About lines and segments

Finding the intersection of lines and segments

Finding intersections

Determining the score point method, using the cross product to calculate the area, using the area ratio to replace the segment length ratio

Point Inter_point (Point a,point b,point c,point D)///returns the intersection of Line AB and segment CD{    if(!intersect (A,B,C,D))return{-inf*1.0,0};///To determine if the line AB intersects the segment CD, the non-intersect must be special    DoubleArea1=fabs ((b-a) * (C-A)); DoubleArea2=fabs ((b-a) * (dA)); Doublex= (area1*d.x+area2*c.x)/(area1+area2); Doubley= (AREA1*D.Y+AREA2*C.Y)/(area1+area2); return{x, y};}

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Judgment intersection, cross product judgment left and right (across the experiment)

bool intersect (Point a,point b,point c,point D) /// determine if line AB intersects the segment CD {    if  returntrue;     return false ;}

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If the segment intersection is judged, it is necessary to use the quick Exclusion experiment and the cross-experiment

To find the intersection of a segment must first determine the intersection

About lines and segments