/* pamstretch - scale up portable anymap by interpolating between pixels. * * This program is based on 'pnminterp' by Russell Marks, rename * pnmstretch for inclusion in Netpbm, then rewritten and renamed to * pamstretch by Bryan Henderson in December 2001. * * Copyright (C) 1998,2000 Russell Marks. * * This program 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 2 of the License, or (at * your option) any later version. * * This program 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 this program; if not, write to the Free Software * Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ #include #include #include #include #include "pm_c_util.h" #include "pam.h" #include "shhopt.h" enum an_edge_mode { EDGE_DROP, /* drop one (source) pixel at right/bottom edges. */ EDGE_INTERP_TO_BLACK, /* interpolate right/bottom edge pixels to black. */ EDGE_NON_INTERP /* don't interpolate right/bottom edge pixels (default, and what zgv does). */ }; struct cmdline_info { /* All the information the user supplied in the command line, in a form easy for the program to use. */ const char *input_filespec; /* Filespecs of input files */ enum an_edge_mode edge_mode; unsigned int xscale; unsigned int yscale; }; tuple blackTuple; /* A "black" tuple. Unless our input image is PBM, PGM, or PPM, we don't really know what "black" means, so this is just something arbitrary in that case. */ static void parse_command_line(int argc, char ** argv, struct cmdline_info *cmdline_p) { /*---------------------------------------------------------------------------- Note that the file spec array we return is stored in the storage that was passed to us as the argv array. -----------------------------------------------------------------------------*/ optStruct3 opt; /* set by OPTENT3 */ optEntry *option_def = malloc(100*sizeof(optEntry)); unsigned int option_def_index; unsigned int blackedge; unsigned int dropedge; unsigned int xscale_spec; unsigned int yscale_spec; option_def_index = 0; /* incremented by OPTENTRY */ OPTENT3('b', "blackedge", OPT_FLAG, NULL, &blackedge, 0); OPTENT3('d', "dropedge", OPT_FLAG, NULL, &dropedge, 0); OPTENT3(0, "xscale", OPT_UINT, &cmdline_p->xscale, &xscale_spec, 0); OPTENT3(0, "yscale", OPT_UINT, &cmdline_p->yscale, &yscale_spec, 0); opt.opt_table = option_def; opt.short_allowed = FALSE; /* We have some short (old-fashioned) options */ opt.allowNegNum = FALSE; /* We have no parms that are negative numbers */ optParseOptions3(&argc, argv, opt, sizeof(opt), 0); /* Uses and sets argc, argv, and some of *cmdline_p and others. */ if (blackedge && dropedge) pm_error("Can't specify both -blackedge and -dropedge options."); else if (blackedge) cmdline_p->edge_mode = EDGE_INTERP_TO_BLACK; else if (dropedge) cmdline_p->edge_mode = EDGE_DROP; else cmdline_p->edge_mode = EDGE_NON_INTERP; if (xscale_spec && cmdline_p->xscale == 0) pm_error("You specified zero for the X scale factor."); if (yscale_spec && cmdline_p->yscale == 0) pm_error("You specified zero for the Y scale factor."); if (xscale_spec && !yscale_spec) cmdline_p->yscale = 1; if (yscale_spec && !xscale_spec) cmdline_p->xscale = 1; if (!