diff options
Diffstat (limited to 'libX11/src/poly.h')
| -rw-r--r-- | libX11/src/poly.h | 588 |
1 files changed, 294 insertions, 294 deletions
diff --git a/libX11/src/poly.h b/libX11/src/poly.h index e064783d7..1a5163d48 100644 --- a/libX11/src/poly.h +++ b/libX11/src/poly.h @@ -1,294 +1,294 @@ -/************************************************************************ - -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. - - -Copyright 1987 by Digital Equipment Corporation, Maynard, 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 name of Digital 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. - -************************************************************************/ - -/* - * This file contains a few macros to help track - * the edge of a filled object. The object is assumed - * to be filled in scanline order, and thus the - * algorithm used is an extension of Bresenham's line - * drawing algorithm which assumes that y is always the - * major axis. - * Since these pieces of code are the same for any filled shape, - * it is more convenient to gather the library in one - * place, but since these pieces of code are also in - * the inner loops of output primitives, procedure call - * overhead is out of the question. - * See the author for a derivation if needed. - */ - - -/* - * In scan converting polygons, we want to choose those pixels - * which are inside the polygon. Thus, we add .5 to the starting - * x coordinate for both left and right edges. Now we choose the - * first pixel which is inside the pgon for the left edge and the - * first pixel which is outside the pgon for the right edge. - * Draw the left pixel, but not the right. - * - * How to add .5 to the starting x coordinate: - * If the edge is moving to the right, then subtract dy from the - * error term from the general form of the algorithm. - * If the edge is moving to the left, then add dy to the error term. - * - * The reason for the difference between edges moving to the left - * and edges moving to the right is simple: If an edge is moving - * to the right, then we want the algorithm to flip immediately. - * If it is moving to the left, then we don't want it to flip until - * we traverse an entire pixel. - */ -#define BRESINITPGON(dy, x1, x2, xStart, d, m, m1, incr1, incr2) { \ - int dx; /* local storage */ \ -\ - /* \ - * if the edge is horizontal, then it is ignored \ - * and assumed not to be processed. Otherwise, do this stuff. \ - */ \ - if ((dy) != 0) { \ - xStart = (x1); \ - dx = (x2) - xStart; \ - if (dx < 0) { \ - m = dx / (dy); \ - m1 = m - 1; \ - incr1 = -2 * dx + 2 * (dy) * m1; \ - incr2 = -2 * dx + 2 * (dy) * m; \ - d = 2 * m * (dy) - 2 * dx - 2 * (dy); \ - } else { \ - m = dx / (dy); \ - m1 = m + 1; \ - incr1 = 2 * dx - 2 * (dy) * m1; \ - incr2 = 2 * dx - 2 * (dy) * m; \ - d = -2 * m * (dy) + 2 * dx; \ - } \ - } \ -} - -#define BRESINCRPGON(d, minval, m, m1, incr1, incr2) { \ - if (m1 > 0) { \ - if (d > 0) { \ - minval += m1; \ - d += incr1; \ - } \ - else { \ - minval += m; \ - d += incr2; \ - } \ - } else {\ - if (d >= 0) { \ - minval += m1; \ - d += incr1; \ - } \ - else { \ - minval += m; \ - d += incr2; \ - } \ - } \ -} - - -/* - * This structure contains all of the information needed - * to run the bresenham algorithm. - * The variables may be hardcoded into the declarations - * instead of using this structure to make use of - * register declarations. - */ -typedef struct { - int minor_axis; /* minor axis */ - int d; /* decision variable */ - int m, m1; /* slope and slope+1 */ - int incr1, incr2; /* error increments */ -} BRESINFO; - - -#define BRESINITPGONSTRUCT(dmaj, min1, min2, bres) \ - BRESINITPGON(dmaj, min1, min2, bres.minor_axis, bres.d, \ - bres.m, bres.m1, bres.incr1, bres.incr2) - -#define BRESINCRPGONSTRUCT(bres) \ - BRESINCRPGON(bres.d, bres.minor_axis, bres.m, bres.m1, bres.incr1, bres.incr2) - - - -/* - * 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; - - - -/* - * - * 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; \ - } \ -} +/************************************************************************
+
+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.
