ref: 6540a9a21ae4f62f512f3e95063561d87e80701c
dir: /sys/src/cmd/jpg/readtga.c/
/*
* TGA is a fairly dead standard, however in the video industry
* it is still used a little for test patterns and the like.
*
* Thus we ignore any alpha channels.
*/
#include <u.h>
#include <libc.h>
#include <bio.h>
#include <draw.h>
#include <ctype.h>
#include "imagefile.h"
enum {
HdrLen = 18,
};
typedef struct {
int idlen; /* length of string after header */
int cmaptype; /* 1 => datatype = 1 => colourmapped */
int datatype; /* see below */
int cmaporigin; /* index of first entry in colour map */
int cmaplen; /* length of colour map */
int cmapbpp; /* bits per pixel of colour map: 16, 24, or 32 */
int xorigin; /* source image origin */
int yorigin;
int width;
int height;
int bpp; /* bits per pixel of image: 16, 24, or 32 */
int descriptor;
uchar *cmap; /* colour map (optional) */
} Tga;
/*
* descriptor:
* d0-3 = number of attribute bits per pixel
* d4 = reserved, always zero
* d6-7 = origin: 0=lower left, 1=upper left, 2=lower right, 3=upper right
* d8-9 = interleave: 0=progressive, 1=2 way, 3=4 way, 4=reserved.
*/
char *datatype[] = {
[0] "No image data",
[1] "Color-mapped",
[2] "RGB",
[3] "B&W",
[9] "RLE color-mapped",
[10] "RLE RGB",
[11] "RLE B&W",
[32] "Compressed color",
[33] "Quadtree compressed color",
};
static int
Bgeti(Biobuf *bp)
{
int x, y;
if((x = Bgetc(bp)) < 0)
return -1;
if((y = Bgetc(bp)) < 0)
return -1;
return (y<<8)|x;
}
static int
fixcmap(uchar *cmap, int *cmapbpp, int cmaplen)
{
int i;
ushort x;
uchar tmp;
switch(*cmapbpp){
case 32:
/* swap B with R */
for(i = 0; i < cmaplen; i++){
tmp = cmap[4*i+0];
cmap[4*i+0] = cmap[4*i+2];
cmap[4*i+2] = tmp;
}
break;
case 24:
/* swap B with R */
for(i = 0; i < cmaplen; i++){
tmp = cmap[3*i+0];
cmap[3*i+0] = cmap[3*i+2];
cmap[3*i+2] = tmp;
}
break;
case 16:
case 15:
/* convert to 24-bit colormap */
if((cmap = realloc(cmap, 3*cmaplen)) == nil)
return -1;
for(i = cmaplen-1; i >= 0; i--){
x = (cmap[2*i+1]<<8) | cmap[2*i+0];
tmp = (x>>0)&0x1f;
cmap[3*i+2] = (tmp<<3) | (tmp>>2);
tmp = (x>>5)&0x1f;
cmap[3*i+1] = (tmp<<3) | (tmp>>2);
tmp = (x>>10)&0x1f;
cmap[3*i+0] = (tmp<<3) | (tmp>>2);
}
*cmapbpp = 24;
break;
default:
break;
}
return 0;
}
static Tga *
rdhdr(Biobuf *bp)
{
int n;
Tga *h;
if((h = malloc(sizeof(Tga))) == nil)
return nil;
if((h->idlen = Bgetc(bp)) == -1)
return nil;
if((h->cmaptype = Bgetc(bp)) == -1)
return nil;
if((h->datatype = Bgetc(bp)) == -1)
return nil;
if((h->cmaporigin = Bgeti(bp)) == -1)
return nil;
if((h->cmaplen = Bgeti(bp)) == -1)
return nil;
if((h->cmapbpp = Bgetc(bp)) == -1)
return nil;
if((h->xorigin = Bgeti(bp)) == -1)
return nil;
if((h->yorigin = Bgeti(bp)) == -1)
return nil;
if((h->width = Bgeti(bp)) == -1)
return nil;
if((h->height = Bgeti(bp)) == -1)
return nil;
if((h->bpp = Bgetc(bp)) == -1)
return nil;
