/*AMPLIT.CPP-TO PLOT AMPLITUDE AND PHASE
This program uses interrupts to read and write to the display by calling bios
routines. After the data is entered the information is read out of display
memory and placed into a string. The string is converted to a float where
the information is used to determine the transfer function of the filter.
The magnitude and the phase of the transfer function is plotted to the graphics
display.By pressing F1 the graph is read from the display and sent to a laser
printer where a hard copy of the screen is obtained. */
#include <math.h>
#include <complex.h>
#include <dos.h>
#include <stdio.h>
#include <stdlib.h>
#include <conio.h>
#include <graphics.h>
#include <string.h>
#define pi 3.1415926
void writechar (char ch, int back_color, int fore_color, int repeat_char);
/*draws a box at defined coordinates and adds a black shadow to the bottom
and right of the box */
void shadow_box (X1, Y1, X2, Y2, back_color, fore_color)
{
int loop;
if (X1 < X2 && X2 <= 80 && Y1 < Y2 && Y2 <= 25)
{
window (X1+2,Y1+1,X2+2,Y2+1);
textattr ((BLACK << 4) + BLACK);
clrscr();
window (X1,Y1,X2,Y2);
textattr ((back_color << 4) + fore_color);
clrscr();
window (1,1,80,25);
gotoxy (X1,Y1);
writechar (201, back_color, fore_color, 1);
gotoxy (X1 + 1, Y1);
writechar (205, back_color, fore_color, (X2 - X1) - 1 );
gotoxy (X2,Y1);
writechar (187, back_color, fore_color, 1);
for (loop = Y2 - 1; loop > Y1; --loop)
{
gotoxy (X1,loop);
writechar (186, back_color, fore_color, 1);
gotoxy (X2,loop);
writechar (186, back_color, fore_color, 1);
}
gotoxy (X1,Y2);
writechar (200, back_color, fore_color, 1);
gotoxy (X1+1,Y2);
writechar (205, back_color, fore_color, (X2 - X1) - 1 );
gotoxy (X2,Y2);
writechar (188, back_color, fore_color, 1);
gotoxy (X1+1,Y1+1);
}
}
/* outputs a character at the current cursor position using the video BIOS
to avoid the scrolling of the screen when writing to location (80,25). */
void writechar (char ch, int back_color, int fore_color, int repeat_char)
{ int att;
back_color <<= 4; //shift color attr backgnd bits
att = (back_color + fore_color); // add backgnd and foregnd attr bits
_AH = 9; // interrupt 0x10 sub-function 9
_AL = ch; // character to be output
_BH = 0; // video page
_BL = att; // video attribute
_CX = repeat_char; // repetition factor
geninterrupt(0x10); // output the char
}
void LJ_Graphic()
{
int xaspect, yaspect, maxX, maxY, line, xword, pixel, xwidth, ywidth;
double xpos, ypos, prnstep, ratio;
char chr;
maxX = getmaxx(); //get number of horizontal pixel
maxY = getmaxy(); //get number of vertical pixel
getaspectratio(&xaspect, &yaspect); //get the screen aspect ratio
ratio = (double) xaspect/ (double) yaspect;
setviewport(0,0,maxX,maxY,0); //set viewport for full screen
xpos = 690; //initial position of prn cursor
ypos = 500; //initial position of prn cursor
prnstep = 7.2/ratio; //match printer aspr fo screen aspr
fprintf (stdprn, "\x1B&E\x1B&11H\x1B&1O\x1B*p0X\x1B*p0Y\x1B*t100R");
for (line = 0; line <= maxY; line++)
{
ywidth = 6;
if (ypos < 1000.0) ywidth--;
if (ypos < 100.0) ywidth--;
if (ypos < 10.0) ywidth--;
fprintf (stdprn, "\x1B&a%-*.1fh%-*.1fV", 5, xpos, ywidth, ypos);
ypos += prnstep;
fprintf (stdprn, "\x1B*r1A\x1B*b%dW", maxX/8);
for (xword = 0; xword < maxX/8; xword++)
{
chr = 0;
for (pixel = 0; pixel < 8; pixel++)
{ //reads series of 8 pixels to create graphics char
chr <<= 1;
if (getpixel (xword*8+pixel, line)) chr++;
}
fprintf (stdprn, "%c", chr); //sends graphic char to printer
