X-Git-Url: https://git.sesse.net/?p=rdpsrv;a=blobdiff_plain;f=Xserver%2Flib%2Ffont%2FType1%2Fhints.c;fp=Xserver%2Flib%2Ffont%2FType1%2Fhints.c;h=0000000000000000000000000000000000000000;hp=fe3499e5d21d5fafda0120ea38a1bdf52990f02a;hb=ce66b81460e5353db09d45c02339d4583fbda255;hpb=7772d71ffd742cfc9b7ff214659d16c5bb56a391 diff --git a/Xserver/lib/font/Type1/hints.c b/Xserver/lib/font/Type1/hints.c deleted file mode 100644 index fe3499e..0000000 --- a/Xserver/lib/font/Type1/hints.c +++ /dev/null @@ -1,919 +0,0 @@ -/* $XConsortium: hints.c,v 1.4 91/10/10 11:18:13 rws Exp $ */ -/* Copyright International Business Machines, Corp. 1991 - * All Rights Reserved - * Copyright Lexmark International, Inc. 1991 - * All Rights Reserved - * - * License to use, copy, modify, and distribute this software and its - * documentation for any purpose and without fee is hereby granted, - * provided that the above copyright notice appear in all copies and that - * both that copyright notice and this permission notice appear in - * supporting documentation, and that the name of IBM or Lexmark not be - * used in advertising or publicity pertaining to distribution of the - * software without specific, written prior permission. - * - * IBM AND LEXMARK PROVIDE THIS SOFTWARE "AS IS", WITHOUT ANY WARRANTIES OF - * ANY KIND, EITHER EXPRESS OR IMPLIED, INCLUDING, BUT NOT LIMITED TO ANY - * IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, - * AND NONINFRINGEMENT OF THIRD PARTY RIGHTS. THE ENTIRE RISK AS TO THE - * QUALITY AND PERFORMANCE OF THE SOFTWARE, INCLUDING ANY DUTY TO SUPPORT - * OR MAINTAIN, BELONGS TO THE LICENSEE. SHOULD ANY PORTION OF THE - * SOFTWARE PROVE DEFECTIVE, THE LICENSEE (NOT IBM OR LEXMARK) ASSUMES THE - * ENTIRE COST OF ALL SERVICING, REPAIR AND CORRECTION. IN NO EVENT SHALL - * IBM OR LEXMARK 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. - */ - /* HINTS CWEB V0006 ******** */ -/* -:h1.HINTS Module - Processing Rasterization Hints - -&author. Sten F. Andler; continuity by Jeffrey B. Lotspiech (lotspiech@almaden.ibm.com) and Duaine -W. Pryor, Jr. - - -:h3.Include Files - -The included files are: -*/ - -#include "objects.h" -#include "spaces.h" -#include "paths.h" -#include "regions.h" -#include "hints.h" - -/* -:h3.Functions Provided to the TYPE1IMAGER User - -None. -*/ - -/* -:h3.Functions Provided to Other Modules - -This module provides the following entry point to other modules: -*/ - - -/*SHARED LINE(S) ORIGINATED HERE*/ - -/* -:h3.Macros Provided to Other Modules - -None. -*/ - -/* -:h2.InitHints() - Initialize hint data structure -*/ - -#define MAXLABEL 20 -static struct { - int inuse; - int computed; - struct fractpoint hint; -} oldHint[MAXLABEL]; - -#define ODD(x) (((int)(x)) & 01) -#define FPFLOOR(fp) TOFRACTPEL((fp) >> FRACTBITS) -#define FPROUND(fp) FPFLOOR((fp) + FPHALF) - -void InitHints() -{ - int i; - - for (i = 0; i < MAXLABEL; i++) - { - oldHint[i].inuse = FALSE; - oldHint[i].computed = FALSE; - } -} - -/* -:h3.CloseHints(hintP) - Reverse hints that are still open -*/ - -void CloseHints(hintP) - struct fractpoint *hintP; -{ - int i; - - for (i = 0; i < MAXLABEL; i++) - { - if (oldHint[i].inuse) - { - hintP->x -= oldHint[i].hint.x; - hintP->y -= oldHint[i].hint.y; - - oldHint[i].inuse = FALSE; - - IfTrace3((HintDebug > 1)," Hint %d was open, hint=(%p,%p)\n", - i, hintP->x, hintP->y); - } - } -} - -/* -:h3.ComputeHint(hP, currX, currY, hintP) - Compute the value of a hint -*/ - -static void ComputeHint(hP, currX, currY, hintP) - struct hintsegment *hP; - fractpel currX, currY; - struct fractpoint *hintP; -{ - fractpel currRef, currWidth; - int idealWidth; - fractpel hintValue; - char orientation; - -/* -By construction, width is never zero. Therefore we can use the -width value to determine if the hint has been rotated by a -multiple of 90 degrees. -*/ - - if (hP->width.y == 0) - { - orientation = 'v'; /* vertical */ - IfTrace0((HintDebug > 0)," vertical hint\n"); - } - else if (hP->width.x == 0) - { - orientation = 'h'; /* horizontal */ - IfTrace0((HintDebug > 0)," horizontal hint\n"); - } - else - { - IfTrace0((HintDebug > 0)," hint not vertical or horizontal\n"); - hintP->x = hintP->y = 0; - return; - } - - /* Compute currRef and currWidth with a unit of 1 pel */ - if (orientation == 'v') /* vertical */ - { - currRef = hP->ref.x + currX; - currWidth = ABS(hP->width.x); - } - else if (orientation == 'h') /* horizontal */ - { - currRef = hP->ref.y + currY; - currWidth = ABS(hP->width.y); - } - else /* error */ - { - abort("ComputeHint: invalid orientation"); - } - - IfTrace4((HintDebug > 1), - " currX=%p, currY=%p, currRef=%p, currWidth=%p\n", - currX, currY, - currRef, currWidth); - - if ((hP->hinttype == 'b') /* Bar or stem */ - || (hP->hinttype == 's')) /* Serif */ - { - idealWidth = NEARESTPEL(currWidth); - if (idealWidth == 0) idealWidth = 1; - if (ODD(idealWidth)) /* Is ideal width odd? */ - { - /* center "ref" over pel */ - hintValue = FPFLOOR(currRef) + FPHALF - currRef; - } - else - { - /* align "ref" on pel boundary */ - hintValue = FPROUND(currRef) - currRef; - } - if (HintDebug > 2) { - IfTrace1(TRUE," idealWidth=%d, ", idealWidth); - } - } - else if (hP->hinttype == 'c') /* Curve extrema */ - { - /* align "ref" on pel boundary */ - hintValue = FPROUND(currRef) - currRef; - } - else /* error */ - { - abort("ComputeHint: invalid hinttype"); - } - - IfTrace1((HintDebug > 1)," hintValue=%p", hintValue); - - if (orientation == 'v') /* vertical */ - { - hintP->x = hintValue; - hintP->y = 0; - } - else if (orientation == 'h') /* horizontal */ - { - hintP->x = 0; - hintP->y = hintValue; - } - else /* error */ - { - abort("ComputeHint: invalid orientation"); - } -} - -/* -:h3.ProcessHint(hP, currX, currY, hintP) - Process a rasterization hint -*/ - -void ProcessHint(hP, currX, currY, hintP) - struct hintsegment *hP; - fractpel currX, currY; - struct fractpoint *hintP; -{ - struct fractpoint thisHint; - - IfTrace4((HintDebug > 1)," ref=(%p,%p), width=(%p,%p)", - hP->ref.x, hP->ref.y, - hP->width.x, hP->width.y); - IfTrace4((HintDebug > 1),", %c %c %c %c", - hP->orientation, hP->hinttype, - hP->adjusttype, hP->direction); - IfTrace1((HintDebug > 1),", label=%d\n", hP->label); - - if ((hP->adjusttype == 'm') /* Move */ - || (hP->adjusttype == 'a')) /* Adjust */ - { - /* Look up hint in oldHint table */ - if ((hP->label >= 0) && (hP->label < MAXLABEL)) - { - if (oldHint[hP->label].computed) - /* Use old hint value if already computed */ - { - thisHint.x = oldHint[hP->label].hint.x; - thisHint.y = oldHint[hP->label].hint.y; - oldHint[hP->label].inuse = TRUE; - } - else - /* Compute new value for hint and store it for future use */ - { - ComputeHint(hP, currX, currY, &thisHint); - - oldHint[hP->label].hint.x = thisHint.x; - oldHint[hP->label].hint.y = thisHint.y; - oldHint[hP->label].inuse = TRUE; - oldHint[hP->label].computed = TRUE; - } - } - else /* error */ - { - abort("ProcessHint: invalid label"); - } - } - else if (hP->adjusttype == 'r') /* Reverse */ - { - /* Use the inverse of the existing hint value to reverse hint */ - if ((hP->label >= 0) && (hP->label < MAXLABEL)) - { - if (oldHint[hP->label].inuse) - { - thisHint.x = -oldHint[hP->label].hint.x; - thisHint.y = -oldHint[hP->label].hint.y; - oldHint[hP->label].inuse = FALSE; - } - else /* error */ - { - abort("ProcessHint: label is not in use"); - } - } - else /* error */ - { - abort("ProcessHint: invalid label"); - } - - } - else /* error */ - { - abort("ProcessHint: invalid adjusttype"); - } - IfTrace3((HintDebug > 1)," label=%d, thisHint=(%p,%p)\n", - hP->label, thisHint.x, thisHint.y); - - hintP->x += thisHint.x; - hintP->y += thisHint.y; - - IfTrace2((HintDebug > 1)," hint=(%p,%p)\n", - hintP->x, hintP->y); -} - -/* -:h2 id=subpath.Navigation Through Edge Lists - -For continuity checking purposes, we need to navigate through edge -lists by the "subpath" chains and answer questions about edges. The -subpath chain links together edges that were part of the same subpath -(no intervening move segments) when the interior of the path was -calculated. Here we use the term "edge" to mean every edge list -that was created in between changes of direction. - -The subpath chains are singly-linked circular chains. For the convenience -of building them, they direction of the list (from edge to edge) is the -reverse of the order in which they were built. Within any single edge, -the subpath chain goes from top-to-bottom. (There might be a violation -of this because of the way the user started the first chain; see -:hdref refid=fixsubp..). - -:h3.ISTOP() and ISBOTTOM() - Flag Bits for Edge Lists at the Top and -Bottom of Their SubPaths -*/ - -#define ISTOP(flag) ((flag)&0x20) -#define ISBOTTOM(flag) ((flag)&0x10) -/* -:h3.ISLEFT() - Flag Bit for Left Edges -*/ - -#define ISLEFT(flag) ((flag)&0x08) - -/* -:h3.XofY() - Macro to Find X Value at Given Y - -This macro can only be used if it is known that the Y is within the -given edgelist's ymin and ymax. -*/ - -#define XofY(edge, y) edge->xvalues[y - edge->ymin] - -/* -:h3.findXofY() - Like XofY(), Except not Restricted - -If the Y is out of bounds of the given edgelist, this macro will -call SearchXofY to search the edge's subpath chain for the correct -Y range. If the Y value is off the edge, MINPEL is returned. -*/ -#define findXofY(edge, y) ((y < edge->ymin || y >= edge->ymax) ? SearchXofY(edge, y) : XofY(edge, y)) - -/* -:h4.SearchXofY() - Routine Called by FindXofY() for Difficult Cases - -The concept of this routine is to follow the subpath chain to find the -edge just below (i.e., next in chain) or just above (i.e., immediately -before in chain. It is assumed that the Y value is no more than one -off of the edge's range; XofY() could be replace by FindXofY() to -call ourselves recursively if this were not true. -*/ - -static pel SearchXofY(edge, y) - register struct edgelist *edge; /* represents edge */ - register pel y; /* 'y' value to find edge for */ -{ - register struct edgelist *e; /* loop variable */ - - if (y < edge->ymin) { - if (ISTOP(edge->flag)) - return(MINPEL); - for (e = edge->subpath; e->subpath != edge; e = e->subpath) { ; } - if (e->ymax == edge->ymin) - return(XofY(e, y)); - } - else if (y >= edge->ymax) { - if (ISBOTTOM(edge->flag)) - return(MINPEL); - e = edge->subpath; - if (e->ymin == edge->ymax) - return(XofY(e, y)); - } - else - return(XofY(edge, y)); - - abort("bad subpath chain"); - /*NOTREACHED*/ -} -/* -:h3.ISBREAK() Macro - Tests if an Edge List is at a "Break" - -The subpath chains are organized top to bottom. When the bottom of -a given edge is reached, the subpath chain points to the top of the -next edge. We call this a "break" in the chain. The following macro -is the simple test for the break condition: -*/ - -#define ISBREAK(top,bot) (top->ymax != bot->ymin) - - -/* -:h3.ImpliedHorizontalLine() - Tests for Horizontal Connectivity - -This function returns true if two edges are connected horizontally. -They are connected horizontally if they are consecutive in the subpath, -and either we are at the bottom and the first edge is going down or we -are at the top and the first edge is going up. -*/ - -#define BLACKABOVE -1 -#define BLACKBELOW +1 -#define NONE 0 - -static int ImpliedHorizontalLine(e1, e2, y) - register struct edgelist *e1,*e2; /* two edges to check */ - register int y; /* y where they might be connected */ -{ - register struct edgelist *e3,*e4; - - if (ISDOWN(e1->flag) == ISDOWN(e2->flag)) - return(NONE); /* can't be consecutive unless different directions */ -/* -Now we check for consecutiveness: Can we get from 'e1' to 'e2' with -only one intervening break? Can we get from 'e2' to 'e1' with only one -intervening break? 'e3' will be as far as we can get after 'e1'; 'e4' -will be has far as we can get after 'e2': -*/ - for (e3 = e1; !ISBREAK(e3, e3->subpath); e3 = e3->subpath) { ; } - for (e3 = e3->subpath; e3 != e2; e3 = e3->subpath) - if (ISBREAK(e3, e3->subpath)) - break; - - for (e4 = e2; !ISBREAK(e4, e4->subpath); e4 = e4->subpath) { ; } - for (e4 = e4->subpath; e4 != e1; e4 = e4->subpath) - if (ISBREAK(e4, e4->subpath)) - break; -/* -If the edges are mutually consecutive, we must have horizontal lines -both top and bottom: -*/ - if (e3 == e2 && e4 == e1) - return(TRUE); -/* -If the edges are not consecutive either way, no horizontal lines are -possible: -*/ - if (e3 != e2 && e4 != e1) - return(NONE); -/* -Now let's swap 'e1' and 'e2' if necessary to enforce the rule that 'e2' -follows 'e1'. Remember that subpath chains go in the opposite direction -from the way the subpaths were built; this led to the simplest way -do build them. -*/ - if (e4 != e1) { - e2 = e1; - e1 = e3; /* remember e3 == e2, this just swaps 'e1' and 'e2' */ - } -/* -Now we have everything to return the answer: -*/ - if (ISTOP(e1->flag) && y == e1->ymin) - return(ISDOWN(e2->flag)); - else if (ISBOTTOM(e1->flag) && y == e1->ymax) - return(!ISDOWN(e2->flag)); - else - abort("ImpliedHorizontalLine: why ask?"); - /*NOTREACHED*/ -} - -/* -:h3 id=fixsubp.FixSubPaths() - Must be Called to Organize Subpath Chains - -The region-building code in Interior(), in particular splitedge(), -maintains