Draw lots of arcs (circles)

This is a custom function to draw lots of circles within C with a single call from R. Use this function when you want to draw lots of circles and need to speed up the creation of the final image.

cairo_arc_vec(cr, xc, yc, radius, angle1, angle2, r, g, b, a, sr, sg, sb, sa)

Arguments

cr	cairo_t *
xc	double
yc	double
radius	double
angle1	double
angle2	double
r, g, b, a	fill colour values in range [0,1]. Set a = 0 to disable filling
sr, sg, sb, sa	stroke colour values in range [0,1]. Set sa = 0 to disable drawing the stroke

Details

Besides the cr context, all arguments should either be the same length as the initial argument (xc) or have a length of 1.

Vectors which have a length of 1 will be considered to have a constant value for all objects

See also

Other bespoke: cairo_image_surface_create_from_array(), cairo_image_surface_get_array(), cairo_image_surface_get_raster(), cairo_image_surface_get_raw(), cairo_image_surface_write_array(), cairo_polygon_vec(), cairo_polygon(), cairo_rectangle_vec(), cairo_segment_vec()

Other vectorised: cairo_polygon_vec(), cairo_rectangle_vec(), cairo_segment_vec()

Examples

if (FALSE) {
# Draw 10 circles of the same radius, with red fill and no outline
N <- 10
xc <- runif(N)
yc <- runif(N)
radius <- 3
cairo_arc_vec(cr, xc, yc, radius, 0, 2*pi,   1, 0, 0, 1,   0, 0, 0, 0)
}