/**
* Show fixed positioned block box using the specified output driver
*
* Note that 'show_fixed' is called to box _nested_ to the fixed-positioned boxes too!
* Thus, we need to check whether actual 'position' values is 'fixed' for this box
* and only in that case attempt to move box
*
* @param OutputDriver $driver The output device driver object
*/
function show_fixed(&$driver)
{
$position = $this->get_css_property(CSS_POSITION);
if ($position == POSITION_FIXED) {
/**
* Calculate the distance between the top page edge and top box content edge
*/
$bottom = $this->get_css_property(CSS_BOTTOM);
$top = $this->get_css_property(CSS_TOP);
if (!$top->isAuto()) {
if ($top->isPercentage()) {
$vertical_offset = $driver->getPageMaxHeight() / 100 * $top->getPercentage();
} else {
$vertical_offset = $top->getPoints();
}
} elseif (!$bottom->isAuto()) {
if ($bottom->isPercentage()) {
$vertical_offset = $driver->getPageMaxHeight() * (100 - $bottom->getPercentage()) / 100 - $this->get_height();
} else {
$vertical_offset = $driver->getPageMaxHeight() - $bottom->getPoints() - $this->get_height();
}
} else {
$vertical_offset = 0;
}
/**
* Calculate the distance between the right page edge and right box content edge
*/
$left = $this->get_css_property(CSS_LEFT);
$right = $this->get_css_property(CSS_RIGHT);
if (!$left->isAuto()) {
if ($left->isPercentage()) {
$horizontal_offset = $driver->getPageWidth() / 100 * $left->getPercentage();
} else {
$horizontal_offset = $left->getPoints();
}
} elseif (!$right->isAuto()) {
if ($right->isPercentage()) {
$horizontal_offset = $driver->getPageWidth() * (100 - $right->getPercentage()) / 100 - $this->get_width();
} else {
$horizontal_offset = $driver->getPageWidth() - $right->getPoints() - $this->get_width();
}
} else {
$horizontal_offset = 0;
}
/**
* Offset current box to the required position on the current page (note that
* fixed-positioned element are placed relatively to the viewport - page in our case)
*/
$this->moveto($driver->getPageLeft() + $horizontal_offset, $driver->getPageTop() - $vertical_offset);
}
/**
* After box have benn properly positioned, render it as usual.
*/
return GenericContainerBox::show_fixed($driver);
}
