External window clipping. C++ to java

Hello! I recently started learning java. Help please with the translation of this code from c ++ to java. It is necessary to write a program that performs an external window clipping. The program should be based on the algorithm of clipping the rectangular Sutherland-Cowan window. I could write it on c ++, but on java I have no idea how.

<pre>#include <vcl.h>
#pragma hdrstop

#include "Unit1.h"
//---------------------------------------------------------------------------
#pragma package(smart_init)
#pragma resource "*.dfm"
#define LEFT  1
#define RIGHT 2
#define BOT   4
#define TOP   8
#define vcode(r, p)((((p)->x < (r)->x_min) ? LEFT : 0)+ (((p)->x > (r)->x_max) ? RIGHT : 0)+(((p)->y < (r)->y_min) ? BOT : 0)+(((p)->y > (r)->y_max) ? TOP : 0))

TForm1 *Form1;
//---------------------------------------------------------------------------
__fastcall TForm1::TForm1(TComponent* Owner)
        : TForm(Owner)
{

}
struct point {double x, y;};
struct rect {double x_min, y_min, x_max, y_max;};
//---------------------------------------------------------------------------
int cohen_sutherland (const struct rect *r, struct point *a, struct point *b){
	int code_a, code_b, code;
	struct point *c;
	code_a = vcode(r, a);
	code_b = vcode(r, b);
	while (code_a | code_b) {
		if (code_a & code_b)return -1;
		if (code_a){
			code = code_a;
			c = a;
		} else {
			code = code_b;
			c = b;
		}
		if (code & LEFT) {
			c->y += (a->y - b->y) * (r->x_min - c->x) / (a->x - b->x);
			c->x = r->x_min;
		} else if (code & RIGHT) {
			c->y += (a->y - b->y) * (r->x_max - c->x) / (a->x - b->x);
			c->x = r->x_max;
		}
		else if (code & BOT) {
			c->x += (a->x - b->x) * (r->y_min - c->y) / (a->y - b->y);
			c->y = r->y_min;
		} else if (code & TOP) {
			c->x += (a->x - b->x) * (r->y_max - c->y) / (a->y - b->y);
			c->y = r->y_max;
		}
		if (code == code_a) {
                        a = c;
			code_a = vcode(r,a);
		} else {
                        b = c;
			code_b = vcode(r,b);
                }
	}
	return 0;
}
void __fastcall TForm1::Button1Click(TObject *Sender)
{
Form1->Repaint();
const int m = 6;
int n = 5;
double EndXmas[m]={225,275,300,250,200,225};
double EndYmas[m]={300,300,250,200,250,300};
const rect r1[100]={200,260,250,290};
const rect r2[100]={260,210,290,290};
const rect r3[100]={200,210,250,240};
if (RadioButton2->Checked){
        for (int i=0, j=1; i<n; i++,j++){
                Canvas->Pen->Color=(TColor)RGB(255,0,0);
                Canvas->Pen->Width=2;
                Canvas->MoveTo(EndXmas[i],EndYmas[i]);
                Canvas->LineTo(EndXmas[j],EndYmas[j]);
        }
}
int x1,x2,x3;
double xa;
double ya;
double xb;
double yb;
for (int i=0, j=1; i<n; i++,j++){
        point a[100]={EndXmas[i],EndYmas[i]};
        point b[100]={EndXmas[j],EndYmas[j]};
        x1 = cohen_sutherland (r1, a, b);
        x2 = cohen_sutherland (r2, a, b);
        x3 = cohen_sutherland (r3, a, b);
        if ((x1==0)||(x2==0)||(x3==0)){
                xa = a->x;
                ya = a->y;
                xb = b->x;
                yb = b->y;
        }

        Canvas->Pen->Color=(TColor)RGB(255,0,0);
        if (RadioButton2->Checked) Canvas->Pen->Color=(TColor)RGB(225,225,225);
        Canvas->Pen->Width=2;
        Canvas->MoveTo(xa,ya);
        Canvas->LineTo(xb,yb);
}
}
//---------------------------------------------------------------------------


void __fastcall TForm1::FormCreate(TObject *Sender)
{
Form1->Color = RGB (225, 225, 225);
}