(xscale_spec || yscale_spec)) { /* scale must be specified in an argument */ if ((argc-1) != 1 && (argc-1) != 2) pm_error("Wrong number of arguments (%d). Without scale options, " "you must supply 1 or 2 arguments: scale and " "optional file specification", argc-1); { char *endptr; /* ptr to 1st invalid character in scale arg */ unsigned int scale; scale = strtol(argv[1], &endptr, 10); if (*argv[1] == '\0') pm_error("Scale argument is a null string. " "Must be a number."); else if (*endptr != '\0') pm_error("Scale argument contains non-numeric character '%c'.", *endptr); else if (scale < 2) pm_error("Scale argument must be at least 2. " "You specified %d", scale); cmdline_p->xscale = scale; cmdline_p->yscale = scale; } if (argc-1 > 1) cmdline_p->input_filespec = argv[2]; else cmdline_p->input_filespec = "-"; } else { /* No scale argument allowed */ if ((argc-1) > 1) pm_error("Too many arguments (%d). With a scale option, " "the only argument is the " "optional file specification", argc-1); if (argc-1 > 0) cmdline_p->input_filespec = argv[1]; else cmdline_p->input_filespec = "-"; } } static void stretch_line(struct pam * const inpamP, const tuple * const line, const tuple * const line_stretched, unsigned int const scale, enum an_edge_mode const edge_mode) { /*---------------------------------------------------------------------------- Stretch the line of tuples 'line' into the output buffer 'line_stretched', by factor 'scale'. -----------------------------------------------------------------------------*/ int scaleincr; int sisize; /* normalizing factor to make fractions representable as integers. E.g. if sisize = 100, one half is represented as 50. */ unsigned int col; unsigned int outcol; sisize=0; while (sisize<256) sisize += scale; scaleincr = sisize/scale; /* (1/scale, normalized) */ outcol = 0; /* initial value */ for (col = 0; col < inpamP->width; ++col) { unsigned int pos; /* The fraction of the way we are from curline to nextline, normalized by sisize. */ if (col >= inpamP->width-1) { /* We're at the edge. There is no column to the right with which to interpolate. */ switch(edge_mode) { case EDGE_DROP: /* No output column needed for this input column */ break; case EDGE_INTERP_TO_BLACK: { unsigned int pos; for (pos = 0; pos < sisize; pos += scaleincr) { unsigned int plane; for (plane = 0; plane < inpamP->depth; ++plane) line_stretched[outcol][plane] = (line[col][plane] * (sisize-pos)) / sisize; ++outcol; } } break; case EDGE_NON_INTERP: { unsigned int pos; for (pos = 0; pos < sisize; pos += scaleincr) { unsigned int plane; for (plane = 0; plane < inpamP->depth; ++plane) line_stretched[outcol][plane] = line[col][plane]; ++outcol; } } break; default: pm_error("INTERNAL ERROR: invalid value for edge_mode"); } } else { /* Interpolate with the next input column to the right */ for (pos = 0; pos < sisize; pos += scaleincr) { unsigned int plane; for (plane = 0; plane < inpamP->depth; ++plane) line_stretched[outcol][plane] = (line[col][plane] * (sisize-pos) + line[col+1][plane] * pos) / sisize; ++outcol; } } } } static void write_interp_rows(struct pam * const outpamP, const tuple * const curline, const tuple * const nextline, tuple * const outbuf, int const scale) { /*---------------------------------------------------------------------------- Write out 'scale' rows, being 'curline' followed by rows that are interpolated between 'curline' and 'nextline'. -----------------------------------------------------------------------------*/ unsigned int scaleincr; unsigned int sisize; unsigned int pos; sisize=0; while(sisize<256) sisize+=scale; scaleincr=sisize/scale; for (pos = 0; pos < sisize; pos += scaleincr) { unsigned int col; for (col = 0; col < outpamP->width; ++col) { unsigned int plane; for (plane = 0; plane < outpamP->depth; ++plane) outbuf[col][plane] = (curline[col][plane] * (sisize-pos) + nextline[col][plane] * pos) / sisize; } pnm_writepamrow(outpamP, outbuf); } } static