int main(int argc,char *argv[])
{
FILE *fin,*fout;
png_structp read_ptr,write_ptr;
fin = fopen("pngtest.png","rb");
fout = fopen("out.png","wb");
png_infop read_info_ptr,write_info_ptr;
read_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, png_voidp_NULL,png_error_ptr_NULL, png_error_ptr_NULL);
read_info_ptr = png_create_info_struct(read_ptr);
write_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, png_voidp_NULL,
png_error_ptr_NULL, png_error_ptr_NULL);
write_info_ptr = png_create_info_struct(write_ptr);
png_init_io(read_ptr, fin);
png_init_io(write_ptr, fout);
png_read_info(read_ptr,read_info_ptr);
png_write_info_before_PLTE(write_ptr, write_info_ptr);
return 0;
}
void PNGAPI
png_write_info(png_structp png_ptr, png_infop info_ptr)
{
#if defined(PNG_WRITE_TEXT_SUPPORTED) || defined(PNG_WRITE_sPLT_SUPPORTED)
int i;
#endif
png_debug(1, "in png_write_info");
if (png_ptr == NULL || info_ptr == NULL)
return;
png_write_info_before_PLTE(png_ptr, info_ptr);
if (info_ptr->valid & PNG_INFO_PLTE)
png_write_PLTE(png_ptr, info_ptr->palette,
(png_uint_32)info_ptr->num_palette);
else if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
png_error(png_ptr, "Valid palette required for paletted images");
#ifdef PNG_WRITE_tRNS_SUPPORTED
if (info_ptr->valid & PNG_INFO_tRNS)
{
#ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
/* Invert the alpha channel (in tRNS) */
if ((png_ptr->transformations & PNG_INVERT_ALPHA) &&
info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
{
int j;
for (j = 0; j<(int)info_ptr->num_trans; j++)
info_ptr->trans_alpha[j] =
(png_byte)(255 - info_ptr->trans_alpha[j]);
}
#endif
png_write_tRNS(png_ptr, info_ptr->trans_alpha, &(info_ptr->trans_color),
info_ptr->num_trans, info_ptr->color_type);
}
#endif
#ifdef PNG_WRITE_bKGD_SUPPORTED
if (info_ptr->valid & PNG_INFO_bKGD)
png_write_bKGD(png_ptr, &(info_ptr->background), info_ptr->color_type);
#endif
#ifdef PNG_WRITE_hIST_SUPPORTED
if (info_ptr->valid & PNG_INFO_hIST)
png_write_hIST(png_ptr, info_ptr->hist, info_ptr->num_palette);
#endif
#ifdef PNG_WRITE_oFFs_SUPPORTED
if (info_ptr->valid & PNG_INFO_oFFs)
png_write_oFFs(png_ptr, info_ptr->x_offset, info_ptr->y_offset,
info_ptr->offset_unit_type);
#endif
#ifdef PNG_WRITE_pCAL_SUPPORTED
if (info_ptr->valid & PNG_INFO_pCAL)
png_write_pCAL(png_ptr, info_ptr->pcal_purpose, info_ptr->pcal_X0,
info_ptr->pcal_X1, info_ptr->pcal_type, info_ptr->pcal_nparams,
info_ptr->pcal_units, info_ptr->pcal_params);
#endif
#ifdef PNG_WRITE_sCAL_SUPPORTED
if (info_ptr->valid & PNG_INFO_sCAL)
png_write_sCAL_s(png_ptr, (int)info_ptr->scal_unit,
info_ptr->scal_s_width, info_ptr->scal_s_height);
#endif /* sCAL */
#ifdef PNG_WRITE_pHYs_SUPPORTED
if (info_ptr->valid & PNG_INFO_pHYs)
png_write_pHYs(png_ptr, info_ptr->x_pixels_per_unit,
info_ptr->y_pixels_per_unit, info_ptr->phys_unit_type);
#endif /* pHYs */
#ifdef PNG_WRITE_tIME_SUPPORTED
if (info_ptr->valid & PNG_INFO_tIME)
{
png_write_tIME(png_ptr, &(info_ptr->mod_time));
png_ptr->mode |= PNG_WROTE_tIME;
}
#endif /* tIME */
#ifdef PNG_WRITE_sPLT_SUPPORTED
if (info_ptr->valid & PNG_INFO_sPLT)
for (i = 0; i < (int)info_ptr->splt_palettes_num; i++)
png_write_sPLT(png_ptr, info_ptr->splt_palettes + i);
#endif /* sPLT */
#ifdef PNG_WRITE_TEXT_SUPPORTED
/* Check to see if we need to write text chunks */
for (i = 0; i < info_ptr->num_text; i++)
{
png_debug2(2, "Writing header text chunk %d, type %d", i,
info_ptr->text[i].compression);
/* An internationalized chunk? */
if (info_ptr->text[i].compression > 0)
{
#ifdef PNG_WRITE_iTXt_SUPPORTED
/* Write international chunk */
png_write_iTXt(png_ptr,
info_ptr->text[i].compression,
info_ptr->text[i].key,
info_ptr->text[i].lang,
info_ptr->text[i].lang_key,
info_ptr->text[i].text);
/* Mark this chunk as written */
if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE)
info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
else
info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR;
#else
png_warning(png_ptr, "Unable to write international text");
#endif
}
/* If we want a compressed text chunk */
else if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_zTXt)
{
#ifdef PNG_WRITE_zTXt_SUPPORTED
/* Write compressed chunk */
png_write_zTXt(png_ptr, info_ptr->text[i].key,
info_ptr->text[i].text, 0,
info_ptr->text[i].compression);
/* Mark this chunk as written */
info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR;
#else
png_warning(png_ptr, "Unable to write compressed text");
#endif
}
else if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE)
{
#ifdef PNG_WRITE_tEXt_SUPPORTED
/* Write uncompressed chunk */
png_write_tEXt(png_ptr, info_ptr->text[i].key,
info_ptr->text[i].text,
0);
/* Mark this chunk as written */
info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
#else
/* Can't get here */
png_warning(png_ptr, "Unable to write uncompressed text");
#endif
}
}
#endif /* tEXt */
#ifdef PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
if (info_ptr->unknown_chunks_num)
{
png_unknown_chunk *up;
png_debug(5, "writing extra chunks");
for (up = info_ptr->unknown_chunks;
up < info_ptr->unknown_chunks + info_ptr->unknown_chunks_num;
up++)
{
int keep = png_handle_as_unknown(png_ptr, up->name);
if (keep != PNG_HANDLE_CHUNK_NEVER &&
up->location &&
(up->location & PNG_HAVE_PLTE) &&
!(up->location & PNG_HAVE_IDAT) &&
!(up->location & PNG_AFTER_IDAT) &&
((up->name[3] & 0x20) || keep == PNG_HANDLE_CHUNK_ALWAYS ||
(png_ptr->flags & PNG_FLAG_KEEP_UNSAFE_CHUNKS)))
{
png_write_chunk(png_ptr, up->name, up->data, up->size);
}
}
}
#endif
}
