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Diffstat (limited to 'mi/mipoly.h')
| -rw-r--r-- | mi/mipoly.h | 228 |
1 files changed, 228 insertions, 0 deletions
diff --git a/mi/mipoly.h b/mi/mipoly.h new file mode 100644 index 000000000..d946388a6 --- /dev/null +++ b/mi/mipoly.h @@ -0,0 +1,228 @@ +/* $Xorg: mipoly.h,v 1.4 2001/02/09 02:05:21 xorgcvs Exp $ */ +/* + +Copyright 1987, 1998 The Open Group + +Permission to use, copy, modify, distribute, and sell 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 and this permission notice appear in supporting +documentation. + +The above copyright notice and this permission notice shall be included +in all copies or substantial portions of the Software. + +THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS +OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF +MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. +IN NO EVENT SHALL THE OPEN GROUP BE LIABLE FOR ANY CLAIM, DAMAGES OR +OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, +ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR +OTHER DEALINGS IN THE SOFTWARE. + +Except as contained in this notice, the name of The Open Group shall +not be used in advertising or otherwise to promote the sale, use or +other dealings in this Software without prior written authorization +from The Open Group. + +*/ + + +/* + * fill.h + * + * Created by Brian Kelleher; Oct 1985 + * + * Include file for filled polygon routines. + * + * These are the data structures needed to scan + * convert regions. Two different scan conversion + * methods are available -- the even-odd method, and + * the winding number method. + * The even-odd rule states that a point is inside + * the polygon if a ray drawn from that point in any + * direction will pass through an odd number of + * path segments. + * By the winding number rule, a point is decided + * to be inside the polygon if a ray drawn from that + * point in any direction passes through a different + * number of clockwise and counter-clockwise path + * segments. + * + * These data structures are adapted somewhat from + * the algorithm in (Foley/Van Dam) for scan converting + * polygons. + * The basic algorithm is to start at the top (smallest y) + * of the polygon, stepping down to the bottom of + * the polygon by incrementing the y coordinate. We + * keep a list of edges which the current scanline crosses, + * sorted by x. This list is called the Active Edge Table (AET) + * As we change the y-coordinate, we update each entry in + * in the active edge table to reflect the edges new xcoord. + * This list must be sorted at each scanline in case + * two edges intersect. + * We also keep a data structure known as the Edge Table (ET), + * which keeps track of all the edges which the current + * scanline has not yet reached. The ET is basically a + * list of ScanLineList structures containing a list of + * edges which are entered at a given scanline. There is one + * ScanLineList per scanline at which an edge is entered. + * When we enter a new edge, we move it from the ET to the AET. + * + * From the AET, we can implement the even-odd rule as in + * (Foley/Van Dam). + * The winding number rule is a little trickier. We also + * keep the EdgeTableEntries in the AET linked by the + * nextWETE (winding EdgeTableEntry) link. This allows + * the edges to be linked just as before for updating + * purposes, but only uses the edges linked by the nextWETE + * link as edges representing spans of the polygon to + * drawn (as with the even-odd rule). + */ + +/* + * for the winding number rule + */ +#define CLOCKWISE 1 +#define COUNTERCLOCKWISE -1 + +typedef struct _EdgeTableEntry { + int ymax; /* ycoord at which we exit this edge. */ + BRESINFO bres; /* Bresenham info to run the edge */ + struct _EdgeTableEntry *next; /* next in the list */ + struct _EdgeTableEntry *back; /* for insertion sort */ + struct _EdgeTableEntry *nextWETE; /* for winding num rule */ + int ClockWise; /* flag for winding number rule */ +} EdgeTableEntry; + + +typedef struct _ScanLineList{ + int scanline; /* the scanline represented */ + EdgeTableEntry *edgelist; /* header node */ + struct _ScanLineList *next; /* next in the list */ +} ScanLineList; + + +typedef struct { + int ymax; /* ymax for the polygon */ + int ymin; /* ymin for the polygon */ + ScanLineList scanlines; /* header node */ +} EdgeTable; + + +/* + * Here is a struct to help with storage allocation + * so we can allocate a big chunk at a time, and then take + * pieces from this heap when we need to. + */ +#define SLLSPERBLOCK 25 + +typedef struct _ScanLineListBlock { + ScanLineList SLLs[SLLSPERBLOCK]; + struct _ScanLineListBlock *next; +} ScanLineListBlock; + +/* + * number of points to buffer before sending them off + * to scanlines() : Must be an even number + */ +#define NUMPTSTOBUFFER 200 + + +/* + * + * a few macros for the inner loops of the fill code where + * performance considerations don't allow a procedure call. + * + * Evaluate the given edge at the given scanline. + * If the edge has expired, then we leave it and fix up + * the active edge table; otherwise, we increment the + * x value to be ready for the next scanline. + * The winding number rule is in effect, so we must notify + * the caller when the edge has been removed so he + * can reorder the Winding Active Edge Table. + */ +#define EVALUATEEDGEWINDING(pAET, pPrevAET, y, fixWAET) { \ + if (pAET->ymax == y) { /* leaving this edge */ \ + pPrevAET->next = pAET->next; \ + pAET = pPrevAET->next; \ + fixWAET = 1; \ + if (pAET) \ + pAET->back = pPrevAET; \ + } \ + else { \ + BRESINCRPGONSTRUCT(pAET->bres); \ + pPrevAET = pAET; \ + pAET = pAET->next; \ + } \ +} + + +/* + * Evaluate the given edge at the given scanline. + * If the edge has expired, then we leave it and fix up + * the active edge table; otherwise, we increment the + * x value to be ready for the next scanline. + * The even-odd rule is in effect. + */ +#define EVALUATEEDGEEVENODD(pAET, pPrevAET, y) { \ + if (pAET->ymax == y) { /* leaving this edge */ \ + pPrevAET->next = pAET->next; \ + pAET = pPrevAET->next; \ + if (pAET) \ + pAET->back = pPrevAET; \ + } \ + else { \ + BRESINCRPGONSTRUCT(pAET->bres); \ + pPrevAET = pAET; \ + pAET = pAET->next; \ + } \ +} + +/* mipolyutil.c */ + +extern Bool miInsertEdgeInET( +#if NeedFunctionPrototypes + EdgeTable * /*ET*/, + EdgeTableEntry * /*ETE*/, + int /*scanline*/, + ScanLineListBlock ** /*SLLBlock*/, + int * /*iSLLBlock*/ +#endif +); + +extern Bool miCreateETandAET( +#if NeedFunctionPrototypes + int /*count*/, + DDXPointPtr /*pts*/, + EdgeTable * /*ET*/, + EdgeTableEntry * /*AET*/, + EdgeTableEntry * /*pETEs*/, + ScanLineListBlock * /*pSLLBlock*/ +#endif +); + +extern void miloadAET( +#if NeedFunctionPrototypes + EdgeTableEntry * /*AET*/, + EdgeTableEntry * /*ETEs*/ +#endif +); + +extern void micomputeWAET( +#if NeedFunctionPrototypes + EdgeTableEntry * /*AET*/ +#endif +); + +extern int miInsertionSort( +#if NeedFunctionPrototypes + EdgeTableEntry * /*AET*/ +#endif +); + +extern void miFreeStorage( +#if NeedFunctionPrototypes + ScanLineListBlock * /*pSLLBlock*/ +#endif +); |