root/trunk/orca/gl/png_save.c

//============================================================================
//
// Orca PNG Writer
//
//============================================================================


#include <png.h>
#include "gx.h"


/**
  Gets image data through the virtual methods and writes a PNG file.
*/
int png_save( FILE* fp, OImage* img )
{
    png_structp png;
    png_infop info;
    png_bytep row_pointer;
    int color_type;
    int bpl;
    int i;

    png = png_create_write_struct( PNG_LIBPNG_VER_STRING, 0, 0, 0 );
    if( ! png )
        return 0;

    info = png_create_info_struct( png );
    if( ! info )
    {
        png_destroy_write_struct( &png, 0 );
        return 0;
    }

    if( setjmp( png_jmpbuf( png ) ) )
    {
error:
        /* If we get here, we had a problem writing the file */
        png_destroy_write_struct( &png, &info );
        return 0;
    }

    png_init_io( png, fp ); /* Using standard C streams */
    //png_set_write_fn(png, (void*) user_io_ptr, user_write_fn, user_io_flush);

#if 0
    // Set up info for write (func calls png_set_IHDR).
    func( png, info, data );
    int png_transforms = PNG_TRANSFORM_IDENTITY;
    png_write_png( png, info, png_transforms, 0 );
#else

    /*
      PNG_COLOR_TYPE_GRAY, PNG_COLOR_TYPE_GRAY_ALPHA, PNG_COLOR_TYPE_PALETTE,
      PNG_COLOR_TYPE_RGB, or PNG_COLOR_TYPE_RGB_ALPHA.
    */
    switch( img->format )
    {
        case OR_IMG_GRAY:
            bpl = img->width;
            color_type = PNG_COLOR_TYPE_GRAY;
            break;

        case OR_IMG_RGB:
            bpl = img->width * 3;
            color_type = PNG_COLOR_TYPE_RGB;
            break;

        case OR_IMG_RGBA:
            bpl = img->width * 4;
            color_type = PNG_COLOR_TYPE_RGB_ALPHA;
            break;

        default: goto error;
    }

    png_set_IHDR( png, info, img->width, img->height, 8, color_type,
                  PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_DEFAULT,
                  PNG_FILTER_TYPE_DEFAULT );

    png_write_info( png, info );

    row_pointer = (png_byte*) (img + 1);
    for( i = 0; i < img->height; i++ )
    {
        png_write_row( png, row_pointer );
        //png_write_rows( png, &row_pointer, 1 );
        row_pointer += bpl;
    }

    png_write_end( png, info );
#endif
    

    png_destroy_write_struct( &png, &info );

    return 1;
}


/*EOF*/