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2cb0039a13
According to the CSS font matching algorithm specification, it is supposed to be executed for each glyph instead of each text run, as is currently done. This change partially implements this by having the font matching algorithm produce a list of fonts against which each glyph will be tested to find its suitable font. Now, it becomes possible to have per-glyph fallback fonts: if the needed glyph is not present in a font, we can check the subsequent fonts in the list.
79 lines
4.1 KiB
C++
79 lines
4.1 KiB
C++
/*
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* Copyright (c) 2023, Bastiaan van der Plaat <bastiaan.v.d.plaat@gmail.com>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#pragma once
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#include <LibWeb/CSS/Parser/Parser.h>
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#include <LibWeb/CSS/StyleComputer.h>
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#include <LibWeb/CSS/StyleValues/ShorthandStyleValue.h>
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#include <LibWeb/DOM/Document.h>
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#include <LibWeb/HTML/Canvas/CanvasState.h>
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namespace Web::HTML {
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// https://html.spec.whatwg.org/multipage/canvas.html#canvastextdrawingstyles
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template<typename IncludingClass>
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class CanvasTextDrawingStyles {
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public:
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~CanvasTextDrawingStyles() = default;
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DeprecatedString font() const
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{
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// When font style value is empty return default string
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if (!my_drawing_state().font_style_value) {
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return "10px sans-serif";
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}
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// On getting, the font attribute must return the serialized form of the current font of the context (with no 'line-height' component).
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auto const& font_style_value = my_drawing_state().font_style_value->as_shorthand();
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auto font_style = font_style_value.longhand(CSS::PropertyID::FontStyle);
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auto font_weight = font_style_value.longhand(CSS::PropertyID::FontWeight);
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auto font_size = font_style_value.longhand(CSS::PropertyID::FontSize);
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auto font_family = font_style_value.longhand(CSS::PropertyID::FontFamily);
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return DeprecatedString::formatted("{} {} {} {}", font_style->to_string(), font_weight->to_string(), font_size->to_string(), font_family->to_string());
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}
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void set_font(StringView font)
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{
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// The font IDL attribute, on setting, must be parsed as a CSS <'font'> value (but without supporting property-independent style sheet syntax like 'inherit'),
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// and the resulting font must be assigned to the context, with the 'line-height' component forced to 'normal', with the 'font-size' component converted to CSS pixels,
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// and with system fonts being computed to explicit values.
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auto parsing_context = CSS::Parser::ParsingContext { reinterpret_cast<IncludingClass&>(*this).realm() };
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auto font_style_value_result = parse_css_value(parsing_context, font, CSS::PropertyID::Font);
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// If the new value is syntactically incorrect (including using property-independent style sheet syntax like 'inherit' or 'initial'), then it must be ignored, without assigning a new font value.
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if (!font_style_value_result) {
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return;
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}
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my_drawing_state().font_style_value = font_style_value_result.release_nonnull();
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// Load font with font style value properties
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auto const& font_style_value = my_drawing_state().font_style_value->as_shorthand();
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auto& canvas_element = reinterpret_cast<IncludingClass&>(*this).canvas_element();
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auto& font_style = *font_style_value.longhand(CSS::PropertyID::FontStyle);
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auto& font_weight = *font_style_value.longhand(CSS::PropertyID::FontWeight);
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auto& font_stretch = *font_style_value.longhand(CSS::PropertyID::FontStretch);
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auto& font_size = *font_style_value.longhand(CSS::PropertyID::FontSize);
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auto& font_family = *font_style_value.longhand(CSS::PropertyID::FontFamily);
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auto font_list = canvas_element.document().style_computer().compute_font_for_style_values(&canvas_element, {}, font_family, font_size, font_style, font_weight, font_stretch);
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my_drawing_state().current_font = font_list->first();
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}
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Bindings::CanvasTextAlign text_align() const { return my_drawing_state().text_align; }
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void set_text_align(Bindings::CanvasTextAlign text_align) { my_drawing_state().text_align = text_align; }
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Bindings::CanvasTextBaseline text_baseline() const { return my_drawing_state().text_baseline; }
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void set_text_baseline(Bindings::CanvasTextBaseline text_baseline) { my_drawing_state().text_baseline = text_baseline; }
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protected:
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CanvasTextDrawingStyles() = default;
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private:
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CanvasState::DrawingState& my_drawing_state() { return reinterpret_cast<IncludingClass&>(*this).drawing_state(); }
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CanvasState::DrawingState const& my_drawing_state() const { return reinterpret_cast<IncludingClass const&>(*this).drawing_state(); }
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};
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}
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