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researchv9-SUN3
/***********************************************************
Copyright 1987 by Digital Equipment Corporation, Maynard, Massachusetts,
and the Massachusetts Institute of Technology, Cambridge, Massachusetts.
All Rights Reserved
Permission 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 names of Digital or MIT not be
used in advertising or publicity pertaining to distribution of the
software without specific, written prior permission.
DIGITAL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING
ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL
DIGITAL 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.
******************************************************************/
/* $Header: /var/lib/cvsd/repos/research/researchv9/X11/src/X.V11R1/server/ddx/mi/miregion.c,v 1.1.1.2 2018/04/24 17:41:54 root Exp $ */
#include "miscstruct.h"
#include "regionstr.h"
#ifdef DEBUG
#define assert(expr) {if (!(expr)) \
FatalError("Assertion failed file %s, line %d: expr\n", \
__FILE__, __LINE__); }
#else
#define assert(expr)
#endif
/*
* The functions in this file implement the Region abstraction used extensively
* throughout the X11 sample server. A Region is simply an area, as the name
* implies, and is implemented as a "y-x-banded" array of rectangles. To
* explain: Each Region is made up of a certain number of rectangles sorted
* by y coordinate first, and then by x coordinate.
*
* Furthermore, the rectangles are banded such that every rectangle with a
* given upper-left y coordinate (y1) will have the same lower-right y
* coordinate (y2) and vice versa. If a rectangle has scanlines in a band, it
* will span the entire vertical distance of the band. This means that some
* areas that could be merged into a taller rectangle will be represented as
* several shorter rectangles to account for shorter rectangles to its left
* or right but within its "vertical scope".
*
* An added constraint on the rectangles is that they must cover as much
* horizontal area as possible. E.g. no two rectangles in a band are allowed
* to touch.
*
* Whenever possible, bands will be merged together to cover a greater vertical
* distance (and thus reduce the number of rectangles). Two bands can be merged
* only if the bottom of one touches the top of the other and they have
* rectangles in the same places (of the same width, of course). This maintains
* the y-x-banding that's so nice to have...
*/
typedef BoxRec BOX; /* this is to cut down on some gratuitous edits */
/* 1: if two BOXs overlap.
/* 0: if two BOXs do not overlap.
* Remember, x2 and y2 are not in the region
*/
#define EXTENTCHECK(r1, r2) \
(!( ((r1)->x2 <= (r2)->x1) || \
( ((r1)->x1 >= (r2)->x2)) || \
( ((r1)->y2 <= (r2)->y1)) || \
( ((r1)->y1 >= (r2)->y2)) ) )
void
miprintRects(rgn)
RegionPtr rgn;
{
register int i;
ErrorF( "num: %d size: %d \n", rgn->numRects, rgn->size);
ErrorF( " extents: %d %d %d %d\n",rgn->extents.x1,
rgn->extents.y1, rgn->extents.x2, rgn->extents.y2);
for (i = 0; i < rgn->numRects; i++)
ErrorF( "%d %d %d %d \n", rgn->rects[i].x1,rgn->rects[i].y1,
rgn->rects[i].x2,rgn->rects[i].y2);
ErrorF( "\n");
}
/*****************************************************************
* RegionCreate(rect, size)
* This routine does a simple malloc to make a structure of
* REGION of "size" number of rectangles.
*****************************************************************/
RegionPtr
miRegionCreate(rect, size)
register BOX *rect;
register int size;
{
register RegionPtr temp; /* new region */
size = max(1, size);
temp = (RegionPtr ) Xalloc (sizeof (RegionRec));
temp->rects = (BOX *) Xalloc (size * (sizeof(BOX)));
if (rect == (BOX *)NULL)
{
temp->numRects = 0;
temp->extents.x1 = 0;
temp->extents.y1 = 0;
temp->extents.x2 = 0;
temp->extents.y2 = 0;
}
else
{
temp->extents = *rect;
temp->rects[0] = *rect;
temp->numRects = 1;
}
temp->size = size;
return(temp);
}
void
miRegionCopy(dstrgn, rgn)
register RegionPtr dstrgn;
register RegionPtr rgn;
{
if (dstrgn != rgn) /* don't want to copy to itself */
{
if (dstrgn->size < rgn->numRects)
{
if (dstrgn->rects)
{
dstrgn->rects = (BOX *) Xrealloc(dstrgn->rects,
rgn->numRects * (sizeof(BOX)));
}
else
ErrorF( "RC HORRIBLE ERROR...\n");
dstrgn->size = rgn->numRects;
}
dstrgn->numRects = rgn->numRects;
dstrgn->extents.x1 = rgn->extents.x1;
dstrgn->extents.y1 = rgn->extents.y1;
dstrgn->extents.x2 = rgn->extents.x2;
dstrgn->extents.y2 = rgn->extents.y2;
bcopy(rgn->rects, dstrgn->rects, rgn->numRects * sizeof(BOX));
}
}
/*======================================================================
* Generic Region Operator
*====================================================================*/
/*-
*-----------------------------------------------------------------------
* miCoalesce --
* Attempt to merge the boxes in the current band with those in the
* previous one. Used only by miRegionOp.
