filegif.C

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#include "assets.h"
#include "file.h"
#include "filetiff.h"
#include "interlacemodes.h"
#include "vframe.h"


FileGIF::FileGIF(Asset *asset)
 : FileBase(asset)
{
        reset_parameters();
        asset->video_data = 1;
        asset->format = FILE_GIF;
}

FileGIF::~FileGIF()
{
        close_file();
}

int FileGIF::reset_parameters_derived()
{
        data = 0;
}

int FileGIF::open_file(int rd, int wr)
{
        this->rd = rd;
        this->wr = wr;

// skip header for write
        if(wr)
        {
        }
        else
        if(rd)
        {
                return read_header();
        }
        return 0;
}

int64_t FileGIF::get_video_length()
{
        return -1;    // infinity
// should be determined by whether the GIF is animated
}

int64_t FileGIF::get_memory_usage()
{
// give buffer length plus padding
        if(data)
                return asset->width * asset->height * sizeof(VPixel);
        else
                return 256;
}

int FileGIF::close_file_derived()
{
        if(data) delete data;
        reset_parameters();
}

int FileGIF::read_header()
{
        GIF *stream;

        if(!(stream = GIFOpen(asset->path, "r")))
        {
                perror("FileGIF::read_header");
                return 1;
        }
        
        GIFGetField(stream, GIFTAG_IMAGEWIDTH, &(asset->width));
        GIFGetField(stream, GIFTAG_IMAGELENGTH, &(asset->height));
        asset->interlacemode = BC_ILACE_MODE_NOTINTERLACED;
        asset->layers = 1;

        GIFClose(stream);
        return 0;
}


VFrame* FileGIF::read_frame(int use_alpha, int use_float)
{
        read_raw();
        return data;
}

int FileGIF::read_raw()
{
        if(!data)
        {
// read the raw data
                GIF *stream;
                unsigned char *raw_data;
                int i;

                if(!(stream = GIFOpen(asset->path, "r")))
                {
                        perror("FileGIF::read_raw");
                        return 1;
                }

                raw_data = new unsigned char[asset->width * asset->height * 4];
                GIFReadRGBAImage(stream, asset->width, asset->height, (uint32*)raw_data, 0);

                GIFClose(stream);

// convert to a Bcast 2000 Frame
                data = new VFrame(asset->width, asset->height);

                for(i = 0; i < asset->height; i++)
                {
                        import_row(data->rows[asset->height - i - 1], &raw_data[i * asset->width * 4]);
                }

// delete temporary buffers
                delete raw_data;
        }
        return 0;
}

int FileGIF::import_row(VPixel *output, unsigned char *row_pointer)
{
        for(int i = 0, j = 0; j < asset->width; j++)
        {
#if (VMAX == 65535)
                output[j].red =  ((VWORD)row_pointer[i++]) << 8;
                output[j].green =  ((VWORD)row_pointer[i++]) << 8;
                output[j].blue = ((VWORD)row_pointer[i++]) << 8;
                output[j].alpha = ((VWORD)row_pointer[i++]) << 8;
#else
                output[j].red =  (VWORD)row_pointer[i++];
                output[j].green =  (VWORD)row_pointer[i++];
                output[j].blue = (VWORD)row_pointer[i++];
                output[j].alpha = (VWORD)row_pointer[i++];
#endif
        }
}

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