# Struct BlendState

    pub struct BlendState<'a> { /* private fields */ }

Expand description

State for processing the blend operator for DICTs and charstrings.

To avoid allocation, scalars are computed on demand but this can be prohibitively expensive in charstrings where blends are applied to large numbers of elements. To amortize the cost, a fixed number of precomputed scalars are stored internally and the overflow is computed as needed.

The `MAX_PRECOMPUTED_SCALARS` constant determines the size of the internal buffer (currently 16).

See https://learn.microsoft.com/en-us/typography/opentype/spec/cff2charstr#45-variation-data-operators

## Implementations§

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### impl<'a> BlendState<'a>

#### pub fn new( store: TableRef<'a, ItemVariationStoreMarker>, coords: &'a [F2Dot14], store_index: u16, ) -> Result<BlendState<'a>, Error>

#### pub fn set_store_index(&mut self, store_index: u16) -> Result<(), Error>

Sets the active variation store index.

This should be called with the operand of the `vsindex` operator for both DICTs and charstrings.

#### pub fn region_count(&self) -> Result<usize, Error>

Returns the number of variation regions for the currently active variation store index.

#### pub fn scalars( &self, ) -> Result<impl Iterator<Item = Result<Fixed, Error>>, Error>

Returns an iterator yielding scalars for each variation region of the currently active variation store index.

## Auto Trait Implementations§

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### impl<'a> Freeze for BlendState<'a>

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### impl<'a> RefUnwindSafe for BlendState<'a>

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### impl<'a> Send for BlendState<'a>

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### impl<'a> Sync for BlendState<'a>

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### impl<'a> Unpin for BlendState<'a>

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### impl<'a> UnwindSafe for BlendState<'a>

## Blanket Implementations§

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### impl<S, D, Swp, Dwp, T> AdaptInto<D, Swp, Dwp, T> for S
where T: Real + Zero + Arithmetics + Clone, Swp: WhitePoint<T>, Dwp: WhitePoint<T>, D: AdaptFrom<S, Swp, Dwp, T>,

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#### fn adapt_into_using<M>(self, method: M) -> D
where M: TransformMatrix<T>,

Convert the source color to the destination color using the specified method.
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#### fn adapt_into(self) -> D

Convert the source color to the destination color using the bradford method by default.
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#### fn also<F>(self, block: F) -> Self
where F: FnOnce(&mut Self),

Apply a function to this value and return the (possibly) modified value.
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#### fn type_id(&self) -> TypeId

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#### fn apply<F>(self, f: F) -> Res
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Apply a function which takes the parameter by reference.
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Apply a function which takes the parameter by mutable reference.
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### impl<T, C> ArraysFrom<C> for T
where C: IntoArrays<T>,

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#### fn arrays_from(colors: C) -> T

Cast a collection of colors into a collection of arrays.
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### impl<T, C> ArraysInto<C> for T
where C: FromArrays<T>,

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#### fn arrays_into(self) -> C

Cast this collection of arrays into a collection of colors.
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#### fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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### impl<WpParam, T, U> Cam16IntoUnclamped<WpParam, T> for U
where T: FromCam16Unclamped<WpParam, U>,

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#### type Scalar = <T as FromCam16Unclamped<WpParam, U>>::Scalar

The number type that’s used in `parameters` when converting.
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#### fn cam16_into_unclamped( self, parameters: BakedParameters<WpParam, <U as Cam16IntoUnclamped<WpParam, T>>::Scalar>, ) -> T

Converts `self` into `C`, using the provided parameters.
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### impl<T, C> ComponentsFrom<C> for T
where C: IntoComponents<T>,

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#### fn components_from(colors: C) -> T

Cast a collection of colors into a collection of color components.
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where T: Any,

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#### fn into_any(self: Box<T>) -> Box<dyn Any>

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#### fn from(t: T) -> T

Returns the argument unchanged.

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Performs a conversion from `angle`.
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#### fn from_stimulus(other: U) -> T

Converts `other` into `Self`, while performing the appropriate scaling, rounding and clamping.
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where T: Cam16FromUnclamped<WpParam, U>,

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#### type Scalar = <T as Cam16FromUnclamped<WpParam, U>>::Scalar

The number type that’s used in `parameters` when converting.
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#### fn into_cam16_unclamped( self, parameters: BakedParameters<WpParam, <U as IntoCam16Unclamped<WpParam, T>>::Scalar>, ) -> T

Converts `self` into `C`, using the provided parameters.
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### impl<T, U> IntoColor<U> for T
where U: FromColor<T>,

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#### fn into_color(self) -> U

Convert into T with values clamped to the color defined bounds Read more
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### impl<T, U> IntoColorUnclamped<U> for T
where U: FromColorUnclamped<T>,

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#### fn into_color_unclamped(self) -> U

Convert into T. The resulting color might be invalid in its color space Read more
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#### fn into_stimulus(self) -> T

Converts `self` into `T`, while performing the appropriate scaling, rounding and clamping.
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#### type Output = T

Should always be `Self`
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### impl<T, C> TryComponentsInto<C> for T
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#### type Error = <C as TryFromComponents<T>>::Error

The error for when `try_into_colors` fails to cast.
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#### fn try_components_into(self) -> Result<C, <T as TryComponentsInto<C>>::Error>

Try to cast this collection of color components into a collection of colors. Read more
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Performs the conversion.
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### impl<T, U> TryIntoColor<U> for T
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#### fn try_into_color(self) -> Result<U, OutOfBounds<U>>

Convert into T, returning ok if the color is inside of its defined range, otherwise an `OutOfBounds` error is returned which contains the unclamped color. Read more
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### impl<C, U> UintsFrom<C> for U
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#### fn uints_from(colors: C) -> U

Cast a collection of colors into a collection of unsigned integers.
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#### fn uints_into(self) -> C

Cast this collection of unsigned integers into a collection of colors.
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