zint/backend/png.c

/* png.c - Handles output to PNG file */

/*
    libzint - the open source barcode library
    Copyright (C) 2009-2021 Robin Stuart <rstuart114@gmail.com>

    Redistribution and use in source and binary forms, with or without
    modification, are permitted provided that the following conditions
    are met:

    1. Redistributions of source code must retain the above copyright
       notice, this list of conditions and the following disclaimer.
    2. Redistributions in binary form must reproduce the above copyright
       notice, this list of conditions and the following disclaimer in the
       documentation and/or other materials provided with the distribution.
    3. Neither the name of the project nor the names of its contributors
       may be used to endorse or promote products derived from this software
       without specific prior written permission.

    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
    ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
    IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
    ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
    FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
    DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
    OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
    HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
    LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
    OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
    SUCH DAMAGE.
 */
/* vim: set ts=4 sw=4 et : */

#include <stdio.h>
#ifdef _MSC_VER
#include <fcntl.h>
#include <io.h>
#include <malloc.h>
#endif
#include "common.h"

#ifndef NO_PNG
#include <png.h>
#include <zlib.h>
#include <setjmp.h>

#define SSET	"0123456789ABCDEF"

struct mainprog_info_type {
    long width;
    long height;
    FILE *outfile;
    jmp_buf jmpbuf;
};

static void writepng_error_handler(png_structp png_ptr, png_const_charp msg) {
    struct mainprog_info_type *graphic;

    fprintf(stderr, "writepng libpng error: %s (F30)\n", msg);
    fflush(stderr);

    graphic = (struct mainprog_info_type*) png_get_error_ptr(png_ptr);
    if (graphic == NULL) {
        /* we are completely hosed now */
        fprintf(stderr,
                "writepng severe error:  jmpbuf not recoverable; terminating. (F31)\n");
        fflush(stderr);
        return;
    }
    longjmp(graphic->jmpbuf, 1);
}

/* Guestimate best compression strategy */
static int guess_compression_strategy(struct zint_symbol *symbol, unsigned char *pixelbuf) {
    (void)pixelbuf;

    /* TODO: Do properly */

    /* It seems the best choice for typical barcode pngs is one of Z_DEFAULT_STRATEGY and Z_FILTERED */

    /* Some guesses */
    if (symbol->symbology == BARCODE_MAXICODE) {
        return Z_DEFAULT_STRATEGY;
    }
    if (symbol->symbology == BARCODE_AZTEC && symbol->bitmap_width <= 30) {
        return Z_DEFAULT_STRATEGY;
    }

    /* Z_FILTERED seems to work better for slightly more barcodes+data so default to that */
    return Z_FILTERED;
}

INTERNAL int png_pixel_plot(struct zint_symbol *symbol, unsigned char *pixelbuf) {
    struct mainprog_info_type wpng_info;
    struct mainprog_info_type *graphic;
    png_structp png_ptr;
    png_infop info_ptr;
    int i;
    int row, column;
    png_color bg, fg;
    unsigned char bg_alpha, fg_alpha;
    unsigned char map[128];
    png_color palette[32];
    int num_palette;
    unsigned char trans_alpha[32];
    int num_trans;
    int bit_depth;
    int compression_strategy;
    unsigned char *pb;

#ifndef _MSC_VER
    unsigned char outdata[symbol->bitmap_width];
#else
    unsigned char* outdata = (unsigned char*) _alloca(symbol->bitmap_width);
#endif

    graphic = &wpng_info;

    graphic->width = symbol->bitmap_width;
    graphic->height = symbol->bitmap_height;

    fg.red = (16 * ctoi(symbol->fgcolour[0])) + ctoi(symbol->fgcolour[1]);
    fg.green = (16 * ctoi(symbol->fgcolour[2])) + ctoi(symbol->fgcolour[3]);
    fg.blue = (16 * ctoi(symbol->fgcolour[4])) + ctoi(symbol->fgcolour[5]);
    bg.red = (16 * ctoi(symbol->bgcolour[0])) + ctoi(symbol->bgcolour[1]);
    bg.green = (16 * ctoi(symbol->bgcolour[2])) + ctoi(symbol->bgcolour[3]);
    bg.blue = (16 * ctoi(symbol->bgcolour[4])) + ctoi(symbol->bgcolour[5]);

