Re: makeLine w/ center coord rather than x1,y1,x2,y2?

Posted by dscho on Jul 17, 2007; 9:53pm
URL: http://imagej.273.s1.nabble.com/makeLine-w-center-coord-rather-than-x1-y1-x2-y2-tp3698838p3698841.html

Hi,

On Tue, 17 Jul 2007, Robert Barton wrote:

> When writing a macro, is it possible to draw a line based upon the
> center point of that line?  IOW, rather than using
> makeLine(156,197,356,197), could I create a line by specifying the
> center point (256,197 in this case) and then specifying how long the
> line should be?

First, you'd need the angle, too.  Second, it is easy to write a (macro)
function which does that:

-- snip --
function makeLine2(centerX, centerY, length, angle)
{
        angle = -angle * PI / 180;
        dX = cos(angle) * length / 2;
        dY = sin(angle) * length / 2;

        makeLine(centerX - dX, centerY - dY, centerX + dX, centerY + dY);
}
-- snap --

Ciao,
Dscho