}
fprintf (stdprn, "\x1B*rB"); //ends graphics line
}
fprintf (stdprn, "\x0C\x1B&10O\x1B&11H\x1B&E");
}
/* reads the character from display memory at current cursor position */
char read_char (void)
{
char ch;
_AH = 8; // call video service 8
_BH = 0; // set display page to 0
geninterrupt(0x10); // call video interrupt
ch = _AL; // screen char in AL
return(ch);
}
void reverse_video (void)
{
textcolor(BLUE);
textbackground(LIGHTGRAY);
}
void normal_video (void)
{
textcolor(LIGHTGRAY);
textbackground(BLUE);
}
/* prepares the display to switch the highlighted line to new position */
void switch_line (void)
{
int loop;
char str[10];
gotoxy(1,wherey());
for (loop = 0; loop <= 9; loop++)
{
str[loop] = read_char();
gotoxy(wherex()+1,wherey());
}
normal_video();
gotoxy(1,wherey());
for (loop = 0; loop <= 9; loop++)
putch(str[loop]);
}
void help (void)
{
struct text_info textinfo;
int top = 4;
int bottom = 19;
int left = 5;
int right = 75;
char buffer[4000];
char ch;
gettextinfo(&textinfo);
window(1,1,80,25);
gettext(left,top,right+2,bottom+1,buffer);
shadow_box(left,top,right,bottom,CYAN,WHITE);
window(left+1,top+1,right-1,bottom-1);
clrscr();
gotoxy (30,1);
cprintf ("HELP SCREEN");
gotoxy (2,3);
textcolor(BLACK);
cprintf ("Input the coefficients to the appropriate powers of z");
gotoxy (2,4);
cprintf ("The following keys can be used to enter the coefficients");
textcolor(WHITE);
gotoxy (10,6);
cprintf ("0 - 9");
gotoxy (10,7);
cprintf ("+ - .");
gotoxy (5,8);
cprintf ("ARROW KEYS");
gotoxy (8,9);
cprintf ("TAB KEY");
gotoxy (6,10);
cprintf ("ENTER KEY");
gotoxy (5,11);
cprintf ("DELETE KEY");
gotoxy (6,12);
cprintf ("BACKSPACE");
gotoxy (23,14);
_setcursortype(_NOCURSOR);
cprintf ("Press any KEY to continue");
textcolor(BLACK);
gotoxy(17,6);
cprintf ("Enters numeric values in the field");
gotoxy(17,7);
cprintf ("Enters the sign or decimal point of the value");
gotoxy(17,8);
cprintf ("Moves the cursor in the corresponding direction");
gotoxy(17,9);
cprintf ("Moves cursor from numerator to denominator");
gotoxy(17,10);
cprintf ("Moves cursor to the begining of the next field");
gotoxy(17,11);
cprintf ("Deletes the entry at the current cursor position");
gotoxy(17,12);
cprintf ("Moves cursor one position left and deletes entry");
while(!kbhit());
ch = getch();
if (ch == 0)
ch = getch();
_setcursortype(_NORMALCURSOR);
puttext(left,top,right+2,bottom+1,buffer);
window(textinfo.winleft,textinfo.wintop,textinfo.winright,textinfo.winbottom);
gotoxy(textinfo.curx,textinfo.cury);
textattr(textinfo.attribute);
}
void beep (void)
{
sound(500);
delay(100);
nosound();
}
/* This function creates a data entry box and several editing keystrokes
to enable the user to easily input his information in the proper area.
The function also limits the available keystrokes to those required
for data entry. The user moves the cursor around the data entry box
and is finished when F10 is pressed. */
void coeff_box (void)
{
int test, loop, tab, num = 1, X, period;
char str[10];
char ch, fk = 0;
textbackground(LIGHTGRAY);
clrscr();
shadow_box (20,3,60,21,BLUE,WHITE);
window(21,4,59,20);
clrscr();
window(20,3,60,21);
gotoxy(11,2);
cprintf ("FILTER COEFFICIENTS");
gotoxy(6,18);
cprintf ("F1 HELP F5 Quit F10 PLOT");
gotoxy(7,4);
cprintf ("NUMERATOR");
gotoxy(26,4);
cprintf ("DENOMINATOR");
gotoxy(1,3);
writechar(204,BLUE,WHITE,1);
gotoxy(2,3);
writechar(205,BLUE,WHITE,39);
gotoxy(41,3);
writechar(185,BLUE,WHITE,1);
