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LibWeb: Allow multiple text-decoration-lines

The spec grammar for `text-decoration-line` is:

`none | [ underline || overline || line-through || blink ]`

Which means that it's either `none`, or any combination of the other
values. This patch makes that parse for `text-decoration-line` and
`text-decoration`, stores the results as a Vector, and adjusts
`paint_text_decoration()` to run as a loop over all the values that are
provided.

As noted, storing a Vector of values is a bit wasteful, as they could be
stored as flags in a single `u8`. But I was getting too confused trying
to do that in a nice way.
This commit is contained in:
Sam Atkins 2022-04-14 16:22:35 +01:00 committed by Andreas Kling
parent 85da8cbb07
commit 7c91fda088
9 changed files with 142 additions and 66 deletions

View file

@ -289,36 +289,11 @@ static void paint_cursor_if_needed(PaintContext& context, Layout::TextNode const
static void paint_text_decoration(Gfx::Painter& painter, Layout::Node const& text_node, Layout::LineBoxFragment const& fragment)
{
Gfx::IntPoint line_start_point {};
Gfx::IntPoint line_end_point {};
auto& font = fragment.layout_node().font();
auto fragment_box = enclosing_int_rect(fragment.absolute_rect());
auto glyph_height = font.pixel_size();
auto baseline = fragment_box.height() / 2 - (glyph_height + 4) / 2 + glyph_height;
switch (text_node.computed_values().text_decoration_line()) {
case CSS::TextDecorationLine::None:
return;
case CSS::TextDecorationLine::Underline:
line_start_point = fragment_box.top_left().translated(0, baseline + 2);
line_end_point = fragment_box.top_right().translated(0, baseline + 2);
break;
case CSS::TextDecorationLine::Overline:
line_start_point = fragment_box.top_left().translated(0, baseline - glyph_height);
line_end_point = fragment_box.top_right().translated(0, baseline - glyph_height);
break;
case CSS::TextDecorationLine::LineThrough: {
auto x_height = font.x_height();
line_start_point = fragment_box.top_left().translated(0, baseline - x_height / 2);
line_end_point = fragment_box.top_right().translated(0, baseline - x_height / 2);
break;
}
case CSS::TextDecorationLine::Blink:
// Conforming user agents may simply not blink the text
return;
}
auto line_color = text_node.computed_values().text_decoration_color();
int line_thickness = [&] {
@ -329,38 +304,66 @@ static void paint_text_decoration(Gfx::Painter& painter, Layout::Node const& tex
return computed_thickness.to_px(text_node);
}();
switch (text_node.computed_values().text_decoration_style()) {
case CSS::TextDecorationStyle::Solid:
painter.draw_line(line_start_point, line_end_point, line_color, line_thickness, Gfx::Painter::LineStyle::Solid);
break;
case CSS::TextDecorationStyle::Double:
switch (text_node.computed_values().text_decoration_line()) {
auto text_decoration_lines = text_node.computed_values().text_decoration_line();
for (auto line : text_decoration_lines) {
Gfx::IntPoint line_start_point {};
Gfx::IntPoint line_end_point {};
switch (line) {
case CSS::TextDecorationLine::None:
return;
case CSS::TextDecorationLine::Underline:
line_start_point = fragment_box.top_left().translated(0, baseline + 2);
line_end_point = fragment_box.top_right().translated(0, baseline + 2);
break;
case CSS::TextDecorationLine::Overline:
line_start_point.translate_by(0, -line_thickness - 1);
line_end_point.translate_by(0, -line_thickness - 1);
line_start_point = fragment_box.top_left().translated(0, baseline - glyph_height);
line_end_point = fragment_box.top_right().translated(0, baseline - glyph_height);
break;
case CSS::TextDecorationLine::LineThrough:
line_start_point.translate_by(0, -line_thickness / 2);
line_end_point.translate_by(0, -line_thickness / 2);
case CSS::TextDecorationLine::LineThrough: {
auto x_height = font.x_height();
line_start_point = fragment_box.top_left().translated(0, baseline - x_height / 2);
line_end_point = fragment_box.top_right().translated(0, baseline - x_height / 2);
break;
default:
VERIFY_NOT_REACHED();
}
case CSS::TextDecorationLine::Blink:
// Conforming user agents may simply not blink the text
return;
}
painter.draw_line(line_start_point, line_end_point, line_color, line_thickness);
painter.draw_line(line_start_point.translated(0, line_thickness + 1), line_end_point.translated(0, line_thickness + 1), line_color, line_thickness);
break;
case CSS::TextDecorationStyle::Dashed:
painter.draw_line(line_start_point, line_end_point, line_color, line_thickness, Gfx::Painter::LineStyle::Dashed);
break;
case CSS::TextDecorationStyle::Dotted:
painter.draw_line(line_start_point, line_end_point, line_color, line_thickness, Gfx::Painter::LineStyle::Dotted);
break;
case CSS::TextDecorationStyle::Wavy:
painter.draw_triangle_wave(line_start_point, line_end_point, line_color, line_thickness + 1, line_thickness);
break;
switch (text_node.computed_values().text_decoration_style()) {
case CSS::TextDecorationStyle::Solid:
painter.draw_line(line_start_point, line_end_point, line_color, line_thickness, Gfx::Painter::LineStyle::Solid);
break;
case CSS::TextDecorationStyle::Double:
switch (line) {
case CSS::TextDecorationLine::Underline:
break;
case CSS::TextDecorationLine::Overline:
line_start_point.translate_by(0, -line_thickness - 1);
line_end_point.translate_by(0, -line_thickness - 1);
break;
case CSS::TextDecorationLine::LineThrough:
line_start_point.translate_by(0, -line_thickness / 2);
line_end_point.translate_by(0, -line_thickness / 2);
break;
default:
VERIFY_NOT_REACHED();
}
painter.draw_line(line_start_point, line_end_point, line_color, line_thickness);
painter.draw_line(line_start_point.translated(0, line_thickness + 1), line_end_point.translated(0, line_thickness + 1), line_color, line_thickness);
break;
case CSS::TextDecorationStyle::Dashed:
painter.draw_line(line_start_point, line_end_point, line_color, line_thickness, Gfx::Painter::LineStyle::Dashed);
break;
case CSS::TextDecorationStyle::Dotted:
painter.draw_line(line_start_point, line_end_point, line_color, line_thickness, Gfx::Painter::LineStyle::Dotted);
break;
case CSS::TextDecorationStyle::Wavy:
painter.draw_triangle_wave(line_start_point, line_end_point, line_color, line_thickness + 1, line_thickness);
break;
}
}
}