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filter/pdftopdf: Add print-as-image option (issue #601) #678

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filter/pdftopdf: Add print-as-image option (issue #601) #678

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260 changes: 214 additions & 46 deletions filter/pdftopdf.c
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Original file line number Diff line number Diff line change
@@ -1,85 +1,253 @@
//
// Legacy CUPS filter wrapper for ppdFilterPDFToPDF() for cups-filters.
//
// Copyright © 2020-2022 by OpenPrinting.
// Adds support for the "print-as-image" job option (issue #601):
// rasterizes each PDF page via Ghostscript before processing, as a
// workaround for printers that misrender PDF vector/font content.
//
// Copyright © 2020-2024 by OpenPrinting.
//
// Licensed under Apache License v2.0. See the file "LICENSE" for more
// information.
//

//
// Include necessary headers...
//

#include <cupsfilters/filter.h>
#include <ppd/ppd-filter.h>
#include <config.h>
#include <signal.h>
#include <sys/wait.h>

static int JobCanceled = 0;

//
// Local globals...
//

static int JobCanceled = 0; // Set to 1 on SIGTERM


//
// Local functions...
//
static void cancel_job(int sig);
static int rasterize_pdf_as_image(const char *infile,
char *outfile,
size_t outfile_size,
int dpi);

static void cancel_job(int sig);


//
// 'main()' - Main entry.
//

int // O - Exit status
main(int argc, // I - Number of command-line args
char *argv[]) // I - Command-line arguments
int
main(int argc,
char *argv[])
{
int ret;
int ret;
int num_options;
cups_option_t *options;
const char *val;
int print_as_image;
int dpi;
char raster_file[4096];
char *new_argv[8];
int i;

#if defined(HAVE_SIGACTION) && !defined(HAVE_SIGSET)
struct sigaction action; // Actions for POSIX signals
#endif // HAVE_SIGACTION && !HAVE_SIGSET
struct sigaction action;
#endif

//
// Register a signal handler to cleanly cancel a job.
//
if (argc < 6 || argc > 7)
{
fprintf(stderr, "Usage: pdftopdf job-id user title copies options [file]\n");
return (1);
}

#ifdef HAVE_SIGSET // Use System V signals over POSIX to avoid bugs
#ifdef HAVE_SIGSET
sigset(SIGTERM, cancel_job);
#elif defined(HAVE_SIGACTION)
memset(&action, 0, sizeof(action));

sigemptyset(&action.sa_mask);
action.sa_handler = cancel_job;
sigaction(SIGTERM, &action, NULL);
#else
signal(SIGTERM, cancel_job);
#endif // HAVE_SIGSET

//
// Fire up the ppdFilterPDFToPDF() filter function
//

ret = ppdFilterCUPSWrapper(argc, argv, ppdFilterPDFToPDF, NULL, &JobCanceled);
#endif

num_options = cupsParseOptions(argv[5], 0, &options);
print_as_image = 0;
dpi = 300;

if ((val = cupsGetOption("print-as-image", num_options, options)) != NULL)
{
if (!strcasecmp(val, "true") || !strcasecmp(val, "yes") ||
!strcasecmp(val, "on") || !strcmp(val, "1"))
{
print_as_image = 1;
fprintf(stderr, "DEBUG: pdftopdf: \"print-as-image\" enabled.\n");
}
}

if (print_as_image)
{
if ((val = cupsGetOption("print-as-image-dpi", num_options, options)) != NULL)
{
int requested = atoi(val);
if (requested >= 72 && requested <= 2400)
dpi = requested;
else
fprintf(stderr, "WARNING: pdftopdf: Invalid print-as-image-dpi \"%s\", using %d dpi.\n", val, dpi);
}
fprintf(stderr, "DEBUG: pdftopdf: print-as-image rasterization DPI: %d\n", dpi);
}

cupsFreeOptions(num_options, options);

raster_file[0] = '\0';
ret = 0;

if (print_as_image && argc == 7)
{
if (rasterize_pdf_as_image(argv[6], raster_file, sizeof(raster_file), dpi) == 0)
{
for (i = 0; i < argc; i ++)
new_argv[i] = argv[i];
new_argv[6] = raster_file;
new_argv[7] = NULL;
fprintf(stderr, "DEBUG: pdftopdf: Using rasterized PDF: %s\n", raster_file);
ret = ppdFilterCUPSWrapper(argc, new_argv, ppdFilterPDFToPDF, NULL, &JobCanceled);
}
else
{
fprintf(stderr, "WARNING: pdftopdf: Rasterization failed, falling back to original PDF.\n");
ret = ppdFilterCUPSWrapper(argc, argv, ppdFilterPDFToPDF, NULL, &JobCanceled);
}
if (raster_file[0] != '\0')
unlink(raster_file);
}
else
{
if (print_as_image && argc == 6)
fprintf(stderr, "WARNING: pdftopdf: \"print-as-image\" requested but input is stdin; skipped.\n");
ret = ppdFilterCUPSWrapper(argc, argv, ppdFilterPDFToPDF, NULL, &JobCanceled);
}

