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/*
* stroke.c
* Copyright (c) 2021 Ben Fuller
*
* This program makes a PNG image "stroke.png" consisting of blocks of colour
* in a gradient. The dimensions of the image, and size of <<pixels>> can be
* easily adjusted - try setting the number of rows and columns to the width
* and height so that each block is one pixel.
*
* Between each pixel is left a small gap, and the background is coloured in
* black.
*/
#include <cairo.h>
#include <stdio.h>
int
main(void)
{
double width, height, scale;
int nx, ny;
cairo_surface_t *surface;
cairo_t *cr;
width = 600;
height = 600;
scale = 1;
/* number of columns and rows */
nx = 60;
ny = 60;
surface = cairo_image_surface_create(CAIRO_FORMAT_ARGB32, width, height);
cr = cairo_create(surface);
cairo_scale(cr, scale, scale);
/* background fill */
cairo_set_source_rgb(cr, 0, 0, 0);
cairo_rectangle(cr, 0, 0, width/scale, height/scale);
cairo_fill(cr);
for (int i = 0; i < nx; i++) {
for (int j = 0; j < ny; j++) {
cairo_set_source_rgb(cr,
(double)j / ny,
(double)i / nx,
0);
cairo_rectangle(cr, i * width/nx/scale, j * height/ny/scale,
width/nx/scale * 0.9,
height/ny/scale * 0.9);
cairo_fill(cr);
}
}
printf("cairo_status: %s\n", cairo_status_to_string(cairo_status(cr)));
/* Write output and clean up */
cairo_surface_write_to_png(surface, "stroke.png");
cairo_destroy(cr);
cairo_surface_destroy(surface);
return 0;
}
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