Here’s some code that I wrote in DevCpp (windows), now I’m trying to get it to run in linux without much success.
Here is the source code
screen.h
#ifndef SCREEN_H
#define SCREEN_H
#include <graphics.h>
class Screen
{
private:
int max_x,max_y,grid_size;
int delta_x,delta_y;
int origin_x,origin_y;
public:
// Default Constructor to Initialize the screen with the grid
Screen(int xcoord=641, int ycoord=641, int grid=8)
{
//variable initialization
max_x = xcoord;
max_y = ycoord;
grid_size = grid;
delta_x = max_x / grid_size;
delta_y = max_y / grid_size;
origin_x = grid_size / 2 * delta_x;
origin_y = grid_size / 2 * delta_y;
//plotting the initial grid
int gd,gm;
initgraph(&gd,&gm,NULL);
//draw the x component of the grid
for(int i=0; i<max_x; i += delta_x)
{
if( i != max_x / 2)
setcolor(GREEN);
else
setcolor(RED);
line(i,0,i,max_y);
}
//draw the y component of the grid
for(int i=0; i<max_y; i += delta_y)
{
if( i != max_y / 2)
setcolor(GREEN);
else
setcolor(RED);
line(0,i,max_x,i);
}
//mark the origin with a white dot to acertain its coordinates for future use
putpixel(origin_x,origin_y,WHITE);
std::cout<<origin_x<<"\t"<<origin_y<<"\n";
}
//Method prototypes
void plot_pixel(int xcoord,int ycoord,int col=WHITE)
{
int l,t,r,b;
l = origin_x + xcoord * delta_x;
r = l + delta_x;
b = origin_y - ycoord * delta_y;
t = b - delta_y;
setcolor(col);
bar(l,t,r,b);
setcolor(WHITE);
}
};
#endif
circles.cpp
#include<iostream>
#include<cmath>
#include "screen.h"
using namespace std;
void draw_midpoint_circle(Screen ob, int radius);
void circlepointplot(Screen ob, int m, int n);
void trigonometric_circle(Screen ob, int radius);
int main() {
Screen scr = Screen(641, 641, 16);
int choice, rad;
cout << "Menu\n 1. Midpoint Circle Drawing Algorithm\n 2. Bresenham's Circle Drawing Algorithm \n 3. Trigonometric Method\n";
cin>>choice;
cout << "Enter Radius \t";
cin>>rad;
switch (choice) {
case 1:
draw_midpoint_circle(scr, rad);
break;
case 2:
draw_midpoint_circle(scr, rad);
break;
case 3:
trigonometric_circle(scr, rad);
break;
default:
cout << "Wrong Choice\n";
break;
}
getch();
return 0;
}
void trigonometric_circle(Screen ob, int radius) {
double angle = 0.0;
while (angle <= 360) {
int dx = 641 / 16;
int x = int(radius * cos(angle));
int y = int(radius * sin(angle));
angle = angle + 5;
ob.plot_pixel(x, y, 0);
cout << "Point Plotted " << x << "\t" << y << endl;
char buffer[50];
sprintf(buffer, "%d,%d", x, y);
outtextxy(320 + ((x + 1) * dx), 320 - ((y - 1) * dx), buffer);
getch();
}
}
void draw_midpoint_circle(Screen ob, int radius) {
float dp;
int x, y;
x = 0;
y = radius;
dp = 1 - radius;
while (x < y) {
circlepointplot(ob, x, y);
if (dp < 0)
dp = dp + 2 * x + 3;
else {
dp = dp + 2 * (x - y) + 5;
y--;
}
x++;
circlepointplot(ob, x, y);
}
}
void circlepointplot(Screen ob, int m, int n) {
ob.plot_pixel(m, n, 0);
ob.plot_pixel(n, m, 0);
ob.plot_pixel(m, -n, 0);
ob.plot_pixel(n, -m, 0);
ob.plot_pixel(-m, n, 0);
ob.plot_pixel(-n, m, 0);
ob.plot_pixel(-m, -n, 0);
ob.plot_pixel(-n, -m, 0);
cout << "Point Plotted" << m << "\t" << n << endl;
cout << "Point Plotted" << n << "\t" << m << endl;
cout << "Point Plotted" << m << "\t" << -n << endl;
cout << "Point Plotted" << n << "\t" << -m << endl;
cout << "Point Plotted" << -m << "\t" << n << endl;
cout << "Point Plotted" << -n << "\t" << m << endl;
cout << "Point Plotted" << -m << "\t" << -n << endl;
cout << "Point Plotted" << -n << "\t" << -m << endl;
int dx = 641 / 16;
char buffer[50];
sprintf(buffer, "%d,%d", m, n);
outtextxy(320 + ((m + 1) * dx), 320 - ((n - 1) * dx), buffer);
getch();
}
I’m using graphics.h for linux. Basic programs run fine.
