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LibWeb: Modernize handling of the CSS flex-basis property

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Instead of a custom struct, use an AK::Variant for flex-basis.
A flex-basis is either `content` or a CSS size value, so we don't need
anything custom for that.

By using a CSS size, we also avoid having to convert in and out of size
in various places, simplifying the code.

This finally gets rid of the "Unsupported main size for flex-basis"
debug spam. :^)
This commit is contained in:
Andreas Kling 2023-06-21 19:39:07 +02:00
parent 8c980cf75b
commit 8648355783
6 changed files with 44 additions and 89 deletions
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67
Userland/Libraries/LibWeb/Layout/FlexFormattingContext.cpp
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@ -27,18 +27,6 @@ template<typename T>
return ::max(min, ::min(value, max));
}
// FIXME: This is a hack helper, remove it when no longer needed.
static CSS::Size to_css_size(CSS::LengthPercentage const& length_percentage)
{
if (length_percentage.is_auto())
return CSS::Size::make_auto();
if (length_percentage.is_length())
return CSS::Size::make_length(length_percentage.length());
if (length_percentage.is_calculated())
return CSS::Size::make_calculated(length_percentage.calculated());
return CSS::Size::make_percentage(length_percentage.percentage());
}
CSSPixels FlexFormattingContext::get_pixel_width(Box const& box, CSS::Size const& size) const
{
auto containing_block_width = containing_block_width_for(box);
@ -537,41 +525,30 @@ void FlexFormattingContext::determine_available_space_for_items(AvailableSpace c
}
// https://drafts.csswg.org/css-flexbox-1/#propdef-flex-basis
CSS::FlexBasisData FlexFormattingContext::used_flex_basis_for_item(FlexItem const& item) const
CSS::FlexBasis FlexFormattingContext::used_flex_basis_for_item(FlexItem const& item) const
{
auto flex_basis = item.box->computed_values().flex_basis();
if (flex_basis.type == CSS::FlexBasis::Auto) {
if (flex_basis.has<CSS::Size>() && flex_basis.get<CSS::Size>().is_auto()) {
// https://drafts.csswg.org/css-flexbox-1/#valdef-flex-basis-auto
// When specified on a flex item, the auto keyword retrieves the value of the main size property as the used flex-basis.
// If that value is itself auto, then the used value is content.
auto const& main_size = is_row_layout() ? item.box->computed_values().width() : item.box->computed_values().height();
if (main_size.is_auto()) {
flex_basis.type = CSS::FlexBasis::Content;
flex_basis = CSS::FlexBasisContent {};
} else {
flex_basis.type = CSS::FlexBasis::LengthPercentage;
if (main_size.is_length()) {
flex_basis.length_percentage = main_size.length();
} else if (main_size.is_percentage()) {
flex_basis.length_percentage = main_size.percentage();
} else if (main_size.is_calculated()) {
flex_basis.length_percentage = CSS::LengthPercentage { main_size.calculated() };
} else {
// FIXME: Support other size values!
dbgln("FIXME: Unsupported main size for flex-basis: {}", main_size);
flex_basis.type = CSS::FlexBasis::Content;
}
flex_basis = main_size;
}
}
// For example, percentage values of flex-basis are resolved against the flex item’s containing block
// (i.e. its flex container); and if that containing block’s size is indefinite,
// the used value for flex-basis is content.
if (flex_basis.type == CSS::FlexBasis::LengthPercentage
&& flex_basis.length_percentage->is_percentage()
if (flex_basis.has<CSS::Size>()
&& flex_basis.get<CSS::Size>().is_percentage()
&& !has_definite_main_size(flex_container())) {
flex_basis.type = CSS::FlexBasis::Content;
flex_basis = CSS::FlexBasisContent {};
}
return flex_basis;
@ -609,20 +586,21 @@ void FlexFormattingContext::determine_flex_base_size_and_hypothetical_main_size(
item.flex_base_size = [&] {
item.used_flex_basis = used_flex_basis_for_item(item);
item.used_flex_basis_is_definite = [&](CSS::FlexBasisData const& flex_basis) -> bool {
