PHP Frame::get_prev_sibling方法代码示例

 /**
  * @return Frame_Decorator
  */
 function get_prev_sibling()
 {
     $s = $this->_frame->get_prev_sibling();
     if ($s && $deco = $s->get_decorator()) {
         while ($tmp = $deco->get_decorator())
             $deco = $tmp;
         return $deco;
     } else if ($s)
         return $s;
     else
         return null;
 }

 /**
  * @return Frame_Decorator
  */
 function get_prev_sibling()
 {
     $s = $this->_frame->get_prev_sibling();
     if ($s && ($deco = $s->get_decorator())) {
         while ($tmp = $deco->get_decorator()) {
             $deco = $tmp;
         }
         return $deco;
     } else {
         if ($s) {
             return $s;
         }
     }
     return null;
 }

 /**
  * Check if $frame will fit on the page.  If the frame does not fit,
  * the frame tree is modified so that a page break occurs in the
  * correct location.
  *
  * @param Frame $frame the frame to check
  * @return Frame the frame following the page break
  */
 function check_page_break(Frame $frame)
 {
     // Do not split if we have already or if the frame was already
     // pushed to the next page (prevents infinite loops)
     if ($this->_page_full || $frame->_already_pushed) {
         return false;
     }
     // If the frame is absolute of fixed it shouldn't break
     $p = $frame;
     do {
         if ($p->is_absolute()) {
             return false;
         }
     } while ($p = $p->get_parent());
     $margin_height = $frame->get_margin_height();
     // FIXME If the row is taller than the page and
     // if it the first of the page, we don't break
     if ($frame->get_style()->display === "table-row" && !$frame->get_prev_sibling() && $margin_height > $this->get_margin_height()) {
         return false;
     }
     // Determine the frame's maximum y value
     $max_y = $frame->get_position("y") + $margin_height;
     // If a split is to occur here, then the bottom margins & paddings of all
     // parents of $frame must fit on the page as well:
     $p = $frame->get_parent();
     while ($p) {
         $style = $p->get_style();
         $max_y += $style->length_in_pt(array($style->margin_bottom, $style->padding_bottom, $style->border_bottom_width));
         $p = $p->get_parent();
     }
     // Check if $frame flows off the page
     if ($max_y <= $this->_bottom_page_margin) {
         // no: do nothing
         return false;
     }
     dompdf_debug("page-break", "check_page_break");
     dompdf_debug("page-break", "in_table: " . $this->_in_table);
     // yes: determine page break location
     $iter = $frame;
     $flg = false;
     $in_table = $this->_in_table;
     dompdf_debug("page-break", "Starting search");
     while ($iter) {
         //       echo "\nbacktrack: " .$iter->get_node()->nodeName ." ".spl_object_hash($iter->get_node()). "";
         if ($iter === $this) {
             dompdf_debug("page-break", "reached root.");
             // We've reached the root in our search.  Just split at $frame.
             break;
         }
         if ($this->_page_break_allowed($iter)) {
             dompdf_debug("page-break", "break allowed, splitting.");
             $iter->split(null, true);
             $this->_page_full = true;
             $this->_in_table = $in_table;
             $frame->_already_pushed = true;
             return true;
         }
         if (!$flg && ($next = $iter->get_last_child())) {
             dompdf_debug("page-break", "following last child.");
             if ($next->is_table()) {
                 $this->_in_table++;
             }
             $iter = $next;
             continue;
         }
         if ($next = $iter->get_prev_sibling()) {
             dompdf_debug("page-break", "following prev sibling.");
             if ($next->is_table() && !$iter->is_table()) {
                 $this->_in_table++;
             } else {
                 if (!$next->is_table() && $iter->is_table()) {
                     $this->_in_table--;
                 }
             }
             $iter = $next;
             $flg = false;
             continue;
         }
         if ($next = $iter->get_parent()) {
             dompdf_debug("page-break", "following parent.");
             if ($iter->is_table()) {
                 $this->_in_table--;
             }
             $iter = $next;
             $flg = true;
             continue;
         }
         break;
     }
     $this->_in_table = $in_table;
     // No valid page break found.  Just break at $frame.
     dompdf_debug("page-break", "no valid break found, just splitting.");
//.........这里部分代码省略.........