The errors that I get are
g++ -c screen.cpp -o screen.o
g++ -c circles.cpp -o circles.o
g++ screen.o circles.o -o "circle.exe" -lgraph
circles.o:(.bss+0x0): multiple definition of `screen'
screen.o:(.bss+0x0): first defined here
circles.o:(.bss+0x8): multiple definition of `Font_surface'
screen.o:(.bss+0x8): first defined here
circles.o:(.bss+0x10): multiple definition of `_fgcolor'
screen.o:(.bss+0x10): first defined here
circles.o:(.bss+0x14): multiple definition of `_bgcolor'
screen.o:(.bss+0x14): first defined here
circles.o:(.bss+0x18): multiple definition of `_fontcolor'
screen.o:(.bss+0x18): first defined here
circles.o:(.bss+0x1c): multiple definition of `_pid'
screen.o:(.bss+0x1c): first defined here
circles.o:(.bss+0x20): multiple definition of `CP'
screen.o:(.bss+0x20): first defined here
circles.o:(.bss+0x40): multiple definition of `InternalFont'
screen.o:(.bss+0x40): first defined here
circles.o:(.bss+0x850): multiple definition of `TP'
screen.o:(.bss+0x850): first defined here
circles.o:(.bss+0x860): multiple definition of `_last_arc'
screen.o:(.bss+0x860): first defined here
circles.o:(.bss+0x878): multiple definition of `_internal_linestyle'
screen.o:(.bss+0x878): first defined here
circles.o:(.bss+0x888): multiple definition of `_scanlist'
screen.o:(.bss+0x888): first defined here
collect2: ld returned 1 exit status
What am I doing wrong, how do I get this to work?
Updated errors after moving the code into the class.
/tmp/ccB2RO2Q.o: In function `main':
circles.cpp:(.text+0x111): undefined reference to `grgetch'
/tmp/ccB2RO2Q.o: In function `trigonometric_circle(Screen, int)':
circles.cpp:(.text+0x242): undefined reference to `outtextxy'
circles.cpp:(.text+0x247): undefined reference to `grgetch'
/tmp/ccB2RO2Q.o: In function `circlepointplot(Screen, int, int)':
circles.cpp:(.text+0x6f2): undefined reference to `outtextxy'
circles.cpp:(.text+0x6f7): undefined reference to `grgetch'
/tmp/ccB2RO2Q.o: In function `Screen::Screen(int, int, int)':
circles.cpp:(.text._ZN6ScreenC2Eiii[_ZN6ScreenC5Eiii]+0xd0): undefined reference to `initgraph'
circles.cpp:(.text._ZN6ScreenC2Eiii[_ZN6ScreenC5Eiii]+0xf7): undefined reference to `setcolor'
circles.cpp:(.text._ZN6ScreenC2Eiii[_ZN6ScreenC5Eiii]+0x103): undefined reference to `setcolor'
circles.cpp:(.text._ZN6ScreenC2Eiii[_ZN6ScreenC5Eiii]+0x11c): undefined reference to `line'
circles.cpp:(.text._ZN6ScreenC2Eiii[_ZN6ScreenC5Eiii]+0x15e): undefined reference to `setcolor'
circles.cpp:(.text._ZN6ScreenC2Eiii[_ZN6ScreenC5Eiii]+0x16a): undefined reference to `setcolor'
circles.cpp:(.text._ZN6ScreenC2Eiii[_ZN6ScreenC5Eiii]+0x182): undefined reference to `line'
circles.cpp:(.text._ZN6ScreenC2Eiii[_ZN6ScreenC5Eiii]+0x1b9): undefined reference to `putpixel'
/tmp/ccB2RO2Q.o: In function `Screen::plot_pixel(int, int, int)':
circles.cpp:(.text._ZN6Screen10plot_pixelEiii[Screen::plot_pixel(int, int, int)]+0x6d): undefined reference to `setcolor'
circles.cpp:(.text._ZN6Screen10plot_pixelEiii[Screen::plot_pixel(int, int, int)]+0x80): undefined reference to `bar'
circles.cpp:(.text._ZN6Screen10plot_pixelEiii[Screen::plot_pixel(int, int, int)]+0x8a): undefined reference to `setcolor'
collect2: ld returned 1 exit status
Here’s the graphics.h file it has a reference to an SDL_Image *screen
