Function fltk::draw::draw_yxline3

pub fn draw_yxline3(x: i32, y: i32, y1: i32, x2: i32, y3: i32)

Draws a vertical line from (x,y) to (x,y1) then a horizontal from (x,y1) to (x2,y1), then another vertical from (x2,y1) to (x2,y3)