old_contents: function bresenhamLine( canvas, p0, p1, color ) {
  
    var dx = p1[0] - p0[0];
    var dy = p1[1] - p0[1];
    var dydx = dy / dx;
    var dxdy = dx / dy;
  
    // this check causes us to draw alo9ng the least-degenerate case
    if ( Math.abs(dx) >= Math.abs(dy) ) {
      for ( var i = 0; i < Math.abs(dx); i++ ) {
        // this handles case where points are in inconvenient order
        if ( dx > 0 ) {
          var tx = i  + p0[0];
          var ty = i*dydx + p0[1];
        } else {
          var tx = -i  + p0[0];
          var ty = -i*dydx + p0[1];
        }
        canvas.putPixel( color, tx, ty );
      }
    } else {
      for ( var i = 0; i < Math.abs(dy); i++ ) {
        // inconvenient check as in above
        if ( dy > 0 ) {
          var tx = i*dxdy  + p0[0];
          var ty = i + p0[1];
        } else {
          var tx = -i*dxdy  + p0[0];
          var ty = -i + p0[1];
        }
        canvas.putPixel( color, tx, ty );
      }
    }
    var color = [0,0,255,255];
    canvas.putPixel( color, p0[0], p0[1] );
    canvas.putPixel( color, p1[0], p1[1] );
  }
  
  console.log("Loaded bresenham line drawing.");
  
new_contents: function bresenhamLine( canvas, p0, p1, color ) {
  
    var dx = p1[0] - p0[0];
    var dy = p1[1] - p0[1];
    var dydx = dy / dx;
    var dxdy = dx / dy;
  
    // this check causes us to draw alo9ng the least-degenerate case
    if ( Math.abs(dx) >= Math.abs(dy) ) {
      for ( var i = 0; i < Math.abs(dx); i++ ) {
        // this handles case where points are in inconvenient order
        if ( dx > 0 ) {
          var tx = i  + p0[0];
          var ty = i*dydx + p0[1];
        } else {
          var tx = -i  + p0[0];
          var ty = -i*dydx + p0[1];
        }
        canvas.putPixel( color, tx, ty );
      }
    } else {
      for ( var i = 0; i < Math.abs(dy); i++ ) {
        // inconvenient check as in above
        if ( dy > 0 ) {
          var tx = i*dxdy  + p0[0];
          var ty = i + p0[1];
        } else {
          var tx = -i*dxdy  + p0[0];
          var ty = -i + p0[1];
        }
        canvas.putPixel( color, tx, ty );
      }
    }
  }
  
  console.log("Loaded bresenham line drawing.");
  
subject: Remove debug points.