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LibWeb: Align GridFormattingContext::run_track_sizing() with the spec

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1. Stop using -1 to indicate infinity value of growth limit. Just use
   INFINITY for that.
2. More complete implementation of "Expand Flexible Tracks" step.
3. Return AvailableSize from get_free_space: spec says that this
   function can return indefinite size and it is ok.
This commit is contained in:
Aliaksandr Kalenik 2023-05-09 05:03:14 +03:00 • committed by Andreas Kling
parent f2323b5b99
commit fb6b52b3fb
12 changed files with 164 additions and 161 deletions
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214
Userland/Libraries/LibWeb/Layout/GridFormattingContext.cpp
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@ -95,7 +95,7 @@ int GridFormattingContext::count_of_repeated_auto_fill_or_fit_tracks(Vector<CSS:
sum_of_grid_track_sizes += min(resolve_definite_track_size(track_sizing_function.grid_size(), available_space), resolve_definite_track_size(track_sizing_function.grid_size(), available_space));
}
}
return max(1, static_cast<int>((get_free_space(available_space.width, m_grid_columns) / sum_of_grid_track_sizes).value()));
return max(1, static_cast<int>((get_free_space(available_space.width, m_grid_columns).to_px() / sum_of_grid_track_sizes).value()));
// For the purpose of finding the number of auto-repeated tracks in a standalone axis, the UA must
// floor the track size to a UA-specified value to avoid division by zero. It is suggested that this
@ -639,20 +639,24 @@ void GridFormattingContext::run_track_sizing(GridDimension const dimension, Avai
switch (track.min_track_sizing_function.type()) {
// - A fixed sizing function
// Resolve to an absolute length and use that size as the track’s initial base size.
case CSS::GridSize::Type::Length:
case CSS::GridSize::Type::Length: {
if (!track.min_track_sizing_function.length().is_auto())
track.base_size = track.min_track_sizing_function.length().to_px(grid_container());
break;
case CSS::GridSize::Type::Percentage:
}
case CSS::GridSize::Type::Percentage: {
if (track_available_size.is_definite())
track.base_size = track.min_track_sizing_function.percentage().as_fraction() * track_available_size.to_px().value();
break;
}
// - An intrinsic sizing function
// Use an initial base size of zero.
case CSS::GridSize::Type::FlexibleLength:
case CSS::GridSize::Type::MaxContent:
case CSS::GridSize::Type::MinContent:
case CSS::GridSize::Type::MinContent: {
track.base_size = 0;
break;
}
default:
VERIFY_NOT_REACHED();
}
@ -661,36 +665,40 @@ void GridFormattingContext::run_track_sizing(GridDimension const dimension, Avai
switch (track.max_track_sizing_function.type()) {
// - A fixed sizing function
// Resolve to an absolute length and use that size as the track’s initial growth limit.
case CSS::GridSize::Type::Length:
case CSS::GridSize::Type::Length: {
if (!track.max_track_sizing_function.length().is_auto())
track.growth_limit = track.max_track_sizing_function.length().to_px(grid_container());
else
// - An intrinsic sizing function
// Use an initial growth limit of infinity.
track.growth_limit = -1;
track.growth_limit = INFINITY;
break;
case CSS::GridSize::Type::Percentage:
}
case CSS::GridSize::Type::Percentage: {
if (track_available_size.is_definite())
track.growth_limit = track.max_track_sizing_function.percentage().as_fraction() * track_available_size.to_px().value();
break;
}
// - A flexible sizing function
// Use an initial growth limit of infinity.
case CSS::GridSize::Type::FlexibleLength:
track.growth_limit = -1;
case CSS::GridSize::Type::FlexibleLength: {
track.growth_limit = INFINITY;
break;
}
// - An intrinsic sizing function
// Use an initial growth limit of infinity.
case CSS::GridSize::Type::MaxContent:
case CSS::GridSize::Type::MinContent:
track.growth_limit = -1;
case CSS::GridSize::Type::MinContent: {
track.growth_limit = INFINITY;
break;
}
default:
VERIFY_NOT_REACHED();
}
// In all cases, if the growth limit is less than the base size, increase the growth limit to match
// the base size.
if (track.growth_limit != -1 && track.growth_limit < track.base_size)
if (track.growth_limit < track.base_size)
track.growth_limit = track.base_size;
}
@ -834,7 +842,7 @@ void GridFormattingContext::run_track_sizing(GridDimension const dimension, Avai
// In all cases, if a track’s growth limit is now less than its base size, increase the growth limit
// to match the base size.
if (track.growth_limit != -1 && track.growth_limit < track.base_size)
if (track.growth_limit < track.base_size)
track.growth_limit = track.base_size;
++index;
@ -918,6 +926,11 @@ void GridFormattingContext::run_track_sizing(GridDimension const dimension, Avai
// FIXME: 5. If any track still has an infinite growth limit (because, for example, it had no items placed in
// it or it is a flexible track), set its growth limit to its base size.