the rule that sub-paths are linked top-to-bottom except -at breaks. However, it is possible that there may be a "false break" -because the user started the subpath in the middle of an edge (and -went in the "wrong" direction from there, up instead of down). This -routine finds and fixes false breaks. - -Also, this routine sets the ISTOP and ISBOTTOM flags in the edge lists. -*/ - -static void FixSubPaths(R) - register struct region *R; /* anchor of region */ -{ - register struct edgelist *e; /* fast loop variable */ - register struct edgelist *edge; /* current edge in region */ - register struct edgelist *next; /* next in subpath after 'edge' */ - register struct edgelist *break1; /* first break after 'next' */ - register struct edgelist *break2; /* last break before 'edge' */ - register struct edgelist *prev; /* previous edge for fixing links */ - int left = TRUE; - - for (edge = R->anchor; edge != NULL; edge = edge->link) { - - if (left) - edge->flag |= ISLEFT(ON); - left = !left; - - next = edge->subpath; - - if (!ISBREAK(edge, next)) - continue; - if (edge->ymax < next->ymin) - abort("disjoint subpath?"); -/* -'edge' now contains an edgelist at the bottom of an edge, and 'next' -contains the next subsequent edgelist in the subpath, which must be at -the top. We refer to this a "break" in the subpath. -*/ - next->flag |= ISTOP(ON); - edge->flag |= ISBOTTOM(ON); - - if (ISDOWN(edge->flag) != ISDOWN(next->flag)) - continue; -/* -We are now in the unusual case; both edges are going in the same -direction so this must be a "false break" due to the way that the user -created the path. We'll have to fix it. -*/ - for (break1 = next; !ISBREAK(break1, break1->subpath); break1 = break1->subpath) { ; } - - for (e = break1->subpath; e != edge; e = e->subpath) - if (ISBREAK(e, e->subpath)) - break2 = e; -/* -Now we've set up 'break1' and 'break2'. I've found the following -diagram invaluable. 'break1' is the first break after 'next'. 'break2' -is the LAST break before 'edge'. -&drawing. - next - +------+ +---->+------+ - +--->| >-----+ | | >-----+ - | | | | | | | | - | +-------------+ | +-------------+ - | | |break1| | | | | - | +->| >-------+ +->| >-----+ - | | | | | | - | | | +-------------+ - | +------+ | | | - | +----------------+ | | | - | | +------+ | +->| >-----+ - | +->| >-----+ | | | | - | | | | | +-------------+ - | +-------------+ | | | | - | | |edge | | | |break2| - | +->| >-----+ | +->| >-----+ - | | | | | | | | - | | | | | | | | - | | | | | | | | - | +------+ | | +------+ | - | | | | - +---------------+ +---------------+ - -&edrawing. -We want to fix this situation by having 'edge' point to where 'break1' -now points, and having 'break1' point to where 'break2' now points. -Finally, 'break2' should point to 'next'. Also, we observe that -'break1' can't be a bottom, and is also not a top unless it is the same -as 'next': -*/ - edge->subpath = break1->subpath; - - break1->subpath = break2->subpath; - if (ISBREAK(break1, break1->subpath)) - abort("unable to fix subpath break?"); - - break2->subpath = next; - - break1->flag &= ~ISBOTTOM(ON); - if (break1 != next) - break1->flag &= ~ISTOP(ON); - } -/* -This region might contain "ambiguous" edges; edges exactly equal to -edge->link. Due to the random dynamics of where they get sorted