if (ret)
fprintf(stderr, "ERROR: pdftopdf filter function failed.\n");

return (ret);
}


//
// 'cancel_job()' - Flag the job as canceled.
//
static int
rasterize_pdf_as_image(const char *infile, char *outfile, size_t outfile_size, int dpi)
{
const char *tmpdir;
int fd;
char res_arg[32];
char outfile_arg[4096];
int pid;
int wstatus;
int devnull_fd;
static const char *gs_candidates[] = {"gs", "/usr/bin/gs", "/usr/local/bin/gs", NULL};
const char *gs_bin = NULL;
int i;

tmpdir = getenv("TMPDIR");
if (!tmpdir || !tmpdir[0])
tmpdir = "/tmp";

snprintf(outfile, outfile_size, "%s/pdftopdf-raster-XXXXXX.pdf", tmpdir);

#ifdef HAVE_MKSTEMPS
fd = mkstemps(outfile, 4);
#else
{
char base_template[4096];
snprintf(base_template, sizeof(base_template), "%s/pdftopdf-raster-XXXXXX", tmpdir);
fd = mkstemp(base_template);
if (fd >= 0)
{
close(fd);
snprintf(outfile, outfile_size - 5, "%s", base_template);
strncat(outfile, ".pdf", outfile_size - strlen(outfile) - 1);
unlink(base_template);
fd = open(outfile, O_CREAT | O_EXCL | O_WRONLY, 0600);
}
}
#endif

if (fd < 0)
{
fprintf(stderr, "ERROR: pdftopdf: Cannot create temp file: %s\n", strerror(errno));
outfile[0] = '\0';
return (-1);
}
close(fd);
unlink(outfile);

for (i = 0; gs_candidates[i]; i ++)
{
if (access(gs_candidates[i], X_OK) == 0)
{
gs_bin = gs_candidates[i];
break;
}
}

if (!gs_bin)
{
fprintf(stderr, "ERROR: pdftopdf: Ghostscript not found.\n");
outfile[0] = '\0';
return (-1);
}

snprintf(res_arg, sizeof(res_arg), "-r%d", dpi);
snprintf(outfile_arg, sizeof(outfile_arg), "-sOutputFile=%s", outfile);

fprintf(stderr, "DEBUG: pdftopdf: rasterize_pdf_as_image: Running: %s -dBATCH -dNOPAUSE -dSAFER -dQUIET -sDEVICE=pdfimage24 %s -dCompressPages=true %s %s\n", gs_bin, res_arg, outfile_arg, infile);

pid = fork();
if (pid < 0)
{
fprintf(stderr, "ERROR: pdftopdf: fork() failed: %s\n", strerror(errno));
outfile[0] = '\0';
return (-1);
}

if (pid == 0)
{
devnull_fd = open("/dev/null", O_WRONLY);
if (devnull_fd >= 0)
{
dup2(devnull_fd, STDOUT_FILENO);
close(devnull_fd);
}
execlp(gs_bin, gs_bin, "-dBATCH", "-dNOPAUSE", "-dSAFER", "-dQUIET",
"-sDEVICE=pdfimage24", res_arg, "-dCompressPages=true",
outfile_arg, infile, (char *)NULL);
fprintf(stderr, "ERROR: pdftopdf: execlp failed: %s\n", strerror(errno));
_exit(1);
}

while (waitpid(pid, &wstatus, 0) < 0)
{
if (errno != EINTR)
{
fprintf(stderr, "ERROR: pdftopdf: waitpid() failed: %s\n", strerror(errno));
outfile[0] = '\0';
return (-1);
}
}

if (!WIFEXITED(wstatus) || WEXITSTATUS(wstatus) != 0)
{
fprintf(stderr, "ERROR: pdftopdf: Ghostscript exited with status %d.\n",
WIFEXITED(wstatus) ? WEXITSTATUS(wstatus) : -1);
unlink(outfile);
outfile[0] = '\0';
return (-1);
}

if (access(outfile, R_OK) != 0)
{
fprintf(stderr, "ERROR: pdftopdf: gs did not produce output file.\n");
outfile[0] = '\0';
return (-1);
}

fprintf(stderr, "DEBUG: pdftopdf: rasterize_pdf_as_image: Rasterized PDF written to %s\n", outfile);
return (0);
}

static void
cancel_job(int sig) // I - Signal number (unused)
cancel_job(int sig)
{
(void)sig;

JobCanceled = 1;
}