static int
png2vips_image( Read *read, VipsImage *out )
{
int interlace_type = png_get_interlace_type( read->pPng, read->pInfo );
VipsImage **t = (VipsImage **)
vips_object_local_array( VIPS_OBJECT( out ), 3 );
if( interlace_type != PNG_INTERLACE_NONE ) {
/* Arg awful interlaced image. We have to load to a huge mem
* buffer, then copy to out.
*/
t[0] = vips_image_new_memory();
if( png2vips_header( read, t[0] ) ||
png2vips_interlace( read, t[0] ) ||
vips_image_write( t[0], out ) )
return( -1 );
}
else {
t[0] = vips_image_new();
if( png2vips_header( read, t[0] ) ||
vips_image_generate( t[0],
NULL, png2vips_generate, NULL,
read, NULL ) ||
vips_sequential( t[0], &t[1],
"tile_height", 8,
"access", read->readbehind ?
VIPS_ACCESS_SEQUENTIAL :
VIPS_ACCESS_SEQUENTIAL_UNBUFFERED,
NULL ) ||
vips_image_write( t[1], out ) )
return( -1 );
}
return( 0 );
}
/* Read a PNG file (header) into a VIPS (header).
*/
static int
png2vips( Read *read, int header_only )
{
int bands, bpp, type;
if( setjmp( read->pPng->jmpbuf ) )
return( -1 );
png_init_io( read->pPng, read->fp );
png_read_info( read->pPng, read->pInfo );
/* png_get_channels() gives us 1 band for palette images ... so look
* at colour_type for output bands.
*/
switch( read->pInfo->color_type ) {
case PNG_COLOR_TYPE_PALETTE:
bands = 3;
/* Don't know if this is really correct. If there are
* transparent pixels, assume we're going to output RGBA.
*/
if( read->pInfo->num_trans )
bands = 4;
break;
case PNG_COLOR_TYPE_GRAY: bands = 1; break;
case PNG_COLOR_TYPE_GRAY_ALPHA: bands = 2; break;
case PNG_COLOR_TYPE_RGB: bands = 3; break;
case PNG_COLOR_TYPE_RGB_ALPHA: bands = 4; break;
default:
im_error( "im_png2vips", "%s", _( "unsupported color type" ) );
return( -1 );
}
/* 8 or 16 bit.
*/
bpp = read->pInfo->bit_depth > 8 ? 2 : 1;
if( bpp > 1 ) {
if( bands < 3 )
type = IM_TYPE_GREY16;
else
type = IM_TYPE_RGB16;
}
else {
if( bands < 3 )
type = IM_TYPE_B_W;
else
type = IM_TYPE_sRGB;
}
/* Expand palette images.
*/
if( read->pInfo->color_type == PNG_COLOR_TYPE_PALETTE )
png_set_expand( read->pPng );
/* Expand <8 bit images to full bytes.
*/
if( read->pInfo->bit_depth < 8 ) {
png_set_packing( read->pPng );
png_set_shift( read->pPng, &(read->pInfo->sig_bit) );
}
/* If we're an INTEL byte order machine and this is 16bits, we need
* to swap bytes.
*/
if( read->pInfo->bit_depth > 8 && !im_amiMSBfirst() )
png_set_swap( read->pPng );
/* Set VIPS header.
*/
im_initdesc( read->out,
read->pInfo->width, read->pInfo->height, bands,
bpp == 1 ? IM_BBITS_BYTE : IM_BBITS_SHORT,
bpp == 1 ? IM_BANDFMT_UCHAR : IM_BANDFMT_USHORT,
IM_CODING_NONE, type, 1.0, 1.0, 0, 0 );
if( !header_only ) {
if( png_set_interlace_handling( read->pPng ) > 1 ) {
if( png2vips_interlace( read ) )
return( -1 );
}
else {
if( png2vips_noninterlace( read ) )
return( -1 );
}
}
return( 0 );
}