*
* Results:
* The new index for the previous band.
*
* Side Effects:
* If coalescing takes place:
* - rectangles in the previous band will have their y2 fields
* altered.
* - pReg->numRects will be decreased.
*
*-----------------------------------------------------------------------
*/
static int
miCoalesce (pReg, prevStart, curStart)
register RegionPtr pReg; /* Region to coalesce */
int prevStart; /* Index of start of previous band */
int curStart; /* Index of start of current band */
{
register BoxPtr pPrevBox; /* Current box in previous band */
register BoxPtr pCurBox; /* Current box in current band */
register BoxPtr pRegEnd; /* End of region */
int curNumRects; /* Number of rectangles in current
* band */
int prevNumRects; /* Number of rectangles in previous
* band */
int bandY1; /* Y1 coordinate for current band */
pRegEnd = &pReg->rects[pReg->numRects];
pPrevBox = &pReg->rects[prevStart];
prevNumRects = curStart - prevStart;
/*
* Figure out how many rectangles are in the current band. Have to do
* this because multiple bands could have been added in miRegionOp
* at the end when one region has been exhausted.
*/
pCurBox = &pReg->rects[curStart];
bandY1 = pCurBox->y1;
for (curNumRects = 0;
(pCurBox != pRegEnd) && (pCurBox->y1 == bandY1);
curNumRects++)
{
pCurBox++;
}
if (pCurBox != pRegEnd)
{
/*
* If more than one band was added, we have to find the start
* of the last band added so the next coalescing job can start
* at the right place... (given when multiple bands are added,
* this may be pointless -- see above).
*/
pRegEnd--;
while (pRegEnd[-1].y1 == pRegEnd->y1)
{
pRegEnd--;
}
curStart = pRegEnd - pReg->rects;
pRegEnd = pReg->rects + pReg->numRects;
}
if ((curNumRects == prevNumRects) && (curNumRects != 0)) {
pCurBox -= curNumRects;
/*
* The bands may only be coalesced if the bottom of the previous
* matches the top scanline of the current.
*/
if (pPrevBox->y2 == pCurBox->y1)
{
/*
* Make sure the bands have boxes in the same places. This
* assumes that boxes have been added in such a way that they
* cover the most area possible. I.e. two boxes in a band must
* have some horizontal space between them.
*/
do
{
if ((pPrevBox->x1 != pCurBox->x1) ||
(pPrevBox->x2 != pCurBox->x2))
{
/*
* The bands don't line up so they can't be coalesced.
*/
return (curStart);
}
pPrevBox++;
pCurBox++;
prevNumRects -= 1;
} while (prevNumRects != 0);
pReg->numRects -= curNumRects;
pCurBox -= curNumRects;
pPrevBox -= curNumRects;
/*
* The bands may be merged, so set the bottom y of each box
* in the previous band to that of the corresponding box in
* the current band.
*/
do
{
pPrevBox->y2 = pCurBox->y2;
pPrevBox++;
pCurBox++;
curNumRects -= 1;
} while (curNumRects != 0);
/*
* If only one band was added to the region, we have to backup
* curStart to the start of the previous band.
*
* If more than one band was added to the region, copy the
* other bands down. The assumption here is that the other bands
* came from the same region as the current one and no further
* coalescing can be done on them since it's all been done
* already... curStart is already in the right place.
*/
if (pCurBox == pRegEnd)
{
curStart = prevStart;
}
else
{
do
{
*pPrevBox++ = *pCurBox++;
} while (pCurBox != pRegEnd);
}
}
}
return (curStart);
}
/*-
*-----------------------------------------------------------------------
* miRegionOp --
* Apply an operation to two regions. Called by miUnion, miInverse,
* miSubtract, miIntersect...
*
* Results:
* None.
*
* Side Effects:
* The new region is overwritten.
*
* Notes:
* The idea behind this function is to view the two regions as sets.
* Together they cover a rectangle of area that this function divides
* into horizontal bands where points are covered only by one region
* or by both. For the first case, the nonOverlapFunc is called with
* each the band and the band's upper and lower extents. For the
* second, the overlapFunc is called to process the entire band. It
* is responsible for clipping the rectangles in the band, though
* this function provides the boundaries.
* At the end of each band, the new region is coalesced, if possible,
* to reduce the number of rectangles in the region.
*
*-----------------------------------------------------------------------
*/
static void
miRegionOp(newReg, reg1, reg2, overlapFunc, nonOverlap1Func, nonOverlap2Func)
register RegionPtr newReg; /* Place to store result */
RegionPtr reg1; /* First region in operation */
RegionPtr reg2; /* 2d region in operation */
void (*overlapFunc)(); /* Function to call for over-
* lapping bands */
void (*nonOverlap1Func)(); /* Function to call for non-
* overlapping bands in region
* 1 */
void (*nonOverlap2Func)(); /* Function to call for non-
* overlapping bands in region
* 2 */
{
register BoxPtr r1; /* Pointer into first region */
register BoxPtr r2; /* Pointer into 2d region */
BoxPtr r1End; /* End of 1st region */
BoxPtr r2End; /* End of 2d region */
register short ybot; /* Bottom of intersection */
register short ytop; /* Top of intersection */
BoxPtr oldRects; /* Old rects for newReg */
int oldSize; /* Old size of newReg */
int prevBand; /* Index of start of
* previous band in newReg */
int curBand; /* Index of start of current
* band in newReg */
register BoxPtr r1BandEnd; /* End of current band in r1 */
register BoxPtr r2BandEnd; /* End of current band in r2 */
short top; /* Top of non-overlapping
* band */
short bot; /* Bottom of non-overlapping
* band */
/*
* Initialization:
* set r1, r2, r1End and r2End appropriately, preserve the important
* parts of the destination region until the end in case it's one of
* the two source regions, then mark the "new" region empty, allocating
* another array of rectangles for it to use.
