/*
Convert an AutoCAD slide (.sld) file to PPM format
An AutoCAD slide is a compressed sequence of vectors and filled
polygons. The ppmdraw package is used to scan convert these
geometrical objects into a portable pixmap.
Author:
John Walker
Autodesk SA
Avenue des Champs-Montants 14b
CH-2074 MARIN
Switzerland
Usenet: kelvin@Autodesk.com
Fax: 038/33 88 15
Voice: 038/33 76 33
Permission to use, copy, modify, and distribute this software and
its documentation for any purpose and without fee is hereby
granted, without any conditions or restrictions. This software is
provided "as is" without express or implied warranty.
*/
#include <string.h>
#include <math.h>
#include "pm_c_util.h"
#include "ppm.h"
#include "ppmdraw.h"
#include "nstring.h"
#include <assert.h>
#include "autocad.h" /* AutoCAD standard color assignments */
/* Define a variable type accepting numbers -127 <= n <= 127. But note
that we still expect it to act UNSIGNED. */
#define smallint unsigned char /* Small integers */
#define EOS '\0'
/* Screen point */
struct spoint {
int x, y;
};
/* Screen polygon */
struct spolygon {
int npoints, /* Number of points in polygon */
fill; /* Fill type */
struct spoint pt[11]; /* Actual points */
};
/* Screen vector */
struct svector {
struct spoint f; /* From point */
struct spoint t; /* To point */
};
typedef void (slvecfn)(struct svector * vec, int color);
typedef void (slfloodfn)(struct spolygon * poly, int color);
static unsigned long const pixmaxval = 255; /* Largest pixel value */
static int ixdots, iydots; /* Screen size in dots */
static FILE * slfile; /* Slide file descriptor */
static bool blither; /* Dump slide file information ? */
static bool info; /* Print header information */
static pixel **pixels; /* Pixel map */
static int pixcols, pixrows; /* Pixel map size */
static double uscale = -1; /* Uniform scale factor */
static int sxsize = -1, sysize = -1; /* Scale to X, Y size ? */
/* Local variables */
struct slhead {
char slh[17]; /* Primate-readable header */
char sntype; /* Machine type (for number compat) */
char slevel; /* Format type */
short sxdots, sydots; /* Display X, Y dots */
double sdsar; /* Display aspect ratio */
short shwfill; /* Display hardware fill type */
char spad; /* Pad to even byte length */
};
static bool adjust; /* Adjust to correct aspect ratio ? */
static struct slhead slfrof; /* Slide file header */
static long xfac, yfac; /* Aspect ratio scale factors */
static bool sdrawkcab;
/* Slide drawing kinematic conversion of ass-backwards data flag */
/* EXTEND -- Turn a smallint into an int with sign extension, whether
or not that happens automatically.
*/
static int
extend(unsigned char const ch) {
return ((int) ((ch & 0x80) ? (ch | ~0xFF) : ch));
}
/* SLI -- Input word from slide file */
static int
sli(void) {
short wd;
if (fread(&wd, sizeof wd, 1, slfile) != 1) {
pm_error("error reading slide file");
} else {
if (sdrawkcab) {
wd = ((wd >> 8) & 0xFF) | (wd << 8);
}
}
return wd;
}
/* SLIB -- Input byte from slide file */
static int
slib(void) {
unsigned char ch;
if (fread(&ch, sizeof(ch), 1, slfile) != 1) {
pm_error("error reading slide file");
}
return extend(ch);
}
/* VSCALE -- scale screen coordinates for mismatched display. */
static void
vscale(int * const px,
int * const py) {
*px = (((unsigned) *px) * xfac) >> 16;
*py = (((unsigned) *py) * yfac) >> 16;
}
static void
upcase(const char * const sname,
char * const uname) {
unsigned int i;
const char * ip;
for (i = 0, ip = sname; i < 31; ++i) {
char const ch = *ip++;
if (ch != EOS)
uname[i] = islower(ch) ? toupper(ch) : ch;
}
uname[i] = EOS;
}
static void
skipBytes(FILE * const fileP,
unsigned int const count) {
unsigned int i;
for (i = 0; i < count; ++i)
getc(fileP);
}
static void
scanDirectory(FILE * const slFileP,
long const dirPos,
bool const dirOnly,
const char * const uname,
bool * const foundP) {
/*----------------------------------------------------------------------------
Scan the directory at the current position in *slFileP, either listing
the directory ('dirOnly' true) or searching for a slide named
'uname' ('dirOnly' false).