for (auto& track : tracks) {
if (track.growth_limit == INFINITY) {
track.growth_limit = track.base_size;
}
}
// https://www.w3.org/TR/css-grid-2/#extra-space
// 12.5.1. Distributing Extra Space Across Spanned Tracks
@ -945,7 +958,7 @@ void GridFormattingContext::run_track_sizing(GridDimension const dimension, Avai
for (auto& track : tracks) {
if (track.is_gap)
continue;
track.space_to_distribute = max(CSSPixels(0), (track.growth_limit == -1 ? track.base_size : track.growth_limit) - track.base_size);
track.space_to_distribute = max(CSSPixels(0), track.growth_limit - track.base_size);
}
auto remaining_free_space = track_available_size.is_definite() ? track_available_size.to_px() - sum_of_track_sizes : 0;
@ -1018,27 +1031,36 @@ void GridFormattingContext::run_track_sizing(GridDimension const dimension, Avai
// https://www.w3.org/TR/css-grid-2/#algo-grow-tracks
// 12.6. Maximize Tracks
auto get_free_space_px = [&]() -> CSSPixels {
// For the purpose of this step: if sizing the grid container under a max-content constraint, the
// free space is infinite; if sizing under a min-content constraint, the free space is zero.
auto free_space = get_free_space(track_available_size, tracks);
if (free_space.is_max_content()) {
return INFINITY;
} else if (free_space.is_min_content()) {
return 0;
} else {
return free_space.to_px();
}
};
auto free_space_px = get_free_space_px();
// If the free space is positive, distribute it equally to the base sizes of all tracks, freezing
// tracks as they reach their growth limits (and continuing to grow the unfrozen tracks as needed).
auto free_space = get_free_space(track_available_size, tracks);
while (free_space > 0) {
auto free_space_to_distribute_per_track = free_space / (tracks.size() - count_of_gap_tracks(tracks));
while (free_space_px > 0) {
auto free_space_to_distribute_per_track = free_space_px / (tracks.size() - count_of_gap_tracks(tracks));
for (auto& track : tracks) {
if (track.is_gap)
continue;
if (track.growth_limit != -1)
track.base_size = min(track.growth_limit, track.base_size + free_space_to_distribute_per_track);
else
track.base_size = track.base_size + free_space_to_distribute_per_track;
VERIFY(track.growth_limit != INFINITY);
track.base_size = min(track.growth_limit, track.base_size + free_space_to_distribute_per_track);
}
if (get_free_space(track_available_size, tracks) == free_space)
if (get_free_space_px() == free_space_px)
break;
free_space = get_free_space(track_available_size, tracks);
free_space_px = get_free_space_px();
}
// For the purpose of this step: if sizing the grid container under a max-content constraint, the
// free space is infinite; if sizing under a min-content constraint, the free space is zero.
// If this would cause the grid to be larger than the grid container’s inner size as limited by its
// max-width/height, then redo this step, treating the available grid space as equal to the grid
// container’s inner size when it’s sized to its max-width/height.
@ -1048,84 +1070,65 @@ void GridFormattingContext::run_track_sizing(GridDimension const dimension, Avai
// This step sizes flexible tracks using the largest value it can assign to an fr without exceeding
// the available space.
// First, find the grid’s used flex fraction:
auto flex_factor_sum = 0;
for (auto& track : tracks) {
if (track.min_track_sizing_function.is_flexible_length())
flex_factor_sum++;
}
// See 12.7.1.
// Let flex factor sum be the sum of the flex factors of the flexible tracks. If this value is less
// than 1, set it to 1 instead.
if (flex_factor_sum < 1)
flex_factor_sum = 1;
auto find_the_size_of_an_fr = [&]() -> CSSPixels {
// https://www.w3.org/TR/css-grid-2/#algo-find-fr-size
// See 12.7.1.
CSSPixels sized_column_widths = 0;
for (auto& track : tracks) {
if (!track.min_track_sizing_function.is_flexible_length())
sized_column_widths += track.base_size;
}
// Let leftover space be the space to fill minus the base sizes of the non-flexible grid tracks.
CSSPixels leftover_space = track_available_size.is_definite() ? track_available_size.to_px() - sized_column_widths : 0;
VERIFY(track_available_size.is_definite());
// If the free space is zero or if sizing the grid container under a min-content constraint:
// The used flex fraction is zero.
// FIXME: Add min-content constraint check.
// Otherwise, if the free space is a definite length:
// The used flex fraction is the result of finding the size of an fr using all of the grid tracks
// and a space to fill of the available grid space.
if (leftover_space > 0) {
// 1. Let leftover space be the space to fill minus the base sizes of the non-flexible grid tracks.
auto leftover_space = track_available_size.to_px();
for (auto& track : tracks) {
if (track.min_track_sizing_function.is_flexible_length()) {
// See 12.7.1.
// Let the hypothetical fr size be the leftover space divided by the flex factor sum.
auto hypothetical_fr_size = leftover_space / flex_factor_sum;
// For each flexible track, if the product of the used flex fraction and the track’s flex factor is
// greater than the track’s base size, set its base size to that product.
track.base_size = max(track.base_size, hypothetical_fr_size);
if (!track.max_track_sizing_function.is_flexible_length()) {
leftover_space -= track.base_size;
}
}
// 2. Let flex factor sum be the sum of the flex factors of the flexible tracks.
