#include <cairo.h>
#include <stdio.h>
/* build with:
 * cc `pkg-config --cflags cairo` -ggdb3 -std=gnu99  `pkg-config --libs cairo`  1x1scale.c   -o 1x1scale
 */

#define foreach(a, as) for(int _i=0, a=as[0]; _i<(sizeof(as)/sizeof(as[0])); ++_i, a = as[_i])

int main()
{
    cairo_filter_t filters[] = {CAIRO_FILTER_NEAREST, CAIRO_FILTER_BEST};
    cairo_filter_t f;
    foreach (f, filters) { 

	// paint 1x1 black
	cairo_surface_t *one = cairo_image_surface_create(CAIRO_FORMAT_ARGB32, 4, 4);
	cairo_t *cr = cairo_create(one);
	cairo_set_source_rgb(cr, 0, 0, 0);
	cairo_paint(cr);
	cairo_destroy(cr);

	cairo_surface_t *s = cairo_image_surface_create(CAIRO_FORMAT_ARGB32, 800, 800);
	cr = cairo_create(s);
	
	cairo_set_source_rgb(cr, 1,1,1);
	cairo_paint(cr);

	cairo_translate(cr, 100, 75);

	cairo_pattern_t *p = cairo_pattern_create_for_surface(one);
	cairo_pattern_set_filter (p, f);

	cairo_select_font_face (cr, "Arial", CAIRO_FONT_SLANT_NORMAL, CAIRO_FONT_WEIGHT_BOLD);
	cairo_set_font_size(cr, 10);
	/* values that make it disapear:
	 * 4.9, 4.7, 4.5, 4.4, 4.2, 4.0, 
	 */

	// write title
	cairo_save(cr);
	cairo_move_to(cr, -55., -20.);
	cairo_set_source_rgb(cr, 0, 0, 0);
	cairo_show_text(cr, "scale");
	cairo_restore(cr);

	for (float sy = 5.0; sy >= 0.1; sy -= 0.3) {
	    char scale_label[18];
	    cairo_set_source_rgb(cr, 0, 0, 0);
	    cairo_move_to(cr, -50.0, 0);
	    sprintf(scale_buf, "%1.1f", sy);
	    cairo_show_text(cr, scale_label);
	    
	    cairo_save(cr);
	    for (float sx = 5.0; sx >= 0.1; sx -= 0.3) {
		cairo_matrix_t matrix;
		cairo_matrix_init_scale(&matrix, sx, sy);
		cairo_pattern_set_matrix(p, &matrix);
		cairo_set_source(cr, p);
		cairo_paint(cr);
		cairo_translate(cr, 40, 0);
	    }
	    cairo_restore(cr);
	    
	    cairo_translate(cr, 0, 40);
	}
	cairo_pattern_destroy(p);
	cairo_destroy(cr);
	
	if (f == CAIRO_FILTER_NEAREST)
	    cairo_surface_write_to_png(s, "scaleone-nearest.png");
	else
	    cairo_surface_write_to_png(s, "scaleone-best.png");
	
	cairo_surface_destroy(one);
	cairo_surface_destroy(s);
    }
}