if (flex_basis.type != CSS::FlexBasis::LengthPercentage)
item.used_flex_basis_is_definite = [&](CSS::FlexBasis const& flex_basis) -> bool {
if (!flex_basis.has<CSS::Size>())
return false;
if (flex_basis.length_percentage->is_auto())
auto const& size = flex_basis.get<CSS::Size>();
if (size.is_auto() || size.is_min_content() || size.is_max_content() || size.is_fit_content())
return false;
if (flex_basis.length_percentage->is_length())
if (size.is_length())
return true;
bool can_resolve_percentages = is_row_layout()
? m_flex_container_state.has_definite_width()
: m_flex_container_state.has_definite_height();
if (flex_basis.length_percentage->is_calculated()) {
auto const& calc_value = *flex_basis.length_percentage->calculated();
if (size.is_calculated()) {
auto const& calc_value = size.calculated();
if (calc_value.resolves_to_percentage())
return can_resolve_percentages;
if (calc_value.resolves_to_length()) {
@ -632,15 +610,16 @@ void FlexFormattingContext::determine_flex_base_size_and_hypothetical_main_size(
}
return false;
}
VERIFY(flex_basis.length_percentage->is_percentage());
VERIFY(size.is_percentage());
return can_resolve_percentages;
}(item.used_flex_basis);
}(*item.used_flex_basis);
// A. If the item has a definite used flex basis, that’s the flex base size.
if (item.used_flex_basis_is_definite) {
auto const& size = item.used_flex_basis->get<CSS::Size>();
if (is_row_layout())
return get_pixel_width(child_box, to_css_size(item.used_flex_basis.length_percentage.value()));
return get_pixel_height(child_box, to_css_size(item.used_flex_basis.length_percentage.value()));
return get_pixel_width(child_box, size);
return get_pixel_height(child_box, size);
}
// B. If the flex item has ...
@ -648,7 +627,7 @@ void FlexFormattingContext::determine_flex_base_size_and_hypothetical_main_size(
// - a used flex basis of content, and
// - a definite cross size,
if (item.box->has_preferred_aspect_ratio()
&& item.used_flex_basis.type == CSS::FlexBasis::Content
&& item.used_flex_basis->has<CSS::FlexBasisContent>()
&& has_definite_cross_size(item.box)) {
// flex_base_size is calculated from definite cross size and intrinsic aspect ratio
return adjust_main_size_through_aspect_ratio_for_cross_size_min_max_constraints(
@ -662,7 +641,7 @@ void FlexFormattingContext::determine_flex_base_size_and_hypothetical_main_size(
// and the flex container is being sized under a min-content or max-content constraint
// (e.g. when performing automatic table layout [CSS21]), size the item under that constraint.
// The flex base size is the item’s resulting main size.
if (item.used_flex_basis.type == CSS::FlexBasis::Content && m_available_space_for_items->main.is_intrinsic_sizing_constraint()) {
if (item.used_flex_basis->has<CSS::FlexBasisContent>() && m_available_space_for_items->main.is_intrinsic_sizing_constraint()) {
if (m_available_space_for_items->main.is_min_content())
return calculate_min_content_main_size(item);
return calculate_max_content_main_size(item);
@ -672,7 +651,7 @@ void FlexFormattingContext::determine_flex_base_size_and_hypothetical_main_size(
// the available main size is infinite, and the flex item’s inline axis is parallel to the main axis,
// lay the item out using the rules for a box in an orthogonal flow [CSS3-WRITING-MODES].
// The flex base size is the item’s max-content main size.
if (item.used_flex_basis.type == CSS::FlexBasis::Content
if (item.used_flex_basis->has<CSS::FlexBasisContent>()
// FIXME: && main_size is infinite && inline axis is parallel to the main axis
&& false && false) {
TODO();
@ -704,7 +683,7 @@ void FlexFormattingContext::determine_flex_base_size_and_hypothetical_main_size(
// This means that *all* intrinsic heights computed within a flex formatting context will
// automatically use the fit-content width in case a used width is not known yet.
if (item.used_flex_basis.type == CSS::FlexBasis::Content) {
if (item.used_flex_basis->has<CSS::FlexBasisContent>()) {
return calculate_max_content_main_size(item);
}