*/
r1 = reg1->rects;
r2 = reg2->rects;
r1End = r1 + reg1->numRects;
r2End = r2 + reg2->numRects;
oldSize = newReg->size;
oldRects = newReg->rects;
EMPTY_REGION(newReg);
/*
* Allocate a reasonable number of rectangles for the new region. The idea
* is to allocate enough so the individual functions don't need to
* reallocate and copy the array, which is time consuming, yet we don't
* have to worry about using too much memory. I hope to be able to
* nuke the Xrealloc() at the end of this function eventually.
*/
newReg->size = max(reg1->numRects,reg2->numRects) * 2;
newReg->rects = (BoxPtr) Xalloc (sizeof(BoxRec) * newReg->size);
/*
* Initialize ybot and ytop.
* In the upcoming loop, ybot and ytop serve different functions depending
* on whether the band being handled is an overlapping or non-overlapping
* band.
* In the case of a non-overlapping band (only one of the regions
* has points in the band), ybot is the bottom of the most recent
* intersection and thus clips the top of the rectangles in that band.
* ytop is the top of the next intersection between the two regions and
* serves to clip the bottom of the rectangles in the current band.
* For an overlapping band (where the two regions intersect), ytop clips
* the top of the rectangles of both regions and ybot clips the bottoms.
*/
if (reg1->extents.y1 < reg2->extents.y1)
{
ybot = reg1->extents.y1;
ytop = reg2->extents.y1;
}
else
{
ybot = reg2->extents.y1;
ytop = reg1->extents.y1;
}
/*
* prevBand serves to mark the start of the previous band so rectangles
* can be coalesced into larger rectangles. qv. miCoalesce, above.
* In the beginning, there is no previous band, so prevBand == curBand
* (curBand is set later on, of course, but the first band will always
* start at index 0). prevBand and curBand must be indices because of
* the possible expansion, and resultant moving, of the new region's
* array of rectangles.
*/
prevBand = 0;
do
{
curBand = newReg->numRects;
/*
* This algorithm proceeds one source-band (as opposed to a
* destination band, which is determined by where the two regions
* intersect) at a time. r1BandEnd and r2BandEnd serve to mark the
* rectangle after the last one in the current band for their
* respective regions.
*/
r1BandEnd = r1;
while ((r1BandEnd != r1End) && (r1BandEnd->y1 == r1->y1))
{
r1BandEnd++;
}
r2BandEnd = r2;
while ((r2BandEnd != r2End) && (r2BandEnd->y1 == r2->y1))
{
r2BandEnd++;
}
/*
* First handle the band that doesn't intersect, if any.
*
* Note that attention is restricted to one band in the
* non-intersecting region at once, so if a region has n
* bands between the current position and the next place it overlaps
* the other, this entire loop will be passed through n times.
*/
if (r1->y1 < r2->y1)
{
top = max(r1->y1,ybot);
bot = min(r1->y2,r2->y1);
if ((top != bot) && (nonOverlap1Func != (void (*)())NULL))
{
(* nonOverlap1Func) (newReg, r1, r1BandEnd, top, bot);
}
ytop = r2->y1;
}
else if (r2->y1 < r1->y1)
{
top = max(r2->y1,ybot);
bot = min(r2->y2,r1->y1);
if ((top != bot) && (nonOverlap2Func != (void (*)())NULL))
{
(* nonOverlap2Func) (newReg, r2, r2BandEnd, top, bot);
}
ytop = r1->y1;
}
else
{
ytop = r1->y1;
}
/*
* If any rectangles got added to the region, try and coalesce them
* with rectangles from the previous band. Note we could just do
* this test in miCoalesce, but some machines incur a not
* inconsiderable cost for function calls, so...
*/
if (newReg->numRects != curBand)
{
prevBand = miCoalesce (newReg, prevBand, curBand);
}
/*
* Now see if we've hit an intersecting band. The two bands only
* intersect if ybot > ytop
*/
ybot = min(r1->y2, r2->y2);
curBand = newReg->numRects;
if (ybot > ytop)
{
(* overlapFunc) (newReg, r1, r1BandEnd, r2, r2BandEnd, ytop, ybot);
}
if (newReg->numRects != curBand)
{
prevBand = miCoalesce (newReg, prevBand, curBand);
}
/*
* If we've finished with a band (y2 == ybot) we skip forward
* in the region to the next band.
