function draw_gift(current_idx, candidate_idx, test_idx, hull){
var ctx = DOM.context2d(width, height);
for(var i = 0; i < num_points; i++){
var color = 'Black'
if(i == current_idx) color = 'Red';
if(i == candidate_idx){
color = 'Green'
draw_segment(ctx, points[current_idx][0], points[current_idx][1],
points[i][0], points[i][1], color);
}
if(i == test_idx){
color = 'Blue'
draw_segment(ctx, points[current_idx][0], points[current_idx][1],
points[i][0], points[i][1], color);
}
draw_point(ctx, points[i][0], points[i][1], 5, color);
}
if(hull.length > 0) draw_hull(ctx, hull, 'Red');
return ctx.canvas;
}