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/*
* Copyright (c) 2021-2023, Andreas Kling <kling@serenityos.org>
* Copyright (c) 2022, Sam Atkins <atkinssj@serenityos.org>
* Copyright (c) 2022, Tobias Christiansen <tobyase@serenityos.org>
* Copyright (c) 2023, MacDue <macdue@dueutil.tech>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <LibWeb/Layout/BlockFormattingContext.h>
#include <LibWeb/Layout/SVGFormattingContext.h>
#include <LibWeb/Layout/SVGGeometryBox.h>
#include <LibWeb/Layout/SVGSVGBox.h>
#include <LibWeb/SVG/SVGForeignObjectElement.h>
#include <LibWeb/SVG/SVGSVGElement.h>
namespace Web::Layout {
SVGFormattingContext::SVGFormattingContext(LayoutState& state, Box const& box, FormattingContext* parent)
: FormattingContext(Type::SVG, state, box, parent)
{
}
SVGFormattingContext::~SVGFormattingContext() = default;
CSSPixels SVGFormattingContext::automatic_content_width() const
{
return 0;
}
CSSPixels SVGFormattingContext::automatic_content_height() const
{
return 0;
}
struct ViewBoxTransform {
CSSPixelPoint offset;
double scale_factor;
};
// https://svgwg.org/svg2-draft/coords.html#PreserveAspectRatioAttribute
static ViewBoxTransform scale_and_align_viewbox_content(SVG::PreserveAspectRatio const& preserve_aspect_ratio,
SVG::ViewBox const& view_box, Gfx::FloatSize viewbox_scale, auto const& svg_box_state)
{
ViewBoxTransform viewbox_transform {};
switch (preserve_aspect_ratio.meet_or_slice) {
case SVG::PreserveAspectRatio::MeetOrSlice::Meet:
// meet (the default) - Scale the graphic such that:
// - aspect ratio is preserved
// - the entire ‘viewBox’ is visible within the SVG viewport
// - the ‘viewBox’ is scaled up as much as possible, while still meeting the other criteria
viewbox_transform.scale_factor = min(viewbox_scale.width(), viewbox_scale.height());
break;
case SVG::PreserveAspectRatio::MeetOrSlice::Slice:
// slice - Scale the graphic such that:
// aspect ratio is preserved
// the entire SVG viewport is covered by the ‘viewBox’
// the ‘viewBox’ is scaled down as much as possible, while still meeting the other criteria
viewbox_transform.scale_factor = max(viewbox_scale.width(), viewbox_scale.height());
break;
default:
VERIFY_NOT_REACHED();
}
// Handle X alignment:
if (svg_box_state.has_definite_width()) {
switch (preserve_aspect_ratio.align) {
case SVG::PreserveAspectRatio::Align::xMinYMin:
case SVG::PreserveAspectRatio::Align::xMinYMid:
case SVG::PreserveAspectRatio::Align::xMinYMax:
// Align the <min-x> of the element's ‘viewBox’ with the smallest X value of the SVG viewport.
viewbox_transform.offset.translate_by(0, 0);
break;
case SVG::PreserveAspectRatio::Align::None: {
// Do not force uniform scaling. Scale the graphic content of the given element non-uniformly
// if necessary such that the element's bounding box exactly matches the SVG viewport rectangle.
// FIXME: None is unimplemented (treat as xMidYMid)
[[fallthrough]];
}
case SVG::PreserveAspectRatio::Align::xMidYMin:
case SVG::PreserveAspectRatio::Align::xMidYMid:
case SVG::PreserveAspectRatio::Align::xMidYMax:
// Align the midpoint X value of the element's ‘viewBox’ with the midpoint X value of the SVG viewport.
viewbox_transform.offset.translate_by((svg_box_state.content_width() - (view_box.width * viewbox_transform.scale_factor)) / 2, 0);
break;
case SVG::PreserveAspectRatio::Align::xMaxYMin:
case SVG::PreserveAspectRatio::Align::xMaxYMid:
case SVG::PreserveAspectRatio::Align::xMaxYMax:
// Align the <min-x>+<width> of the element's ‘viewBox’ with the maximum X value of the SVG viewport.
viewbox_transform.offset.translate_by((svg_box_state.content_width() - (view_box.width * viewbox_transform.scale_factor)), 0);
break;
default:
VERIFY_NOT_REACHED();
}
}
if (svg_box_state.has_definite_width()) {
switch (preserve_aspect_ratio.align) {
case SVG::PreserveAspectRatio::Align::xMinYMin:
case SVG::PreserveAspectRatio::Align::xMidYMin:
case SVG::PreserveAspectRatio::Align::xMaxYMin:
// Align the <min-y> of the element's ‘viewBox’ with the smallest Y value of the SVG viewport.
viewbox_transform.offset.translate_by(0, 0);
break;
case SVG::PreserveAspectRatio::Align::None: {
// Do not force uniform scaling. Scale the graphic content of the given element non-uniformly
// if necessary such that the element's bounding box exactly matches the SVG viewport rectangle.