*/
if (r1->y2 == ybot)
{
r1 = r1BandEnd;
}
if (r2->y2 == ybot)
{
r2 = r2BandEnd;
}
} while ((r1 != r1End) && (r2 != r2End));
/*
* Deal with whichever region still has rectangles left.
*/
curBand = newReg->numRects;
if (r1 != r1End)
{
if (nonOverlap1Func != (void (*)())NULL)
{
do
{
r1BandEnd = r1;
while ((r1BandEnd < r1End) && (r1BandEnd->y1 == r1->y1))
{
r1BandEnd++;
}
(* nonOverlap1Func) (newReg, r1, r1BandEnd,
max(r1->y1,ybot), r1->y2);
r1 = r1BandEnd;
} while (r1 != r1End);
}
}
else if ((r2 != r2End) && (nonOverlap2Func != (void (*)())NULL))
{
do
{
r2BandEnd = r2;
while ((r2BandEnd < r2End) && (r2BandEnd->y1 == r2->y1))
{
r2BandEnd++;
}
(* nonOverlap2Func) (newReg, r2, r2BandEnd,
max(r2->y1,ybot), r2->y2);
r2 = r2BandEnd;
} while (r2 != r2End);
}
if (newReg->numRects != curBand)
{
(void) miCoalesce (newReg, prevBand, curBand);
}
/*
* A bit of cleanup. To keep regions from growing without bound,
* we shrink the array of rectangles to match the new number of
* rectangles in the region. This never goes to 0, however...
*
* Only do this stuff if the number of rectangles allocated is more than
* twice the number of rectangles in the region (a simple optimization...).
*/
if (newReg->numRects < (newReg->size >> 1))
{
if (REGION_NOT_EMPTY(newReg))
{
newReg->size = newReg->numRects;
newReg->rects = (BoxPtr) Xrealloc (newReg->rects,
sizeof(BoxRec) * newReg->size);
}
else
{
/*
* No point in doing the extra work involved in an Xrealloc if
* the region is empty
*/
newReg->size = 1;
Xfree(newReg->rects);
newReg->rects = (BoxPtr) Xalloc(sizeof(BoxRec));
}
}
Xfree (oldRects);
}
/*-
*-----------------------------------------------------------------------
* miSetExtents --
* Reset the extents of a region to what they should be. Called by
* miSubtract and miIntersect b/c they can't figure it out along the
* way or do so easily, as miUnion can.
*
* Results:
* None.
*
* Side Effects:
* The region's 'extents' structure is overwritten.
*
*-----------------------------------------------------------------------
*/
static void
miSetExtents (pReg)
RegionPtr pReg;
{
register BoxPtr pBox,
pBoxEnd,
pExtents;
pExtents = &pReg->extents;
pBox = pReg->rects;
pBoxEnd = &pBox[pReg->numRects - 1];
/*
* Since pBox is the first rectangle in the region, it must have the
* smallest y1 and since pBoxEnd is the last rectangle in the region,
* it must have the largest y2, because of banding. Initialize x1 and
* x2 from pBox and pBoxEnd, resp., as good things to initialize them
* to...
*/
pExtents->x1 = pBox->x1;
pExtents->y1 = pBox->y1;
pExtents->x2 = pBoxEnd->x2;
pExtents->y2 = pBoxEnd->y2;
assert(pExtents->y1 < pExtents->y2);
while (pBox <= pBoxEnd)
{
if (pBox->x1 < pExtents->x1)
{
pExtents->x1 = pBox->x1;
}
if (pBox->x2 > pExtents->x2)
{
pExtents->x2 = pBox->x2;
}
pBox++;
}
assert(pExtents->x1 < pExtents->x2);
}
/*======================================================================
* Region Inversion
*====================================================================*/
/*-
*-----------------------------------------------------------------------
* miInverse --
* Take a region and a box and return a region that is everything
* in the box but not in the region. The careful reader will note
* that this is the same as subtracting the region from the box...
*
* Results:
* TRUE.
*
* Side Effects:
* newReg is overwritten.
*
*-----------------------------------------------------------------------
*/
int
miInverse(newReg, reg1, invRect)
RegionPtr newReg; /* Destination region */
RegionPtr reg1; /* Region to invert */
BOX *invRect; /* Bounding box for inversion */
{
RegionRec invReg; /* Quick and dirty region made from the
* bounding box */
invReg.size = 1;
invReg.numRects = 1;
invReg.extents = *invRect;
invReg.rects = invRect;
return (miSubtract (newReg, &invReg, reg1));
}
/*======================================================================
* Region Intersection
*====================================================================*/
/*-
*-----------------------------------------------------------------------
* miIntersectO --
* Handle an overlapping band for miIntersect.
*
* Results:
* None.
*
* Side Effects:
* Rectangles may be added to the region.
*
*-----------------------------------------------------------------------
*/
static void
miIntersectO (pReg, r1, r1End, r2, r2End, y1, y2)
register RegionPtr pReg;
register BoxPtr r1;
BoxPtr r1End;
register BoxPtr r2;
BoxPtr r2End;
short y1;
short y2;
{
register short x1;
register short x2;
register BoxPtr pNextRect;
pNextRect = &pReg->rects[pReg->numRects];
while ((r1 != r1End) && (r2 != r2End))
{
x1 = max(r1->x1,r2->x1);
x2 = min(r1->x2,r2->x2);
/*
* If there's any overlap between the two rectangles, add that
* overlap to the new region.
