skia_safe/core/
font_arguments.rs

use crate::prelude::*;
use sb::SkFontArguments_Palette;
use skia_bindings::{self as sb, SkFontArguments, SkFontArguments_VariationPosition};
use std::{fmt, marker::PhantomData, mem};

#[derive(Clone, Debug)]
pub struct VariationPosition<'a> {
    pub coordinates: &'a [variation_position::Coordinate],
}

pub mod variation_position {
    use crate::FourByteTag;
    use skia_bindings::SkFontArguments_VariationPosition_Coordinate;

    #[derive(Copy, Clone, PartialEq, Default, Debug)]
    #[repr(C)]
    pub struct Coordinate {
        pub axis: FourByteTag,
        pub value: f32,
    }

    native_transmutable!(
        SkFontArguments_VariationPosition_Coordinate,
        Coordinate,
        coordinate_layout
    );
}

#[derive(Clone, Debug)]
pub struct Palette<'a> {
    pub index: i32,
    pub overrides: &'a [palette::Override],
}

pub mod palette {
    use crate::Color;
    use skia_bindings::SkFontArguments_Palette_Override;

    #[derive(Copy, Clone, PartialEq, Eq, Default, Debug)]
    #[repr(C)]
    pub struct Override {
        pub index: u16,
        pub color: Color,
    }

    native_transmutable!(SkFontArguments_Palette_Override, Override, override_layout);
}

#[repr(C)]
pub struct FontArguments<'vp, 'p> {
    args: SkFontArguments,
    pd_vp: PhantomData<&'vp [variation_position::Coordinate]>,
    pd_p: PhantomData<&'p [palette::Override]>,
}

native_transmutable!(
    SkFontArguments,
    FontArguments<'_, '_>,
    font_arguments_layout
);

impl Drop for FontArguments<'_, '_> {
    fn drop(&mut self) {
        unsafe { sb::C_SkFontArguments_destruct(self.native_mut()) }
    }
}

impl Default for FontArguments<'_, '_> {
    fn default() -> Self {
        FontArguments::new()
    }
}

impl fmt::Debug for FontArguments<'_, '_> {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        f.debug_struct("FontArguments")
            .field("collection_index", &self.collection_index())
            .field(
                "variation_design_position",
                &self.variation_design_position(),
            )
            .field("palette", &self.palette())
            .finish()
    }
}

impl FontArguments<'_, '_> {
    pub fn new() -> Self {
        Self::construct(|fa| unsafe {
            sb::C_SkFontArguments_construct(fa);
        })
    }

    pub fn set_collection_index(&mut self, collection_index: usize) -> &mut Self {
        self.native_mut().fCollectionIndex = collection_index.try_into().unwrap();
        self
    }

    // This function consumes self for it to be able to change its lifetime,
    // because it borrows the coordinates referenced by [`VariationPosition`].
    //
    // If we would return `Self`, position's Coordinates would not be borrowed.
    pub fn set_variation_design_position(mut self, position: VariationPosition) -> FontArguments {
        let position = SkFontArguments_VariationPosition {
            coordinates: position.coordinates.native().as_ptr(),
            coordinateCount: position.coordinates.len().try_into().unwrap(),
        };
        unsafe {
            sb::C_SkFontArguments_setVariationDesignPosition(self.native_mut(), position);
            // note: we are _not_ returning Self here, but VariationPosition with a
            // changed lifetime.
            mem::transmute(self)
        }
    }

    pub fn collection_index(&self) -> usize {
        self.native().fCollectionIndex.try_into().unwrap()
    }

    pub fn variation_design_position(&self) -> VariationPosition {
        unsafe {
            let position = sb::C_SkFontArguments_getVariationDesignPosition(self.native());
            VariationPosition {
                coordinates: safer::from_raw_parts(
                    position.coordinates as *const _,
                    position.coordinateCount.try_into().unwrap(),
                ),
            }
        }
    }

    // This function consumes `self` for it to be able to change its lifetime, because it borrows
    // the coordinates referenced by `[Palette]`.
    pub fn set_palette(mut self, palette: Palette) -> FontArguments {
        let palette = SkFontArguments_Palette {
            index: palette.index,
            overrides: palette.overrides.native().as_ptr(),
            overrideCount: palette.overrides.len().try_into().unwrap(),
        };
        unsafe {
            sb::C_SkFontArguments_setPalette(self.native_mut(), palette);
            mem::transmute(self)
        }
    }

    pub fn palette(&self) -> Palette {
        unsafe {
            let palette = sb::C_SkFontArguments_getPalette(self.native());
            Palette {
                index: palette.index,
                overrides: safer::from_raw_parts(
                    palette.overrides as *const _,
                    palette.overrideCount.try_into().unwrap(),
                ),
            }
        }
    }
}

#[test]
fn test_font_arguments_with_no_coordinates() {
    let fa = FontArguments::new();
    let coordinates = fa.variation_design_position();
    assert_eq!(coordinates.coordinates, []);
}

#[test]
#[allow(clippy::float_cmp)]
fn access_coordinates() {
    let coordinates = Box::new([variation_position::Coordinate {
        axis: 0.into(),
        value: 1.0,
    }]);
    let args = FontArguments::new();
    let pos = VariationPosition {
        coordinates: coordinates.as_ref(),
    };
    let args = args.set_variation_design_position(pos);
    assert_eq!(args.variation_design_position().coordinates[0].value, 1.0);
    drop(args);
}
skia_safe/core/font_arguments.rs

skia_safe/core/
font_arguments.rs