into -the list, they can yield false crossings, where the edges appear -to cross. This confuses our continuity logic no end. Since we can -swap them without changing the region, we do. -*/ - for (edge = R->anchor, prev = NULL; VALIDEDGE(edge); prev = edge, edge = prev->link) { - - if (! ISAMBIGUOUS(edge->flag)) - continue; - - next = edge->subpath; - - while (ISAMBIGUOUS(next->flag) && next != edge) - next = next->subpath; -/* -We've finally found a non-ambiguous edge; we make sure it is left/right -compatible with 'edge': -*/ - if ( (ISLEFT(edge->flag) == ISLEFT(next->flag) && ISDOWN(edge->flag) == ISDOWN(next->flag) ) - || (ISLEFT(edge->flag) != ISLEFT(next->flag) && ISDOWN(edge->flag) != ISDOWN(next->flag) ) ) - continue; - -/* -Incompatible, we will swap 'edge' and the following edge in the list. -You may think that there must be a next edge in this swath. So did I. -No! If there is a totally ambiguous inner loop, for example, we could -get all the way to the outside without resolving ambiguity. -*/ - next = edge->link; /* note new meaning of 'next' */ - if (next == NULL || edge->ymin != next->ymin) - continue; - if (prev == NULL) - R->anchor = next; - else - prev->link = next; - edge->link = next->link; - next->link = edge; - edge->flag ^= ISLEFT(ON); - edge->flag &= ~ISAMBIGUOUS(ON); - next->flag ^= ISLEFT(ON); - next->flag &= ~ISAMBIGUOUS(ON); - edge = next; - } -} -/* -:h3.DumpSubPaths() - -A debug tool. -*/ - -static struct edgelist *before(); /* subroutine of DumpSubPaths */ - -static void DumpSubPaths(anchor) - struct edgelist *anchor; -{ - - register struct edgelist *edge,*e,*e2; - pel y; - - for (edge = anchor; VALIDEDGE(edge); edge = edge->link) { - if (ISPERMANENT(edge->flag)) - continue; - IfTrace0(TRUE, "BEGIN Subpath\n"); - for (e2 = edge; !ISPERMANENT(e2->flag);) { - if (ISDOWN(e2->flag)) { - IfTrace1(TRUE, ". Downgoing edge's top at %x\n", e2); - for (e = e2;; e = e->subpath) { - IfTrace4(TRUE, ". . [%5d] %5d @ %x[%x]\n", - e->ymin, *e->xvalues, e, e->flag); - for (y=e->ymin+1; y < e->ymax; y++) - IfTrace2(TRUE, ". . [%5d] %5d \"\n", y, e->xvalues[y-e->ymin]); - e->flag |= ISPERMANENT(ON); - if (ISBREAK(e, e->subpath)) - break; - } - } - else { - IfTrace1(TRUE, ". Upgoing edge's top at %x\n", e2); - for (e = e2; !ISBREAK(e, e->subpath); e = e->subpath) { ; } - for (;; e=before(e)) { - IfTrace4(TRUE, ". . [%5d] %5d @ %x[%x]\n", - e->ymax-1, e->xvalues[e->ymax-1-e->ymin], e, e->flag); - for (y=e->ymax-2; y >= e->ymin; y--) - IfTrace2(TRUE, ". . [%5d] %5d \"\n", y, e->xvalues[y-e->ymin]); - e->flag |= ISPERMANENT(ON); - if (e == e2) - break; - } - } - do { - e2 = before(e2); - } while (!ISBREAK(before(e2), e2)); - } - } -} - -static struct edgelist *before(e) - struct edgelist *e; -{ - struct edgelist *r; - for (r = e->subpath; r->subpath != e; r = r->subpath) { ; } - return(r); -} - -/* -:h2.Fixing Region Continuity Problems - -Small regions may become disconnected when their connecting segments are -less than a pel wide. This may be correct in some applications, but in -many (especially small font characters), it is more pleasing to keep -connectivity. ApplyContinuity() (invoked by +CONTINUITY on the -Interior() fill rule) fixes connection breaks. The resulting region -is geometrically less accurate, but may be more pleasing to the eye. -*/ -/* -Here are some macros which we will need: -*/ - -#define IsValidPel(j) (j!