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//! The `image` element.
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use markup5ever::{expanded_name, local_name, namespace_url, ns};
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use crate::aspect_ratio::AspectRatio;
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use crate::bbox::BoundingBox;
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use crate::document::{AcquiredNodes, Document, Resource};
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use crate::drawing_ctx::{DrawingCtx, SvgNesting, Viewport};
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use crate::element::{set_attribute, ElementTrait};
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use crate::error::*;
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use crate::href::{is_href, set_href};
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use crate::layout::{self, Layer, LayerKind, StackingContext};
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use crate::length::*;
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use crate::node::{CascadedValues, Node, NodeBorrow};
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use crate::parsers::ParseValue;
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use crate::rect::Rect;
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use crate::rsvg_log;
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use crate::session::Session;
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use crate::surface_utils::shared_surface::{SharedImageSurface, SurfaceType};
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use crate::xml::Attributes;
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/// The `<image>` element.
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///
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/// Note that its x/y/width/height are properties in SVG2, so they are
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/// defined as part of [the properties machinery](properties.rs).
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#[derive(Default)]
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pub struct Image {
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    aspect: AspectRatio,
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    href: Option<String>,
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}
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impl ElementTrait for Image {
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    fn set_attributes(&mut self, attrs: &Attributes, session: &Session) {
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        for (attr, value) in attrs.iter() {
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            match attr.expanded() {
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                expanded_name!("", "preserveAspectRatio") => {
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                    set_attribute(&mut self.aspect, attr.parse(value), session)
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                }
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                // "path" is used by some older Adobe Illustrator versions
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                ref a if is_href(a) || *a == expanded_name!("", "path") => {
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                    set_href(a, &mut self.href, Some(value.to_string()))
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                }
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                _ => (),
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            }
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        }
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    }
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    fn layout(
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        &self,
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        node: &Node,
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        acquired_nodes: &mut AcquiredNodes<'_>,
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        cascaded: &CascadedValues<'_>,
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        viewport: &Viewport,
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        draw_ctx: &mut DrawingCtx,
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        _clipping: bool,
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    ) -> Result<Option<Layer>, InternalRenderingError> {
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        if let Some(ref url) = self.href {
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            self.layout_from_url(url, node, acquired_nodes, cascaded, viewport, draw_ctx)
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        } else {
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            Ok(None)
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        }
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    }
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    fn draw(
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        &self,
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        node: &Node,
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        acquired_nodes: &mut AcquiredNodes<'_>,
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        cascaded: &CascadedValues<'_>,
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        viewport: &Viewport,
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        draw_ctx: &mut DrawingCtx,
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        clipping: bool,
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    ) -> Result<BoundingBox, InternalRenderingError> {
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        let layer = self.layout(node, acquired_nodes, cascaded, viewport, draw_ctx, clipping)?;
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        if let Some(layer) = layer {
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            draw_ctx.draw_layer(&layer, acquired_nodes, clipping, viewport)
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        } else {
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            Ok(draw_ctx.empty_bbox())
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        }
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    }
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}
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impl Image {
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    fn layout_from_url(
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        &self,
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        url: &str,
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        node: &Node,
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        acquired_nodes: &mut AcquiredNodes<'_>,
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        cascaded: &CascadedValues<'_>,
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        viewport: &Viewport,
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        draw_ctx: &mut DrawingCtx,
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    ) -> Result<Option<Layer>, InternalRenderingError> {
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        match acquired_nodes.lookup_resource(url) {
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            Ok(Resource::Image(surface)) => self.layout_from_surface(
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                &surface,
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                node,
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                acquired_nodes,
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                cascaded,
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                viewport,
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                draw_ctx,
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            ),
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            Ok(Resource::Document(document)) => self.layout_from_svg(
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                &document,
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                node,
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                acquired_nodes,
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                cascaded,
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                viewport,
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                draw_ctx,
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            ),
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            Err(e) => {
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                rsvg_log!(
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                    draw_ctx.session(),
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                    "could not load image \"{}\": {}",
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                    url,
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                    e
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                );
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                Ok(None)
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            }
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        }
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    }
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    /// Draw an `<image>` from a raster image.