// FIXME: None is unimplemented (treat as xMidYMid)
[[fallthrough]];
}
case SVG::PreserveAspectRatio::Align::xMinYMid:
case SVG::PreserveAspectRatio::Align::xMidYMid:
case SVG::PreserveAspectRatio::Align::xMaxYMid:
// Align the midpoint Y value of the element's ‘viewBox’ with the midpoint Y value of the SVG viewport.
viewbox_transform.offset.translate_by(0, (svg_box_state.content_height() - (view_box.height * viewbox_transform.scale_factor)) / 2);
break;
case SVG::PreserveAspectRatio::Align::xMinYMax:
case SVG::PreserveAspectRatio::Align::xMidYMax:
case SVG::PreserveAspectRatio::Align::xMaxYMax:
// Align the <min-y>+<height> of the element's ‘viewBox’ with the maximum Y value of the SVG viewport.
viewbox_transform.offset.translate_by(0, (svg_box_state.content_height() - (view_box.height * viewbox_transform.scale_factor)));
break;
default:
VERIFY_NOT_REACHED();
}
}
return viewbox_transform;
}
void SVGFormattingContext::run(Box const& box, LayoutMode layout_mode, AvailableSpace const& available_space)
{
auto& svg_svg_element = verify_cast<SVG::SVGSVGElement>(*box.dom_node());
auto svg_box_state = m_state.get(box);
auto root_offset = svg_box_state.offset;
box.for_each_child_of_type<BlockContainer>([&](BlockContainer const& child_box) {
if (is<SVG::SVGForeignObjectElement>(child_box.dom_node())) {
Layout::BlockFormattingContext bfc(m_state, child_box, this);
bfc.run(child_box, LayoutMode::Normal, available_space);
auto& child_state = m_state.get_mutable(child_box);
child_state.set_content_offset(child_state.offset.translated(root_offset));
}
return IterationDecision::Continue;
});
box.for_each_in_subtree_of_type<Box>([&](Box const& descendant) {
if (is<SVGGeometryBox>(descendant)) {
auto const& geometry_box = static_cast<SVGGeometryBox const&>(descendant);
auto& geometry_box_state = m_state.get_mutable(geometry_box);
auto& dom_node = const_cast<SVGGeometryBox&>(geometry_box).dom_node();
auto& path = dom_node.get_path();
auto path_transform = dom_node.get_transform();
double viewbox_scale = 1;
auto& maybe_view_box = svg_svg_element.view_box();
if (maybe_view_box.has_value()) {
// FIXME: This should allow just one of width or height to be specified.
// E.g. We should be able to layout <svg width="100%"> where height is unspecified/auto.
if (!svg_box_state.has_definite_width() || !svg_box_state.has_definite_height()) {
dbgln("FIXME: Attempting to layout indefinitely sized SVG with a viewbox -- this likely won't work!");
}
auto view_box = maybe_view_box.value();
auto scale_width = svg_box_state.has_definite_width() ? svg_box_state.content_width().value() / view_box.width : 1;
auto scale_height = svg_box_state.has_definite_height() ? svg_box_state.content_height().value() / view_box.height : 1;
// The initial value for preserveAspectRatio is xMidYMid meet.
auto preserve_aspect_ratio = svg_svg_element.preserve_aspect_ratio().value_or(SVG::PreserveAspectRatio {});
auto viewbox_transform = scale_and_align_viewbox_content(preserve_aspect_ratio, view_box, { scale_width, scale_height }, svg_box_state);
path_transform = Gfx::AffineTransform {}.translate(viewbox_transform.offset.to_type<double>().to_type<float>()).scale(viewbox_transform.scale_factor, viewbox_transform.scale_factor).translate({ -view_box.min_x, -view_box.min_y }).multiply(path_transform);
viewbox_scale = viewbox_transform.scale_factor;
}
// Stroke increases the path's size by stroke_width/2 per side.
auto path_bounding_box = path_transform.map(path.bounding_box()).to_type<CSSPixels>();
CSSPixels stroke_width = static_cast<double>(geometry_box.dom_node().visible_stroke_width()) * viewbox_scale;
path_bounding_box.inflate(stroke_width, stroke_width);
geometry_box_state.set_content_offset(path_bounding_box.top_left());
geometry_box_state.set_content_width(path_bounding_box.width());
geometry_box_state.set_content_height(path_bounding_box.height());
} else if (is<SVGSVGBox>(descendant)) {
SVGFormattingContext nested_context(m_state, descendant, this);
nested_context.run(descendant, layout_mode, available_space);
}
return IterationDecision::Continue;
});
}
}
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