+
+
+Copyright 1987 by Digital Equipment Corporation, Maynard, 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 name of Digital 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.
+
+************************************************************************/
+
+/*
+ * This file contains a few macros to help track
+ * the edge of a filled object. The object is assumed
+ * to be filled in scanline order, and thus the
+ * algorithm used is an extension of Bresenham's line
+ * drawing algorithm which assumes that y is always the
+ * major axis.
+ * Since these pieces of code are the same for any filled shape,
+ * it is more convenient to gather the library in one
+ * place, but since these pieces of code are also in
+ * the inner loops of output primitives, procedure call
+ * overhead is out of the question.
+ * See the author for a derivation if needed.
+ */
+
+
+/*
+ * In scan converting polygons, we want to choose those pixels
+ * which are inside the polygon. Thus, we add .5 to the starting
+ * x coordinate for both left and right edges. Now we choose the
+ * first pixel which is inside the pgon for the left edge and the
+ * first pixel which is outside the pgon for the right edge.
+ * Draw the left pixel, but not the right.
+ *
+ * How to add .5 to the starting x coordinate:
+ * If the edge is moving to the right, then subtract dy from the
+ * error term from the general form of the algorithm.
+ * If the edge is moving to the left, then add dy to the error term.
+ *
+ * The reason for the difference between edges moving to the left
+ * and edges moving to the right is simple: If an edge is moving
+ * to the right, then we want the algorithm to flip immediately.
+ * If it is moving to the left, then we don't want it to flip until
+ * we traverse an entire pixel.
+ */
+#define BRESINITPGON(dy, x1, x2, xStart, d, m, m1, incr1, incr2) { \
+ int dx; /* local storage */ \
+\
+ /* \
+ * if the edge is horizontal, then it is ignored \
+ * and assumed not to be processed. Otherwise, do this stuff. \
+ */ \
+ if ((dy) != 0) { \
+ xStart = (x1); \
+ dx = (x2) - xStart; \
+ if (dx < 0) { \
+ m = dx / (dy); \
+ m1 = m - 1; \
+ incr1 = -2 * dx + 2 * (dy) * m1; \
+ incr2 = -2 * dx + 2 * (dy) * m; \
+ d = 2 * m * (dy) - 2 * dx - 2 * (dy); \
+ } else { \
+ m = dx / (dy); \
+ m1 = m + 1; \
+ incr1 = 2 * dx - 2 * (dy) * m1; \
+ incr2 = 2 * dx - 2 * (dy) * m; \
+ d = -2 * m * (dy) + 2 * dx; \
+ } \
+ } \
+}
+
+#define BRESINCRPGON(d, minval, m, m1, incr1, incr2) { \
+ if (m1 > 0) { \
+ if (d > 0) { \
+ minval += m1; \
+ d += incr1; \
+ } \
+ else { \
+ minval += m; \
+ d += incr2; \
+ } \
+ } else {\
+ if (d >= 0) { \
+ minval += m1; \
+ d += incr1; \
+ } \
+ else { \
+ minval += m; \
+ d += incr2; \
+ } \
+ } \
+}
+
+
+/*
+ * This structure contains all of the information needed
+ * to run the bresenham algorithm.
+ * The variables may be hardcoded into the declarations
+ * instead of using this structure to make use of
+ * register declarations.
+ */
+typedef struct {
+ int minor_axis; /* minor axis */
+ int d; /* decision variable */
+ int m, m1; /* slope and slope+1 */
+ int incr1, incr2; /* error increments */
+} BRESINFO;
+
+
+#define BRESINITPGONSTRUCT(dmaj, min1, min2, bres) \
+ BRESINITPGON(dmaj, min1, min2, bres.minor_axis, bres.d, \
+ bres.m, bres.m1, bres.incr1, bres.incr2)
+
+#define BRESINCRPGONSTRUCT(bres) \
+ BRESINCRPGON(bres.d, bres.minor_axis, bres.m, bres.m1, bres.incr1, bres.incr2)
+
+
+
+/*
+ * 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;
+
+
+
+/*
+ *
+ * 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; \
+ } \
+}
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