void swap_buffers(tuple ** const buffer1P, tuple ** const buffer2P) { /* Advance "next" line to "current" line by switching line buffers */ tuple *tmp; tmp = *buffer1P; *buffer1P = *buffer2P; *buffer2P = tmp; } static void stretch(struct pam * const inpamP, struct pam * const outpamP, int const xscale, int const yscale, enum an_edge_mode const edge_mode) { tuple *linebuf1, *linebuf2; /* Input buffers for two rows at a time */ tuple *curline, *nextline; /* Pointers to one of the two above buffers */ /* And the stretched versions: */ tuple *stretched_linebuf1, *stretched_linebuf2; tuple *curline_stretched, *nextline_stretched; tuple *outbuf; /* One-row output buffer */ unsigned int row; unsigned int rowsToStretch; linebuf1 = pnm_allocpamrow(inpamP); linebuf2 = pnm_allocpamrow(inpamP); stretched_linebuf1 = pnm_allocpamrow(outpamP); stretched_linebuf2 = pnm_allocpamrow(outpamP); outbuf = pnm_allocpamrow(outpamP); curline = linebuf1; curline_stretched = stretched_linebuf1; nextline = linebuf2; nextline_stretched = stretched_linebuf2; pnm_readpamrow(inpamP, curline); stretch_line(inpamP, curline, curline_stretched, xscale, edge_mode); if (edge_mode == EDGE_DROP) rowsToStretch = inpamP->height - 1; else rowsToStretch = inpamP->height; for (row = 0; row < rowsToStretch; row++) { if (row == inpamP->height-1) { /* last line is about to be output. there is no further * `next line'. if EDGE_DROP, we stop here, with output * of rows-1 rows. if EDGE_INTERP_TO_BLACK we make next * line black. if EDGE_NON_INTERP (default) we make it a * copy of the current line. */ switch (edge_mode) { case EDGE_INTERP_TO_BLACK: { int col; for (col = 0; col < outpamP->width; col++) nextline_stretched[col] = blackTuple; } break; case EDGE_NON_INTERP: { /* EDGE_NON_INTERP */ int col; for (col = 0; col < outpamP->width; col++) nextline_stretched[col] = curline_stretched[col]; } break; case EDGE_DROP: pm_error("INTERNAL ERROR: processing last row, but " "edge_mode is EDGE_DROP."); } } else { pnm_readpamrow(inpamP, nextline); stretch_line(inpamP, nextline, nextline_stretched, xscale, edge_mode); } /* interpolate curline towards nextline into outbuf */ write_interp_rows(outpamP, curline_stretched, nextline_stretched, outbuf, yscale); swap_buffers(&curline, &nextline); swap_buffers(&curline_stretched, &nextline_stretched); } pnm_freerow(outbuf); pnm_freerow(stretched_linebuf2); pnm_freerow(stretched_linebuf1); pnm_freerow(linebuf2); pnm_freerow(linebuf1); } int main(int argc,char *argv[]) { FILE *ifp; struct cmdline_info cmdline; struct pam inpam, outpam; pnm_init(&argc, argv); parse_command_line(argc, argv, &cmdline); ifp = pm_openr(cmdline.input_filespec); pnm_readpaminit(ifp, &inpam, PAM_STRUCT_SIZE(tuple_type)); if (inpam.width < 2) pm_error("Image is too narrow. Must be at least 2 columns."); if (inpam.height < 2) pm_error("Image is too short. Must be at least 2 lines."); outpam = inpam; /* initial value */ outpam.file = stdout; if (PNM_FORMAT_TYPE(inpam.format) == PBM_TYPE) { outpam.format = PGM_TYPE; /* usual filter message when reading PBM but writing PGM: */ pm_message("promoting from PBM to PGM"); } else { outpam.format = inpam.format; } { unsigned int const dropped = cmdline.edge_mode == EDGE_DROP ? 1 : 0; outpam.width = (inpam.width - dropped) * cmdline.xscale; outpam.height = (inpam.height - dropped) * cmdline.yscale; pnm_writepaminit(&outpam); } pnm_createBlackTuple(&outpam, &blackTuple); stretch(&inpam, &outpam, cmdline.xscale, cmdline.yscale, cmdline.edge_mode); pm_close(ifp); exit(0); }