To retain color space value for Monochrome images during flattening.

Question

In our project, we are extracting image content from PDF file and doing some raster operation by using LeadTool and then flattening the processed image in PDF file.
Input PDf file: One page which has monochrome image
For extracting image content from PDF file, we are using below Acro Plugin API:
AVConversionConvertFromPDFWithHandler
After this, we will perform some raster operations by using LeadTool and then flattening will happen.
While doing flatten we are performing below operations in sequence:
1. Set bitspercomponent  =1.
2. Create a new color table using DeviceRGB.
3. Create image by using below Acro Plugin API:
pdeimage = PDEImageCreate(&attrs, sizeof(attrs), &matrix, 0, cols1, NULL, &fil, asstm, NULL, 0);
4. Add image in PDF content.
Now flattening is successful, but monochrome(Original Image format) is changed to RGB. We want to retain the color space(DeviceGrey).
We have tried the below solution to retain the color space:
1. Using the old image's color space value for new image creation. But this gives inverted color(Black to White and vice versa)
Please help us to retain the color space while flattening.

Answer 1

We are using JPG file format.
Please find below the code portions which we used to add image in PDF file,
//Read Image Data
========================================================================================== ==================
ASBool ret = TRUE;
// analyze img
ASInt32 index = 0, quadSize = 0;
BITMAPFILEHEADER* bmfh = NULL;
// BITMAPFILEHEADER
if(  !bQuadSize )
  bmfh = (BITMAPFILEHEADER*)img;
  index += sizeof(BITMAPFILEHEADER);
// BITMAPINFOHEADER
BITMAPINFOHEADER* bmih = (BITMAPINFOHEADER*)(img+index);
index += sizeof(BITMAPINFOHEADER);
// RGBQUAD
if( !bQuadSize )
  quadSize = bmfh->bfOffBits - sizeof(BITMAPFILEHEADER) - sizeof(BITMAPINFOHEADER);
else
  quadSize = size -  bmih->biSize -  bmih->biSizeImage;
ASInt32 rgbquadNum = 0;
char* quad = NULL;
if (quadSize > 0)
  rgbquadNum = quadSize/sizeof(RGBQUAD);
  quad = (char*)(img+index);
  index += quadSize;
// Image
//ULONG imgSize = size - bmfh->bfOffBits;
char* image = (img+index);
DURING
   if(!pd)
    E_RETURN(FALSE);
   PDPage pp = PDDocAcquirePage(pd, page-1); // Get Page(PDPage) of specified page number
   PDEContent pdeContent = PDPageAcquirePDEContent(pp, gExtensionID); // Get PageContent(PDEContent)
   ASInt32 numElems = PDEContentGetNumElems(pdeContent);  // Get PageContent num
   // Check BitMap width, height, biXPelsPerMeter, biYPelsPerMeter changed
   ASFixedRect mb;
   PDPageGetMediaBox(pp, &mb);
   ASFixedRect chgMediaBox;
   memset(&chgMediaBox, 0 , sizeof(ASFixedRect));
   if (paperSizeChangeType == PAPERSIZE_SIZESPECIFICATION)
    chgMediaBox.right = width;
    chgMediaBox.top = height;
   // Get PDEImage's Attributes & Filters & ColorSpace from Old Image in PDF file
========================================================================================== ===================================
   PDEElement pdeElement;
   ASInt32 importIndex;
   ASInt32 type;
   PDEImageAttrs attrs1;
   PDEColorSpace cols1;
   //ASAtom colname;
   PDEFilterArray fil1[20];
   ASInt32 filNum1;
   ASFixedMatrix matrix1;
   bool isTransformedPage = false; //EV2.8.02000_19651_Retain color space_20141016
   for (int i = 0; i < numElems; i++)
    pdeElement = PDEContentGetElem(pdeContent, i);
    PDEObject obj=_objHelper.TraversePDPageContentsImage((PDEObject)pdeElement);
     if(obj == NULL)
      continue;
     pdeElement= (PDEElement)obj;
    type = PDEObjectGetType((PDEObject)pdeElement);
    if (type == kPDEImage)
     // Get Attr
     PDEImageGetAttrs((PDEImage)pdeElement, &attrs1, sizeof(PDEImageAttrs));