* There's no need to check for subsumption because the only way
* such a need could arise is if some region has two rectangles
* right next to each other. Since that should never happen...
*/
if (x1 < x2)
{
assert(y1<y2);
MEMCHECK(pReg, pNextRect, pReg->rects);
pNextRect->x1 = x1;
pNextRect->y1 = y1;
pNextRect->x2 = x2;
pNextRect->y2 = y2;
pReg->numRects += 1;
pNextRect++;
assert(pReg->numRects <= pReg->size);
}
/*
* Need to advance the pointers. Shift the one that extends
* to the right the least, since the other still has a chance to
* overlap with that region's next rectangle, if you see what I mean.
*/
if (r1->x2 < r2->x2)
{
r1++;
}
else if (r2->x2 < r1->x2)
{
r2++;
}
else
{
r1++;
r2++;
}
}
}
int
miIntersect(newReg, reg1, reg2)
register RegionPtr newReg; /* destination Region */
RegionPtr reg1;
RegionPtr reg2; /* source regions */
{
/* check for trivial reject */
if ( (!(reg1->numRects)) || (!(reg2->numRects)) ||
(!EXTENTCHECK(®1->extents, ®2->extents)))
{
newReg->numRects = 0;
return(1);
}
miRegionOp (newReg, reg1, reg2, miIntersectO, NULL, NULL);
if (newReg->numRects != 0)
{
/*
* Can't alter newReg's extents before we call miRegionOp because
* it might be one of the source regions and miRegionOp depends
* on the extents of those regions being the same. Besides, this
* way there's no checking against rectangles that will be nuked
* due to coalescing, so we have to examine fewer rectangles.
*/
miSetExtents(newReg);
}
return(1);
}
/*======================================================================
* Region Union
*====================================================================*/
/*-
*-----------------------------------------------------------------------
* miUnionNonO --
* Handle a non-overlapping band for the union operation. Just
* Adds the rectangles into the region. Doesn't have to check for
* subsumption or anything.
*
* Results:
* None.
*
* Side Effects:
* pReg->numRects is incremented and the final rectangles overwritten
* with the rectangles we're passed.
*
*-----------------------------------------------------------------------
*/
static void
miUnionNonO (pReg, r, rEnd, y1, y2)
register RegionPtr pReg;
register BoxPtr r;
BoxPtr rEnd;
register short y1;
register short y2;
{
register BoxPtr pNextRect;
pNextRect = &pReg->rects[pReg->numRects];
assert(y1 < y2);
while (r != rEnd)
{
assert(r->x1 < r->x2);
MEMCHECK(pReg, pNextRect, pReg->rects);
pNextRect->x1 = r->x1;
pNextRect->y1 = y1;
pNextRect->x2 = r->x2;
pNextRect->y2 = y2;
pReg->numRects += 1;
pNextRect++;
assert(pReg->numRects<=pReg->size);
r++;
}
}
/*-
*-----------------------------------------------------------------------
* miUnionO --
* Handle an overlapping band for the union operation. Picks the
* left-most rectangle each time and merges it into the region.
*
* Results:
* None.
*
* Side Effects:
* Rectangles are overwritten in pReg->rects and pReg->numRects will
* be changed.
*
*-----------------------------------------------------------------------
*/
static void
miUnionO (pReg, r1, r1End, r2, r2End, y1, y2)
register RegionPtr pReg;
register BoxPtr r1;
BoxPtr r1End;
register BoxPtr r2;
BoxPtr r2End;
register short y1;
register short y2;
{
register BoxPtr pNextRect;
pNextRect = &pReg->rects[pReg->numRects];
#define MERGERECT(r) \
if ((pReg->numRects != 0) && \
(pNextRect[-1].y1 == y1) && \
(pNextRect[-1].y2 == y2) && \
(pNextRect[-1].x2 >= r->x1)) \
{ \
if (pNextRect[-1].x2 < r->x2) \
{ \
pNextRect[-1].x2 = r->x2; \
assert(pNextRect[-1].x1<pNextRect[-1].x2); \
} \
} \
else \
{ \
MEMCHECK(pReg, pNextRect, pReg->rects); \
pNextRect->y1 = y1; \
pNextRect->y2 = y2; \
pNextRect->x1 = r->x1; \
pNextRect->x2 = r->x2; \
pReg->numRects += 1; \
pNextRect += 1; \
} \
assert(pReg->numRects<=pReg->size);\
r++;
assert (y1<y2);
while ((r1 != r1End) && (r2 != r2End))
{
if (r1->x1 < r2->x1)
{
MERGERECT(r1);
}
else
{
MERGERECT(r2);
}
}
if (r1 != r1End)
{
do
{
MERGERECT(r1);
} while (r1 != r1End);
}
else while (r2 != r2End)
{
MERGERECT(r2);
}
