[ 0 -1 ]
[ 1 0 ]
假设第一条直线的点为(x1,y1)
, (x2,y2)
,有x=x2-x1
, y=y2-y1
。
我们还有L=sqrt(x*x+y*y)
,即该直线的长度(请原谅这种符号表示方式)。那么下一条直线应该进行偏移。
[ 0 -1 ] [x]
[ 1 0 ] [y]
=> dx = -y / L
,dy = x / L
,这是新行的标准化偏移量。
在类C#伪代码中:
var x1 = ..., x2 = ..., y1 = ..., y2 = ... // The original line
var L = Math.Sqrt((x1-x2)*(x1-x2)+(y1-y2)*(y1-y2))
var offsetPixels = 10.0
// This is the second line
var x1p = x1 + offsetPixels * (y2-y1) / L
var x2p = x2 + offsetPixels * (y2-y1) / L
var y1p = y1 + offsetPixels * (x1-x2) / L
var y2p = y2 + offsetPixels * (x1-x2) / L
g.MoveTo(x1p,y1p) // I don't remember if this is the way
g.LineTo(x2p,y2p) // to draw a line in GDI+ but you get the idea
你尝试过在x1和x2上加n,同时在y1和y2上减去n吗?我猜那可能会起作用。