java - How can I draw directional path and detect if traced - Android -

i working on application draws letters on canvas , detect if user traces letter in correct form. tried different techniques , can't seem find best approach cover letters. letters in comic sans font , due formations in f , s pretty difficult. it's lowercase letters

there number of attempts answer needed answer posted here: path measure example

this did accomplish task:

1. get starting point of path

2. then created separate path started @ point when user touch close start point (lets call trail path)

3. finally went on calculate point of path ahead of user trail path , see if difference in touch , expected point close.

here bit of code

    path measure pm = new pathmeasure(mypath, false);     pm.getpostan(0, floatpoints, null);      //this functions says whether offset path great accept     private boolean ismajoroffset(float point1, float point2, int tolerance){                 float difference = math.abs(point1 - point2);                 return tolerance < math.floor(difference) && tolerance < math.ceil(difference);             }  private void touch_start(float x, float y){         //get point float         float floatpoints[] = {0f, 0f};         //get current start point         pm.getpostan(0, floatpoints, null);          point startpoint = new point((int)floatpoints[0], (int)floatpoints[1]);          //if startpoint selected set path started         if((startpoint.x >= x - touch_tolerance && startpoint.x <= x + touch_tolerance)                 && (startpoint.y >= y - touch_tolerance && startpoint.y <= y + touch_tolerance))         {             pathstarted = true;             toast.maketext(this.getcontext(), "started", toast.length_short).show();              //move trail path point             trailpath.moveto(startpoint.x, startpoint.y);         }     }  private void touch_move(float x, float y){         if(pathstarted==false){             return;         }         //get lenght of trail path         pathmeasure tm = new pathmeasure(trailpath, false);          //get point float         float floatpoints[] = {0f, 0f};         //get current start point         pm.getpostan(tm.getlength() + 1, floatpoints, null);          point point = new point((int)floatpoints[0], (int)floatpoints[1]);          //if offset ok continue trail path         if(!ismajoroffset(point.x, x, touch_tolerance) && !ismajoroffset(point.y, y, touch_tolerance))         {             //move current path point             trailpath.lineto(point.x, point.y);         }         else {             pathstarted = false;             toast.maketext(this.getcontext(), "ended", toast.length_short).show();          }     } 

hope helps someone!