}
int
miUnion(newReg, reg1, reg2)
RegionPtr newReg; /* destination Region */
RegionPtr reg1;
RegionPtr reg2; /* source regions */
{
/* checks all the simple cases */
/*
* Region 1 and 2 are the same or region 1 is empty
*/
if ( (reg1 == reg2) || (!(reg1->numRects)) )
{
if (newReg != reg2)
miRegionCopy(newReg, reg2);
return(TRUE);
}
/*
* if nothing to union (region 2 empty)
*/
if (!(reg2->numRects))
{
if (newReg != reg1)
miRegionCopy(newReg, reg1);
return(TRUE);
}
/*
* Region 1 completely subsumes region 2
*/
if ((reg1->numRects == 1) &&
(reg1->extents.x1 <= reg2->extents.x1) &&
(reg1->extents.y1 <= reg2->extents.y1) &&
(reg1->extents.x2 >= reg2->extents.x2) &&
(reg1->extents.y2 >= reg2->extents.y2))
{
if (newReg != reg1)
miRegionCopy(newReg, reg1);
return(TRUE);
}
/*
* Region 2 completely subsumes region 1
*/
if ((reg2->numRects == 1) &&
(reg2->extents.x1 <= reg1->extents.x1) &&
(reg2->extents.y1 <= reg1->extents.y1) &&
(reg2->extents.x2 >= reg1->extents.x2) &&
(reg2->extents.y2 >= reg1->extents.y2))
{
if (newReg != reg2)
miRegionCopy(newReg, reg2);
return(TRUE);
}
miRegionOp (newReg, reg1, reg2, miUnionO, miUnionNonO, miUnionNonO);
newReg->extents.x1 = min(reg1->extents.x1, reg2->extents.x1);
newReg->extents.y1 = min(reg1->extents.y1, reg2->extents.y1);
newReg->extents.x2 = max(reg1->extents.x2, reg2->extents.x2);
newReg->extents.y2 = max(reg1->extents.y2, reg2->extents.y2);
return(1);
}
/*======================================================================
* Region Subtraction
*====================================================================*/
/*-
*-----------------------------------------------------------------------
* miSubtractNonO --
* Deal with non-overlapping band for subtraction. Any parts from
* region 2 we discard. Anything from region 1 we add to the region.
*
* Results:
* None.
*
* Side Effects:
* pReg may be affected.
*
*-----------------------------------------------------------------------
*/
static void
miSubtractNonO1 (pReg, r, rEnd, y1, y2)
register RegionPtr pReg;
register BoxPtr r;
BoxPtr rEnd;
register short y1;
register short y2;
{
register BoxPtr pNextRect;
pNextRect = &pReg->rects[pReg->numRects];
assert(y1<y2);
while (r != rEnd)
{
assert(r->x1<r->x2);
MEMCHECK(pReg, pNextRect, pReg->rects);
pNextRect->x1 = r->x1;
pNextRect->y1 = y1;
pNextRect->x2 = r->x2;
pNextRect->y2 = y2;
pReg->numRects += 1;
pNextRect++;
assert(pReg->numRects <= pReg->size);
r++;
}
}
/*-
*-----------------------------------------------------------------------
* miSubtractO --
* Overlapping band subtraction. x1 is the left-most point not yet
* checked.
*
* Results:
* None.
*
* Side Effects:
* pReg may have rectangles added to it.
*
*-----------------------------------------------------------------------
*/
static void
miSubtractO (pReg, r1, r1End, r2, r2End, y1, y2)
register RegionPtr pReg;
register BoxPtr r1;
BoxPtr r1End;
register BoxPtr r2;
BoxPtr r2End;
register short y1;
register short y2;
{
register BoxPtr pNextRect;
register int x1;
x1 = r1->x1;
assert(y1<y2);
pNextRect = &pReg->rects[pReg->numRects];
while ((r1 != r1End) && (r2 != r2End))
{
if (r2->x2 <= x1)
{
/*
* Subtrahend missed the boat: go to next subtrahend.
*/
r2++;
}
else if (r2->x1 <= x1)
{
/*
* Subtrahend preceeds minuend: nuke left edge of minuend.
*/
x1 = r2->x2;
if (x1 >= r1->x2)
{
/*
* Minuend completely covered: advance to next minuend and
* reset left fence to edge of new minuend.
*/
r1++;
x1 = r1->x1;
}
else
{
/*
* Subtrahend now used up since it doesn't extend beyond
* minuend
*/
r2++;
}
}
else if (r2->x1 < r1->x2)
{
/*
* Left part of subtrahend covers part of minuend: add uncovered
* part of minuend to region and skip to next subtrahend.
*/
assert(x1<r2->x1);
MEMCHECK(pReg, pNextRect, pReg->rects);
pNextRect->x1 = x1;
pNextRect->y1 = y1;
pNextRect->x2 = r2->x1;
pNextRect->y2 = y2;
pReg->numRects += 1;
pNextRect++;
assert(pReg->numRects<=pReg->size);
x1 = r2->x2;
if (x1 >= r1->x2)
{
/*
* Minuend used up: advance to new...