 /**
  * Determine if a page break is allowed before $frame
  * http://www.w3.org/TR/CSS21/page.html#allowed-page-breaks
  *
  * In the normal flow, page breaks can occur at the following places:
  *
  *    1. In the vertical margin between block boxes. When a page
  *    break occurs here, the used values of the relevant
  *    'margin-top' and 'margin-bottom' properties are set to '0'.
  *    2. Between line boxes inside a block box.
  *
  * These breaks are subject to the following rules:
  *
  *   * Rule A: Breaking at (1) is allowed only if the
  *     'page-break-after' and 'page-break-before' properties of
  *     all the elements generating boxes that meet at this margin
  *     allow it, which is when at least one of them has the value
  *     'always', 'left', or 'right', or when all of them are
  *     'auto'.
  *
  *   * Rule B: However, if all of them are 'auto' and the
  *     nearest common ancestor of all the elements has a
  *     'page-break-inside' value of 'avoid', then breaking here is
  *     not allowed.
  *
  *   * Rule C: Breaking at (2) is allowed only if the number of
  *     line boxes between the break and the start of the enclosing
  *     block box is the value of 'orphans' or more, and the number
  *     of line boxes between the break and the end of the box is
  *     the value of 'widows' or more.
  *
  *   * Rule D: In addition, breaking at (2) is allowed only if
  *     the 'page-break-inside' property is 'auto'.
  *
  * If the above doesn't provide enough break points to keep
  * content from overflowing the page boxes, then rules B and D are
  * dropped in order to find additional breakpoints.
  *
  * If that still does not lead to sufficient break points, rules A
  * and C are dropped as well, to find still more break points.
  *
  * We will also allow breaks between table rows.  However, when
  * splitting a table, the table headers should carry over to the
  * next page (but they don't yet).
  *
  * @param Frame $frame the frame to check
  * @return bool true if a break is allowed, false otherwise
  */
 protected function _page_break_allowed(Frame $frame)
 {
     $block_types = array("block", "list-item", "table", "-dompdf-image");
     dompdf_debug("page-break", "_page_break_allowed(" . $frame->get_node()->nodeName . ")");
     $display = $frame->get_style()->display;
     // Block Frames (1):
     if (in_array($display, $block_types)) {
         // Avoid breaks within table-cells
         if ($this->_in_table) {
             dompdf_debug("page-break", "In table: " . $this->_in_table);
             return false;
         }
         // Rules A & B
         if ($frame->get_style()->page_break_before === "avoid") {
             dompdf_debug("page-break", "before: avoid");
             return false;
         }
         // Find the preceeding block-level sibling
         $prev = $frame->get_prev_sibling();
         while ($prev && !in_array($prev->get_style()->display, $block_types)) {
             $prev = $prev->get_prev_sibling();
         }
         // Does the previous element allow a page break after?
         if ($prev && $prev->get_style()->page_break_after === "avoid") {
             dompdf_debug("page-break", "after: avoid");
             return false;
         }
         // If both $prev & $frame have the same parent, check the parent's
         // page_break_inside property.
         $parent = $frame->get_parent();
         if ($prev && $parent && $parent->get_style()->page_break_inside === "avoid") {
             dompdf_debug("page-break", "parent inside: avoid");
             return false;
         }
         // To prevent cascading page breaks when a top-level element has
         // page-break-inside: avoid, ensure that at least one frame is
         // on the page before splitting.
         if ($parent->get_node()->nodeName === "body" && !$prev) {
             // We are the body's first child
             dompdf_debug("page-break", "Body's first child.");
             return false;
         }
         // If the frame is the first block-level frame, use the value from
         // $frame's parent instead.
         if (!$prev && $parent) {
             return $this->_page_break_allowed($parent);
         }
         dompdf_debug("page-break", "block: break allowed");
         return true;
     } else {
         if (in_array($display, Style::$INLINE_TYPES)) {
             // Avoid breaks within table-cells
//.........这里部分代码省略.........