'dirPos' is the offset in the file of the directory, i.e. the current
position of *slFileP.
In the latter case, return as *foundP whether the slide name is there.
-----------------------------------------------------------------------------*/
bool found;
bool eof;
long pos;
unsigned char libent[36];
for (found = false, eof = false, pos = dirPos; !found && !eof; ) {
size_t readCt;
readCt = fread(libent, 36, 1, slFileP);
if (readCt != 1)
eof = true;
else {
/* The directory entry is 32 bytes of NUL-terminated slide name
followed by 4 bytes of offset of the next directory entry.
*/
const char * const slideName = (const char *)(&libent[0]);
if (pm_strnlen(slideName, 32) == 32)
pm_error("Invalid input: slide name field is not "
"nul-terminated");
else {
if (strlen(slideName) == 0)
eof = true;
else {
pos += 36;
if (dirOnly) {
pm_message(" %s", slideName);
} else if (streq(slideName, uname)) {
long const dpos =
(((((libent[35] << 8) | libent[34]) << 8) |
libent[33]) << 8) | libent[32];
if ((slFileP == stdin) ||
(fseek(slFileP, dpos, 0) == -1)) {
skipBytes(slFileP, dpos - pos);
}
found = true;
}
}
}
}
}
*foundP = found;
}
/* SLIDEFIND -- Find a slide in a library or, if DIRONLY is
nonzero, print a directory listing of the library.
If UCASEN is nonzero, the requested slide name is
converted to upper case. */
static void
slidefind(const char * const slideName,
bool const dirOnly,
bool const ucasen) {
char uname[32]; /* upper case translation of 'slideName' */
char header[32]; /* (supposed) header read from file */
bool found;
if (dirOnly)
pm_message("Slides in library:");
else {
upcase(slideName, uname);
}
/* Read slide library header and verify. */
if ((fread(header, 32, 1, slfile) != 1) ||
(!STRSEQ(header, "AutoCAD Slide Library 1.0\r\n\32"))) {
pm_error("not an AutoCAD slide library file.");
}
scanDirectory(slfile, 32, dirOnly, ucasen ? uname : slideName, &found);
if (!found && !dirOnly)
pm_error("slide '%s' not in library.", slideName);
}
/* DRAW -- Draw a vector in the given AutoCAD color. */
static slvecfn draw;
static void
draw(struct svector * vec,
int color) {
pixel rgbcolor;
if (blither) {
pm_message("Vector (%d, %d) - (%d, %d) Color %d",
vec->f.x, vec->f.y, vec->t.x, vec->t.y, color);
}
assert(vec->f.x >= 0 && vec->f.x < pixcols);
assert(vec->f.y >= 0 && vec->f.y < pixrows);
assert(vec->t.x >= 0 && vec->t.x < pixcols);
assert(vec->t.y >= 0 && vec->t.y < pixrows);
PPM_ASSIGN(rgbcolor,
acadcol[color][0], acadcol[color][1], acadcol[color][2]);
ppmd_line(pixels, pixcols, pixrows, pixmaxval,
vec->f.x, iydots - vec->f.y, vec->t.x, iydots - vec->t.y,
PPMD_NULLDRAWPROC,
(char *) &rgbcolor);
}
/* FLOOD -- Draw a filled polygon. */
static slfloodfn flood;
static void
flood(struct spolygon * const poly,
int const color) {
unsigned int i;
struct fillobj * handle;
pixel rgbcolor;
handle = ppmd_fill_create();
if (blither) {
unsigned int i;
pm_message("Polygon: %d points, fill type %d, color %d",
poly->npoints, poly->fill, color);
for (i = 0; i < poly->npoints; i++) {
pm_message(" Point %d: (%d, %d)", i + 1,
poly->pt[i].x, poly->pt[i].y);
}
}
PPM_ASSIGN(rgbcolor,
acadcol[color][0], acadcol[color][1], acadcol[color][2]);
for (i = 0; i < poly->npoints; i++) {
assert(poly->pt[i].x >= 0 && poly->pt[i].x < pixcols);
assert(poly->pt[i].y >= 0 && poly->pt[i].y < pixrows);
ppmd_line(pixels, pixcols, pixrows, pixmaxval,
poly->pt[i].x, iydots - poly->pt[i].y,
poly->pt[(i + 1) % poly->npoints].x,
iydots - poly->pt[(i + 1) % poly->npoints].y,
ppmd_fill_drawproc, handle);
}
ppmd_fill(pixels, pixcols, pixrows, pixmaxval,
handle, PPMD_NULLDRAWPROC, (char *) &rgbcolor);
ppmd_fill_destroy(handle);
}
/* SLIDER -- Read slide file. This is called with the name of the
file to be read and function pointers to the routines
which process vectors and polygon fill requests
respectively.