if((h->descriptor = Bgetc(bp)) == -1)
return nil;
/* skip over ID, usually empty anyway */
if(Bseek(bp, h->idlen, 1) < 0){
free(h);
return nil;
}
if(h->cmaptype == 0){
h->cmap = 0;
return h;
}
/* skip over unused color map data */
n = (h->cmapbpp/8)*h->cmaporigin;
if(Bseek(bp, n, 1) < 0){
free(h);
return nil;
}
h->cmaplen -= h->cmaporigin;
n = (h->cmapbpp/8)*h->cmaplen;
if((h->cmap = malloc(n)) == nil){
free(h);
return nil;
}
if(Bread(bp, h->cmap, n) != n){
free(h);
free(h->cmap);
return nil;
}
if(fixcmap(h->cmap, &h->cmapbpp, h->cmaplen) != 0){
free(h);
free(h->cmap);
return nil;
}
return h;
}
static int
cmap(Biobuf *bp, uchar *l, int num)
{
return Bread(bp, l, num);
}
static int
luma(Biobuf *bp, int bpp, uchar *l, int num)
{
char tmp[2];
int got;
if(bpp == 8){
got = Bread(bp, l, num);
}
else{
for(got = 0; got < num; got++){
if(Bread(bp, tmp, 2) != 2)
break;
*l++ = tmp[0];
}
}
return got;
}
static int
luma_rle(Biobuf *bp, int bpp, uchar *l, int num)
{
uchar len, p;
int got;
for(got = 0; got < num;){
if(Bread(bp, &len, 1) != 1)
break;
if(len & 0x80){
len &= 0x7f;
if(luma(bp, bpp, &p, 1) != 1)
break;
for(len++; len > 0 && got < num; len--, got++)
*l++ = p;
}
else{
for(len++; len > 0 && got < num; len--, got++)
if(luma(bp, bpp, l++, 1) != 1)
return got;
}
}
return got;
}
static int
cmap_rle(Biobuf *bp, uchar *l, int num)
{
return luma_rle(bp, 8, l, num);
}
static int
rgba(Biobuf *bp, int bpp, uchar *r, uchar *g, uchar *b, int num)
{
int i;
uchar buf[4], tmp;
ushort x;
switch(bpp){
case 16:
case 15:
for(i = 0; i < num; i++){
if(Bread(bp, buf, 2) != 2)
break;
x = (buf[1]<<8) | buf[0];
tmp = (x>>0)&0x1f;
*b++ = (tmp<<3) | (tmp>>2);
tmp = (x>>5)&0x1f;
*g++ = (tmp<<3) | (tmp>>2);
tmp = (x>>10)&0x1f;
*r++ = (tmp<<3) | (tmp>>2);
}
break;
case 24:
for(i = 0; i < num; i++){
if(Bread(bp, buf, 3) != 3)
break;
*b++ = buf[0];
*g++ = buf[1];
*r++ = buf[2];
}
break;
case 32:
for(i = 0; i < num; i++){
if(Bread(bp, buf, 4) != 4)
break;
*b++ = buf[0];
*g++ = buf[1];
*r++ = buf[2];
}
break;
default:
i = 0;
break;
}
return i;
}
static int
rgba_rle(Biobuf *bp, int bpp, uchar *r, uchar *g, uchar *b, int num)
{
uchar len;
int i, got;
for(got = 0; got < num; got += len){
if(Bread(bp, &len, 1) != 1)
break;
if(len & 0x80){
len &= 0x7f;
len += 1; /* run of zero is meaningless */
if(rgba(bp, bpp, r, g, b, 1) != 1)
break;
for(i = 1; i < len && got+i < num; i++){
r[i] = *r;
g[i] = *g;
b[i] = *b;
}
len = i;
}
else{
len += 1; /* raw block of zero is meaningless */
if(rgba(bp, bpp, r, g, b, len) != len)
break;
}
r += len;
g += len;
b += len;
}
return got;
}
int
flip(Rawimage *ar)
{
int w, h, c, l;
uchar *t, *s, *d;
w = Dx(ar->r);
h = Dy(ar->r);
if((t = malloc(w)) == nil){
werrstr("ReadTGA: no memory - %r\n");
return -1;
}
for(c = 0; c < ar->nchans; c++){
s = ar->chans[c];
d = ar->chans[c] + ar->chanlen - w;
for(l = 0; l < (h/2); l++){
