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Diffstat (limited to 'tkblt/generic/tkbltGrMisc.C')
| -rw-r--r-- | tkblt/generic/tkbltGrMisc.C | 335 |
1 files changed, 335 insertions, 0 deletions
diff --git a/tkblt/generic/tkbltGrMisc.C b/tkblt/generic/tkbltGrMisc.C new file mode 100644 index 0000000..d951494 --- /dev/null +++ b/tkblt/generic/tkbltGrMisc.C @@ -0,0 +1,335 @@ +/* + * Smithsonian Astrophysical Observatory, Cambridge, MA, USA + * This code has been modified under the terms listed below and is made + * available under the same terms. + */ + +/* + * Copyright 1993-2004 George A Howlett. + * + * Permission is hereby granted, free of charge, to any person obtaining + * a copy of this software and associated documentation files (the + * "Software"), to deal in the Software without restriction, including + * without limitation the rights to use, copy, modify, merge, publish, + * distribute, sublicense, and/or sell copies of the Software, and to + * permit persons to whom the Software is furnished to do so, subject to + * the following conditions: + * + * 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 AUTHORS OR COPYRIGHT HOLDERS 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. + */ + +#include <limits.h> +#include <float.h> +#include <string.h> +#include <stdlib.h> + +#include <cmath> + +#include <tk.h> +#include <tkInt.h> + +#include "tkbltGraph.h" +#include "tkbltGrMisc.h" + +using namespace Blt; + +char* Blt::dupstr(const char* str) +{ + char* copy =NULL; + if (str) { + copy=new char[strlen(str)+1]; + strcpy(copy,str); + } + + return copy; +} + +int Blt::pointInPolygon(Point2d *s, Point2d *points, int nPoints) +{ + int count = 0; + for (Point2d *p=points, *q=p+1, *qend=p + nPoints; q < qend; p++, q++) { + if (((p->y <= s->y) && (s->y < q->y)) || + ((q->y <= s->y) && (s->y < p->y))) { + double b; + + b = (q->x - p->x) * (s->y - p->y) / (q->y - p->y) + p->x; + if (s->x < b) { + count++; /* Count the number of intersections. */ + } + } + } + return (count & 0x01); +} + +static int ClipTest (double ds, double dr, double *t1, double *t2) +{ + double t; + + if (ds < 0.0) { + t = dr / ds; + if (t > *t2) { + return 0; + } + if (t > *t1) { + *t1 = t; + } + } else if (ds > 0.0) { + t = dr / ds; + if (t < *t1) { + return 0; + } + if (t < *t2) { + *t2 = t; + } + } else { + /* d = 0, so line is parallel to this clipping edge */ + if (dr < 0.0) { /* Line is outside clipping edge */ + return 0; + } + } + return 1; +} + +/* + *--------------------------------------------------------------------------- + * Clips the given line segment to a rectangular region. The coordinates + * of the clipped line segment are returned. The original coordinates + * are overwritten. + * + * Reference: + * Liang, Y-D., and B. Barsky, A new concept and method for + * Line Clipping, ACM, TOG,3(1), 1984, pp.1-22. + *--------------------------------------------------------------------------- + */ +int Blt::lineRectClip(Region2d* regionPtr, Point2d *p, Point2d *q) +{ + double t1, t2; + double dx, dy; + + t1 = 0.0, t2 = 1.0; + dx = q->x - p->x; + if ((ClipTest (-dx, p->x - regionPtr->left, &t1, &t2)) && + (ClipTest (dx, regionPtr->right - p->x, &t1, &t2))) { + dy = q->y - p->y; + if ((ClipTest (-dy, p->y - regionPtr->top, &t1, &t2)) && + (ClipTest (dy, regionPtr->bottom - p->y, &t1, &t2))) { + if (t2 < 1.0) { + q->x = p->x + t2 * dx; + q->y = p->y + t2 * dy; + } + if (t1 > 0.0) { + p->x += t1 * dx; + p->y += t1 * dy; + } + return 1; + } + } + return 0; +} + +/* + *--------------------------------------------------------------------------- + * Clips the given polygon to a rectangular region. The resulting + * polygon is returned. Note that the resulting polyon may be complex, + * connected by zero width/height segments. The drawing routine (such as + * XFillPolygon) will not draw a connecting segment. + * + * Reference: + * Liang Y. D. and Brian A. Barsky, "Analysis and Algorithm for + * Polygon Clipping", Communications of ACM, Vol. 26, + * p.868-877, 1983 + *--------------------------------------------------------------------------- + */ +#define AddVertex(vx, vy) r->x=(vx), r->y=(vy), r++, count++ +#define LastVertex(vx, vy) r->x=(vx), r->y=(vy), count++ + +int Blt::polyRectClip(Region2d *regionPtr, Point2d *points, int nPoints, + Point2d *clipPts) +{ + Point2d* r = clipPts; + // Counts # of vertices in output polygon. + int count = 0; + + points[nPoints] = points[0]; + for (Point2d *p=points, *q=p+1, *pend=p+nPoints; p<pend; p++, q++) { + double dx, dy; + double tin1, tin2, tinx, tiny; + double xin, yin, xout, yout; + + dx = q->x - p->x; /* X-direction */ + dy = q->y - p->y; /* Y-direction */ + + if (fabs(dx) < FLT_EPSILON) + dx = (p->x > regionPtr->left) ? -FLT_EPSILON : FLT_EPSILON ; + + if (fabs(dy) < FLT_EPSILON) + dy = (p->y > regionPtr->top) ? -FLT_EPSILON : FLT_EPSILON ; + + if (dx > 0.0) { /* Left */ + xin = regionPtr->left; + xout = regionPtr->right + 1.0; + } + else { /* Right */ + xin = regionPtr->right + 1.0; + xout = regionPtr->left; + } + if (dy > 0.0) { /* Top */ + yin = regionPtr->top; + yout = regionPtr->bottom + 1.0; + } + else { /* Bottom */ + yin = regionPtr->bottom + 1.0; + yout = regionPtr->top; + } + + tinx = (xin - p->x) / dx; + tiny = (yin - p->y) / dy; + + if (tinx < tiny) { /* Hits x first */ + tin1 = tinx; + tin2 = tiny; + } + else { /* Hits y first */ + tin1 = tiny; + tin2 = tinx; + } + + if (tin1 <= 1.0) { + if (tin1 > 0.0) { + AddVertex(xin, yin); + } + if (tin2 <= 1.0) { + double toutx = (xout - p->x) / dx; + double touty = (yout - p->y) / dy; + double tout1 = MIN(toutx, touty); + + if ((tin2 > 0.0) || (tout1 > 0.0)) { + if (tin2 <= tout1) { + if (tin2 > 0.0) { + if (tinx > tiny) { + AddVertex(xin, p->y + tinx * dy); + } else { + AddVertex(p->x + tiny * dx, yin); + } + } + if (tout1 < 1.0) { + if (toutx < touty) { + AddVertex(xout, p->y + toutx * dy); + } else { + AddVertex(p->x + touty * dx, yout); + } + } else { + AddVertex(q->x, q->y); + } + } else { + if (tinx > tiny) { + AddVertex(xin, yout); + } else { + AddVertex(xout, yin); + } + + } + } + } + } + } + if (count > 0) { + LastVertex(clipPts[0].x, clipPts[0].y); + } + return count; +} + +/* + *--------------------------------------------------------------------------- + * Computes the projection of a point on a line. The line (given by two + * points), is assumed the be infinite. + * + * Compute the slope (angle) of the line and rotate it 90 degrees. Using + * the slope-intercept method (we know the second line from the sample + * test point and the computed slope), then find the intersection of both + * lines. This will be the projection of the sample point on the first + * line. + *--------------------------------------------------------------------------- + */ +Point2d Blt::getProjection(int x, int y, Point2d *p, Point2d *q) +{ + double dx = p->x - q->x; + double dy = p->y - q->y; + + /* Test for horizontal and vertical lines */ + Point2d t; + if (fabs(dx) < DBL_EPSILON) { + t.x = p->x; + t.y = (double)y; + } + else if (fabs(dy) < DBL_EPSILON) { + t.x = (double)x; + t.y = p->y; + } + else { + /* Compute the slope and intercept of PQ. */ + double m1 = (dy / dx); + double b1 = p->y - (p->x * m1); + + /* + * Compute the slope and intercept of a second line segment: one that + * intersects through sample X-Y coordinate with a slope perpendicular + * to original line. + */ + + /* Find midpoint of PQ. */ + double midX = (p->x + q->x) * 0.5; + double midY = (p->y + q->y) * 0.5; + + /* Rotate the line 90 degrees */ + double ax = midX - (0.5 * dy); + double ay = midY - (0.5 * -dx); + double bx = midX + (0.5 * dy); + double by = midY + (0.5 * -dx); + + double m2 = (ay - by) / (ax - bx); + double b2 = y - (x * m2); + + /* + * Given the equations of two lines which contain the same point, + * + * y = m1 * x + b1 + * y = m2 * x + b2 + * + * solve for the intersection. + * + * x = (b2 - b1) / (m1 - m2) + * y = m1 * x + b1 + * + */ + + t.x = (b2 - b1) / (m1 - m2); + t.y = m1 * t.x + b1; + } + + return t; +} + +Graph* Blt::getGraphFromWindowData(Tk_Window tkwin) +{ + while (tkwin) { + TkWindow* winPtr = (TkWindow*)tkwin; + if (winPtr->instanceData != NULL) { + Graph* graphPtr = (Graph*)winPtr->instanceData; + if (graphPtr) + return graphPtr; + } + tkwin = Tk_Parent(tkwin); + } + return NULL; +} + |