    if (strlen(symbol->fgcolour) > 6) {
        fg_alpha = (16 * ctoi(symbol->fgcolour[6])) + ctoi(symbol->fgcolour[7]);
    } else {
        fg_alpha = 0xff;
    }

    if (strlen(symbol->bgcolour) > 6) {
        bg_alpha = (16 * ctoi(symbol->bgcolour[6])) + ctoi(symbol->bgcolour[7]);
    } else {
        bg_alpha = 0xff;
    }

    num_trans = 0;
    if (symbol->symbology == BARCODE_ULTRA) {
        static const int ultra_chars[8] = { 'W', 'C', 'B', 'M', 'R', 'Y', 'G', 'K' };
        static png_color ultra_colours[8] = {
            { 0xff, 0xff, 0xff, }, /* White */
            {    0, 0xff, 0xff, }, /* Cyan */
            {    0,    0, 0xff, }, /* Blue */
            { 0xff,    0, 0xff, }, /* Magenta */
            { 0xff,    0,    0, }, /* Red */
            { 0xff, 0xff,    0, }, /* Yellow */
            {    0, 0xff,    0, }, /* Green */
            {    0,    0,    0, }, /* Black */
        };
        for (i = 0; i < 8; i++) {
            map[ultra_chars[i]] = i;
            palette[i] = ultra_colours[i];
            if (fg_alpha != 0xff) {
                trans_alpha[i] = fg_alpha;
            }
        }
        num_palette = 8;
        if (fg_alpha != 0xff) {
            num_trans = 8;
        }

        /* For Ultracode, have background only if have whitespace/quiet zones */
        if (pixelbuf[0] == '0' || pixelbuf[symbol->bitmap_width - 1] == '0'
                || pixelbuf[symbol->bitmap_height * (symbol->bitmap_width - 1)] == '0'
                || pixelbuf[symbol->bitmap_height * symbol->bitmap_width - 1] == '0') {
            /* Check whether can re-use white */
            if (bg.red == 0xff && bg.green == 0xff && bg.blue == 0xff && bg_alpha == fg_alpha) {
                map['0'] = 0; /* Re-use white */
            } else {
                if (bg_alpha == 0xff || fg_alpha != 0xff) {
                    /* No alpha or have foreground alpha - add to end */
                    map['0'] = num_palette;
                    palette[num_palette++] = bg;
                } else {
                    /* Alpha and no foreground alpha - add to front & move white to end */
                    map['0'] = 0;
                    palette[0] = bg;
                    map['W'] = num_palette;
                    palette[num_palette++] = ultra_colours[0];
                }
                if (bg_alpha != 0xff) {
                    trans_alpha[num_trans++] = bg_alpha;
                }
            }
        }
    } else {
        int bg_idx = 0, fg_idx = 1;
        /* Do alphas first so can swop indexes if background not alpha */
        if (bg_alpha != 0xff) {
            trans_alpha[num_trans++] = bg_alpha;
        }
        if (fg_alpha != 0xff) {
            trans_alpha[num_trans++] = fg_alpha;
            if (num_trans == 1) {
                /* Only foreground has alpha so swop indexes - saves a byte! */
                bg_idx = 1;
                fg_idx = 0;
            }
        }

        map['0'] = bg_idx;
        palette[bg_idx] = bg;
        map['1'] = fg_idx;
        palette[fg_idx] = fg;
        num_palette = 2;
    }

    if (num_palette <= 2) {
        bit_depth = 1;
    } else if (num_palette <= 16) {
        bit_depth = 4;
    } else {
        bit_depth = 8;
    }