*/
r1++;
x1 = r1->x1;
}
else
{
/*
* Subtrahend used up
*/
r2++;
}
}
else
{
/*
* Minuend used up: add any remaining piece before advancing.
*/
if (r1->x2 > x1)
{
MEMCHECK(pReg, pNextRect, pReg->rects);
pNextRect->x1 = x1;
pNextRect->y1 = y1;
pNextRect->x2 = r1->x2;
pNextRect->y2 = y2;
pReg->numRects += 1;
pNextRect++;
assert(pReg->numRects<=pReg->size);
}
r1++;
x1 = r1->x1;
}
}
/*
* Add remaining minuend rectangles to region.
*/
while (r1 != r1End)
{
assert(x1<r1->x2);
MEMCHECK(pReg, pNextRect, pReg->rects);
pNextRect->x1 = x1;
pNextRect->y1 = y1;
pNextRect->x2 = r1->x2;
pNextRect->y2 = y2;
pReg->numRects += 1;
pNextRect++;
assert(pReg->numRects<=pReg->size);
r1++;
if (r1 != r1End)
{
x1 = r1->x1;
}
}
}
/*-
*-----------------------------------------------------------------------
* miSubtract --
* Subtract regS from regM and leave the result in regD.
* S stands for subtrahend, M for minuend and D for difference.
*
* Results:
* TRUE.
*
* Side Effects:
* regD is overwritten.
*
*-----------------------------------------------------------------------
*/
int
miSubtract(regD, regM, regS)
register RegionPtr regD;
RegionPtr regM;
RegionPtr regS;
{
/* check for trivial reject */
if ( (!(regM->numRects)) || (!(regS->numRects)) ||
(!EXTENTCHECK(®M->extents, ®S->extents)) )
{
miRegionCopy(regD, regM);
return(1);
}
miRegionOp (regD, regM, regS, miSubtractO, miSubtractNonO1, NULL);
if (regD->numRects != 0)
{
/*
* Can't alter newReg's extents before we call miRegionOp because
* it might be one of the source regions and miRegionOp depends
* on the extents of those regions being the unaltered. Besides, this
* way there's no checking against rectangles that will be nuked
* due to coalescing, so we have to examine fewer rectangles.
*/
miSetExtents (regD);
}
return(1);
}
/*
* RectIn(region, rect)
* This routine takes a pointer to a region and a pointer to a box
* and determines if the box is outside/inside/partly inside the region.
*
* The idea is to travel through the list of rectangles trying to cover the
* passed box with them. Anytime a piece of the rectangle isn't covered
* by a band of rectangles, partOut is set TRUE. Any time a rectangle in
* the region covers part of the box, partIn is set TRUE. The process ends
* when either the box has been completely covered (we reached a band that
* doesn't overlap the box, partIn is TRUE and partOut is false), the
* box has been partially covered (partIn == partOut == TRUE -- because of
* the banding, the first time this is true we know the box is only
* partially in the region) or is outside the region (we reached a band
* that doesn't overlap the box at all and partIn is false)
*/
int
miRectIn(region, prect)
register RegionPtr region;
register BoxPtr prect;
{
register short x;
register short y;
register BoxPtr pbox;
register BoxPtr pboxEnd;
int partIn, partOut;
/* this is (just) a useful optimization */
if ((region->numRects == 0) || !EXTENTCHECK(®ion->extents, prect))
return(rgnOUT);
partOut = FALSE;
partIn = FALSE;
/* (x,y) starts at upper left of rect, moving to the right and down */
x = prect->x1;
y = prect->y1;
/* can stop when both partOut and partIn are TRUE, or we reach prect->y2 */
for (pbox = region->rects, pboxEnd = pbox + region->numRects;
pbox < pboxEnd;
pbox++)
{
if (pbox->y2 <= y)
continue; /* getting up to speed or skipping remainder of band */
if (pbox->y1 > y)
{
partOut = TRUE; /* missed part of rectangle above */
if (partIn || (pbox->y1 >= prect->y2))
break;
y = pbox->y1; /* x guaranteed to be == prect->x1 */
}
if (pbox->x2 <= x)
continue; /* not far enough over yet */
if (pbox->x1 > x)
{
partOut = TRUE; /* missed part of rectangle to left */
if (partIn)
break;
}
if (pbox->x1 < prect->x2)
{
partIn = TRUE; /* definitely overlap */
if (partOut)
break;
}
if (pbox->x2 >= prect->x2)
{
y = pbox->y2; /* finished with this band */
if (y >= prect->y2)
break;
x = prect->x1; /* reset x out to left again */
}
else
{
/*
* Because boxes in a band are maximal width, if the first box
* to overlap the rectangle doesn't completely cover it in that
* band, the rectangle must be partially out, since some of it
* will be uncovered in that band. partIn will have been set true
* by now...
