servo/components/layout/table.rs

401 lines
18 KiB
Rust

/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
//! CSS table formatting contexts.
#![deny(unsafe_block)]
use block::{BlockFlow, MarginsMayNotCollapse, ISizeAndMarginsComputer};
use block::{ISizeConstraintInput, ISizeConstraintSolution};
use construct::FlowConstructor;
use context::LayoutContext;
use floats::FloatKind;
use flow::{TableFlowClass, FlowClass, Flow, ImmutableFlowUtils};
use fragment::Fragment;
use layout_debug;
use model::{IntrinsicISizes, IntrinsicISizesContribution};
use table_wrapper::{TableLayout, FixedLayout, AutoLayout};
use wrapper::ThreadSafeLayoutNode;
use servo_util::geometry::Au;
use servo_util::logical_geometry::LogicalRect;
use std::cmp::max;
use std::fmt;
use style::computed_values::{LPA_Auto, LPA_Length, LPA_Percentage, table_layout};
use style::CSSFloat;
/// A table flow corresponded to the table's internal table fragment under a table wrapper flow.
/// The properties `position`, `float`, and `margin-*` are used on the table wrapper fragment,
/// not table fragment per CSS 2.1 § 10.5.
#[deriving(Encodable)]
pub struct TableFlow {
pub block_flow: BlockFlow,
/// Information about the inline-sizes of each column.
pub column_inline_sizes: Vec<ColumnInlineSize>,
/// Table-layout property
pub table_layout: TableLayout,
}
impl TableFlow {
pub fn from_node_and_fragment(node: &ThreadSafeLayoutNode,
fragment: Fragment)
-> TableFlow {
let mut block_flow = BlockFlow::from_node_and_fragment(node, fragment);
let table_layout = if block_flow.fragment().style().get_table().table_layout ==
table_layout::fixed {
FixedLayout
} else {
AutoLayout
};
TableFlow {
block_flow: block_flow,
column_inline_sizes: Vec::new(),
table_layout: table_layout
}
}
pub fn from_node(constructor: &mut FlowConstructor,
node: &ThreadSafeLayoutNode)
-> TableFlow {
let mut block_flow = BlockFlow::from_node(constructor, node);
let table_layout = if block_flow.fragment().style().get_table().table_layout ==
table_layout::fixed {
FixedLayout
} else {
AutoLayout
};
TableFlow {
block_flow: block_flow,
column_inline_sizes: Vec::new(),
table_layout: table_layout
}
}
pub fn float_from_node(constructor: &mut FlowConstructor,
node: &ThreadSafeLayoutNode,
float_kind: FloatKind)
-> TableFlow {
let mut block_flow = BlockFlow::float_from_node(constructor, node, float_kind);
let table_layout = if block_flow.fragment().style().get_table().table_layout ==
table_layout::fixed {
FixedLayout
} else {
AutoLayout
};
TableFlow {
block_flow: block_flow,
column_inline_sizes: Vec::new(),
table_layout: table_layout
}
}
/// Update the corresponding value of `self_inline_sizes` if a value of `kid_inline_sizes` has
/// a larger value than one of `self_inline_sizes`. Returns the minimum and preferred inline
/// sizes.
pub fn update_column_inline_sizes(parent_inline_sizes: &mut Vec<ColumnInlineSize>,
child_inline_sizes: &Vec<ColumnInlineSize>)
-> IntrinsicISizes {
let mut total_inline_sizes = IntrinsicISizes::new();
for (parent_sizes, child_sizes) in parent_inline_sizes.iter_mut()
.zip(child_inline_sizes.iter()) {
*parent_sizes = ColumnInlineSize {
minimum_length: max(parent_sizes.minimum_length, child_sizes.minimum_length),
percentage: parent_sizes.greatest_percentage(child_sizes),
preferred: max(parent_sizes.preferred, child_sizes.preferred),
constrained: parent_sizes.constrained || child_sizes.constrained
};
total_inline_sizes.minimum_inline_size = total_inline_sizes.minimum_inline_size +
parent_sizes.minimum_length;
total_inline_sizes.preferred_inline_size = total_inline_sizes.preferred_inline_size +
parent_sizes.preferred;
}
total_inline_sizes
}
/// Assign block-size for table flow.
///
/// TODO(#2014, pcwalton): This probably doesn't handle margin collapse right.
///
/// inline(always) because this is only ever called by in-order or non-in-order top-level
/// methods
#[inline(always)]
fn assign_block_size_table_base<'a>(&mut self, layout_context: &'a LayoutContext<'a>) {
self.block_flow.assign_block_size_block_base(layout_context, MarginsMayNotCollapse);
}
pub fn build_display_list_table(&mut self, layout_context: &LayoutContext) {
debug!("build_display_list_table: same process as block flow");
self.block_flow.build_display_list_block(layout_context);
}
}
impl Flow for TableFlow {
fn class(&self) -> FlowClass {
TableFlowClass
}
fn as_table<'a>(&'a mut self) -> &'a mut TableFlow {
self
}
fn as_immutable_table<'a>(&'a self) -> &'a TableFlow {
self
}
fn as_block<'a>(&'a mut self) -> &'a mut BlockFlow {
&mut self.block_flow
}
fn column_inline_sizes<'a>(&'a mut self) -> &'a mut Vec<ColumnInlineSize> {
&mut self.column_inline_sizes
}
/// The specified column inline-sizes are set from column group and the first row for the fixed
/// table layout calculation.
