45 lines
1.5 KiB
Plaintext
45 lines
1.5 KiB
Plaintext
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intersect_with_centroid = function(node, sx,sy)
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local h = node_height(Edge.source)
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local c = {
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sx=Edge.source.x + Edge.source.w/2,
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sy=Edge.source.y + h/2
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}
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if c.sx == sx then
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if sy > c.sy then
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return {sx=sx, sy=Edge.source.y + h + 10}
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else
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return {sx=sx, sy=Edge.source.y - 10}
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end
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end
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-- collect nearest intersection with all 4 boundaries
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local candidates = {}
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local y = y_at_x(sx,sy, c.sx,c.sy, Edge.source.x-10)
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if y and y >= Edge.source.y-10 and y < Edge.source.x+h+10 then
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table.insert(candidates, {sx=Edge.source.x-10, sy=y})
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end
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y = y_at_x(sx,sy, c.sx,c.sy, Edge.source.x + Edge.source.w + 10)
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if y and y >= Edge.source.y-10 and y < Edge.source.x+h+10 then
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table.insert(candidates, {sx=Edge.source.x+Edge.source.w+10, sy=y})
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end
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local x = x_at_y(sx,sy, c.sx,c.sy, Edge.source.y-10)
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if x and x >= Edge.source.x-10 and x < Edge.source.x + Edge.source.w + 10 then
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table.insert(candidates, {sx=x, sy=Edge.source.y-10})
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end
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x = x_at_y(sx,sy, c.sx,c.sy, Edge.source.y+h+10)
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if x and x >= Edge.source.x-10 and x < Edge.source.x + Edge.source.w + 10 then
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table.insert(candidates, {sx=x, sy=Edge.source.y+h+10})
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end
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if #candidates == 0 then
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-- no intersection; just return the same point
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return {sx=sx, sy=sy}
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end
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if #candidates == 1 then
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return candidates[1]
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end
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assert(#candidates == 2)
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if distance_sq(sx,sy, candidates[1].sx, candidates[1].sy) < distance_sq(sx,sy, candidates[2].sx, candidates[2].sy) then
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return candidates[1]
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else
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return candidates[2]
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end
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end
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