Cairo.jl hatching

test.jl

using Cairo, LinearAlgebra
c = CairoRGBSurface(256,256);
cr = CairoContext(c);

save(cr);
set_source_rgb(cr,0.8,0.8,0.8);    # light gray
rectangle(cr,0.0,0.0,256.0,256.0); # background
fill(cr);
restore(cr);

save(cr);
b = Cairo.Colors.ARGB32(Cairo.Colors.colorant"black")
w = Cairo.Colors.ARGB32(Cairo.Colors.colorant"white")
N = 10
image = fill(w, N, N)
for i = 1:N
    image[N+1-i, i] = b
end
image = CairoImageSurface(image)
w = N
h = N

pattern = CairoPattern(image);
pattern_set_extend(pattern, Cairo.EXTEND_REPEAT);

translate(cr, 128.0, 128.0);
scale(cr, 1 / sqrt(2), 1 / sqrt(2));
translate(cr, -128.0, -128.0);

S = 20.0
m = CairoMatrix(w/256.0 * S,0,0,h/256.0 * S,0,0);

set_matrix(pattern, m);
set_source(cr, pattern);

rectangle(cr, 0, 0, 256.0, 256.0);
fill(cr);

## mark picture with current date
restore(cr);
move_to(cr,0.0,12.0);
set_source_rgb(cr, 0,0,0);
show_text(cr,Libc.strftime(time()));
write_to_png(c,"sample_imagepattern.png");