utils — text attribute helpers

Small pure functions for packing and unpacking the u32 text-attribute value carried by TextChunk and renderables. The layout of that u32 is documented in types: bits 0–7 are the standard TextAttributes flags; bits 8–31 may carry a link id.

Building attributes from options

pub struct TextAttributeOptions {
    pub bold: bool,
    pub italic: bool,
    pub underline: bool,
    pub dim: bool,
    pub blink: bool,
    pub inverse: bool,
    pub hidden: bool,
    pub strikethrough: bool,
}

pub const fn create_text_attributes(options: TextAttributeOptions) -> u32

create_text_attributes ORs the enabled flags into a u32. Use it instead of hand-computing bit masks:

let attrs = create_text_attributes(TextAttributeOptions {
    bold: true,
    underline: true,
    ..Default::default()
});
// attrs == TextAttributes::BOLD.bits() | TextAttributes::UNDERLINE.bits()

Link-id packing

Two helpers store and retrieve a 24-bit link id in bits 8–31 of the attribute value:

pub const fn attributes_with_link(base_attributes: u32, link_id: u32) -> u32
pub const fn get_link_id(attributes: u32) -> u32

let attrs = attributes_with_link(create_text_attributes(TextAttributeOptions { ..Default::default() }), 42);
assert_eq!(get_link_id(attrs), 42);

attributes_with_link masks the base to the low 8 bits, shifts the link id up by 8 (masked to 24 bits), and ORs them together.

Next: lib/ — colors, borders, text, unicode.