*/
partOut = TRUE;
break;
}
}
return(partIn ? ((y < prect->y2) ? rgnPART : rgnIN) : rgnOUT);
}
/* TranslateRegion(pRegion, x, y)
translates in place
added by raymond
*/
void
miTranslateRegion(pRegion, x, y)
register RegionPtr pRegion;
register int x;
register int y;
{
register int nbox;
register BOX *pbox;
pbox = pRegion->rects;
nbox = pRegion->numRects;
while(nbox--)
{
pbox->x1 += x;
pbox->x2 += x;
pbox->y1 += y;
pbox->y2 += y;
pbox++;
}
pRegion->extents.x1 += x;
pRegion->extents.x2 += x;
pRegion->extents.y1 += y;
pRegion->extents.y2 += y;
}
void
miRegionDestroy(pRegion)
RegionPtr pRegion;
{
Xfree(pRegion->rects);
Xfree(pRegion);
}
void
miRegionReset(pRegion, pBox)
RegionPtr pRegion;
BOX *pBox;
{
assert(pBox->x1<pBox->x2);
assert(pBox->y1<pBox->y2);
pRegion->extents.x1 = pRegion->rects->x1 = pBox->x1;
pRegion->extents.y1 = pRegion->rects->y1 = pBox->y1;
pRegion->extents.x2 = pRegion->rects->x2 = pBox->x2;
pRegion->extents.y2 = pRegion->rects->y2 = pBox->y2;
pRegion->numRects = 1;
}
#define INBOX(r, x, y) \
( ( ((r).x2 > x)) && \
( ((r).x1 <= x)) && \
( ((r).y2 > y)) && \
( ((r).y1 <= y)) )
Bool
miPointInRegion(pRegion, x, y, box)
register RegionPtr pRegion;
register int x, y;
BOX *box; /* "return" value */
{
register BOX *pbox, *pboxEnd;
if (pRegion->numRects == 0)
return(FALSE);
if (!INBOX(pRegion->extents, x, y))
return(FALSE);
for (pbox = pRegion->rects, pboxEnd = pbox + pRegion->numRects;
pbox < pboxEnd;
pbox++)
{
if (y >= pbox->y2)
continue; /* not there yet */
if ((y < pbox->y1) || (x < pbox->x1))
break; /* missed it */
if (x >= pbox->x2)
continue; /* not there yet */
*box = *pbox;
return(TRUE);
}
return(FALSE);
}
Bool
miRegionNotEmpty(pRegion)
RegionPtr pRegion;
{
return(pRegion->numRects != 0);
}
void
miRegionEmpty(pRegion)
RegionPtr pRegion;
{
pRegion->numRects = 0;
}
BoxPtr
miRegionExtents(pReg)
RegionPtr pReg;
{
return((BoxPtr) &pReg->extents);
}
/*
Clip a list of scanlines to a region. The caller has allocated the
spce. FSorted is non-zero if the scanline origins are in ascending
order.
returns the number of new, clipped scanlines.
*/
int
miClipSpans(prgnDst, ppt, pwidth, nspans, pptNew, pwidthNew, fSorted)
RegionPtr prgnDst;
register DDXPointPtr ppt;
register int *pwidth;
int nspans;
register DDXPointPtr pptNew;
int *pwidthNew;
int fSorted;
{
register BoxPtr pbox, pboxLast;
BoxPtr pboxTest;
register DDXPointPtr pptLast;
int yMax;
int *pwidthNewThatWeWerePassed; /* the vengeance
of Xerox! */
pptLast = ppt + nspans;
pboxTest = prgnDst->rects;
pboxLast = pboxTest + prgnDst->numRects;
yMax = prgnDst->extents.y2;
pwidthNewThatWeWerePassed = pwidthNew;
for (; ppt < pptLast; ppt++, pwidth++)
{
if(fSorted)
{
if(ppt->y >= yMax)
break;
pbox = pboxTest;
}
else
{
if(ppt->y >= yMax)
continue;
pbox = prgnDst->rects;
}
if(*pwidth == 0)
continue;
while(pbox < pboxLast)
{
if(pbox->y1 > ppt->y)
{
/* scanline is before clip box */
break;
}
if(pbox->y2 <= ppt->y)
{
/* clip box is before scanline */
pboxTest = ++pbox;
continue;
}
if(pbox->x1 >= ppt->x + *pwidth)
{
/* clip box is to right of scanline */
break;
}
if(pbox->x2 <= ppt->x)
{
/* scanline is to right of clip box */
pbox++;
continue;
}
/* at least some of the scanline is in the current clip box */
pptNew->x = max(pbox->x1, ppt->x);
pptNew->y = ppt->y;
*pwidthNew++ = min(ppt->x + *pwidth, pbox->x2) - pptNew->x;
pptNew++;
pbox++;
}
}
return (pwidthNew - pwidthNewThatWeWerePassed);
}
/* find the band in a region with the most rectangles */
int
miFindMaxBand(prgn)
RegionPtr prgn;
{
register int nbox;
register BoxPtr pbox;
register int nThisBand;
register int nMaxBand = 0;
short yThisBand;
nbox = prgn->numRects;
pbox = prgn->rects;
while(nbox > 0)
{
yThisBand = pbox->y1;
nThisBand = 0;
while((nbox--) && (pbox->y1 == yThisBand))
{
pbox++;
nThisBand++;
}
if (nThisBand > nMaxBand)
nMaxBand = nThisBand;
}
return (nMaxBand);
}
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