=MINPEL) - -/* -:h3.writeXofY() - Stuffs an X Value Into an "edgelist" - -writeXofY writes an x value into an edge at position 'y'. It must -update the edge's xmin and xmax. If there is a possibility that this -new x might exceed the region's bounds, updating those are the -responsibility of the caller. -*/ - -static void writeXofY(e, y, x) - struct edgelist *e; /* relevant edgelist */ - int y; /* y value */ - int x; /* new x value */ -{ - if (e->xmin > x) e->xmin = x; - if (e->xmax < x) e->xmax = x; - e->xvalues[y - e->ymin] = x; -} - -/*-------------------------------------------------------------------------*/ -/* the following three macros tell us whether we are at a birth point, a */ -/* death point, or simply in the middle of the character */ -/*-------------------------------------------------------------------------*/ -#define WeAreAtTop(e,i) (ISTOP(e->flag) && e->ymin == i) -#define WeAreAtBottom(e,i) (ISBOTTOM(e->flag) && e->ymax-1 == i) -#define WeAreInMiddle(e,i) \ - ((!ISTOP(e->flag) && !ISBOTTOM(e->flag))||(i < e->ymax-1 && i > e->ymin)) -/* -The following macro tests if two "edgelist" structures are in the same -swath: -*/ -#define SAMESWATH(e1,e2) (e1->ymin == e2->ymin) - -/* -:h3.CollapseWhiteRun() - Subroutine of ApplyContinuity() - -When we have a white run with an implied horizontal line above or -below it, we better have black on the other side of this line. This -function both tests to see if black is there, and adjusts the end -points (collapses) the white run as necessary if it is not. The -goal is to collapse the white run as little as possible. -*/ - -static void CollapseWhiteRun(anchor, yblack, left, right, ywhite) - struct edgelist *anchor; /* anchor of edge list */ - pel yblack; /* y of (hopefully) black run above or below */ - struct edgelist *left; /* edgelist at left of WHITE run */ - struct edgelist *right; /* edgelist at right of WHITE run */ - pel ywhite; /* y location of white run */ -{ - struct edgelist *edge; - struct edgelist *swathstart = anchor; - register pel x; - - if (XofY(left, ywhite) >= XofY(right, ywhite)) - return; -/* -Find the swath with 'yblack'. If we don't find it, completely collapse -the white run and return: -*/ - while (VALIDEDGE(swathstart)) { - if (yblack < swathstart->ymin) { - writeXofY(left, ywhite, XofY(right, ywhite)); - return; - } - if (yblack < swathstart->ymax) break; - swathstart = swathstart->link->link; - } - if(!VALIDEDGE(swathstart)) { - writeXofY(left, ywhite, XofY(right, ywhite)); - return; - } -/* -Now we are in the swath that contains 'y', the reference line above -or below that we are trying to maintain continuity with. If black -in this line begins in the middle of our white run, we must collapse -the white run from the left to that point. If black ends in the -middle of our white run, we must collapse the white run from the right -to that point. -*/ - for (edge = swathstart; VALIDEDGE(edge); edge = edge->link) { - - if (!SAMESWATH(swathstart,edge)) - break; - if( XofY(edge, yblack) > XofY(left, ywhite)) { - if (ISLEFT(edge->flag)) { - x = XofY(edge, yblack); - if (XofY(right, ywhite) < x) - x = XofY(right, ywhite); - writeXofY(left, ywhite, x); - } - else { - x = XofY(edge, yblack); - while (edge->link != NULL && SAMESWATH(edge, edge->link) - && x >= XofY(edge->link, yblack) ) { - edge = edge->link->link; - x = XofY(edge, yblack); - } - if (x < XofY(right, ywhite)) - writeXofY(right, ywhite, x); - return; - } - } - } - writeXofY(left, ywhite, XofY(right, ywhite)); -} - -/* -:h3.ApplyContinuity() - Fix False Breaks in a Region - -This is the externally visible routine called from the REGIONS module -when the +CONTINUITY flag is on the Interior() fill rule. -*/ - -void ApplyContinuity(R) -struct region *R; -{ - struct edgelist *left; - struct edgelist *right; - struct edgelist *edge,*e2; - pel rightXabove,rightXbelow,leftXabove,leftXbelow; - pel leftX,rightX; - int i; - long newcenter,abovecenter,belowcenter; - - FixSubPaths(R); - if (RegionDebug >= 3) - DumpSubPaths(R->anchor); - left = R->anchor; -/* loop through and do all of the easy checking. ( no tops or bottoms) */ - while(VALIDEDGE(left)) - { - right = left->link; - for(i=left->ymin;iymax;++i) - { - leftX = findXofY(left,i); - rightX = findXofY(right,i); - leftXbelow = findXofY(left,i+1); - rightXbelow = findXofY(right,i+1); - if(rightX <= leftX) - { -/* then, we have a break in a near vertical line */ - leftXabove = findXofY(left,i-1); - rightXabove = findXofY(right,i-1); - if( IsValidPel(leftXabove) && IsValidPel(rightXabove) ) - { - abovecenter = leftXabove + rightXabove; - } - else - { - abovecenter = leftX + rightX; - } - if( IsValidPel(leftXbelow) && IsValidPel(rightXbelow) ) - { - belowcenter = leftXbelow + rightXbelow; - } - else - { - belowcenter = leftX + rightX; - } - newcenter = abovecenter + belowcenter; - if( newcenter > 4*leftX ) - { - rightX = rightX + 1; - } - else if( newcenter < 4*leftX) - { - leftX = leftX - 1; - } - else - { - rightX = rightX + 1; - } - writeXofY(right,i,rightX); - writeXofY(left,i,leftX); - if(rightX > R->xmax) {R->xmax = rightX;} - if(leftX < R->xmin) {R->xmin = leftX;} - } - if( !WeAreAtBottom(left,i) && (leftXbelow>=rightX)) - { -/* then we have a break in a near horizontal line in the middle */ - writeXofY(right,i,leftXbelow); - } - if( !WeAreAtBottom(right,i) && (leftX >=rightXbelow)) - { -/* then we have a break in a near horizontal line in the middle */ - writeXofY(left,i,rightXbelow); - } - } - left = right->link; - } -/* -There may be "implied horizontal lines" between edges that have -implications for continuity. This loop looks for white runs that -have implied horizontal lines on the top or bottom, and calls -CollapseWhiteRuns to check and fix any continuity problems from -them. -*/ - for (edge = R->anchor; VALIDEDGE(edge); edge = edge->link) { - if ((!ISTOP(edge->flag) && !ISBOTTOM(edge->flag)) || ISLEFT(edge->flag)) - continue; /* at some future date we may want left edge logic here too */ - for (e2 = edge->link; VALIDEDGE(e2) && SAMESWATH(edge,e2); e2 = e2->link) { - if (ISTOP(e2->flag) && ISTOP(edge->flag) - && NONE != ImpliedHorizontalLine(edge,e2,edge->ymin)) { - if (ISLEFT(e2->flag)) - CollapseWhiteRun(R->anchor, edge->ymin-1, - edge, e2, edge->ymin); - } - if (ISBOTTOM(e2->flag) && ISBOTTOM(edge->flag) - && NONE != ImpliedHorizontalLine(edge,e2, edge->ymax)) { - if (ISLEFT(e2->flag)) - CollapseWhiteRun(R->anchor, edge->ymax, - edge, e2, edge->ymax-1); - } - } - } -} - - - -