[Duvida] Novo script de zoom

{
initial_x = 0;
initial_y = 0;
initial_w = view_wview[0];
initial_h = view_hview[0];
initial_zoom = 0;
view_scale = 1;
}

{
// Get the positions of the two fingers
var mx0, my0, mx1, my1, mx0raw, my0raw, mx1raw, my1raw;
mx0 = device_mouse_x(0); my0 = device_mouse_y(0);
mx1 = device_mouse_x(1); my1 = device_mouse_y(1);
mx0raw = device_mouse_raw_x(0); my0raw = device_mouse_raw_y(0);
mx1raw = device_mouse_raw_x(1); my1raw = device_mouse_raw_y(1);
// Check whether the second finger is put on the screen
if ( device_mouse_check_button_pressed(1, mb_left) )
{
initial_x = mean(mx0, mx1);
initial_y = mean(my0, my1);
initial_zoom = point_distance(mx0raw, my0raw, mx1raw ,my1raw) * view_scale;
};
// Check whether both fingers are down
if ( device_mouse_check_button(1, mb_left) )
{
// Compute the new scale factor
view_scale = initial_zoom / point_distance(mx0raw, my0raw, mx1raw, my1raw);
if (view_scale > 1) view_scale = 1; // Remove to also reduce the size
// Compute the new view
view_wview[0] = initial_w * view_scale;
view_hview[0] = initial_h * view_scale;
view_xview[0] += initial_x - mean(mx0, mx1);
view_yview[0] += initial_y - mean(my0, my1);
// Keep it within in the room area (remove when you don't want this)
if (view_xview[0] < 0) view_xview[0] = 0
if (view_xview[0] + view_wview[0] > room_width)
view_xview[0] = room_width - view_wview[0];
if (view_yview[0] < 0) view_yview[0] = 0
if (view_yview[0] + view_hview[0] > room_height)
view_yview[0] = room_height - view_hview[0];
};
}