*/
static void
slider(slvecfn slvec,
slfloodfn slflood) {
int i, rescale;
unsigned char ubfr[4]; /* Utility character buffer */
int lx, ly; /* Last x and y point */
int slx, sly; /* Last x and y scaled screen point */
struct svector vec; /* Screen vector */
struct spolygon poly; /* Screen polygon */
unsigned short cw; /* Control word */
double dsar; /* Screen aspect ratio */
long ldsar; /* Scaled long DSAR */
short rtest; /* Value to test byte reversal */
short btest = 0x1234; /* Value to test byte-reversal */
static struct slhead slhi = /* Master slide header sample */
{"AutoCAD Slide\r\n\32", 86,2, 0,0, 0.0, 0};
int curcolor = 7; /* Current vector color */
pixel rgbcolor; /* Pixel used to clear pixmap */
lx = ly = 32000;
/* Process the header of the slide file. */
sdrawkcab = false; /* Initially guess byte order is OK */
fread(slfrof.slh, 17, 1, slfile);
fread(&slfrof.sntype, sizeof(char), 1, slfile);
fread(&slfrof.slevel, sizeof(char), 1, slfile);
fread(&slfrof.sxdots, sizeof(short), 1, slfile);
fread(&slfrof.sydots, sizeof(short), 1, slfile);
fread(ubfr, 4, 1, slfile);
fread(&slfrof.shwfill, sizeof(short), 1, slfile);
fread(&rtest, sizeof rtest, 1, slfile);
/* Verify that slide format is compatible with this program. */
if (!STRSEQ(slfrof.slh, slhi.slh))
pm_error("this is not an AutoCAD slide file.");
/* Verify that the number format and file level in the header are
compatible. All slides written by versions of AutoCAD released
since September of 1987 are compatible with this format. */
if ((slfrof.sntype != slhi.sntype) || (slfrof.slevel != slhi.slevel))
pm_error("incompatible slide file format");
/* Build SDSAR value from long scaled version. */
ldsar = 0L;
for (i = 3; i >= 0; --i)
ldsar = (ldsar << 8) | ubfr[i];
slfrof.sdsar = ((double) ldsar) / 1E7;
/* Examine the byte order test value. If it's backwards, set the
byte-reversal flag and correct all of the values we've read in
so far.
*/
if (btest != rtest) {
sdrawkcab = true;
#define rshort(x) x = ((x >> 8) & 0xFF) | (x << 8)
rshort(slfrof.sxdots);
rshort(slfrof.sydots);
rshort(slfrof.shwfill);
#undef rshort
}
/* Dump the header if we're blithering. */
if (blither || info) {
pm_message("Slide file type %d, level %d, hwfill type %d.",
slfrof.sntype, slfrof.slevel, slfrof.shwfill);
pm_message("Original screen size %dx%d, aspect ratio %.3f.",
slfrof.sxdots + 1, slfrof.sydots + 1, slfrof.sdsar);
pm_message("Byte order is %s.",
sdrawkcab ? "being reversed" : "the same");
}
/* If the display aspect ratio indicates that the pixels on the
sending screen were not square, adjust the size of the
generated bitmap to correct the aspect ratio to square the
pixels.
We always correct the aspect ratio by adjusting the width of
the image. This guarantees that output from the SHADE command,
which is essentially scan-line data written in vector form,
will not be corrupted.
