GLUT zooming to cursor by clicking, dragging to pan - c++

Question

I'm trying to make this functions like google maps or http://phrogz.net/tmp/canvas_zoom_to_cursor.html.
How to use mouse position like centre of zooming?
How to drag image by moving cursor? Want to do it with button==0 && state==GLUT_DOWN.
Any help much appreciated
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <math.h>
#include "glut.h"
#define windowSize 900.0
double zoomFactor = 1;
int mouseX=0, mouseY=0;
void reshape (int w, int h)
{
}
void mouse(int button, int state, int x, int y) {
if (button == 0)
{
if (state == GLUT_UP) return;
zoomFactor -= 0.05;
}
else if (button == 2) {
if (state == GLUT_UP) return;
zoomFactor += 0.05;
}
else return;
glutPostRedisplay();
}
void motion(int ax, int ay) {
mouseX = ax;
mouseY = ay;
}
Void display(){
glClear(GL_COLOR_BUFFER_BIT);
glViewport (0.0, 0.0, glutGet(GLUT_INIT_WINDOW_WIDTH), glutGet(GLUT_INIT_WINDOW_HEIGHT));
glMatrixMode (GL_PROJECTION);
glLoadIdentity ();
gluOrtho2D (-glutGet(GLUT_INIT_WINDOW_WIDTH)*zoomFactor, glutGet(GLUT_INIT_WINDOW_WIDTH)*zoomFactor,\
-glutGet(GLUT_INIT_WINDOW_HEIGHT)*zoomFactor, glutGet(GLUT_INIT_WINDOW_HEIGHT)*zoomFactor);
glBegin(GL_LINES);
glVertex2f ((0),(0));
glVertex2f ((100),(0));
glEnd();
glBegin(GL_LINES);
glVertex2f ((100),(0));
glVertex2f ((100),(100));
glEnd();
glFlush();
}
int main(int argc,char** argv) {
glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);
glutInitWindowSize(windowSize, windowSize);
glutInitWindowPosition(500,0);
glutCreateWindow("test");
glClearColor(0, 0.1,0.8,0.90);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
gluOrtho2D(0, 200, 200,0);
glutDisplayFunc( display );
glutPassiveMotionFunc(motion);
glutMouseFunc(mouse);
glutMainLoop(;
return(0);
}