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zoomedit: simplifyPolygon neu geschrieben

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neoraider 2007-09-16 00:50:01 +00:00
parent d21f73c498
commit 61145c32c9
1 changed files with 71 additions and 58 deletions
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129
geometry.c
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@ -288,68 +288,81 @@ gboolean linePolygonIntersection(const LINE *l, const POLYGON *p) {
return FALSE; return FALSE;
} }
static void edgeVertex(VERTEX *v, int edge, const RECTANGLE *rect) {
if(edge == EDGE_NONE)
edge = vertexInRect(v, rect);
if(edge & EDGE_LEFT) v->x = rect->x;
else if(edge & EDGE_RIGHT) v->x = rect->x+rect->width;
if(edge & EDGE_TOP) v->y = rect->y;
else if(edge & EDGE_BOTTOM) v->y = rect->y+rect->height;
}
static int simplifyVertex(VERTEX *v, const VERTEX *to, const RECTANGLE *rect) {
LINE l = {*v, *to};
int edge, edge2;
edge = vertexInRect(v, rect);
if(edge == EDGE_NONE) return EDGE_NONE;
edge2 = lineRectIntersection(&l, rect, edge, v);
if(edge2 != EDGE_NONE) return edge2;
edgeVertex(v, edge, rect);
return edge;
}
static void addSimplifiedLine(const VERTEX *v1, const VERTEX *v2, const RECTANGLE *rect, int last, POLYGON *out) {
const LINE d1 = {{rect->x, rect->y}, {rect->x+rect->width, rect->y+rect->height}};
const LINE d2 = {{rect->x, rect->y+rect->height}, {rect->x+rect->width, rect->y}};
LINE l = {*v1, *v2};
VERTEX v, vi;
int edge1, edge2;
v = *v1;
if((edge1 = simplifyVertex(&v, v2, rect)) != EDGE_NONE)
addVertex(out, &v);
v = *v2;
edge2 = simplifyVertex(&v, v1, rect);
if(edge1 != EDGE_NONE && edge2 != EDGE_NONE && !(edge1 & edge2)) {
if(lineIntersection(&l, &d1, &vi) == INTERSECTION_SEGMENT_LINE) {
edgeVertex(&vi, 0, rect);
addVertex(out, &vi);
}
else if(lineIntersection(&l, &d2, &vi) == INTERSECTION_SEGMENT_LINE) {
edgeVertex(&vi, 0, rect);
addVertex(out, &vi);
}
}
if(!last)
addVertex(out, &v);
}
void simplifyPolygon(const POLYGON *in, const RECTANGLE *rect, POLYGON *out) { void simplifyPolygon(const POLYGON *in, const RECTANGLE *rect, POLYGON *out) {
int i, j; VERTEX v;
int a; int i;
int lastVertex, thisVertex;
VERTEX v, v2;
VERTEX_LIST vl = {0, NULL};
LINE line;
LINE d1 = {{rect->x, rect->y}, {rect->x+rect->width, rect->y+rect->height}};
LINE d2 = {{rect->x, rect->y+rect->height}, {rect->x+rect->width, rect->y}};
if(in->nVertices == 0) return;
else if(in->nVertices == 1) {
addVertex(out, &in->vertices[0]);
return;
}
thisVertex = vertexInRect(&in->vertices[0], rect); v = in->vertices[0];
simplifyVertex(&v, &in->vertices[in->nVertices-1], rect);
addVertex(out, &v);
for(i = 0; i < in->nVertices; i++) { for(i = 0; i < in->nVertices; i++) {
line.v1 = in->vertices[i]; addSimplifiedLine(&in->vertices[i], &in->vertices[(i+1)%in->nVertices], rect, (i == in->nVertices-1), out);
line.v2 = in->vertices[(i+1)%in->nVertices];
lastVertex = thisVertex;
thisVertex = vertexInRect(&line.v2, rect);
if(thisVertex == EDGE_NONE) {
if(lastVertex != EDGE_NONE && lineRectIntersection(&line, rect, lastVertex, &v))
addVertex(&vl, &v);
addVertex(&vl, &line.v2);
}
else if(lastVertex == EDGE_NONE) {
if(lineRectIntersection(&line, rect, thisVertex, &v))
addVertex(&vl, &v);
}
else {
a = lineRectIntersections(&line, rect, lastVertex, &v, &v2);
if((a & lastVertex) && (a & thisVertex)) {
addVertex(&vl, &v);
addVertex(&vl, &v2);
}
if(lineIntersection(&line, &d1, &v) == INTERSECTION_SEGMENT_LINE) {
if(v.x <= rect->x) addVertex(&vl, &d1.v1);
else addVertex(&vl, &d1.v2);
}
if(lineIntersection(&line, &d2, &v) == INTERSECTION_SEGMENT_LINE) {
if(v.x <= rect->x) addVertex(&vl, &d2.v1);
else addVertex(&vl, &d2.v2);
}
}
while(vl.nVertices > 0) {
a = 0;
for(j = 0; j < vl.nVertices; j++) {
if(vertexDistanceSquare(&line.v1, &vl.vertices[j]) < vertexDistanceSquare(&line.v1, &vl.vertices[a]))
a = j;
}
if(out->nVertices == 0 || out->vertices[out->nVertices-1].x != vl.vertices[a].x ||
out->vertices[out->nVertices-1].y != vl.vertices[a].y)
addVertex(out, &vl.vertices[a]);
deleteVertex(&vl, a);
}
} }
} }