/// The maximum min/pref inline-sizes of each column are set from the rows for the automatic
/// table layout calculation.
fn bubble_inline_sizes(&mut self) {
let _scope = layout_debug_scope!("table::bubble_inline_sizes {:x}",
self.block_flow.base.debug_id());
let mut computation = IntrinsicISizesContribution::new();
let mut did_first_row = false;
for kid in self.block_flow.base.child_iter() {
debug_assert!(kid.is_proper_table_child());
if kid.is_table_colgroup() {
for specified_inline_size in kid.as_table_colgroup().inline_sizes.iter() {
self.column_inline_sizes.push(ColumnInlineSize {
minimum_length: match *specified_inline_size {
LPA_Auto | LPA_Percentage(_) => Au(0),
LPA_Length(length) => length,
},
percentage: match *specified_inline_size {
LPA_Auto | LPA_Length(_) => 0.0,
LPA_Percentage(percentage) => percentage,
},
preferred: Au(0),
constrained: false,
})
}
} else if kid.is_table_rowgroup() || kid.is_table_row() {
// Read column inline-sizes from the table-row-group/table-row, and assign
// inline-size=0 for the columns not defined in the column group.
// FIXME: Need to read inline-sizes from either table-header-group OR the first
// table-row.
match self.table_layout {
FixedLayout => {
// Fixed table layout only looks at the first row.
if !did_first_row {
did_first_row = true;
for child_column_inline_size in kid.column_inline_sizes().iter() {
self.column_inline_sizes.push(*child_column_inline_size);
}
}
}
AutoLayout => {
let child_column_inline_sizes = kid.column_inline_sizes();
let mut child_intrinsic_sizes =
TableFlow::update_column_inline_sizes(&mut self.column_inline_sizes,
child_column_inline_sizes);
// Add new columns if processing this row caused us to discover them.
let child_column_count = child_column_inline_sizes.len();
let parent_column_count = self.column_inline_sizes.len();
debug!("table until the previous row has {} column(s) and this row has {} \
column(s)",
parent_column_count,
child_column_count);
self.column_inline_sizes.reserve(child_column_count);
for i in range(parent_column_count, child_column_count) {
let inline_size_for_new_column = (*child_column_inline_sizes)[i];
child_intrinsic_sizes.minimum_inline_size =
child_intrinsic_sizes.minimum_inline_size +
inline_size_for_new_column.minimum_length;
child_intrinsic_sizes.preferred_inline_size =
child_intrinsic_sizes.preferred_inline_size +
inline_size_for_new_column.preferred;
self.column_inline_sizes.push(inline_size_for_new_column);
}
computation.union_block(&child_intrinsic_sizes)
}
}
}
}
self.block_flow.base.intrinsic_inline_sizes = computation.finish()
}
/// Recursively (top-down) determines the actual inline-size of child contexts and fragments.
/// When called on this context, the context has had its inline-size set by the parent context.
fn assign_inline_sizes(&mut self, layout_context: &LayoutContext) {
let _scope = layout_debug_scope!("table::assign_inline_sizes {:x}",
self.block_flow.base.debug_id());
debug!("assign_inline_sizes({}): assigning inline_size for flow", "table");
// The position was set to the containing block by the flow's parent.
let containing_block_inline_size = self.block_flow.base.block_container_inline_size;
let mut num_unspecified_inline_sizes = 0;
let mut total_column_inline_size = Au(0);
for column_inline_size in self.column_inline_sizes.iter() {
let this_column_inline_size = column_inline_size.minimum_length;
if this_column_inline_size == Au(0) {
num_unspecified_inline_sizes += 1
} else {
total_column_inline_size = total_column_inline_size + this_column_inline_size
}
}
let inline_size_computer = InternalTable;
inline_size_computer.compute_used_inline_size(&mut self.block_flow,
layout_context,
containing_block_inline_size);
let inline_start_content_edge = self.block_flow.fragment.border_padding.inline_start;
let padding_and_borders = self.block_flow.fragment.border_padding.inline_start_end();
let content_inline_size =
self.block_flow.fragment.border_box.size.inline - padding_and_borders;
match self.table_layout {
FixedLayout => {
// In fixed table layout, we distribute extra space among the unspecified columns
// if there are any, or among all the columns if all are specified.
