/* ********************************************************************** *\ * Copyright IBM Corporation 1988,1991 - All Rights Reserved * * For full copyright information see:'andrew/config/COPYRITE' * \* ********************************************************************** */ /* $Disclaimer: * Permission to use, copy, modify, and distribute this software and its * documentation for any purpose is hereby granted without fee, * provided that the above copyright notice appear in all copies and that * both that copyright notice, this permission notice, and the following * disclaimer appear in supporting documentation, and that the names of * IBM, Carnegie Mellon University, and other copyright holders, not be * used in advertising or publicity pertaining to distribution of the software * without specific, written prior permission. * * IBM, CARNEGIE MELLON UNIVERSITY, AND THE OTHER COPYRIGHT HOLDERS * DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING * ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT * SHALL IBM, CARNEGIE MELLON UNIVERSITY, OR ANY OTHER COPYRIGHT HOLDER * BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY * DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, * WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE * OF THIS SOFTWARE. * $ */ #ifndef NORCSID #define NORCSID static char rcsid[]="$Header: /afs/cs.cmu.edu/project/atk-dist/auis-6.3/atk/preview/RCS/dvi2disp.c,v 2.10 1992/12/15 21:39:11 rr2b R6tape $"; #endif /* ***************************************************************** */ /* dvi2disp.c Troff DVI preview program */ /* Uses the ITC window manager. Part of prview.c */ /* ***************************************************************** */ #include #include #include #include #define AUXMODULE 1 #include #include #include #include preview_coordinate DX = 5; /* step size in x */ preview_coordinate DY = 5; /* step size in y */ preview_coordinate maxdots = 32000; /* maximum number of dots in an object */ static int geti (self ) struct preview *self; { register FILE * f = self->DviFileIn; register int n = 0; register Boolean neg = FALSE; register int c; if (self->peekc == 0 || isspace(c = self->peekc)) while (isspace(c = getc(f))); if (c == '-') { neg = TRUE; c = getc(f); } while (isdigit(c)) { n = n * 10 + c - '0'; c = getc(f); } self->peekc = c; return(neg ? -n : n); } static char *pregets (self) struct preview *self; { register FILE * f = self->DviFileIn; register char *p; static Preview_Line buf; register c; if (self->peekc == 0 || isspace(c = self->peekc)) while (isspace(c = getc(f))); p = buf; while (c != EOF && !isspace(c)) { *p++ = c; c = getc(f); } *p++ = '\0'; self->peekc = c; return(buf); } /* ************************************************************ */ /* */ /* */ /* ************************************************************ */ /* compute the physical position; return FALSE if not on screen */ static Boolean SetPosition(self) register struct preview *self; { register cvx = self->LogicalX * self->DisplayResolution / self->InputResolution; register cvy = self->LogicalY * self->DisplayResolution / self->InputResolution; if (cvx+self->xoff < 0 || self->WindowWidth+self->cursize <= cvx+self->xoff || cvy+self->yoff < 0 || self->WindowHeight+self->cursize <= cvy+self->yoff) return(FALSE); if (self->PhysicalX != cvx || self->PhysicalY != cvy) { preview_MoveTo(self,cvx + self->xoff, cvy + self->yoff); self->PhysicalX = cvx; self->PhysicalY = cvy; } return(TRUE); } /* ************************************************************ */ /* */ /* */ /* ************************************************************ */ static UseFont(self,f,s) struct preview *self; int f,s; { register h, l, m; register struct preview_fontname *p; int n; s = self->DisplayResolution*s/preview_DISPLAY_RESOLUTION; n = f*60+s; h = self->NWMFonts - 1; l = 0; while (l < h) { m = (l + h) >> 1; p = &(self->WMFonts[m]); if (n < p->number) h = m - 1; else if (n > p->number) l = m + 1; else { l = m; break; } } p = &(self->WMFonts[l]); if (self->NWMFonts == 0 || p->number != n) { Preview_Line fname; static char *format[] = { "AndySymbol%d", "AndySymbolA%d", "Andy%d", "Andy%db", "Andy%di", "Andy%dbi", "AndyType%df", "AndyType%dbf", "AndyType%dif", "AndyType%dbif", "AndySans%d", "AndySans%db", "AndySans%di", "AndySans%dbi", "AndyType%df", "AndyType%dbf", "AndyType%dif", "AndyType%dbif", }; bcopy(p, p + 1,(self->NWMFonts - l) * sizeof(struct preview_fontname)); p->number = n; if (f >= 17) p->font = NULL; else { char namebuf[100]; long style; long size; sprintf(fname, format[f], s); fontdesc_ExplodeFontName(fname,namebuf,(long) sizeof(namebuf),&style,&size); p->font = fontdesc_Create(namebuf,style,size); } } if (p->font != NULL) preview_SetFont(self,p->font); } /* ************************************************************ */ /* */ /* */ /* ************************************************************ */ static DrawThing(self) struct preview *self; { char *com = pregets (self); switch (com[0]) { case 'l': /* draw line from current to +dx,+dy */ { preview_coordinate dx = geti (self); preview_coordinate dy = geti (self); /* Don't use the SetPosition call here,since it won't move off screen */ preview_coordinate cvx = self->LogicalX * self->DisplayResolution / self->InputResolution; preview_coordinate cvy = self->LogicalY * self->DisplayResolution / self->InputResolution; if (self->PhysicalX != cvx || self->PhysicalY != cvy) preview_MoveTo(self,cvx + self->xoff, cvy + self->yoff); self->PhysicalX = cvx + dx * self->DisplayResolution / self->InputResolution; self->PhysicalY = cvy + dy * self->DisplayResolution / self->InputResolution; preview_DrawLineTo(self,self->PhysicalX + self->xoff, self->PhysicalY + self->yoff); self->LogicalX += dx; self->LogicalY += dy; break; } case 'a': { preview_coordinate dx1, dy1, dx2, dy2; dx1 = geti(self); dy1 = geti(self); dx2 = geti(self); dy2 = geti(self); drawarc(self,dx1, dy1, dx2, dy2); break; } case 'c': drawcirc(self,geti(self)); break; case 'e': { preview_coordinate a, b; a = geti(self); b = geti(self); drawellip(self,a, b); break; } case '~': { char buf[1000]; fgets(buf, sizeof buf, self->DviFileIn); drawwig(self,buf); break; } default: printf("Unimplemented draw