drawcbox.c

来自「The art and science of c_source code!」· C语言 代码 · 共 60 行

/*
 * File: drawcbox.c
 * ----------------
 * Program to draw a centered box.
 */

#include <stdio.h>

#include "genlib.h"
#include "graphics.h"

/* Function prototypes */

void DrawBox(double x, double y, double width, double height);
void DrawCenteredBox(double x, double y,
                     double width, double height);

/* Main program */

main()
{
    double cx, cy;

    InitGraphics();
    cx = GetWindowWidth() / 2;
    cy = GetWindowHeight() / 2;
    DrawCenteredBox(cx, cy, 2.0, 1.0);
}

/*
 * Function: DrawBox
 * Usage: DrawBox(x, y, width, height)
 * -----------------------------------
 * This function draws a rectangle of the given width and
 * height with its lower left corner at (x, y).
 */

void DrawBox(double x, double y, double width, double height)
{
    MovePen(x, y);
    DrawLine(0, height);
    DrawLine(width, 0);
    DrawLine(0, -height);
    DrawLine(-width, 0);
}

/*
 * Function: DrawCenteredBox
 * Usage: DrawCenteredBox(x, y, width, height)
 * -------------------------------------------
 * This function draws a rectangle of the given width and
 * height with its center at (x, y).
 */

void DrawCenteredBox(double x, double y,
                     double width, double height)
{
    DrawBox(x - width / 2, y - height / 2, width, height);
}