if total_column_inline_size < content_inline_size &&
num_unspecified_inline_sizes == 0 {
let extra_column_inline_size = content_inline_size;
(content_inline_size - total_column_inline_size) /
(self.column_inline_sizes.len() as i32);
for column_inline_size in self.column_inline_sizes.iter_mut() {
column_inline_size.minimum_length = column_inline_size.minimum_length +
extra_column_inline_size;
column_inline_size.percentage = 0.0;
}
} else if num_unspecified_inline_sizes != 0 {
let extra_column_inline_size =
(content_inline_size - total_column_inline_size) /
num_unspecified_inline_sizes;
for column_inline_size in self.column_inline_sizes.iter_mut() {
if column_inline_size.minimum_length == Au(0) &&
column_inline_size.percentage == 0.0 {
column_inline_size.minimum_length = extra_column_inline_size /
num_unspecified_inline_sizes
}
column_inline_size.percentage = 0.0;
}
}
}
_ => {}
}
// As tables are always wrapped inside a table wrapper, they are never impacted by floats.
self.block_flow.base.flags.set_impacted_by_left_floats(false);
self.block_flow.base.flags.set_impacted_by_right_floats(false);
self.block_flow.propagate_assigned_inline_size_to_children(
inline_start_content_edge,
content_inline_size,
Some(self.column_inline_sizes.as_slice()));
}
fn assign_block_size<'a>(&mut self, ctx: &'a LayoutContext<'a>) {
debug!("assign_block_size: assigning block_size for table");
self.assign_block_size_table_base(ctx);
}
fn compute_absolute_position(&mut self) {
self.block_flow.compute_absolute_position()
}
fn generated_containing_block_rect(&self) -> LogicalRect<Au> {
self.block_flow.generated_containing_block_rect()
}
fn update_late_computed_inline_position_if_necessary(&mut self, inline_position: Au) {
self.block_flow.update_late_computed_inline_position_if_necessary(inline_position)
}
fn update_late_computed_block_position_if_necessary(&mut self, block_position: Au) {
self.block_flow.update_late_computed_block_position_if_necessary(block_position)
}
}
impl fmt::Show for TableFlow {
/// Outputs a debugging string describing this table flow.
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
write!(f, "TableFlow: {}", self.block_flow)
}
}
/// Table, TableRowGroup, TableRow, TableCell types.
/// Their inline-sizes are calculated in the same way and do not have margins.
pub struct InternalTable;
impl ISizeAndMarginsComputer for InternalTable {
/// Compute the used value of inline-size, taking care of min-inline-size and max-inline-size.
///
/// CSS Section 10.4: Minimum and Maximum inline-sizes
fn compute_used_inline_size(&self,
block: &mut BlockFlow,
ctx: &LayoutContext,
parent_flow_inline_size: Au) {
let input = self.compute_inline_size_constraint_inputs(block,
parent_flow_inline_size,
ctx);
let solution = self.solve_inline_size_constraints(block, &input);
self.set_inline_size_constraint_solutions(block, solution);
}
/// Solve the inline-size and margins constraints for this block flow.
fn solve_inline_size_constraints(&self, _: &mut BlockFlow, input: &ISizeConstraintInput)
-> ISizeConstraintSolution {
ISizeConstraintSolution::new(input.available_inline_size, Au(0), Au(0))
}
}
/// Information about the inline sizes of columns within a table.
///
/// During table inline-size bubbling, we might need to store both a percentage constraint and a
/// specific width constraint. For instance, one cell might say that it wants to be 100 pixels wide
/// in the inline direction and another cell might say that it wants to take up 20% of the inline-
/// size of the table. Now because we bubble up these constraints during the bubble-inline-sizes
/// phase of layout, we don't know yet how wide the table is ultimately going to be in the inline
/// direction. As we need to pick the maximum width of all cells for a column (in this case, the
/// maximum of 100 pixels and 20% of the table), the preceding constraint means that we must
/// potentially store both a specified width *and* a specified percentage, so that the inline-size
/// assignment phase of layout will know which one to pick.
#[deriving(Clone, Encodable, Show)]
pub struct ColumnInlineSize {
/// The preferred intrinsic inline size.
pub preferred: Au,
/// The largest specified size of this column as a length.
pub minimum_length: Au,
/// The largest specified size of this column as a percentage (`width` property).
pub percentage: CSSFloat,
/// Whether the column inline size is *constrained* per INTRINSIC § 4.1.
pub constrained: bool,
}
impl ColumnInlineSize {
/// Returns the true minimum size of this column, given the containing block's inline size.
/// Beware that this is generally only correct for fixed table layout. (Compare CSS 2.1 §
/// 17.5.2.1 with the algorithm in INTRINSIC § 4.)
pub fn minimum(&self, containing_block_inline_size: Au) -> Au {
max(self.minimum_length, containing_block_inline_size.scale_by(self.percentage))
}
/// Returns the higher of the two percentages specified in `self` and `other`.
pub fn greatest_percentage(&self, other: &ColumnInlineSize) -> CSSFloat {
if self.percentage > other.percentage {
self.percentage
} else {
other.percentage
}
}
}