Perpendicular Line

[usamaalam]

Hello,

I have drawn a line on the VB Form as follows:

Line (OriginX, OriginY)-(OriginX + WeightX, OriginY - WeightY)

Where OriginX and OriginY are both zero and WeightX and WeightY are any two values. Now I want to draw a line which is perpendicular to this line on the origin point. For clear viewing, I have shifted the axis to some other point.

So, my question is how can I find two points to construct a line which is perpendicular to another line whose one point is origin and other point is also known.

Any help will be appreciated.

Thanks.

[sql_lall]

two lines are perpendicular if they are negative inverses.

so...after checking for horizontal/vertical lines {You can't invert zero, or infinity, in VB }, do some algebra:

Slope = (-WeightY)/WeightX
NewSlope = -1 / Slope (BTW, this is just WeightX/WeightY)

now draw a line (OriginX, OriginY) - (OriginX + ScaleFactor, OriginY + ScaleFactor * NewSlope)

where Scale Factor depends on how big you want the line, and in which direction.

[alkatran]

No reason to be complexe at all, SQL.

(originx,originy) to (originx + weight y, originy - weight x)