ref: aba0c7fceac419c426da85b3f5d4bfe82d410e00
dir: /sys/src/cmd/jpg/writeppm.c/
#include <u.h> #include <libc.h> #include <draw.h> #include <memdraw.h> #include <bio.h> #define MAXLINE 70 /* imported from libdraw/arith.c to permit an extern log2 function */ static int log2[] = { -1, 0, 1, -1, 2, -1, -1, -1, 3, -1, -1, -1, -1, -1, -1, -1, 4, -1, -1, -1, -1, -1, -1, -1, 4 /* BUG */, -1, -1, -1, -1, -1, -1, -1, 5 }; static int bitc = 0; static int nbit = 0; static void Bputbit(Biobufhdr *b, int c) { if(c >= 0x0){ bitc = (bitc << 1) | (c & 0x1); nbit++; }else if(nbit > 0){ for(; nbit < 8; nbit++) bitc <<= 1; } if(nbit == 8){ Bputc(b, bitc); bitc = nbit = 0; } } /* * Write data */ static char* writedata(Biobuf *fd, Image *image, Memimage *memimage, int rflag) { char *err; uchar *data; int i, x, y, ndata, depth, col, pix, xmask, pmask; ulong chan; Rectangle r; if(memimage != nil){ r = memimage->r; depth = memimage->depth; chan = memimage->chan; }else{ r = image->r; depth = image->depth; chan = image->chan; } /* * Read image data into memory * potentially one extra byte on each end of each scan line */ ndata = Dy(r)*(2+Dx(r)*depth/8); data = malloc(ndata); if(data == nil) return "WritePPM: malloc failed"; if(memimage != nil) ndata = unloadmemimage(memimage, r, data, ndata); else ndata = unloadimage(image, r, data, ndata); if(ndata < 0){ err = malloc(ERRMAX); if(err == nil) return "WritePPM: malloc failed"; snprint(err, ERRMAX, "WritePPM: %r"); free(data); return err; } /* Encode and emit the data */ col = 0; switch(chan){ case GREY1: case GREY2: case GREY4: pmask = (1<<depth)-1; xmask = 7>>log2[depth]; for(y=r.min.y; y<r.max.y; y++){ i = (y-r.min.y)*bytesperline(r, depth); for(x=r.min.x; x<r.max.x; x++){ pix = (data[i]>>depth*((xmask-x)&xmask))&pmask; if(((x+1)&xmask) == 0) i++; if(chan == GREY1){ pix ^= 1; if(rflag){ Bputbit(fd, pix); continue; } } else { if(rflag){ Bputc(fd, pix); continue; } } col += Bprint(fd, "%d", pix); if(col >= MAXLINE-(2+1)){ Bprint(fd, "\n"); col = 0; }else if(y < r.max.y-1 || x < r.max.x-1) col += Bprint(fd, " "); } if(rflag) Bputbit(fd, -1); } break; case GREY8: for(i=0; i<ndata; i++){ if(rflag){ Bputc(fd, data[i]); continue; } col += Bprint(fd, "%d", data[i]); if(col >= MAXLINE-(4+1)){ Bprint(fd, "\n"); col = 0; }else if(i < ndata-1) col += Bprint(fd, " "); } break; case RGB24: for(i=0; i<ndata; i+=3){ if(rflag){ Bputc(fd, data[i+2]); Bputc(fd, data[i+1]); Bputc(fd, data[i]); continue; } col += Bprint(fd, "%d %d %d", data[i+2], data[i+1], data[i]); if(col >= MAXLINE-(4+4+4+1)){ Bprint(fd, "\n"); col = 0; }else if(i < ndata-3) col += Bprint(fd, " "); } break; default: return "WritePPM: can't handle channel type"; } return nil; } static char* writeppm0(Biobuf *fd, Image *image, Memimage *memimage, Rectangle r, int chan, char *comment, int rflag) { char *err; switch(chan){ case GREY1: Bprint(fd, "%s\n", rflag? "P4": "P1"); break; case GREY2: case GREY4: case GREY8: Bprint(fd, "%s\n", rflag? "P5": "P2"); break; case RGB24: Bprint(fd, "%s\n", rflag? "P6": "P3"); break; default: return "WritePPM: can't handle channel type"; } if(comment!=nil && comment[0]!='\0'){ Bprint(fd, "# %s", comment); if(comment[strlen(comment)-1] != '\n') Bprint(fd, "\n"); } Bprint(fd, "%d %d\n", Dx(r), Dy(r)); /* maximum pixel value */ switch(chan){ case GREY2: Bprint(fd, "%d\n", 3); break; case GREY4: Bprint(fd, "%d\n", 15); break; case GREY8: case RGB24: Bprint(fd, "%d\n", 255); break; } err = writedata(fd, image, memimage, rflag); if(!rflag) Bprint(fd, "\n"); Bflush(fd); return err; } char* writeppm(Biobuf *fd, Image *image, char *comment, int rflag) { return writeppm0(fd, image, nil, image->r, image->chan, comment, rflag); } char* memwriteppm(Biobuf *fd, Memimage *memimage, char *comment, int rflag) { return writeppm0(fd, nil, memimage, memimage->r, memimage->chan, comment, rflag); }