/* libgraph - TurboC graphics API on GNU/Linux
* graphics.h: Core initialization and configuration functions
*
* Copyright (C) 2003 Faraz Shahbazker
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the Free
* Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
* MA 02111-1307, USA
*
* Author: Faraz Shahbazker <faraz_ms@rediffmail.com>
*/
/* Graphic functions using SDL */
#ifndef GRAPHICS_H
#define GRAPHICS_H 1
#include <SDL/SDL.h>
#include <unistd.h>
#include <sys/types.h>
#include <signal.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#ifdef __cplusplus
extern "C"
{
#endif /* __cplusplus */
/* graphic drivers */
enum _driver{DETECT=0, USER, VGA=9};
enum graphics_modes{VGALO=0, VGAMED, VGAHI, VGAMAX, VGA640, VGA800, VGA1024, USERMODE};
/* 16 colors */
enum _color{BLACK=0, BLUE, GREEN, CYAN, RED, MAGENTA, BROWN, LIGHTGRAY, DARKGRAY,LIGHTBLUE, LIGHTGREEN, LIGHTCYAN, LIGHTRED, LIGHTMAGENTA, YELLOW, WHITE};
/* global variables */
SDL_Surface *screen; //main drawing screen
SDL_Surface *Font_surface; //font screen
Uint32 _fgcolor, _bgcolor, _fontcolor; //global color numbers
pid_t _pid; //Don't bother with this
/* function prototypes */
void initgraph(int *graphdriver,int *graphmode,char *pathtodriver);
void closegraph(void);
void setgraphmode(int gmode);
int getgraphmode(void);
void restorecrtmode(void);
int getmaxx(void);
int getmaxy(void);
void putpixel(int x, int y, int color);
int getpixel(int, int);
void setbkcolor(int color);
int getbkcolor(void);
void setcolor(int color);
int getcolor(void);
int getmaxcolor(void);
char* getdrivername(void);
char* getmodename(int mode_number);
int getmaxmode(void);
void detectgraph(int* graphdriver, int* graphmode);
void getmoderange(int graphdriver, int* lomode, int* himode);
int delay(float);
void setfontcolor(int color);
int getfontcolor(void);
/*** library specific functions - not for users ***/
void initialize_settings (void);
void mappixel(int, int); //marks a pixel without updating screen
void clippixel(int *, int *); /* Clip pixel (x,y) to current
screen size*/
void mapword(int,int,int);
void mapvword(int,int,int);
int colorrev(const Uint8); // maps 0..255 8-bit color to 0..15 TC color
Uint8 colortrans(const int); // maps 0..15 TC color to 0..255 8-bit color
void ctrlbreak(void); // To detect user interrupt
void inthandler(int); // clean up on user interrupt
void safe_update(int top, int left, int right, int bottom);
/* update screen within boundary */
#define CHECK_INITIALIZATION\
if (!getenv("LIBGRAPHICS_ACTIVE")) \
{ \
fprintf(stderr, "*** The graphics system has not been initialized!\n"); \
fprintf(stderr, "*** Call initgraph() before trying to use graphics functions.\n"); \
exit(-1); \
}
struct {int x;int y;}CP;
#include "grtext.h"
#include "shapes.h"
#include "polygon.h"
#ifdef __cplusplus
}
#endif /* __cplusplus */
#endif /* LIBGRAPH_H */
graphics.h contains the following lines:
This is a bit strange, but this h-file creates global variables. This means, if you include this file to more than one .cpp files, you have multiple definition error. I don’t know why this h-file is written by such way, the program will be linked only if graphics.h is included to only one cpp file. If your can change this file, add extern keyword before every global variable, and create these variables (if necessary) in some .cpp file.