     // Get ColorSpace
     cols1 = PDEImageGetColorSpace((PDEImage)pdeElement);
     // Get Filter Array
     filNum1 = PDEImageGetFilterArray((PDEImage)pdeElement, fil1);
     // Get ASFixedMatrix
     PDEElementGetMatrix(pdeElement, &matrix1);
     //EV2.8.02000_19651_Retain color space_20141016 - Start
     if (matrix1.a < 0 || matrix1.b < 0 ||
                    matrix1.c < 0 || matrix1.d < 0 ||
                    matrix1.h < 0 || matrix1.v < 0)
      isTransformedPage = true;
     //EV2.8.02000_19651_Retain color space_20141016 - End
     // Set Import and Delete Index
     importIndex = i;
     break;
   // Create image data (for PDEImage)
========================================================================================== =================================
   ASInt32 bitPerComponent = bmih->biBitCount;
   ASInt32 bitWidth = 0;
   ASInt32 width1 = bmih->biWidth;
   ASInt32 height1 = bmih->biHeight;
   // Create image size
   if (bitPerComponent == 1)
    if (width1%8)
     bitWidth = (width1/8) + 1;
    else
     bitWidth = width1/8;
   else if (bitPerComponent == 4)
    if (width1%2)
     bitWidth = (width1/2)+1;
    else
     bitWidth = width1/2;
   else if (bitPerComponent == 8)
    bitWidth = width1;
   else if (bitPerComponent == 32)
    bitWidth = width1*4;
   else // if (bitPerComponent == 24)
    bitWidth = width1*3;
   ASInt32 imgSize4Acrobat = height1 * bitWidth;
   char* image4Acrobat = (char*)ASmalloc(imgSize4Acrobat);
   if( image4Acrobat == NULL )
    E_RETURN(FALSE);
   memset(image4Acrobat, 0, imgSize4Acrobat);
   // Create image
   ASInt32 nokori = (bitWidth)%4;
   ASInt32 bitWidth4hokan = 0;
   if (nokori)
    bitWidth4hokan = bitWidth + (4-nokori);
   else
    bitWidth4hokan = bitWidth;
   ASInt32 hbw = 0;
   ASInt32 hbw4hokan = 0;
   if (bitPerComponent == 1)
    for (int k = height1-1, l = 0; k >= 0; k--, l++)
     hbw = l*bitWidth;
     hbw4hokan = k*bitWidth4hokan;
     memcpy((image4Acrobat+hbw), (image+hbw4hokan), bitWidth);
   else if (bitPerComponent == 4)
    for (int k = height1-1, l = 0; k >= 0; k--, l++)
     hbw = l*bitWidth;
     hbw4hokan = k*bitWidth4hokan;
     memcpy((image4Acrobat+hbw), (image+hbw4hokan), bitWidth);
   else if (bitPerComponent == 8)
    for (int k = height1-1, l = 0; k >= 0; k--, l++)
     hbw = l*bitWidth;
     hbw4hokan = k*bitWidth4hokan;
     memcpy((image4Acrobat+hbw), (image+hbw4hokan), bitWidth);
   else if (bitPerComponent == 32)
    for (int k = height1-1, l = 0; k >= 0; k--, l++)
     hbw = l*bitWidth;
     hbw4hokan = k*bitWidth4hokan;
     for (int kk = 0; kk < bitWidth; kk += 4)
      *(image4Acrobat+hbw+kk) = *(image+hbw4hokan+(kk+3));
      *(image4Acrobat+hbw+kk+1) = *(image+hbw4hokan+(kk+2));
      *(image4Acrobat+hbw+kk+2) = *(image+hbw4hokan+(kk+1));
      *(image4Acrobat+hbw+kk+3) = *(image+hbw4hokan+(kk));
   else
    for (int k = height1-1, l = 0; k >= 0; k--, l++)
     hbw = l*bitWidth;
     hbw4hokan = k*bitWidth4hokan;
     for (int kk = 0; kk < bitWidth; kk += 3)
      *(image4Acrobat+hbw+kk) = *(image+hbw4hokan+(kk+2));
      *(image4Acrobat+hbw+kk+1) = *(image+hbw4hokan+(kk+1));
      *(image4Acrobat+hbw+kk+2) = *(image+hbw4hokan+(kk));
   //Invert Image Data
========================================================================================== ================================
   for(int it = 0; it < imgSize4Acrobat; it++)
      image4Acrobat[it] = 255 -image4Acrobat[it];
   // Open Image Data
========================================================================================== ================================
   ASStm asstm = ASMemStmRdOpen(image4Acrobat, imgSize4Acrobat);  
   // Create PDEImage Attribute etc.