gotoxy(1,5);
writechar(199,BLUE,WHITE,1);
gotoxy(1,17);
writechar(199,BLUE,WHITE,1);
gotoxy(2,5);
writechar(196,BLUE,WHITE,39);
gotoxy(41,5);
writechar(182,BLUE,WHITE,1);
gotoxy(41,17);
writechar(182,BLUE,WHITE,1);
gotoxy(2,17);
writechar(196,BLUE,WHITE,39);
gotoxy(20,3);
writechar(209,BLUE,WHITE,1);
gotoxy(20,17);
writechar(193,BLUE,WHITE,1);
for (loop = 4; loop <= 16; loop++)
{
gotoxy(20,loop);
writechar (179,BLUE,WHITE,1);
}
gotoxy(20,5);
writechar (197,BLUE,WHITE,1);
for (loop = 6; loop <= 15; loop++)
{
gotoxy(3,loop);
cprintf("z-%i", loop-6);
gotoxy(22,loop);
cprintf("z-%i", loop-6);
}
gotoxy(2,16);
cprintf("z-10");
gotoxy(21,16);
cprintf("z-10");
window(27,8,59,18);
gotoxy(1,1);
textcolor (LIGHTGRAY);
test = 0;
do // data entry loop
{
tab = 0;
for (loop = 0; loop <= 9; loop++)
{
str[loop] = read_char();
gotoxy(wherex()+1,wherey());
}
reverse_video();
gotoxy(1,wherey());
for (loop = 0; loop <= 9; loop++) //creates reversed bar
{
putch(str[loop]);
}
gotoxy(1,wherey());
do
{
tab = 0;
ch = getch();
if (ch >= '0' && ch <= '9')
{
if (wherex() != 10)
putch(ch);
else
{
writechar(ch,LIGHTGRAY,BLUE,1);
beep();
}
}
else
if (ch != 0)
{
switch(ch)
{
case 13 : fk = 1; ch = 80; break; //enter key pressed
case 8 : //backspace key
if (wherex() != 1)
{
writechar(0,LIGHTGRAY,BLUE,1);
putch(ch);
writechar(0,LIGHTGRAY,BLUE,1);
}
else beep();
break;
case '.' :
X = wherex();
gotoxy(1, wherey());
period = 0;
for (loop = 1; loop <= 10; loop++)
{
gotoxy(loop, wherey());
if (read_char() == '.') period = 1;
}
gotoxy(X,wherey());
if (period == 1) beep();
else
putch(ch);
break;
case '+' :
if (wherex() == 1)
putch(ch);
else
beep();
break;
case '-' :
if (wherex() == 1)
putch(ch);
else
beep();
break;
case 9 :
if (num)
num = 0;
else
num = 1;
switch_line();
if (!num)
window(47,8,59,18);
else
window(27,8,59,18);
gotoxy(1,1);
for (loop = 0; loop <= 9; loop++)
{
str[loop] = read_char();
gotoxy(wherex()+1,wherey());
}
reverse_video();
gotoxy(1,wherey());
for (loop = 0; loop <= 9; loop++)
{
putch(str[loop]);
}
gotoxy(1,wherey());
tab = 1;
break;
default : beep(); break;
}
}
else
{
ch = getch();
fk = 0;
switch (ch)
{
case 75 : //left arrow key pressed
if (wherex() != 1)
gotoxy(wherex()-1,wherey());
else
beep();
break;
case 77 : //right arrow key pressed
if (wherex() != 10)
gotoxy(wherex()+1,wherey());
else
beep();
break;
case 59 : help(); break; // F1 key pressed
case 63 : // F5 key pressed
window (1,1,80,25);
textbackground(BLACK);
textcolor(WHITE);
clrscr();
exit(0);
default : fk = 1;
}
}
}
while (!fk || tab);
if (fk == 1)
{
fk = 0;
switch (ch)
{
case 72 : //up arrow key pressed
switch_line();
if (wherey() != 1)
gotoxy(1,wherey()-1);
else
gotoxy(1,11);
break;
case 80 : //down arrow key pressed
switch_line();
if (wherey() != 11)
gotoxy(1,wherey()+1);
else
gotoxy(1,1);
break;
case 68 : test = 1; break; // F10 key pressed
default : beep(); gotoxy(1,wherey()); break;
}
}
}
while (!test);
}
main()
{
int left, top, right, bottom, maxx, maxy, loop, loop1;
double v, mag, mag_1, real_part, imag_part, phase, phase_1;
char str[10];
char ch;
double A[11] = {0.0};
double B[11] = {0.0};
complex NUM, DEN;
textmode(C80);
coeff_box();
window(27,8,59,18);
for (loop = 0; loop <= 10; loop++) //reads data info from the display
{
for (loop1 = 1; loop1 <= 10; loop1++)
{
gotoxy(loop1,loop+1); //move cursor to read next char
str[loop1-1] = read_char();
}
A[loop] = atof(str); //converts string to float
for (loop1 = 1; loop1 <= 10; loop1++)
{
gotoxy(loop1+20,loop+1);
