", RealPixelFunc);
     GDALAddDerivedBandPixelFunc("imag", ImagPixelFunc);
+    GDALAddDerivedBandPixelFunc("makecomplex", MakeComplexPixelFunc);
     GDALAddDerivedBandPixelFunc("mod", ModulePixelFunc);
     GDALAddDerivedBandPixelFunc("phase", PhasePixelFunc);
     GDALAddDerivedBandPixelFunc("conj", ConjPixelFunc);