ladybird/Userland/Libraries/LibWeb/Painting/SVGTextPaintable.cpp
MacDue 909bcfe9a4 LibWeb: Resolve and paint simple SVG masks
This allows applying SVG <mask>s to elements. It is only implemented for
the simplest (and default) case:

	- mask-type = luminance
 	- maskContentUnits = maskContentUnits
 	- maskUnits = objectBoundingBox
	- Default masking area

It should be possible to extend to cover more cases. Though the layout
for maskContentUnits = objectBoundingBox will be tricky to figure out.
2023-09-19 10:46:05 +02:00

101 lines
3.7 KiB
C++

/*
* Copyright (c) 2023, Aliaksandr Kalenik <kalenik.aliaksandr@gmail.com>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <LibWeb/Painting/SVGTextPaintable.h>
#include <LibWeb/SVG/SVGSVGElement.h>
namespace Web::Painting {
JS::NonnullGCPtr<SVGTextPaintable> SVGTextPaintable::create(Layout::SVGTextBox const& layout_box)
{
return layout_box.heap().allocate_without_realm<SVGTextPaintable>(layout_box);
}
SVGTextPaintable::SVGTextPaintable(Layout::SVGTextBox const& layout_box)
: SVGGraphicsPaintable(layout_box)
{
}
Optional<HitTestResult> SVGTextPaintable::hit_test(CSSPixelPoint position, HitTestType type) const
{
(void)position;
(void)type;
return {};
}
void SVGTextPaintable::paint(PaintContext& context, PaintPhase phase) const
{
if (!is_visible())
return;
if (!layout_node().computed_values().fill().has_value())
return;
if (layout_node().computed_values().fill()->is_url()) {
dbgln("FIXME: Using url() as fill is not supported for svg text");
return;
}
SVGGraphicsPaintable::paint(context, phase);
if (phase != PaintPhase::Foreground)
return;
auto& painter = context.painter();
auto& text_element = layout_box().dom_node();
auto const* svg_element = text_element.shadow_including_first_ancestor_of_type<SVG::SVGSVGElement>();
auto svg_element_rect = svg_element->paintable_box()->absolute_rect();
Gfx::PainterStateSaver save_painter { painter };
auto svg_context_offset = context.floored_device_point(svg_element_rect.location()).to_type<int>();
painter.translate(svg_context_offset);
auto const& dom_node = layout_box().dom_node();
auto child_text_content = dom_node.child_text_content();
auto maybe_transform = layout_box().layout_transform();
if (!maybe_transform.has_value())
return;
auto transform = Gfx::AffineTransform(context.svg_transform()).multiply(*maybe_transform);
// FIXME: Support arbitrary path transforms for fonts.
// FIMXE: This assumes transform->x_scale() == transform->y_scale().
auto& scaled_font = layout_node().scaled_font(static_cast<float>(context.device_pixels_per_css_pixel()) * transform.x_scale());
Utf8View text_content { child_text_content };
auto text_offset = context.floored_device_point(dom_node.get_offset().transformed(transform).to_type<CSSPixels>());
// FIXME: Once SVGFormattingContext does text layout this logic should move there.
// https://svgwg.org/svg2-draft/text.html#TextAnchoringProperties
switch (text_element.text_anchor().value_or(SVG::TextAnchor::Start)) {
case SVG::TextAnchor::Start:
// The rendered characters are aligned such that the start of the resulting rendered text is at the initial
// current text position.
break;
case SVG::TextAnchor::Middle: {
// The rendered characters are shifted such that the geometric middle of the resulting rendered text
// (determined from the initial and final current text position before applying the text-anchor property)
// is at the initial current text position.
text_offset.translate_by(-scaled_font.width(text_content) / 2, 0);
break;
}
case SVG::TextAnchor::End: {
// The rendered characters are shifted such that the end of the resulting rendered text (final current text
// position before applying the text-anchor property) is at the initial current text position.
text_offset.translate_by(-scaled_font.width(text_content), 0);
break;
}
default:
VERIFY_NOT_REACHED();
}
painter.draw_text_run(text_offset.to_type<int>(), text_content, scaled_font, layout_node().computed_values().fill()->as_color());
}
}