All the data that the camera returns get stored in this structure from camera.h
Code:
// camera t packet data structure
typedef struct
{
unsigned char mx;
unsigned char my;
unsigned char x1;
unsigned char y1;
unsigned char x2;
unsigned char y2;
unsigned char pixels;
unsigned char confidence;
} T_Packet_Data_Type;
So yes its T_Packet_Data.x1 and T_Packet_Data.x2