*/
dsar = ((double) slfrof.sxdots) / slfrof.sydots;
if (fabs(slfrof.sdsar - dsar) > 0.0001) {
if (adjust) {
ixdots = slfrof.sxdots * (slfrof.sdsar / dsar) + 0.5;
iydots = slfrof.sydots;
dsar = ((double) ixdots) / iydots;
} else {
pm_message("Warning - pixels on source screen were non-square. "
"Specifying -adjust will correct image width "
"to compensate.");
ixdots = slfrof.sxdots;
iydots = slfrof.sydots;
dsar = slfrof.sdsar;
}
} else {
/* Source pixels were square. */
ixdots = slfrof.sxdots;
iydots = slfrof.sydots;
dsar = slfrof.sdsar;
adjust = false; /* Mark no adjustment needed */
}
/* If there's a uniform scale factor specified, apply it. */
if (uscale > 0) {
ixdots = (ixdots * uscale) + 0.5;
iydots = (iydots * uscale) + 0.5;
}
/* If the image is to be stretched to a given width, set the
output image sizes accordingly. If only a height or width is
given, scale the other direction proportionally to preserve the
aspect ratio.
*/
if (sxsize > 0) {
if (sysize > 0) {
iydots = sysize - 1;
} else {
iydots = ((((long) iydots) * (sxsize - 1)) +
(iydots / 2)) / ixdots;
}
ixdots = sxsize - 1;
} else if (sysize > 0) {
if (sxsize > 0) {
ixdots = sxsize - 1;
} else {
ixdots = ((((long) ixdots) * (sysize - 1)) +
(ixdots / 2)) / iydots;
}
iydots = sysize - 1;
}
if (adjust) {
pm_message(
"Resized from %dx%d to %dx%d to correct pixel aspect ratio.",
slfrof.sxdots + 1, slfrof.sydots + 1, ixdots + 1, iydots + 1);
}
/* Allocate image buffer and clear it to black. */
pixels = ppm_allocarray(pixcols = ixdots + 1, pixrows = iydots + 1);
PPM_ASSIGN(rgbcolor, 0, 0, 0);
ppmd_filledrectangle(pixels, pixcols, pixrows, pixmaxval, 0, 0,
pixcols, pixrows, PPMD_NULLDRAWPROC,
(char *) &rgbcolor);
if ((rescale = slfrof.sxdots != ixdots ||
slfrof.sydots != iydots ||
slfrof.sdsar != dsar) != 0) {
/* Rescale all coords. so they'll look (more or less)
right on this display.
*/
xfac = (ixdots + 1) * 0x10000L;
xfac /= (long) (slfrof.sxdots + 1);
yfac = (iydots + 1) * 0x10000L;
yfac /= (long) (slfrof.sydots + 1);
if (dsar < slfrof.sdsar) {
yfac = yfac * dsar / slfrof.sdsar;
} else {
xfac = xfac * slfrof.sdsar / dsar;
}
}
poly.npoints = 0; /* No flood in progress. */
while ((cw = sli()) != 0xFC00) {
switch (cw & 0xFF00) {
case 0xFB00: /* Short vector compressed */
vec.f.x = lx + extend(cw & 0xFF);
vec.f.y = ly + slib();
vec.t.x = lx + slib();
vec.t.y = ly + slib();
lx = vec.f.x;
ly = vec.f.y;
if (rescale) {
vscale(&vec.f.x, &vec.f.y);
vscale(&vec.t.x, &vec.t.y);
}
(*slvec)(&vec, curcolor);/* Draw vector on screen */
slx = vec.f.x; /* Save scaled point */
sly = vec.f.y;
break;
case 0xFC00: /* End of file */
break;
case 0xFD00: /* Flood command */
vec.f.x = sli();
vec.f.y = sli();
if ((int) vec.f.y < 0) { /* start or end */
if (poly.npoints != 0) { /* end? */
if (poly.npoints > 2 && poly.npoints < 11) {
(*slflood)(&poly, curcolor);
} else {
pm_error("Bad polygon vertex count (%d)",
poly.npoints);
}
poly.npoints = 0;
} else {
poly.fill = -vec.f.y; /* Start */
}
} else { /* Polygon vertex */
if (poly.npoints < 10) {
if (rescale) {
vscale(&vec.f.x, &vec.f.y);
}
poly.pt[poly.npoints].x = vec.f.x;
poly.pt[poly.npoints].y = vec.f.y;