command: %s\n", com); break; } /* skip to end of line */ while (self->peekc != '\n' && self->peekc != EOF) self->peekc = getc(self->DviFileIn); } /* ***************************************************************** */ #define Sansserif 8 #define Typewriter 4 #define Italic 2 #define Bold 1 #define SerifNormal 0 #define SerifItalic Italic #define SerifBold Bold #define SerifBoldItalic (Bold + Italic) #define BoldItalic (Bold + Italic) #define Symbol 0 #define SymbolA 1 #define Normal 2 struct trs { char name[2]; unsigned char ch; char font; } trs[] = { "!<", 0000, Symbol, "!=", 0071, SymbolA, "!>", 0000, Symbol, "**", 0052, Symbol, "*A", 0101, Symbol, "*B", 0102, Symbol, "*C", 0130, Symbol, "*D", 0104, Symbol, "*E", 0105, Symbol, "*F", 0106, Symbol, "*G", 0107, Symbol, "*H", 0121, Symbol, "*I", 0111, Symbol, "*K", 0113, Symbol, "*L", 0114, Symbol, "*M", 0115, Symbol, "*N", 0116, Symbol, "*O", 0117, Symbol, "*P", 0120, Symbol, "*Q", 0131, Symbol, "*R", 0122, Symbol, "*S", 0123, Symbol, "*T", 0124, Symbol, "*U", 0125, Symbol, "*W", 0127, Symbol, "*X", 0103, Symbol, "*Y", 0110, Symbol, "*Z", 0132, Symbol, "*a", 0141, Symbol, "*b", 0142, Symbol, "*c", 0170, Symbol, "*d", 0144, Symbol, "*e", 0145, Symbol, "*f", 0146, Symbol, "*g", 0147, Symbol, "*h", 0161, Symbol, "*i", 0151, Symbol, "*k", 0153, Symbol, "*l", 0154, Symbol, "*m", 0155, Symbol, "*n", 0156, Symbol, "*o", 0157, Symbol, "*p", 0160, Symbol, "*q", 0171, Symbol, "*r", 0162, Symbol, "*s", 0163, Symbol, "*t", 0164, Symbol, "*u", 0165, Symbol, "*w", 0167, Symbol, "*x", 0143, Symbol, "*y", 0150, Symbol, "*z", 0172, Symbol, "+-", 0061, SymbolA, "->", 0056, SymbolA, "<-", 0054, SymbolA, "<=", 0043, SymbolA, "==", 0072, SymbolA, ">=", 0063, SymbolA, /* "Fi", 0021, Normal, "Fl", 0022, Normal, */ "\\'", '\'', Normal, "\\-", '-', Normal, "\\^",0000, Normal, "\\`", '`', Normal, "\\|", 0000, Normal, /* "aa", 0000, Normal, */ "ap", 0176, Symbol, "br", 0075, SymbolA, "bu", 0067, SymbolA, "bv", 0157, SymbolA, "ca", 0107, SymbolA, "co", 0123, SymbolA, /* "ct", 0000, Normal, */ "cu", 0110, SymbolA, "da", 0057, SymbolA, /* "dd", 0106, Symbol, */ "de", 0060, SymbolA, /* "dg", 0041, Symbol, */ "di", 0070, SymbolA, /* "em", 0000, Normal, "en", 0000, Symbol, */ "eq", 0075, Symbol, "es", 0106, SymbolA, /* "ff", 0006, Normal, "fi", 0024, Normal, "fl", 0025, Normal, */ "fm", 0042, SymbolA, /* "ga", 0000, Symbol, */ "gr", 0121, SymbolA, "hy", 0055, Normal, "ib", 0115, SymbolA, "if", 0045, SymbolA, "ip", 0112, SymbolA, "is", 0162, SymbolA, "lb", 0150, SymbolA, "lc", 0151, SymbolA, "lf", 0153, SymbolA, "lk", 0155, SymbolA, "lt", 0146, SymbolA, "mi", 0055, Symbol, "mo", 0116, SymbolA, "mu", 0064, SymbolA, "or", 0075, SymbolA, "pd", 0066, SymbolA, "pl", 0053, Symbol, "pt", 0065, SymbolA, "rb", 0170, SymbolA, "rc", 0171, SymbolA, "rf", 0173, SymbolA, "rk", 0175, SymbolA, "rn", 0140, Symbol, "rt", 0166, SymbolA, "ru", 0137, Symbol, "sb", 0114, SymbolA, /* "sc", 0000, Symbol, */ "sl", 0044, SymbolA, "sr", 0126, SymbolA, "tm", 0124, SymbolA, "ts", 0126, Symbol, "ua", 0055, SymbolA, "ul", 0137, Symbol, "~=", 0100, Symbol, }; static