bmpReader, to make Nuke (The Foundry) handle .bmp reading through freeimage

bmpReader.cpp

// vim: set hls is si et sw=4 sts=4 nu:
#include <stdio.h>
#include <string.h>
 
#include <FreeImage.h>
 
#include "DDImage/DDWindows.h"
#include "DDImage/Reader.h"
#include "DDImage/Row.h"
#include "DDImage/Knob.h"
#include "DDImage/Knobs.h"
#include "DDImage/Thread.h"
#include "DDImage/Memory.h"
 
using namespace DD::Image;
 
class BmpReader : public Reader
{
    private:
        unsigned int m_bpp;
        unsigned int m_width;
        unsigned int m_height;
        FIBITMAP* m_bitmap;
 
        FreeImageIO m_io;
    public:
        BmpReader(Read*);
        ~BmpReader();
 
        void engine(int y, int x, int r, ChannelMask, Row&);
        static const Description d;
};
 
BmpReader::BmpReader(Read* r) : Reader(r)
{
    FreeImage_Initialise(TRUE);
 
    m_bpp = 0;
    m_width = 0;
    m_height = 0;
 
    m_bitmap = FreeImage_Load(FIF_BMP, filename(), BMP_DEFAULT);
    if( m_bitmap ) {
        m_bpp = FreeImage_GetBPP(m_bitmap);
        m_width = FreeImage_GetWidth(m_bitmap);
        m_height = FreeImage_GetHeight(m_bitmap);
 
        //printf("bpp: %d\n", m_bpp);
        //printf("width: %d\n", m_width);
        //printf("height: %d\n", m_height);
 
        set_info(m_width, m_height, m_bpp/8);
    }
    else {
    }
}
 
BmpReader::~BmpReader()
{
    if( m_bitmap ) {
        FreeImage_Unload(m_bitmap);
        m_bitmap = NULL;
    }
    FreeImage_DeInitialise();
}
 
void BmpReader::engine(int y, int x, int r, ChannelMask channels, Row& row)
{
    BYTE* pixel = FreeImage_GetScanLine(m_bitmap, y);
 
    // BGR !!!!
    if( channels & Mask_Blue ) {
        from_byte(Chan_Blue, row.writable(Chan_Blue)+x, pixel+0, NULL, r-x, m_bpp/8);
    }
    if( channels & Mask_Green ) {
        from_byte(Chan_Green, row.writable(Chan_Green)+x, pixel+1, NULL, r-x, m_bpp/8);
    }
    if( channels & Mask_Red ) {
        from_byte(Chan_Red, row.writable(Chan_Red)+x, pixel+2, NULL, r-x, m_bpp/8);
    }
}
 
static Reader* build(Read* iop, int fd, const unsigned char* b, int n)
{
    close(fd);
    return new BmpReader(iop);
}
 
static bool test(int fd, const unsigned char* block, int length)
{
    FreeImage_Initialise(TRUE);
    FREE_IMAGE_FORMAT fif = FIF_UNKNOWN;
    FIMEMORY* hmem = FreeImage_OpenMemory((BYTE *)block, length);
    fif = FreeImage_GetFileTypeFromMemory(hmem);
    FreeImage_DeInitialise();
 
    return(fif == FIF_BMP);
}
 
const Reader::Description BmpReader::d("bmp\0", build, test);