-- card: 63593 from stack: in
-- bmap block id: 0
-- flags: 0000
-- background id: 4755
-- name: 


-- part 1 (field)
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-- high flags: 0007
-- rect: left=30 top=78 right=296 bottom=478
-- title width / last selected line: 0
-- icon id / first selected line: 0 / 0
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-- font id: 4
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-- part contents for card part 1
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/*
*   FILE:     graftest.c
*   AUTHOR:   R. Gonzalez
*   CREATED:  Aug. 5, 1990
*
*   Demonstrate use of Mac_Screen class.
*
*   PROJECT CONTENTS:
*   screen.c, graftest.c, ANSI, oops, MacTraps
*/

# include   "screen.h"
# include   <math.h>
# include   <oops.h>

# define    PI          3.1415926

double      get_input(void);

main()
{
    Mac_Screen  *mac_screen;
    double      angle,
                x,
                y,
                old_x,
                old_y,
                width;
    boolean     done;

    mac_screen = new(Mac_Screen);
    mac_screen->init();

    while ((width = get_input()) != 0.)
    {
        mac_screen->set_view(width,
                width/mac_screen->get_aspect_ratio(),
                width/2.,
                width/2./mac_screen->get_aspect_ratio());

        for (angle = 0.,done = FALSE ; angle < 6*PI && !done;
            angle+=PI/50.)
        {
            if (angle != 0.)
            {
                mac_screen->color(BLACK);
                mac_screen->draw_line(0.,0.,old_x,old_y);
                mac_screen->draw_circle(old_x,old_y,.2);
            }

            x = cos(angle);
            y = sin(angle);

            mac_screen->color(WHITE);
            mac_screen->draw_line(0.,0.,x,y);
            mac_screen->draw_circle(x,y,.2);

            old_x = x;
            old_y = y;

            if (mac_screen->mouse_button_is_down())
                done = TRUE;
        }
    }

    delete(mac_screen);
}

double   get_input(void)
{
    double   width;

    printf("Width of view window (between 1 and 10, 0 to quit)?\n");
    scanf("%lg",&width);
    return width;
}




-- part contents for background part 4
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File 3 of 3.  Example application of foregoing Mac_Screen class:

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