decal 0.6.0

Declarative DSL for describing scenes and rendering them to SVG or PNG
Documentation 
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use crate::primitives::{
    Ellipsize,
    FontStyle,
    FontWeight,
    Paint,
    TextAlign,
    TextWrap,
};

/// Stores both explicitly specified text properties and values inherited from
/// ancestor nodes during layout and rendering.
///
/// Most fields are optional and participate in cascading.
#[derive(Debug, Clone, Default)]
pub(crate) struct Typography {
    pub(crate) family: Option<String>,
    pub(crate) size: Option<f32>,
    pub(crate) line_height: Option<f32>,
    pub(crate) weight: Option<FontWeight>,
    pub(crate) color: Option<Paint>,
    pub(crate) style: Option<FontStyle>,
    pub(crate) letter_spacing: Option<f32>,
    pub(crate) align: Option<TextAlign>,
    pub(crate) wrap: Option<TextWrap>,
    pub(crate) ellipsize: Option<Ellipsize>,
    // TODO pub word_spacing: Option<f32>,
    // TODO pub decoration: Option<TextDecoration>,
    // computed during layout
    pub(crate) resolved_family: String,
}

impl Typography {
    // noinspection RsLiveness
    /// Cascades typography properties from a parent typography context.
    ///
    /// Any field that is not explicitly set on `self` will inherit the
    /// corresponding value from `parent`. Fields that are already set are left
    /// unchanged.
    ///
    /// # Arguments
    /// - `parent`: The parent [`Typography`] to inherit values from.
    pub(crate) fn cascade_from(&mut self, parent: &Typography) {
        macro_rules! inherit {
            ($field:ident) => {
                if self.$field.is_none() {
                    self.$field = parent.$field.clone();
                }
            };
        }

        inherit!(family);
        inherit!(size);
        inherit!(line_height);
        inherit!(weight);
        inherit!(color);
        inherit!(style);
        inherit!(letter_spacing);
        inherit!(align);
        inherit!(wrap);
        inherit!(ellipsize);
    }
}