71 lines
1.6 KiB
C
71 lines
1.6 KiB
C
#include <stdio.h>
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#include <cairo.h>
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#define M_PI 3.14159265358979323846
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static double width, height;
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static char path_output[512];
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static cairo_t *cr;
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static cairo_surface_t *surface;
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struct rgb {
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double r, g, b;
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} values[] = {
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{0, .7, .9},
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{.5, .9, .5},
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{1., 1., .4},
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{1., .8, .5},
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{1., .6, .65},
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{1., .4, .9},
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};
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#define NVALUES 6
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int start = 0;
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void lain_rainbow(cairo_t * cr) {
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unsigned ii, jj;
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double dy, dx, x0, y0, x1, y1, red, green, blue;
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/* Outer black border */
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red = green = blue = 1.;
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cairo_set_line_width(cr, 0);
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cairo_set_source_rgba(cr, red, green, blue, 1.);
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cairo_rectangle(cr, 0, 0, width, height);
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cairo_fill(cr);
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/* Colors */
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x1 = width;
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dx = width / 36;
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y1 = dy = height / 36;
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x0 = 0;
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y0 = 0;
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for (ii = start, jj = 0; jj < 36; jj++, ii++) {
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cairo_rectangle(cr, x0, y0, x1, y1);
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cairo_set_source_rgba(cr, values[ii % NVALUES].r, values[ii % NVALUES].g, values[ii % NVALUES].b, 1.);
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cairo_fill(cr);
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y0 += dy;
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x1 += dx;
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y1 += dy;
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}
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}
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int main(int argc, char **argv) {
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int n;
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width = 3840;
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height = 2160;
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sprintf (path_output, "stage1-00.png");
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if (argc == 2) {
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n = 0;
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sscanf(argv[1], "%d", &n);
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start = n;
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sprintf (path_output, "stage1-%02d.png", n);
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}
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surface = cairo_image_surface_create (CAIRO_FORMAT_ARGB32, width, height);
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cr = cairo_create(surface);
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lain_rainbow(cr);
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cairo_surface_write_to_png (surface, path_output);
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cairo_surface_destroy(surface);
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cairo_destroy(cr);
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return 0;
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}
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