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    fn layout_from_surface(
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        &self,
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        surface: &SharedImageSurface,
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        node: &Node,
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        acquired_nodes: &mut AcquiredNodes<'_>,
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        cascaded: &CascadedValues<'_>,
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        viewport: &Viewport,
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        draw_ctx: &mut DrawingCtx,
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    ) -> Result<Option<Layer>, InternalRenderingError> {
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        let values = cascaded.get();
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        let params = NormalizeParams::new(values, viewport);
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        let x = values.x().0.to_user(&params);
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        let y = values.y().0.to_user(&params);
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        let w = match values.width().0 {
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            LengthOrAuto::Length(l) => l.to_user(&params),
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            LengthOrAuto::Auto => surface.width() as f64,
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        };
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        let h = match values.height().0 {
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            LengthOrAuto::Length(l) => l.to_user(&params),
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            LengthOrAuto::Auto => surface.height() as f64,
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        };
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        let is_visible = values.is_visible();
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        let rect = Rect::new(x, y, x + w, y + h);
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        let overflow = values.overflow();
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        let image = Box::new(layout::Image {
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            surface: surface.clone(),
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            is_visible,
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            rect,
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            aspect: self.aspect,
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            overflow,
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            image_rendering: values.image_rendering(),
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        });
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        let elt = node.borrow_element();
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        let stacking_ctx = StackingContext::new(
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            draw_ctx.session(),
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            acquired_nodes,
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            &elt,
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            values.transform(),
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            None,
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            values,
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        );
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        let layer = Layer {
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            kind: LayerKind::Image(image),
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            stacking_ctx,
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        };
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        Ok(Some(layer))
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    }
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    /// Draw an `<image>` from an SVG image.
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    ///
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    /// Per the [spec], we need to rasterize the SVG ("The result of processing an ‘image’
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    /// is always a four-channel RGBA result.")  and then composite it as if it were a PNG
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    /// or JPEG.
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    ///
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    /// [spec]: https://www.w3.org/TR/SVG2/embedded.html#ImageElement
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    fn layout_from_svg(
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        &self,
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        document: &Document,
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        node: &Node,
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        acquired_nodes: &mut AcquiredNodes<'_>,
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        cascaded: &CascadedValues<'_>,
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        viewport: &Viewport,
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        draw_ctx: &mut DrawingCtx,
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    ) -> Result<Option<Layer>, InternalRenderingError> {
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        let dimensions = document.get_intrinsic_dimensions();
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        let values = cascaded.get();
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        let params = NormalizeParams::new(values, viewport);
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        let x = values.x().0.to_user(&params);
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        let y = values.y().0.to_user(&params);
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        let w = match values.width().0 {
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            LengthOrAuto::Length(l) => l.to_user(&params),
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            LengthOrAuto::Auto => dimensions.width.to_user(&params),
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        };
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        let h = match values.height().0 {
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            LengthOrAuto::Length(l) => l.to_user(&params),
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            LengthOrAuto::Auto => dimensions.height.to_user(&params),
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        };
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        let is_visible = values.is_visible();
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        let rect = Rect::new(x, y, x + w, y + h);
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        let overflow = values.overflow();
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        let dest_rect = match dimensions.vbox {
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            None => Rect::from_size(w, h),
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            Some(vbox) => self.aspect.compute(&vbox, &Rect::new(x, y, x + w, y + h)),
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        };
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        let dest_size = dest_rect.size();
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        let surface_dest_rect = Rect::from_size(dest_size.0, dest_size.1);
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        // We use ceil() to avoid chopping off the last pixel if it is partially covered.
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        let surface_width = checked_i32(dest_size.0.ceil())?;
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        let surface_height = checked_i32(dest_size.1.ceil())?;
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        let surface =
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            cairo::ImageSurface::create(cairo::Format::ARgb32, surface_width, surface_height)?;
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        {
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            let cr = cairo::Context::new(&surface)?;
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            let options = draw_ctx.rendering_options(SvgNesting::ReferencedFromImageElement);
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            document.render_document(
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                draw_ctx.session(),
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                &cr,
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                &cairo::Rectangle::from(surface_dest_rect),
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                &options,
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            )?;
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        }
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        let surface = SharedImageSurface::wrap(surface, SurfaceType::SRgb)?;
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        let image = Box::new(layout::Image {
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            surface,
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            is_visible,
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            rect,
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            aspect: self.aspect,
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            overflow,
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            image_rendering: values.image_rendering(),
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        });
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        let elt = node.borrow_element();
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        let stacking_ctx = StackingContext::new(
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            draw_ctx.session(),
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            acquired_nodes,
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            &elt,
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            values.transform(),
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            None,
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            values,
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        );
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        let layer = Layer {
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            kind: LayerKind::Image(image),
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            stacking_ctx,
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        };
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        Ok(Some(layer))
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    }
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}
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pub fn checked_i32(x: f64) -> Result<i32, cairo::Error> {
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    cast::i32(x).map_err(|_| cairo::Error::InvalidSize)
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}