[Commit] papers/xr_ols2003/examples splines_tolerance.c,NONE,1.1

[Carl Worth]

Committed by: cworth

Update of /local/src/CVS/papers/xr_ols2003/examples
In directory home.keithp.com:/tmp/cvs-serv21300/examples

Added Files:
	splines_tolerance.c 
Log Message:
Added splines_tolerance.c

--- NEW FILE: splines_tolerance.c ---
#include <Xr.h>

#include "write_png.h"

void
draw_spline (XrState *xrs, double height);

void
draw_splines (XrState *xrs, int width, int height);

#define WIDTH 600
#define HEIGHT 300
#define STRIDE (WIDTH * 4)

char image[STRIDE*HEIGHT];

int
main (void)
{
    XrState *xrs;

    xrs = XrCreate ();

    XrSetTargetImage (xrs, image, XrFormatARGB32,
		      WIDTH, HEIGHT, STRIDE);

    XrRectangle (xrs, 0, 0, WIDTH, HEIGHT);
    XrSetRGBColor (xrs, 1, 1, 1);
    XrFill (xrs);

    draw_splines (xrs, WIDTH, HEIGHT);

    write_png_argb32 (image, "splines_tolerance.png", WIDTH, HEIGHT, STRIDE);

    XrDestroy (xrs);

    return 0;
}

void
draw_spline (XrState *xrs, double height)
{
    XrMoveTo (xrs, 0, .1 * height);
    height = .8 * height;
    XrRelCurveTo (xrs,
		  -height/2, height/2,
		  height/2, height/2,
		  0, height);
    XrStroke (xrs);
}

void
draw_splines (XrState *xrs, int width, int height)
{
    int i;
    double tolerance[5] = {.1, .5, 1, 5, 10};
    double line_width = .08 * width;
    double gap = width / 6;

    XrSetRGBColor (xrs, 0, 0, 0);
    XrSetLineWidth (xrs, line_width);

    XrTranslate (xrs, gap, 0);
    for (i=0; i < 5; i++) {
	XrSetTolerance (xrs, tolerance[i]);
	draw_spline (xrs, height);
	XrTranslate (xrs, gap, 0);
    }
}