How to identify whether a page is color page or monochrome page?

Question

Could anyone tell me how to identify whether a page is color page or B/W page. I'm creating a plugin.
I tried using the following code
HDC hdcMem = CreateCompatibleDC(NULL);
if(!hdcMem){
PDPageRelease(objPDPage);
return FALSE;}
char  *palette = (char*)malloc(4);
ASFixedMatrix matrixFlipped;
PDPageGetFlippedMatrix(objPDPage,&matrixFlipped);
char *palette = (char*)malloc(4);PDPageDrawContentsToWindow(objPDPage,(void*)NULL,(void*)hdc,false,&matrixFlipped,(ASFixedRect*)NULL,NULL,NULL); 
if(PDPageGetPalette(objPDPage,(void*)hdc,palette)){
here the PDPageGetPalette always returns false.
I don't know whats wrong in the code. Please help me.
Any other simpler way to active my task would be appreciable.
Thanks in advance.

Answer 1

HDC hdcMem = CreateCompatibleDC(NULL); 
char*palette = (char*)malloc(4);                                      
ASFixedMatrix matrixFlipped;
PDPageGetFlippedMatrix(objPDPage,&matrixFlipped);
PDPageDrawContentsToWindow(objPDPage,(void*)NULL,(void*)hdc,false,&matrixFlipped,(ASFixedRect*)NULL,NULL,NULL);
if(PDPageGetPalette(objPDPage,(void*)hdc,palette))
here the PDPageGetPalette() always returns false. Whats wrong with the code?
I want to check the palette values.
Please help.