pdfio/examples/code128.c
Michael R Sweet 53967552df
Add some documentation on the code128 example.
Clean up the code128 code a bit and use the Helvetica font for the text.

Add support for writing to a PDF file on the command-line vs. just doing
redirection.
2024-12-15 22:52:03 -05:00

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//
// Code 128 barcode example for PDFio.
//
// Copyright © 2024 by Michael R Sweet.
//
// Licensed under Apache License v2.0. See the file "LICENSE" for more
// information.
//
// Usage:
//
// ./code128 "BARCODE" ["TEXT"] >FILENAME.pdf
//
#include <pdfio.h>
#include <pdfio-content.h>
//
// 'make_code128()' - Make a Code 128 barcode string.
//
// This function produces a Code B (printable ASCII) representation of the
// source string and doesn't try to optimize using Code C. Non-printable and
// extended characters are ignored in the source string.
//
static char * // O - Output string
make_code128(char *dst, // I - Destination buffer
const char *src, // I - Source string
size_t dstsize) // I - Size of destination buffer
{
char *dstptr, // Pointer into destination buffer
*dstend; // End of destination buffer
int sum; // Weighted sum
static const char *code128_chars = // Code 128 characters
" !\"#$%&'()*+,-./0123456789:;<=>?"
"@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_"
"`abcdefghijklmnopqrstuvwxyz{|}~\303"
"\304\305\306\307\310\311\312";
static const char code128_fnc_3 = '\304';
// FNC 3
static const char code128_fnc_2 = '\305';
// FNC 2
static const char code128_shift_b = '\306';
// Shift B (for lowercase)
static const char code128_code_c = '\307';
// Code C
static const char code128_code_b = '\310';
// Code B
static const char code128_fnc_4 = '\311';
// FNC 4
static const char code128_fnc_1 = '\312';
// FNC 1
static const char code128_start_code_a = '\313';
// Start code A
static const char code128_start_code_b = '\314';
// Start code B
static const char code128_start_code_c = '\315';
// Start code C
static const char code128_stop = '\316';
// Stop pattern
// Start a Code B barcode...
dstptr = dst;
dstend = dst + dstsize - 3;
*dstptr++ = code128_start_code_b;
sum = code128_start_code_b - 100;
while (*src && dstptr < dstend)
{
if (*src >= ' ' && *src < 0x7f)
{
sum += (dstptr - dst) * (*src - ' ');
*dstptr++ = *src;
}
src ++;
}
// Add the weighted sum modulo 103
*dstptr++ = code128_chars[sum % 103];
// Add the stop pattern and return...
*dstptr++ = code128_stop;
*dstptr = '\0';
return (dst);
}
//
// 'output_cb()' - Write PDF data to the standard output...
//
static ssize_t // O - Number of bytes written
output_cb(void *output_cbdata, // I - Callback data (not used)
const void *buffer, // I - Buffer to write
size_t bytes) // I - Number of bytes to write
{
(void)output_cbdata;
return ((ssize_t)fwrite(buffer, 1, bytes, stdout));
}
//
// 'main()' - Produce a single-page barcode file.
//
int // O - Exit status
main(int argc, // I - Number of command-line arguments
char *argv[]) // I - Command-line arguments
{
const char *barcode, // Barcode to show
*text; // Text to display under barcode
pdfio_file_t *pdf; // Output PDF file
pdfio_obj_t *barcode_font; // Barcode font object
pdfio_obj_t *text_font = NULL; // Text font object
pdfio_dict_t *page_dict; // Page dictionary
pdfio_rect_t media_box; // Media/CropBox for page
pdfio_stream_t *page_st; // Page stream
char barcode_temp[256]; // Barcode buffer
double barcode_height = 36.0, // Height of barcode
barcode_width, // Width of barcode
text_height = 0.0, // Height of text
text_width = 0.0; // Width of text
// Get the barcode and optional text from the command-line...
if (argc < 2 || argc > 3)
{
fputs("Usage: code128 \"BARCODE\" [\"TEXT\"] >FILENAME.pdf\n", stderr);
return (1);
}
barcode = argv[1];
text = argv[2];
// Output a PDF file to the standard output...
#ifdef _WIN32
setmode(1, O_BINARY); // Force binary output on Windows
#endif // _WIN32
if ((pdf = pdfioFileCreateOutput(output_cb, /*output_cbdata*/NULL, /*version*/NULL, /*media_box*/NULL, /*crop_box*/NULL, /*error_cb*/NULL, /*error_data*/NULL)) == NULL)
return (1);
// Load fonts...
barcode_font = pdfioFileCreateFontObjFromFile(pdf, "code128.ttf", /*unicode*/false);
if (text)
text_font = pdfioFileCreateFontObjFromBase(pdf, "Helvetica");
// Generate Code128 characters for the desired barcode...
if (!(barcode[0] & 0x80))
barcode = make_code128(barcode_temp, barcode, sizeof(barcode_temp));
// Compute sizes of the text...
barcode_width = pdfioContentTextMeasure(barcode_font, barcode, barcode_height);
if (text && text_font)
{
text_height = 9.0;
text_width = pdfioContentTextMeasure(text_font, text, text_height);
}
// Compute the size of the PDF page...
media_box.x1 = 0.0;
media_box.y1 = 0.0;
media_box.x2 = (barcode_width > text_width ? barcode_width : text_width) + 18.0;
media_box.y2 = barcode_height + text_height + 18.0;
// Start a page for the barcode...
page_dict = pdfioDictCreate(pdf);
pdfioDictSetRect(page_dict, "MediaBox", &media_box);
pdfioDictSetRect(page_dict, "CropBox", &media_box);
pdfioPageDictAddFont(page_dict, "B128", barcode_font);
if (text_font)
pdfioPageDictAddFont(page_dict, "TEXT", text_font);
page_st = pdfioFileCreatePage(pdf, page_dict);
// Draw the page...
pdfioContentSetFillColorGray(page_st, 0.0);
pdfioContentSetTextFont(page_st, "B128", barcode_height);
pdfioContentTextBegin(page_st);
pdfioContentTextMoveTo(page_st, 0.5 * (media_box.x2 - barcode_width), 9.0 + text_height);
pdfioContentTextShow(page_st, /*unicode*/false, barcode);
pdfioContentTextEnd(page_st);
if (text && text_font)
{
pdfioContentSetTextFont(page_st, "TEXT", text_height);
pdfioContentTextBegin(page_st);
pdfioContentTextMoveTo(page_st, 0.5 * (media_box.x2 - text_width), 9.0);
pdfioContentTextShow(page_st, /*unicode*/false, text);
pdfioContentTextEnd(page_st);
}
pdfioStreamClose(page_st);
// Close and return...
pdfioFileClose(pdf);
return (0);
}