Macro egcircle

macro_rules! egcircle {
    (center = $center:expr, radius = $r:expr $(,)?) => { ... };
    (center = $center:expr, radius = $r:expr, style = $style:expr $(,)?) => { ... };
}

Create a Circle with optional styling using a convenient macro.

use embedded_graphics::{
    egcircle,
    pixelcolor::Rgb565,
    prelude::*,
    primitive_style,
    primitives::Circle,
    style::{PrimitiveStyle, Styled},
};

// Coordinates can be defined as any type that implements `Into<Point>`
let line_circle: Styled<Circle, PrimitiveStyle<Rgb565>> =
    egcircle!(center = (10, 20), radius = 30);

let filled_circle: Styled<Circle, PrimitiveStyle<Rgb565>> = egcircle!(
    center = (10, 20),
    radius = 30,
    style = primitive_style!(stroke_color = Rgb565::RED, fill_color = Rgb565::GREEN)
);

Style properties like stroke_color map to methods on the PrimitiveStyleBuilder struct. For example, the following code makes two identical circles:

use embedded_graphics::{
    egcircle,
    pixelcolor::Rgb565,
    prelude::*,
    primitive_style,
    primitives::Circle,
    style::{PrimitiveStyle, PrimitiveStyleBuilder, Styled},
};

let circle_1: Styled<Circle, PrimitiveStyle<Rgb565>> = egcircle!(
    center = (10, 20),
    radius = 30,
    style = primitive_style!(
        stroke_color = Rgb565::RED,
        fill_color = Rgb565::GREEN,
        stroke_width = 1
    )
);

let style = PrimitiveStyleBuilder::new()
    .fill_color(Rgb565::GREEN)
    .stroke_color(Rgb565::RED)
    .stroke_width(1)
    .build();

let circle_2: Styled<Circle, PrimitiveStyle<Rgb565>> =
    Circle::new(Point::new(10, 20), 30).into_styled(style);

assert_eq!(circle_1, circle_2);