    /* Open output file in binary mode */
    if (symbol->output_options & BARCODE_STDOUT) {
#ifdef _MSC_VER
        if (-1 == _setmode(_fileno(stdout), _O_BINARY)) {
            strcpy(symbol->errtxt, "631: Can't open output file");
            return ZINT_ERROR_FILE_ACCESS;
        }
#endif
        graphic->outfile = stdout;
    } else {
        if (!(graphic->outfile = fopen(symbol->outfile, "wb"))) {
            strcpy(symbol->errtxt, "632: Can't open output file");
            return ZINT_ERROR_FILE_ACCESS;
        }
    }

    /* Set up error handling routine as proc() above */
    png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, graphic, writepng_error_handler, NULL);
    if (!png_ptr) {
        strcpy(symbol->errtxt, "633: Out of memory");
        return ZINT_ERROR_MEMORY;
    }

    info_ptr = png_create_info_struct(png_ptr);
    if (!info_ptr) {
        png_destroy_write_struct(&png_ptr, NULL);
        strcpy(symbol->errtxt, "634: Out of memory");
        return ZINT_ERROR_MEMORY;
    }

    /* catch jumping here */
    if (setjmp(graphic->jmpbuf)) {
        png_destroy_write_struct(&png_ptr, &info_ptr);
        strcpy(symbol->errtxt, "635: libpng error occurred");
        return ZINT_ERROR_MEMORY;
    }

    /* open output file with libpng */
    png_init_io(png_ptr, graphic->outfile);

    /* set compression */
    png_set_compression_level(png_ptr, 9);

    /* Compression strategy can make a difference */
    compression_strategy = guess_compression_strategy(symbol, pixelbuf);
    if (compression_strategy != Z_DEFAULT_STRATEGY) {
        png_set_compression_strategy(png_ptr, compression_strategy);
    }

    /* set Header block */
    png_set_IHDR(png_ptr, info_ptr, graphic->width, graphic->height,
            bit_depth, PNG_COLOR_TYPE_PALETTE, PNG_INTERLACE_NONE,
            PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);

    png_set_PLTE(png_ptr, info_ptr, palette, num_palette);
    if (num_trans) {
        png_set_tRNS(png_ptr, info_ptr, trans_alpha, num_trans, NULL);
    }

    /* write all chunks up to (but not including) first IDAT */
    png_write_info(png_ptr, info_ptr);

    /* Pixel Plotting */
    pb = pixelbuf;
    if (bit_depth == 1) {
        for (row = 0; row < symbol->bitmap_height; row++) {
            unsigned char *image_data = outdata;
            for (column = 0; column < symbol->bitmap_width; column += 8, image_data++) {
                unsigned char byte = 0;
                for (i = 0; i < 8 && column + i < symbol->bitmap_width; i++, pb++) {
                    byte |= map[*pb] << (7 - i);
                }
                *image_data = byte;
            }
            /* write row contents to file */
            png_write_row(png_ptr, outdata);
        }
    } else if (bit_depth == 4) {
        for (row = 0; row < symbol->bitmap_height; row++) {
            unsigned char *image_data = outdata;
            for (column = 0; column < symbol->bitmap_width; column += 2, image_data++) {
                unsigned char byte = map[*pb++] << 4;
                if (column + 1 < symbol->bitmap_width) {
                    byte |= map[*pb++];
                }
                *image_data = byte;
            }
            /* write row contents to file */
            png_write_row(png_ptr, outdata);
        }
    } else { /* Bit depth 8 */
        for (row = 0; row < symbol->bitmap_height; row++) {
            unsigned char *image_data = outdata;
            for (column = 0; column < symbol->bitmap_width; column++, pb++, image_data++) {
                *image_data = map[*pb];
            }
            /* write row contents to file */
            png_write_row(png_ptr, outdata);
        }
    }

    /* End the file */
    png_write_end(png_ptr, NULL);

    /* make sure we have disengaged */
    if (png_ptr && info_ptr) png_destroy_write_struct(&png_ptr, &info_ptr);
    if (symbol->output_options & BARCODE_STDOUT) {
        fflush(wpng_info.outfile);
    } else {
        fclose(wpng_info.outfile);
    }

    return 0;
}
#endif /* NO_PNG */