========================================================================================== ================================
   PDEImageAttrs attrs;
   memset(&attrs, 0, sizeof(PDEImageAttrs)); // necessary
   attrs.width = width1;
   attrs.height = height1;
   if (bitPerComponent == 1) {
    attrs.bitsPerComponent = 1;
    if (rgbquadNum) {
     attrs.flags = kPDEImageIsIndexed | kPDEImageExternal; // Indicates image uses an indexed color space.
    } else {
     attrs.flags = kPDEImageExternal; // Indicates image is an XObject.
     // B&W
   } else if (bitPerComponent == 4) {
    attrs.bitsPerComponent = 4;
    if (rgbquadNum) {
     attrs.flags = kPDEImageIsIndexed | kPDEImageExternal; // Indicates image uses an indexed color space.
    } else {
     attrs.flags = kPDEImageExternal; // Indicates image is an XObject.
   } else if (bitPerComponent == 8) {
    attrs.bitsPerComponent = 8;
    if (rgbquadNum) {
     attrs.flags = kPDEImageIsIndexed | kPDEImageExternal; // Indicates image uses an indexed color space.
    } else {
     attrs.flags = kPDEImageExternal; // Indicates image is an XObject.
   } else if (bitPerComponent == 32) {
    // not support (acrobat)
   } else { // (bitPerComponent == 24)
    attrs.flags = kPDEImageExternal;  // Indicates image is an XObject.
    attrs.bitsPerComponent = 8;
   // matrix
   ASFixedMatrix matrix;
   memcpy(&matrix, &matrix1, sizeof(matrix1));
   if (paperSizeChangeType == PAPERSIZE_SIZESPECIFICATION)
    matrix.a = chgMediaBox.right;
    matrix.b = 0;
    matrix.c = 0;
    matrix.d = chgMediaBox.top;
    matrix.h = 0;
    matrix.v = 0;
   // Filter
   PDEFilterArray fil;
   memset (&fil, 0, sizeof (PDEFilterArray));
   PDEFilterSpec spec;
   memset (&spec, 0, sizeof (PDEFilterSpec));
   memcpy(&fil, &fil1, sizeof(PDEFilterArray));
   CosDoc cosDoc;
   CosObj cosDict;
   // Build the CosObj for the filter specification
   cosDoc = PDDocGetCosDoc(pd);
   cosDict = CosNewDict(cosDoc, false, 2);
   CosDictPut(cosDict, ASAtomFromString("K"), CosNewInteger (cosDoc, false, -1));
   CosDictPut(cosDict, ASAtomFromString("Columns"), CosNewInteger (cosDoc, false, width1));
   //memset the filterspec so there are no garbage values if we leave members empty
   spec.encodeParms = cosDict;
   spec.decodeParms = cosDict;
   spec.name = ASAtomFromString("CCITTFaxDecode"); 
   fil.spec[0] = spec;
   // Create PDEImage
========================================================================================== =================================
   PDEImage pdeimage;
   pdeimage = PDEImageCreate(&attrs, sizeof(attrs), &matrix, 0, cols1, NULL, &fil, asstm, NULL, 0);
   // Delete PDEImage at importIndex(==j) of page -> Delete old image in PDF file
========================================================================================== ====================
   PDEContentRemoveElem(pdeContent, importIndex);
   // Add PDEImage
========================================================================================== ==========================
   PDEContentAddElem(pdeContent, importIndex, (PDEElement)pdeimage);
   PDPageSetPDEContent (pp, gExtensionID);
   PDPageReleasePDEContent(pp, gExtensionID);
   // Release object
   PDERelease((PDEObject)pdeimage);
   PDPageNotifyContentsDidChangeEx(pp, TRUE);
   PDPageRelease(pp);
   ASStmClose(asstm);
   if (image4Acrobat)
    ASfree(image4Acrobat);
   if (lookupTable)
    ASfree(lookupTable);
  HANDLER
   ret = FALSE;
  END_HANDLER
return ret;