memcpy(t, s, w);
memcpy(s, d, w);
memcpy(d, t, w);
s += w;
d -= w;
}
}
free(t);
return 0;
}
int
reflect(Rawimage *ar)
{
int w, h, c, l, p;
uchar t, *sol, *eol, *s, *d;
w = Dx(ar->r);
h = Dy(ar->r);
for(c = 0; c < ar->nchans; c++){
sol = ar->chans[c];
eol = ar->chans[c] +w -1;
for(l = 0; l < h; l++){
s = sol;
d = eol;
for(p = 0; p < w/2; p++){
t = *s;
*s = *d;
*d = t;
s++;
d--;
}
sol += w;
eol += w;
}
}
return 0;
}
Rawimage**
Breadtga(Biobuf *bp)
{
Tga *h;
int n, c, num;
uchar *r, *g, *b;
Rawimage *ar, **array;
if((h = rdhdr(bp)) == nil){
werrstr("ReadTGA: bad header %r");
return nil;
}
if(0){
fprint(2, "idlen=%d\n", h->idlen);
fprint(2, "cmaptype=%d\n", h->cmaptype);
fprint(2, "datatype=%s\n", datatype[h->datatype]);
fprint(2, "cmaporigin=%d\n", h->cmaporigin);
fprint(2, "cmaplen=%d\n", h->cmaplen);
fprint(2, "cmapbpp=%d\n", h->cmapbpp);
fprint(2, "xorigin=%d\n", h->xorigin);
fprint(2, "yorigin=%d\n", h->yorigin);
fprint(2, "width=%d\n", h->width);
fprint(2, "height=%d\n", h->height);
fprint(2, "bpp=%d\n", h->bpp);
fprint(2, "descriptor=%d\n", h->descriptor);
}
array = nil;
if((ar = calloc(1, sizeof(Rawimage))) == nil){
werrstr("ReadTGA: no memory - %r\n");
goto Error;
}
if((array = calloc(2, sizeof(Rawimage *))) == nil){
werrstr("ReadTGA: no memory - %r\n");
goto Error;
}
array[0] = ar;
array[1] = nil;
if(h->datatype == 3 || h->datatype == 11){
ar->nchans = 1;
ar->chandesc = CY;
}
else if(h->datatype == 1){
ar->nchans = 1;
ar->chandesc = CRGB1;
}
else if(h->datatype == 9){
ar->nchans = 1;
ar->chandesc = (h->cmapbpp == 32) ? CRGBV : CRGB1;
}
else{
ar->nchans = 3;
ar->chandesc = CRGB;
}
ar->cmap = h->cmap;
ar->cmaplen = (h->cmapbpp/8)*h->cmaplen;
ar->chanlen = h->width*h->height;
ar->r = Rect(0, 0, h->width, h->height);
for(c = 0; c < ar->nchans; c++)
if((ar->chans[c] = malloc(h->width*h->height)) == nil){
werrstr("ReadTGA: no memory - %r\n");
goto Error;
}
r = ar->chans[0];
g = ar->chans[1];
b = ar->chans[2];
num = h->width*h->height;
switch(h->datatype){
case 1:
n = cmap(bp, r, num);
break;
case 2:
n = rgba(bp, h->bpp, r, g, b, num);
break;
case 3:
n = luma(bp, h->bpp, r, num);
break;
case 9:
n = cmap_rle(bp, r, num);
break;
case 10:
n = rgba_rle(bp, h->bpp, r, g, b, num);
break;
case 11:
n = luma_rle(bp, h->bpp, r, num);
break;
default:
werrstr("ReadTGA: type=%d (%s) unsupported\n", h->datatype, datatype[h->datatype]);
goto Error;
}
if(n != num){
werrstr("ReadTGA: decode fail (%d!=%d) - %r\n", n, num);
goto Error;
}
if((h->descriptor&(1<<4)) != 0)
reflect(ar);
if((h->descriptor&(1<<5)) == 0)
flip(ar);
free(h);
return array;
Error:
if(ar)
for (c = 0; c < ar->nchans; c++)
free(ar->chans[c]);
free(ar);
free(array);
free(h->cmap);
free(h);
return nil;
}
Rawimage**
readtga(int fd)
{
Rawimage * *a;
Biobuf b;
if(Binit(&b, fd, OREAD) < 0)
return nil;
a = Breadtga(&b);
Bterm(&b);
return a;
}