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/* sane - Scanner Access Now Easy.
Copyright (C) 2019 Touboul Nathane
Copyright (C) 2019 Thierry HUCHARD <thierry@ordissimo.com>
This file is part of the SANE package.
SANE is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free
Software Foundation; either version 3 of the License, or (at your
option) any later version.
SANE is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
for more details.
You should have received a copy of the GNU General Public License
along with sane; see the file COPYING.
If not, see <https://www.gnu.org/licenses/>.
This file implements a SANE backend for eSCL scanners. */
#define DEBUG_DECLARE_ONLY
#include "../include/sane/config.h"
#include "escl.h"
#include "../include/sane/sanei.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#if(defined HAVE_LIBPNG)
#include <png.h>
#endif
#include <setjmp.h>
#if(defined HAVE_LIBPNG)
/**
* \fn SANE_Status escl_sane_decompressor(escl_sane_t *handler)
* \brief Function that aims to decompress the png image to SANE be able to read the image.
* This function is called in the "sane_read" function.
*
* \return SANE_STATUS_GOOD (if everything is OK, otherwise, SANE_STATUS_NO_MEM/SANE_STATUS_INVAL)
*/
SANE_Status
get_PNG_data(capabilities_t *scanner, int *width, int *height, int *bps)
{
unsigned int w = 0;
unsigned int h = 0;
int components = 3;
unsigned char *surface = NULL; /* Image data */
unsigned int i = 0;
png_byte magic[8];
SANE_Status status = SANE_STATUS_GOOD;
// read magic number
fread (magic, 1, sizeof (magic), scanner->tmp);
// check for valid magic number
if (!png_check_sig (magic, sizeof (magic)))
{
DBG( 1, "Escl Png : PNG error is not a valid PNG image!\n");
status = SANE_STATUS_INVAL;
goto close_file;
}
// create a png read struct
png_structp png_ptr = png_create_read_struct
(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
if (!png_ptr)
{
DBG( 1, "Escl Png : PNG error create a png read struct\n");
status = SANE_STATUS_INVAL;
goto close_file;
}
// create a png info struct
png_infop info_ptr = png_create_info_struct (png_ptr);
if (!info_ptr)
{
DBG( 1, "Escl Png : PNG error create a png info struct\n");
png_destroy_read_struct (&png_ptr, NULL, NULL);
status = SANE_STATUS_INVAL;
goto close_file;
}
// initialize the setjmp for returning properly after a libpng
// error occurred
if (setjmp (png_jmpbuf (png_ptr)))
{
png_destroy_read_struct (&png_ptr, &info_ptr, NULL);
if (surface)
free (surface);
DBG( 1, "Escl Png : PNG read error.\n");
status = SANE_STATUS_INVAL;
goto close_file;
}
// setup libpng for using standard C fread() function
// with our FILE pointer
png_init_io (png_ptr, scanner->tmp);
// tell libpng that we have already read the magic number
png_set_sig_bytes (png_ptr, sizeof (magic));
// read png info
png_read_info (png_ptr, info_ptr);
int bit_depth, color_type;
// get some useful information from header
bit_depth = png_get_bit_depth (png_ptr, info_ptr);
color_type = png_get_color_type (png_ptr, info_ptr);
// convert index color images to RGB images
if (color_type == PNG_COLOR_TYPE_PALETTE)
png_set_palette_to_rgb (png_ptr);
else if (color_type != PNG_COLOR_TYPE_RGB && color_type != PNG_COLOR_TYPE_RGB_ALPHA)
{
DBG(1, "PNG format not supported.\n");
status = SANE_STATUS_NO_MEM;
goto close_file;
}
if (color_type == PNG_COLOR_TYPE_RGB_ALPHA)
components = 4;
else
components = 3;
if (png_get_valid (png_ptr, info_ptr, PNG_INFO_tRNS))
png_set_tRNS_to_alpha (png_ptr);
if (bit_depth == 16)
png_set_strip_16 (png_ptr);
else if (bit_depth < 8)
png_set_packing (png_ptr);
// update info structure to apply transformations
png_read_update_info (png_ptr, info_ptr);
// retrieve updated information
png_get_IHDR (png_ptr, info_ptr,
(png_uint_32*)(&w),
(png_uint_32*)(&h),
&bit_depth, &color_type,
NULL, NULL, NULL);
*bps = components;
// we can now allocate memory for storing pixel data
surface = (unsigned char *)malloc (sizeof (unsigned char) * w
* h * components);
if (!surface) {
DBG( 1, "Escl Png : texels Memory allocation problem\n");
status = SANE_STATUS_NO_MEM;
goto close_file;
}
png_bytep *row_pointers;
// setup a pointer array. Each one points at the begening of a row.
row_pointers = (png_bytep *)malloc (sizeof (png_bytep) * h);
if (!row_pointers) {
DBG( 1, "Escl Png : row_pointers Memory allocation problem\n");
free(surface);
status = SANE_STATUS_NO_MEM;
goto close_file;
}
for (i = 0; i < h; ++i)
{
row_pointers[i] = (png_bytep)(surface +
((h - (i + 1)) * w * components));
}
// read pixel data using row pointers
png_read_image (png_ptr, row_pointers);
// If necessary, trim the image.
surface = escl_crop_surface(scanner, surface, w, h, components, width, height);
if (!surface) {
DBG( 1, "Escl Png : Surface Memory allocation problem\n");
status = SANE_STATUS_NO_MEM;
goto close_file;
}
free (row_pointers);
close_file:
if (scanner->tmp)
fclose(scanner->tmp);
scanner->tmp = NULL;
return (status);
}
#else
SANE_Status
get_PNG_data(capabilities_t __sane_unused__ *scanner,
int __sane_unused__ *width,
int __sane_unused__ *height,
int __sane_unused__ *bps)
{
return (SANE_STATUS_INVAL);
}
#endif
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