}
poly.npoints++;
}
break;
case 0xFE00: /* Common endpoint compressed */
vec.f.x = lx + extend(cw & 0xFF);
vec.f.y = ly + slib();
lx = vec.f.x;
ly = vec.f.y;
vec.t.x = slx;
vec.t.y = sly;
if (rescale) {
vscale(&vec.f.x, &vec.f.y);
}
(*slvec)(&vec, curcolor);/* Draw vector */
slx = vec.f.x; /* Save scaled point */
sly = vec.f.y;
break;
case 0xFF00: /* Change color */
curcolor = cw & 0xFF;
break;
default: /* Co-ordinates */
lx = vec.f.x = cw;
ly = vec.f.y = sli();
vec.t.x = sli();
vec.t.y = sli();
if (rescale) {
vscale(&vec.f.x, &vec.f.y);
vscale(&vec.t.x, &vec.t.y);
}
(*slvec)(&vec, curcolor);
slx = vec.f.x; /* Save scaled point */
sly = vec.f.y;
break;
}
}
}
/* Main program. */
int
main(int argc,
const char * argv[]) {
int argn;
const char * const usage = "[-verbose] [-info] [-adjust] [-scale <s>]\n\
[-dir] [-lib|-Lib <name>]\n\
[-xsize|-width <x>] [-ysize|-height <y>] [sldfile]";
bool dironly;
bool hgtspec;
bool widspec;
bool scalespec;
bool ucasen;
const char * slobber; /* Slide library item */
pm_proginit(&argc, argv);
argn = 1;
slobber = NULL;
dironly = false;
hgtspec = false;
widspec = false;
scalespec = false;
ucasen = false;
blither = false;
info = false;
adjust = false;
while (argn < argc && argv[argn][0] == '-' && argv[argn][1] != '\0') {
if (pm_keymatch(argv[argn], "-verbose", 2)) {
blither = true;
} else if (pm_keymatch(argv[argn], "-adjust", 2)) {
adjust = true;
} else if (pm_keymatch(argv[argn], "-dir", 2)) {
dironly = true;
} else if (pm_keymatch(argv[argn], "-info", 2)) {
info = true;
} else if (pm_keymatch(argv[argn], "-lib", 2)) {
if (slobber)
pm_error("already specified a library item");
ucasen = argv[argn][1] != 'L';
argn++;
if (argn == argc) {
pm_usage(usage);
}
slobber = argv[argn];
} else if (pm_keymatch(argv[argn], "-scale", 2)) {
if (scalespec) {
pm_error("already specified a scale factor");
}
argn++;
if ((argn == argc) || (sscanf(argv[argn], "%lf", &uscale) != 1))
pm_usage(usage);
if (uscale <= 0.0) {
pm_error("scale factor must be greater than 0");
}
scalespec = true;
} else if (pm_keymatch(argv[argn], "-xsize", 2) ||
pm_keymatch(argv[argn], "-width", 2)) {
if (widspec) {
pm_error("already specified a width/xsize");
}
argn++;
if ((argn == argc) || (sscanf(argv[argn], "%d", &sxsize) != 1))
pm_usage(usage);
widspec = true;
} else if (pm_keymatch(argv[argn], "-ysize", 2) ||
pm_keymatch(argv[argn], "-height", 2)) {
if (hgtspec) {
pm_error("already specified a height/ysize");
}
argn++;
if ((argn == argc) || (sscanf(argv[argn], "%d", &sysize) != 1))
pm_usage(usage);
hgtspec = true;
} else {
pm_usage(usage);
}
argn++;
}
/* If a file name is specified, open it. Otherwise read from
standard input.
*/
if (argn < argc) {
slfile = pm_openr(argv[argn]);
argn++;
} else {
slfile = stdin;
}
if (argn != argc) { /* Extra bogus arguments ? */
pm_usage(usage);
}
/* If we're extracting an item from a slide library, position the
input stream to the start of the chosen slide.
*/
if (dironly || slobber)
slidefind(slobber, dironly, ucasen);
if (!dironly) {
slider(draw, flood);
ppm_writeppm(stdout, pixels, pixcols, pixrows, pixmaxval, 0);
}
pm_close(slfile);
pm_close(stdout);
return 0;
}