Struct rsvg::filters::context::FilterContext

pub struct FilterContext {
    stroke_paint: Rc<UserSpacePaintSource>,
    fill_paint: Rc<UserSpacePaintSource>,
    source_surface: SharedImageSurface,
    last_result: Option<FilterOutput>,
    previous_results: HashMap<CustomIdent, FilterOutput>,
    background_surface: OnceCell<Result<SharedImageSurface, FilterError>>,
    stroke_paint_surface: OnceCell<Result<SharedImageSurface, FilterError>>,
    fill_paint_surface: OnceCell<Result<SharedImageSurface, FilterError>>,
    primitive_units: CoordUnits,
    effects_region: Rect,
    _affine: Transform,
    paffine: Transform,
}

The filter rendering context.

Fields

stroke_paint: Rc<UserSpacePaintSource>

Paint source for primitives which have an input value equal to StrokePaint.

fill_paint: Rc<UserSpacePaintSource>

Paint source for primitives which have an input value equal to FillPaint.

source_surface: SharedImageSurface

The source graphic surface.

last_result: Option<FilterOutput>

Output of the last filter primitive.

previous_results: HashMap<CustomIdent, FilterOutput>

Surfaces of the previous filter primitives by name.

background_surface: OnceCell<Result<SharedImageSurface, FilterError>>

Input surface for primitives that require an input of BackgroundImage or BackgroundAlpha. Computed lazily.

stroke_paint_surface: OnceCell<Result<SharedImageSurface, FilterError>>

fill_paint_surface: OnceCell<Result<SharedImageSurface, FilterError>>

primitive_units: CoordUnits

Primtive units

effects_region: Rect

The filter effects region.

_affine: Transform

The filter element affine matrix.

If filterUnits == userSpaceOnUse, equal to the drawing context matrix, so, for example, if the target node is in a group with transform="translate(30, 20)", this will be equal to a matrix that translates to 30, 20 (and does not scale). Note that the target node bounding box isn’t included in the computations in this case.

If filterUnits == objectBoundingBox, equal to the target node bounding box matrix multiplied by the drawing context matrix, so, for example, if the target node is in a group with transform="translate(30, 20)" and also has x="1", y="1", width="50", height="50", this will be equal to a matrix that translates to 31, 21 and scales to 50, 50.

This is to be used in conjunction with setting the viewbox size to account for the scaling. For filterUnits == userSpaceOnUse, the viewbox will have the actual resolution size, and for filterUnits == objectBoundingBox, the viewbox will have the size of 1, 1.

paffine: Transform

The filter primitive affine matrix.

See the comments for _affine, they largely apply here.

Implementations

impl FilterContext

pub fn new( filter: &UserSpaceFilter, stroke_paint: Rc<UserSpacePaintSource>, fill_paint: Rc<UserSpacePaintSource>, source_surface: &SharedImageSurface, draw_transform: Transform, node_bbox: BoundingBox, ) -> Result<Self, FilterError>

Creates a new FilterContext.

pub fn source_graphic(&self) -> &SharedImageSurface

Returns the surface corresponding to the source graphic.

fn background_image( &self, draw_ctx: &DrawingCtx, ) -> Result<SharedImageSurface, FilterError>

Returns the surface corresponding to the background image snapshot.

fn stroke_paint_image( &self, acquired_nodes: &mut AcquiredNodes<'_>, draw_ctx: &mut DrawingCtx, ) -> Result<SharedImageSurface, FilterError>

Returns a surface filled with the current stroke’s paint, for StrokePaint inputs in primitives.

Filter Effects 1: https://www.w3.org/TR/filter-effects/#attr-valuedef-in-strokepaint

fn fill_paint_image( &self, acquired_nodes: &mut AcquiredNodes<'_>, draw_ctx: &mut DrawingCtx, ) -> Result<SharedImageSurface, FilterError>

Returns a surface filled with the current fill’s paint, for FillPaint inputs in primitives.

Filter Effects 1: https://www.w3.org/TR/filter-effects/#attr-valuedef-in-fillpaint

pub fn into_output(self) -> Result<SharedImageSurface, Error>

Converts this FilterContext into the surface corresponding to the output of the filter chain.

The returned surface is in the sRGB color space.

pub fn store_result(&mut self, result: FilterResult)

Stores a filter primitive result into the context.

pub fn paffine(&self) -> Transform

Returns the paffine matrix.

pub fn primitive_units(&self) -> CoordUnits

Returns the primitive units.

pub fn effects_region(&self) -> Rect

Returns the filter effects region.

fn get_unspecified_input(&self) -> FilterInput

Get a filter primitive’s default input as if its in=\"...\" were not specified.

Per https://drafts.fxtf.org/filter-effects/#element-attrdef-filter-primitive-in, “References to non-existent results will be treated as if no result was specified”. That is, fall back to the last result in the filter chain, or if this is the first in the chain, just use SourceGraphic.

fn get_input_raw( &self, acquired_nodes: &mut AcquiredNodes<'_>, draw_ctx: &mut DrawingCtx, in_: &Input, ) -> Result<FilterInput, FilterError>

Retrieves the filter input surface according to the SVG rules.

pub fn get_input( &self, acquired_nodes: &mut AcquiredNodes<'_>, draw_ctx: &mut DrawingCtx, in_: &Input, color_interpolation_filters: ColorInterpolationFilters, ) -> Result<FilterInput, FilterError>

Retrieves the filter input surface according to the SVG rules.

The surface will be converted to the color space specified by color_interpolation_filters.