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LibWeb: Flexbox: Care more about cross-axis margins

Auto margins are still not supported at all, but this is a good start
into supporting margins on flex items.
The way cross-before (top for row, left for column) is handled is very
naive.
This commit is contained in:
Tobias Christiansen 2021-10-04 13:46:10 +02:00 committed by Andreas Kling
parent 9af85881f5
commit 873e95cb6a

View file

@ -26,11 +26,19 @@ FlexFormattingContext::~FlexFormattingContext()
{
}
struct DirectionAgnosticMargins {
float main_before { 0 };
float main_after { 0 };
float cross_before { 0 };
float cross_after { 0 };
};
struct FlexItem {
Box& box;
float flex_base_size { 0 };
float hypothetical_main_size { 0 };
float hypothetical_cross_size { 0 };
float hypothetical_cross_size_with_margins() { return hypothetical_cross_size + margins.cross_before + margins.cross_after; }
float target_main_size { 0 };
bool frozen { false };
Optional<float> flex_factor {};
@ -40,6 +48,7 @@ struct FlexItem {
float cross_size { 0 };
float main_offset { 0 };
float cross_offset { 0 };
DirectionAgnosticMargins margins {};
bool is_min_violation { false };
bool is_max_violation { false };
};
@ -274,6 +283,20 @@ void FlexFormattingContext::run(Box& box, LayoutMode)
else
box.box_model().margin.bottom = margin;
};
auto populate_specified_margins = [&is_row](FlexItem& item) {
auto width_of_containing_block = item.box.width_of_logical_containing_block();
if (is_row) {
item.margins.main_before = item.box.computed_values().margin().left.resolved_or_zero(item.box, width_of_containing_block).to_px(item.box);
item.margins.main_after = item.box.computed_values().margin().right.resolved_or_zero(item.box, width_of_containing_block).to_px(item.box);
item.margins.cross_before = item.box.computed_values().margin().top.resolved_or_zero(item.box, width_of_containing_block).to_px(item.box);
item.margins.cross_after = item.box.computed_values().margin().bottom.resolved_or_zero(item.box, width_of_containing_block).to_px(item.box);
} else {
item.margins.main_before = item.box.computed_values().margin().left.resolved_or_zero(item.box, width_of_containing_block).to_px(item.box);
item.margins.main_after = item.box.computed_values().margin().right.resolved_or_zero(item.box, width_of_containing_block).to_px(item.box);
item.margins.cross_before = item.box.computed_values().margin().top.resolved_or_zero(item.box, width_of_containing_block).to_px(item.box);
item.margins.cross_after = item.box.computed_values().margin().bottom.resolved_or_zero(item.box, width_of_containing_block).to_px(item.box);
}
};
// 1. Generate anonymous flex items
// More like, sift through the already generated items.
@ -307,7 +330,9 @@ void FlexFormattingContext::run(Box& box, LayoutMode)
return IterationDecision::Continue;
child_box.set_flex_item(true);
flex_items.append({ child_box });
FlexItem flex_item = { child_box };
populate_specified_margins(flex_item);
flex_items.append(move(flex_item));
return IterationDecision::Continue;
});
@ -660,8 +685,8 @@ void FlexFormattingContext::run(Box& box, LayoutMode)
// 8.2
float largest_hypothetical_cross_size = 0;
for (auto& flex_item : flex_line.items) {
if (largest_hypothetical_cross_size < flex_item->hypothetical_cross_size)
largest_hypothetical_cross_size = flex_item->hypothetical_cross_size;
if (largest_hypothetical_cross_size < flex_item->hypothetical_cross_size_with_margins())
largest_hypothetical_cross_size = flex_item->hypothetical_cross_size_with_margins();
}
// 8.3
@ -684,7 +709,6 @@ void FlexFormattingContext::run(Box& box, LayoutMode)
for (auto& flex_line : flex_lines) {
for (auto& flex_item : flex_line.items) {
if (is_cross_auto(flex_item->box) && box.computed_values().align_items() == CSS::AlignItems::Stretch) {
// FIXME: Take margins into account
flex_item->cross_size = flex_line.cross_size;
} else {
flex_item->cross_size = flex_item->hypothetical_cross_size;
@ -758,7 +782,7 @@ void FlexFormattingContext::run(Box& box, LayoutMode)
// 14. Align all flex items along the cross-axis
// FIXME: Get the alignment via "align-self" of the item (which accesses "align-items" of the parent if unset)
// FIXME: Take margins into account
// FIXME: Take better care of margins
float line_cross_offset = 0;
for (auto& flex_line : flex_lines) {
for (auto* flex_item : flex_line.items) {
@ -768,7 +792,7 @@ void FlexFormattingContext::run(Box& box, LayoutMode)
// Fallthrough
case CSS::AlignItems::FlexStart:
case CSS::AlignItems::Stretch:
flex_item->cross_offset = line_cross_offset;
flex_item->cross_offset = line_cross_offset + flex_item->margins.cross_before;
break;
case CSS::AlignItems::FlexEnd:
flex_item->cross_offset = line_cross_offset + flex_line.cross_size - flex_item->cross_size;