str[loop1-1] = read_char();
}
B[loop] = atof(str);
}
window(1,1,80,25);
clrscr();
int gdriver = DETECT, gmode, errorcode; // request auto detection
initgraph(&gdriver, &gmode, ""); // initialize graphics mode
errorcode = graphresult(); // read result of initialization
if (errorcode != grOk) // an error occurred
{
printf("Graphics error: %s\n", grapherrormsg(errorcode));
printf("Press any key to halt:");
getch();
}
maxx = getmaxx(); //number of horizonal screen pixel
maxy = getmaxy(); //number of vertical screen pixel
left = maxx/2 - 200; //left side of graph
right = maxx/2 + 200; //right side of graph
top = maxy/2 - 170; //top side of graph
bottom = maxy/2 + 130; //bottom side of graph
rectangle (left, top, right, bottom);
setviewport (left, top, right, bottom, 1);
for (loop = 1; loop <= 5; loop++)
{
line(loop*80,300,loop*80,292); //draws vert hash marks
line(0,loop*100,5,loop*100); //draws horz hash marks
}
setlinestyle (SOLID_LINE,1,1);
setviewport (left, top, right, bottom, 0);
settextjustify(CENTER_TEXT,CENTER_TEXT);
outtextxy(200,330, "Normalized Frequency = f/fN");
outtextxy(200,345, "F1 for PRINTOUT ENTER to continue");
for (loop = 0; loop <= 5; loop++)
{
gcvt(loop/5.0, 10, str); //converts float to string
outtextxy(loop*80,310,str);
}
settextstyle(DEFAULT_FONT, VERT_DIR, 1);
outtextxy(-75,150, "Magnitude");
settextstyle(DEFAULT_FONT, HORIZ_DIR, 1);
settextjustify (RIGHT_TEXT,CENTER_TEXT);
outtextxy(-10,300,"0.0");
outtextxy(-10,200,"0.5");
outtextxy(-10,100,"1.0");
outtextxy(-10,0,"1.5");
setviewport (left, top, right, bottom, 1);
for (loop = 1; loop <= 400; loop++) //loop to plot graph
{
v = loop/400.0;
NUM = complex(A[0],0); //numerator
DEN = complex(B[0],0); //denominator
for (loop1 = 1; loop1 <= 10; loop1++) //transfer fuction
{
NUM += complex(A[loop1]*cos(pi*v*loop1),-A[loop1]*sin(pi*v*loop1));
DEN += complex(B[loop1]*cos(pi*v*loop1),-B[loop1]*sin(pi*v*loop1));
}
mag = sqrt(norm(NUM/DEN)); //magnitude of transfer function
if (loop == 1)
mag_1 = mag;
else //plot graph
{
line (loop-1, 300 - mag_1*200, loop, 300 - mag*200);
mag_1 = mag;
}
}
while(!kbhit());
ch = getch();
if (ch == 0)
{
ch = getch();
if (ch == 59)
LJ_Graphic(); //print graphics
}
setviewport(0,0,115,maxy,0);
clearviewport();
setviewport(left+1,top+1,right-1,bottom-1,1);
clearviewport();
setviewport(left,top,right,bottom,0);
setlinestyle(DASHED_LINE,1,1);
line(0,150,400,150);
setlinestyle(SOLID_LINE,1,1);
for (loop = 1; loop <= 5; loop++)
line(loop*80,300,loop*80,292); //draws vert hash marks
outtextxy(-15,0,"1.57");
outtextxy(-15,150,"0.0");
outtextxy(-15,300,"-1.57");
settextstyle(DEFAULT_FONT,VERT_DIR,1);
outtextxy(-75,150,"RADIANS");
settextstyle(DEFAULT_FONT,HORIZ_DIR,1);
setviewport (left, top, right, bottom, 1);
for (loop = 1; loop <= 400; loop++)
{
v = loop/400.0;
NUM = complex(A[0],0);
DEN = complex(B[0],0);
for (loop1 = 1; loop1 <= 10; loop1++)
{
NUM += complex(A[loop1]*cos(pi*v*loop1),-A[loop1]*sin(pi*v*loop1));
DEN += complex(B[loop1]*cos(pi*v*loop1),-B[loop1]*sin(pi*v*loop1));
}
real_part = real(NUM/DEN);
imag_part = imag(NUM/DEN);
phase = atan(imag_part/real_part); //phase of transfer function
if (loop == 1)
phase_1 = phase;
else //plot phase
{
line (loop-1, 150-(150*phase_1/(pi*0.5)), loop, 150-(150*phase)/(pi*0.5));
phase_1 = phase;
}
}
while (!kbhit());
ch = getch();
if (ch == 0)
{
ch = getch();
if (ch == 59)
LJ_Graphic();
}
closegraph();
textcolor(WHITE);
textbackground(BLACK);
clrscr();
return(0);
}