javascript - How to update line while pressing "Shift" key? -

javascript - How to update line while pressing "Shift" key? -

i trying draw straight line pressing key "shift".after pressing "shift" want set cursor on line @ 45/90 grade angle. while drawing line on mouse_move event. diagrammatically want this.

for have written code below:

if (isshiftkeypressed) { endx = evt.x; endy = evt.y; var deltax = endx -startx; var deltay = endy - starty; var angleinradian = math.atan2(deltay, deltax); var angleindegree = angleinradian * 180 / math.pi;//error in line if (deltax > 0 && deltay > 0) { if (angleindegree > 45 && angleindegree < 90) { updatelastposition(endx,starty); } if (angleindegree < 45 && angleindegree > 0) { updatelastposition(startx,endy); } }

i think you're asking how tell if shift key down.

evt.shiftkey true if shift key downwards when event generated, false if wasn't.

so your

![if (isshiftkeypressed) {

would be

if (evt.shiftkey) { // shift key downwards when event generated } else { // wasn't }

(i assume ! before if typo.)

example (source)

javascript