// If this value is less than 1, set it to 1 instead.
auto flex_factor_sum = 0;
for (auto& track : tracks) {
if (track.max_track_sizing_function.is_flexible_length())
flex_factor_sum++;
}
if (flex_factor_sum < 1)
flex_factor_sum = 1;
// 3. Let the hypothetical fr size be the leftover space divided by the flex factor sum.
auto hypothetical_fr_size = leftover_space / flex_factor_sum;
// FIXME: 4. If the product of the hypothetical fr size and a flexible track’s flex factor is less than the track’s
// base size, restart this algorithm treating all such tracks as inflexible.
// 5. Return the hypothetical fr size.
return hypothetical_fr_size;
};
// First, find the grid’s used flex fraction:
auto flex_fraction = [&]() {
auto free_space = get_free_space(track_available_size, tracks);
// If the free space is zero or if sizing the grid container under a min-content constraint:
if (free_space.to_px() == 0 || track_available_size.is_min_content()) {
// The used flex fraction is zero.
return CSSPixels(0);
// Otherwise, if the free space is a definite length:
} else if (free_space.is_definite()) {
// The used flex fraction is the result of finding the size of an fr using all of the grid tracks and a space
// to fill of the available grid space.
return find_the_size_of_an_fr();
} else {
// FIXME
return CSSPixels(0);
}
}();
// For each flexible track, if the product of the used flex fraction and the track’s flex factor is greater than
// the track’s base size, set its base size to that product.
for (auto& track : tracks) {
if (track.max_track_sizing_function.flexible_length() * flex_fraction > track.base_size) {
track.base_size = track.max_track_sizing_function.flexible_length() * flex_fraction;
}
}
// Otherwise, if the free space is an indefinite length:
// FIXME: No tracks will have indefinite length as per current implementation.
// The used flex fraction is the maximum of:
// For each flexible track, if the flexible track’s flex factor is greater than one, the result of
// dividing the track’s base size by its flex factor; otherwise, the track’s base size.
// For each grid item that crosses a flexible track, the result of finding the size of an fr using
// all the grid tracks that the item crosses and a space to fill of the item’s max-content
// contribution.
// If using this flex fraction would cause the grid to be smaller than the grid container’s
// min-width/height (or larger than the grid container’s max-width/height), then redo this step,
// treating the free space as definite and the available grid space as equal to the grid container’s
// inner size when it’s sized to its min-width/height (max-width/height).
// For each flexible track, if the product of the used flex fraction and the track’s flex factor is
// greater than the track’s base size, set its base size to that product.
// https://drafts.csswg.org/css-grid/#algo-find-fr-size
// 12.7.1. Find the Size of an fr
// This algorithm finds the largest size that an fr unit can be without exceeding the target size.
// It must be called with a set of grid tracks and some quantity of space to fill.
// 1. Let leftover space be the space to fill minus the base sizes of the non-flexible grid tracks.
// 2. Let flex factor sum be the sum of the flex factors of the flexible tracks. If this value is less
// than 1, set it to 1 instead.
// 3. Let the hypothetical fr size be the leftover space divided by the flex factor sum.
// FIXME: 4. If the product of the hypothetical fr size and a flexible track’s flex factor is less than the
// track’s base size, restart this algorithm treating all such tracks as inflexible.
// 5. Return the hypothetical fr size.
// https://drafts.csswg.org/css-grid/#algo-stretch
// 12.8. Stretch auto Tracks
@ -1505,19 +1508,20 @@ bool GridFormattingContext::is_auto_positioned_track(CSS::GridTrackPlacement con
return grid_track_start.is_auto_positioned() && grid_track_end.is_auto_positioned();
}
CSSPixels GridFormattingContext::get_free_space(AvailableSize const& available_size, Vector<TemporaryTrack> const& tracks) const
AvailableSize GridFormattingContext::get_free_space(AvailableSize const& available_size, Vector<TemporaryTrack> const& tracks) const
{
// https://www.w3.org/TR/css-grid-2/#algo-terms
// free space: Equal to the available grid space minus the sum of the base sizes of all the grid
// tracks (including gutters), floored at zero. If available grid space is indefinite, the free
// space is indefinite as well.
// FIXME: do indefinite space
if (!available_size.is_definite())
return 0;
CSSPixels sum_base_sizes = 0;
for (auto& track : tracks)
sum_base_sizes += track.base_size;
return max(CSSPixels(0), available_size.to_px() - sum_base_sizes);
if (available_size.is_definite()) {
CSSPixels sum_base_sizes = 0;
for (auto& track : tracks)
sum_base_sizes += track.base_size;
return AvailableSize::make_definite(max(CSSPixels(0), available_size.to_px() - sum_base_sizes));
}
return available_size;
}
int GridFormattingContext::get_line_index_by_line_name(String const& needle, CSS::GridTrackSizeList grid_track_size_list)