ShowSpecial(self) struct preview *self; { register char *s = pregets (self); register h, l, m; register struct trs *p; /* if (s[0] == 'u' && s[1] == 'l' && s[2] == 0) { if (SetPosition(self)) preview_EraseRectSize(self,self->PhysicalX + self->xoff, self->PhysicalY + 1 + self->yoff, (self->cursize * 17 * self->DisplayResolution + 1200) / 2400, 1); } else if (s[0] == 'r' && s[1] == 'u' && s[2] == 0) { if (SetPosition(self)) preview_EraseRectSize(self,self->PhysicalX + self->xoff, self->PhysicalY + 1 + self->yoff, (self->cursize * self->DisplayResolution + 120) / 240, 1); } else if (s[0] == 'b' && s[1] == 'r' && s[2] == 0) { if (SetPosition(self)) preview_EraseRectSize(self,self->PhysicalX + self->xoff, self->PhysicalY + 2 + self->yoff, 1, ((-10 * self->cursize) / 3 *self->DisplayResolution - 120) / 240); } else */ if (s[0] == 'f' && s[1] == 'i' && s[2] == 0) { if (SetPosition(self)) preview_DrawString(self,"fi",0); } else if (s[0] == 'f' && s[1] == 'f' && s[2] == 0) { if (SetPosition(self)) preview_DrawString(self,"ff",0); } else if (s[0] == 'f' && s[1] == 'l' && s[2] == 0) { if (SetPosition(self)) preview_DrawString(self,"fl",0); } else if (s[0] == 'F' && s[1] == 'i' && s[2] == 0) { if (SetPosition(self)) preview_DrawString(self,"ffi",0); } else if (s[0] == 'F' && s[1] == 'l' && s[2] == 0) { if (SetPosition(self)) preview_DrawString(self,"ffl",0); } else { l = 0; h = sizeof trs / sizeof trs[0]; while (l < h - 1) { m = (l + h) >> 1; p = &trs[m]; if (s[0] < p->name[0] || (s[0] == p->name[0] && s[1] < p->name[1])) h = m; else l = m; } p = &trs[l]; if (s[0] == p->name[0] && s[1] == p->name[1] && p->ch) { struct fontdesc *ofont = preview_GetFont(self); if (p->font != Normal) UseFont(self,p->font, self->cursize); if (SetPosition(self)) preview_DrawText(self,&(p->ch),1,0); if (ofont != preview_GetFont(self)) preview_SetFont(self,ofont); } } self->PhysicalX = -1; } /* ************************************************************ */ /* */ /* */ /* ************************************************************ */ static void DeviceControl(self) struct preview *self; { char com = pregets (self)[0]; if (self->debug) fprintf(stderr,"device control %c\n",com); switch (com) { case 'i': case 'p': case 's': case 't': break; case 'T': (void) pregets(self); break; case 'r': self->InputResolution = geti(self); (void) geti(self); (void) geti(self); break; case 'f': com = geti(self); { char *name = pregets (self); int value; value = SerifNormal; switch (name[0]) { case 'R': break; case 'I': value = SerifItalic; break; case 'B': value = (name[1] == 'I') ? SerifBoldItalic : SerifBold; break; case 'H': case 'C': value = (name[0] == 'C') ? Typewriter : Sansserif; switch (name[1]) { case 'R': break; case 'O': value += Italic; break; case 'B': value += Bold; break; case 'D': value += BoldItalic; break; } } self->DviFonts[com] = value + 2; } break; case 'H': self->cursize = geti(self); UseFont( self,self->curfont, self->cursize); break; case 'S': self->slant = geti(self); break; default: printf("Unknown device command: %c\n", com); break; } } /* ************************************************************ */ /* */ /* */ /* ************************************************************ */ static void DumpCharacter(self,c) struct preview *self; char c; { self->CharactersOnThisPage = TRUE; if (SetPosition(self)) { if (c == '_') preview_FillRectSize(self,self->PhysicalX + self->xoff, self->PhysicalY + 1 + self->yoff, (17 * self->cursize * self->DisplayResolution + 1200) / 2400, 1,preview_BlackPattern(self)); else preview_DrawText(self,&c,1L,0); /* putc(c, winout); */ } self->PhysicalX = -1; } void preview__DviToDisplay(self) struct preview *self; { register FILE * f = self->DviFileIn; register int c,lastc; self->CharactersOnThisPage = FALSE; self->peekc = getc(f); while ((c = self->peekc) != EOF) { self->peekc = 0; if (isdigit(c)) { self->LogicalX += (c - '0') * 10 + getc(f) - '0'; c = getc(f); DumpCharacter(self,c); if (self->debug) fprintf(stderr, "%d%c", self->LogicalX, c); } else { if (self->debug) fprintf(stderr,"%c ", c); switch (c) { case ' ': case '\t': case '\n': break; case 's': self->cursize = geti(self); UseFont( self, self->curfont, self->cursize); break; case 'f': self->curfont = self->DviFonts[geti(self)]; UseFont( self, self->curfont, self->cursize); break; case 'c': c = getc(f); DumpCharacter(self,c); break; case 'C': ShowSpecial(self); break; case 'H': self->LogicalX = geti(self); break; case 'V': self->LogicalY = geti(self); break; case 'h': self->LogicalX += geti(self); break; case 'v': self->LogicalY += geti(self); break; case 'n': (void) geti(self); (void) geti(self); break; case 'w': break; case 'p': return; case 'x': DeviceControl(self); break; case 'D': DrawThing(self); break; case '%': /* skip over postscript */ while((c = getc(f)) != EOF){ if(c == '.' && lastc == '\n' && (((c = getc(f)) == '\n') || c == EOF)) break; lastc = c; } break; } } if ( self->peekc == 0) self->peekc = getc(f); if ( self->SizeChanged/* || --(PollCount) == 0 && PollWinin() */) return; } } /* ******************************************************************* *\ * * * File: draw.c * * Date: Tue Apr 3 16:43:15 1984 * * Author: ? * * * * This file started out as draw.c from the Unix DVI troff distribution * * It contains all the intense routines that understand arcs and splines* * * * Converted to deal with the WM by James Gosling. * * * * * \********************************************************************* */ #define PI 3.141592654 #define hmot(n) self->LogicalX += n #define hgoto(n) self->LogicalX = n #define vgoto(n) self->LogicalY = n #define vmot(n) self->LogicalY += n #define sgn(n) ((n > 0) ? 1 : ((n < 0) ? -1 : 0)) #define abs(n) ((n) >= 0 ? (n) : -(n)) #define max(x,y) ((x) > (y) ? (x) : (y)) #define min(x,y) ((x) < (y) ? (x) : (y)) #define arcmove(X,Y) { hgoto(X); vmot(-y-(Y)); } #define scale(v) (((v)* self->DisplayResolution+( self->InputResolution>>1))/ self->InputResolution) static drawwig(self,s) /* draw wiggly line */ struct preview *self; char *s; { preview_coordinate xc[50], yc[50], xp, yp, pxp, pyp; float t1, t2, t3, w; preview_coordinate i, j, numdots, N; char temp[50], *p, *getstr (); p = s; for (N = 2; (p = getstr (p, temp)) != NULL && N < sizeof (xc) / sizeof (xc[0]); N++) { xc[N] = atoi (temp); p = getstr (p, temp); yc[N] = atoi (temp); } xc[0] = xc[1] = self->LogicalX; yc[0] = yc[1] = self->LogicalY; for (i = 1; i < N; i++) { xc[i + 1] += xc[i]; yc[i + 1] += yc[i]; } self->LogicalX = xc[N] = xc[N - 1]; self->LogicalY = yc[N] = yc[N - 1]; for (i = 0; i <= N; i++) { xc[i] = scale(xc[i]); yc[i] = scale(yc[i]); } preview_MoveTo (self,xc[1]+ self->xoff, yc[1]+ self->yoff); pxp = pyp = -9999; for (i = 0; i < N - 1; i++) {/* interval */ numdots = (dist (xc[i], yc[i], xc[i + 1], yc[i + 1]) + dist (xc[i + 1], yc[i + 1], xc[i + 2], yc[i + 2])) / 2; numdots /= DX; numdots = min (numdots, maxdots); for (j = 0; j < numdots; j++) {/* points within */ w = (float) j / numdots; t1 = 0.5 * w * w; w = w - 0.5; t2 = 0.75 - w * w; w = w - 0.5; t3 = 0.5 * w * w; xp = t1 * xc[i + 2] + t2 * xc[i + 1] + t3 * xc[i] + 0.5; yp = t1 * yc[i + 2] + t2 * yc[i + 1] + t3 * yc[i] + 0.5; if (xp != pxp || yp != pyp) { preview_DrawLineTo (self,xp+self->xoff, yp+self->yoff); pxp = xp; pyp = yp; } } } } static char *getstr(p, temp) /* copy next non-blank string from p to temp, update p */ char *p, *temp; { while (*p == ' ' || *p == '\t' || *p == '\n') p++; if (*p == '\0') { temp[0] = 0; return (NULL); } while (*p != ' ' && *p != '\t' && *p != '\n' && *p != '\0') *temp++ = *p++; *temp = '\0'; return (p); } static drawcirc (self,d) struct preview *self;{ preview_coordinate xc, yc; xc = self->LogicalX; yc = self->LogicalY; conicarc (self, self->LogicalX + d / 2, - self->LogicalY, self->LogicalX, - self->LogicalY, self->LogicalX, - self->LogicalY, d / 2, d / 2); hgoto (xc + d); /* circle goes to right side */ vgoto (yc); } static dist(x1, y1, x2, y2) /* integer distance from x1,y1 to x2,y2 */ { float dx, dy; dx = x2 - x1; dy = y2 - y1; return sqrt (dx * dx + dy * dy) + 0.5; } static drawarc(self,dx1, dy1, dx2, dy2) struct preview *self; { preview_coordinate x0, y0, x2, y2, r; x0 = self->LogicalX + dx1; /* center */ y0 = self->LogicalY + dy1; x2 = x0 + dx2; /* "to" */ y2 = y0 + dy2; r = sqrt ((float) dx1 * dx1 + (float) dy1 * dy1) + 0.5; conicarc (self,x0, -y0, self->LogicalX, - self->LogicalY, x2, -y2, r, r); self->LogicalX = x2; self->LogicalY = y2; } static drawellip(self,a, b) struct preview *self; { preview_coordinate xc, yc; xc = self->LogicalX; yc = self->LogicalY; conicarc (self, self->LogicalX + a / 2, - self->LogicalY, self->LogicalX, - self->LogicalY, self->LogicalX, - self->LogicalY, a / 2, b / 2); hgoto (xc + a); vgoto (yc); } #define sqr(x) (long int)(x)*(x) static conicarc(self,xp, yp, x0, y0, x1, y1, a, b) struct preview *self; { /* based on Bresenham, CACM, Feb 77, pp 102-3 */ /* by Chris Van Wyk */ /* capitalized vars are an internal reference frame */ long dotcount = 0; preview_coordinate xs, ys, xt, yt, Xs, Ys, qs, Xt, Yt, qt, M1x, M1y, M2x, M2y, M3x, M3y, Q, move, Xc, Yc; preview_coordinate ox1, oy1; long delta; float xc, yc; float radius, slope; float xstep, ystep; xp = scale(xp); yp = scale(yp); x0 = scale(x0); y0 = scale(y0); x1 = scale(x1); y1 = scale(y1); a = scale(a); b = scale(b); ox1 = x1; oy1 = y1; if (a != b) /* an arc of an ellipse; internally, will still think of circle */ if (a > b) { xstep = (float)a / b; ystep = 1; radius = b; } else { xstep = 1; ystep = (float)b / a; radius = a; } else { /* a circular arc; radius is computed from center and first point */ xstep = 1; ystep = 1; radius = sqrt((float)(sqr(x0 - xp) + sqr(y0 - yp))); } xc = x0; yc = y0; /* now, use start and end point locations to figure out the angle at which start and end happen; use these angles with known radius to figure out where start and end should be */ slope = atan2((double)(y0 - yp), (double)(x0 - xp) ); if (slope == 0.0 && x0 < xp) slope = 3.14159265; x0 = xp + radius * cos(slope) + 0.5; y0 = yp + radius * sin(slope) + 0.5; slope = atan2((double)(y1 - yp), (double)(x1 - xp)); if (slope == 0.0 && x1 < xp) slope = 3.14159265; x1 = xp + radius * cos(slope) + 0.5; y1 = yp + radius * sin(slope) + 0.5; /* step 2: translate to zero-centered circle */ xs = x0 - xp; ys = y0 - yp; xt = x1 - xp; yt = y1 - yp; /* step 3: normalize to first quadrant */ if (xs < 0) if (ys < 0) { Xs = abs(ys); Ys = abs(xs); qs = 3; M1x = 0; M1y = -1; M2x = 1; M2y = -1; M3x = 1; M3y = 0; } else { Xs = abs(xs); Ys = abs(ys); qs = 2; M1x = -1; M1y = 0; M2x = -1; M2y = -1; M3x = 0; M3y = -1; } else if (ys < 0) { Xs = abs(xs); Ys = abs(ys); qs = 0; M1x = 1; M1y = 0; M2x = 1; M2y = 1; M3x = 0; M3y = 1; } else { Xs = abs(ys); Ys = abs(xs); qs = 1; M1x = 0; M1y = 1; M2x = -1; M2y = 1; M3x = -1; M3y = 0; } Xc = Xs; Yc = Ys; if (xt < 0) if (yt < 0) { Xt = abs(yt); Yt = abs(xt); qt = 3; } else { Xt = abs(xt); Yt = abs(yt); qt = 2; } else if (yt < 0) { Xt = abs(xt); Yt = abs(yt); qt = 0; } else { Xt = abs(yt); Yt = abs(xt); qt = 1; } /* step 4: calculate number of quadrant crossings */ if (((4 + qt - qs) % 4 == 0) && (Xt <= Xs) && (Yt >= Ys) ) Q = 3; else Q = (4 + qt - qs) % 4 - 1; /* step 5: calculate initial decision difference */ delta = sqr(Xs + 1) + sqr(Ys - 1) -sqr(xs) -sqr(ys); /* here begins the work of drawing we hope it ends here too */ preview_MoveTo (self,((preview_coordinate)xc)+ self->xoff, ((preview_coordinate)-yc)+ self->yoff); while ((Q >= 0) || ((Q > -2) && ((Xt > Xc) && (Yt < Yc) ) ) ) { if (dotcount++ > DX) { preview_DrawLineTo (self,((preview_coordinate)xc)+ self->xoff, (-(preview_coordinate)yc)+ self->yoff); dotcount = 0; } if (Yc < 0.5) { /* reinitialize */ Xs = Xc = 0; Ys = Yc = sqrt((float)(sqr(xs) + sqr(ys))); delta = sqr(Xs + 1) + sqr(Ys - 1) - sqr(xs) - sqr(ys); Q--; M1x = M3x; M1y = M3y; { int T; T = M2y; M2y = M2x; M2x = -T; T = M3y; M3y = M3x; M3x = -T; } } else { if (delta <= 0) if (2 * delta + 2 * Yc - 1 <= 0) move = 1; else move = 2; else if (2 * delta - 2 * Xc - 1 <= 0) move = 2; else move = 3; switch (move) { case 1: Xc++; delta += 2 * Xc + 1; xc += M1x * xstep; yc += M1y * ystep; break; case 2: Xc++; Yc--; delta += 2 * Xc - 2 * Yc + 2; xc += M2x * xstep; yc += M2y * ystep; break; case 3: Yc--; delta -= 2 * Yc + 1; xc += M3x * xstep; yc += M3y * ystep; break; } } } preview_DrawLineTo (self,((preview_coordinate)ox1)+ self->xoff,(-(preview_coordinate)oy1)+ self->yoff); }