function &_layout_item($data_id, &$media, $offset, &$context, &$postponed_filter)
{
$this->_reset_page_at_rules();
$this->reset_css();
$font = $this->_cssState[0]->get_property(CSS_FONT);
$font->units2pt(0);
$this->_cssState[0]->set_property(CSS_FONT, $font);
$data = $this->fetch($data_id);
if (is_null($data)) {
$dummy = null;
return $dummy;
}
// Run raw data filters
for ($i = 0; $i < count($this->data_filters); $i++) {
$data = $this->data_filters[$i]->process($data);
}
// Parse the raw data
$box =& $this->parser->process($data->get_content(), $this, $media);
$this->_dispatcher->fire('after-parse', array('pipeline' => &$this, 'document' => &$box, 'media' => $media));
/**
* Run obligatory tree filters
*/
/**
* height-constraint processing filter;
*/
$filter = new PreTreeFilterHeightConstraint();
$filter->process($box, $data, $this);
/**
* Footnote support filter
*/
$filter = new PreTreeFilterFootnotes();
$filter->process($box, $data, $this);
// Run pre-layout tree filters
for ($i = 0, $size = count($this->pre_tree_filters); $i < $size; $i++) {
$this->pre_tree_filters[$i]->process($box, $data, $this);
}
$context = new FlowContext();
/**
* Extract absolute/fixed positioned boxes
*/
$positioned_filter = new PostTreeFilterPositioned($context);
$positioned_filter->process($box, null, $this);
$postponed_filter = new PostTreeFilterPostponed($this->output_driver);
$postponed_filter->process($box, null, $this);
$this->output_driver->prepare();
// Force generation of custom characters for margin boxes
for ($i = 0; $i <= 1; $i++) {
$this->get_page_media(1, $media);
$at_rules = $this->_getMarginBoxes($i, $media);
$boxes = array();
foreach ($at_rules as $at_rule) {
$selector = $at_rule->getSelector();
$boxes[$selector] =& BoxPageMargin::create($this, $at_rule);
}
}
$status = $this->layout_engine->process($box, $media, $this->output_driver, $context);
if (is_null($status)) {
error_log('Pipeline::_process_item: layout routine failed');
$dummy = null;
return $dummy;
}
// Run post-layout tree filters
for ($i = 0; $i < count($this->post_tree_filters); $i++) {
$this->post_tree_filters[$i]->process($box);
}
return $box;
}
function &reflow_margin_boxes($page_no, &$media)
{
$at_rules = $this->_getMarginBoxes($page_no, $media);
$boxes = array();
foreach ($at_rules as $at_rule) {
$selector = $at_rule->getSelector();
$boxes[$selector] =& BoxPageMargin::create($this, $at_rule);
}
foreach ($boxes as $selector => $box) {
$linebox_started = false;
$previous_whitespace = false;
$boxes[$selector]->reflow_whitespace($linebox_started, $previous_whitespace);
$boxes[$selector]->reflow_text($this->output_driver);
}
foreach ($boxes as $selector => $box) {
$boxes[$selector]->reflow($this->output_driver, $media, $boxes);
}
return $boxes;
}