//Oguz Yetkin
//graph.cpp
//10/4/1997, Physics 505
#include<graphics.h>
#include<conio.h>
#include<stdio.h>
#include<iostream.h>

#include "graph.h"

//unfortunately, we're using borland c++ graphics drivers


//int init(int &maxx, int &maxy);

int init(int &maxx, int &maxy);	//internal

static struct graphparam{

	int maxx;
	int maxy;
	float xmin;	//user specified
	float xmax;	//user specified
	float ymin;	//user specified
	float ymax;	//user specified
	int OK;

} graph;

/*
int main(int argc, char** argv){

	//int maxx, maxy;

	//init(maxx, maxy);

	//printf("\nmaxx: %d, maxy:%d",maxx, maxy);

	float xmin, xmax, ymin, ymax;
	float x,y;	//dummy
	cout<<"\nenter xmin xmax ymin ymax"<<endl;
	cin>>xmin>>xmax>>ymin>>ymax;

	if(graphsetup(xmin, xmax, ymin, ymax)<0){
		cout<<"\ngraphsetup failed!"<<endl;
		return 1;
	}

	for(int i=0;i<10;i++){
		cout<<"\nenter x y to plot\n";
		cin>>x>>y;
		plot(x,y);
	}





	return 0;
}

*/


int init(int &maxx, int &maxy){

	//initialize graphics
	//************************************
	int driver=DETECT;
	int mode;
	//int maxx, maxy;	//will be 640x480


	//**************INIT GRAPHICS**********************
	initgraph(&driver, &mode, "h:\\borlandc\\bgi");
	setbkcolor(BLACK);

	setcolor(WHITE);
	maxx=getmaxx();
	maxy=getmaxy();


	return 1;
	//***************END GRAPHICS INITIALIZATION**********************


}//end init

void graphclose(){


	closegraph();
}


//uses global struct graph
int graphsetup(float xmin, float xmax, float ymin, float ymax){

	if((xmax<=xmin)||(ymax<=ymin)){

		cerr<<"\ninvalid parameters";
		return -1;
	}//end if

	graph.xmin=xmin;
	graph.ymin=ymin;
	graph.xmax=xmax;
	graph.ymax=ymax;

	init(graph.maxx, graph.maxy);
	setbkcolor(BLACK);

	setcolor(WHITE);
	graph.OK=1;

	return 1;	//now we have all the variables we need from user

}


//return x resolution in world coordinate units
//call AFTER graphsetup!!!

float deltax(){

	if(graph.OK!=1){
		cout<<"\ncan't call deltax() before initializing graphics"<<endl;
		return -1;

	}

	return ((graph.xmax-graph.xmin)/graph.maxx);

}


//return y resolution in world coordinate units
float deltay(){

	if(graph.OK!=1){
		cout<<"\ncan't call deltay() before initializing graphics"<<endl;
		return -1;

	}

	return ((graph.ymax-graph.ymin)/graph.maxy);
}


int graphline(float worldx1, float worldy1, float worldx2, float worldy2){

	if(graph.OK!=1){
		cout<<"\ncan't call graphline() before initializing graphics"<<endl;
		return -1;

	}

	float px, py;

	float dx=deltax();
	float dy=deltay();


	for(px=worldx1;px<=worldx2;px+=dx){

		for(py=worldy1;py<=worldy2;py+=dy){

 			plot(px, py);
		}
	}


	return 1;
}


int grid(){

	if(graph.OK!=1){
		cout<<"\ncan't call graphline() before initializing graphics"<<endl;
		return -1;

	}


	graphline(0, graph.ymin, 0, graph.ymax);	//y axis
	graphline(graph.xmin, 0, graph.xmax, 0);  //x axis

	return 1;

}

int plot(float worldx, float worldy){


	if(graph.OK!=1){
		cout<<"\n init graphics before using plot! exiting\n";
		return -1;
	}

	int devicex=0;
	int devicey=0;


	devicex=(graph.maxx/(graph.xmax-graph.xmin)*(worldx + graph.xmin)) + graph.maxx;
	devicey=(graph.maxy/(graph.ymax-graph.ymin)*(-worldy + graph.ymin)) + graph.maxy;

	/*
	printf("\nworldx: %f, worldy: %f\ndevicex: %d, devicey: %d\n",
			worldx, worldy, devicex, devicey);
	*/

	putpixel(devicex, devicey, WHITE);
	return 1;


}