 /**
  * Determine if a page break is allowed before $frame
  *
  * @param Frame $frame the frame to check
  * @return bool true if a break is allowed, false otherwise
  */
 protected function _page_break_allowed(Frame $frame)
 {
     /**
      *
      * http://www.w3.org/TR/CSS21/page.html#allowed-page-breaks
      * /*
      * In the normal flow, page breaks can occur at the following places:
      * 
      *    1. In the vertical margin between block boxes. When a page
      *    break occurs here, the used values of the relevant
      *    'margin-top' and 'margin-bottom' properties are set to '0'.
      *    2. Between line boxes inside a block box.
      * 
      * These breaks are subject to the following rules:
      * 
      *   * Rule A: Breaking at (1) is allowed only if the
      *     'page-break-after' and 'page-break-before' properties of
      *     all the elements generating boxes that meet at this margin
      *     allow it, which is when at least one of them has the value
      *     'always', 'left', or 'right', or when all of them are
      *     'auto'.
      *
      *   * Rule B: However, if all of them are 'auto' and the
      *     nearest common ancestor of all the elements has a
      *     'page-break-inside' value of 'avoid', then breaking here is
      *     not allowed.
      *
      *   * Rule C: Breaking at (2) is allowed only if the number of
      *     line boxes between the break and the start of the enclosing
      *     block box is the value of 'orphans' or more, and the number
      *     of line boxes between the break and the end of the box is
      *     the value of 'widows' or more.
      *
      *   * Rule D: In addition, breaking at (2) is allowed only if
      *     the 'page-break-inside' property is 'auto'.
      * 
      * If the above doesn't provide enough break points to keep
      * content from overflowing the page boxes, then rules B and D are
      * dropped in order to find additional breakpoints.
      * 
      * If that still does not lead to sufficient break points, rules A
      * and C are dropped as well, to find still more break points.
      *
      * [endquote]
      *
      * We will also allow breaks between table rows.  However, when
      * splitting a table, the table headers should carry over to the
      * next page (but they don't yet).
      */
     $block_types = array("block", "list-item", "table");
     //      echo "\nbreak_allowed: " . $frame->get_node()->nodeName ."\n";
     $display = $frame->get_style()->display;
     // Block Frames (1):
     if (in_array($display, $block_types)) {
         // Avoid breaks within table-cells
         if ($this->_in_table) {
             //          echo "In table: " . $this->_in_table ."\n";
             return false;
         }
         // Rules A & B
         if ($frame->get_style()->page_break_before == "avoid") {
             //          echo "before: avoid\n";
             return false;
         }
         // Find the preceeding block-level sibling
         $prev = $frame->get_prev_sibling();
         while ($prev && !in_array($prev->get_style()->display, $block_types)) {
             $prev = $prev->get_prev_sibling();
         }
         // Does the previous element allow a page break after?
         if ($prev && $prev->get_style()->page_break_after == "avoid") {
             //        echo "after: avoid\n";
             return false;
         }
         // If both $prev & $frame have the same parent, check the parent's
         // page_break_inside property.
         $parent = $frame->get_parent();
         if ($prev && $parent && $parent->get_style()->page_break_inside == "avoid") {
             //          echo "parent inside: avoid\n";
             return false;
         }
         // To prevent cascading page breaks when a top-level element has
         // page-break-inside: avoid, ensure that at least one frame is
         // on the page before splitting.
         if ($parent->get_node()->nodeName == "body" && !$prev) {
             // We are the body's first child
             //          echo "Body's first child.\n";
             return false;
         }
         // If the frame is the first block-level frame, use the value from
         // $frame's parent instead.
         if (!$prev && $parent) {
             return $this->_page_break_allowed($parent);
         }
//.........这里部分代码省略.........

 function check_page_break(Frame $frame)
 {
     if ($this->_page_full || $frame->_already_pushed) {
         return false;
     }
     $p = $frame;
     do {
         if ($p->is_absolute()) {
             return false;
         }
     } while ($p = $p->get_parent());
     $margin_height = $frame->get_margin_height();
     if ($frame->get_style()->display === "table-row" && !$frame->get_prev_sibling() && $margin_height > $this->get_margin_height()) {
         return false;
     }
     $max_y = $frame->get_position("y") + $margin_height;
     $p = $frame->get_parent();
     while ($p) {
         $style = $p->get_style();
         $max_y += $style->length_in_pt(array($style->margin_bottom, $style->padding_bottom, $style->border_bottom_width));
         $p = $p->get_parent();
     }
     if ($max_y <= $this->_bottom_page_margin) {
         return false;
     }
     dompdf_debug("page-break", "check_page_break");
     dompdf_debug("page-break", "in_table: " . $this->_in_table);
     $iter = $frame;
     $flg = false;
     $in_table = $this->_in_table;
     dompdf_debug("page-break", "Starting search");
     while ($iter) {
         if ($iter === $this) {
             dompdf_debug("page-break", "reached root.");
             break;
         }
         if ($this->_page_break_allowed($iter)) {
             dompdf_debug("page-break", "break allowed, splitting.");
             $iter->split(null, true);
             $this->_page_full = true;
             $this->_in_table = $in_table;
             $frame->_already_pushed = true;
             return true;
         }
         if (!$flg && ($next = $iter->get_last_child())) {
             dompdf_debug("page-break", "following last child.");
             if ($next->is_table()) {
                 $this->_in_table++;
             }
             $iter = $next;
             continue;
         }
         if ($next = $iter->get_prev_sibling()) {
             dompdf_debug("page-break", "following prev sibling.");
             if ($next->is_table() && !$iter->is_table()) {
                 $this->_in_table++;
             } else {
                 if (!$next->is_table() && $iter->is_table()) {
                     $this->_in_table--;
                 }
             }
             $iter = $next;
             $flg = false;
             continue;
         }
         if ($next = $iter->get_parent()) {
             dompdf_debug("page-break", "following parent.");
             if ($iter->is_table()) {
                 $this->_in_table--;
             }
             $iter = $next;
             $flg = true;
             continue;
         }
         break;
     }
     $this->_in_table = $in_table;
     dompdf_debug("page-break", "no valid break found, just splitting.");
     if ($this->_in_table) {
         $num_tables = $this->_in_table - 1;
         $iter = $frame;
         while ($iter && $num_tables && $iter->get_style()->display !== "table") {
             $iter = $iter->get_parent();
             $num_tables--;
         }
         $iter = $frame;
         while ($iter && $iter->get_style()->display !== "table-row") {
             $iter = $iter->get_parent();
         }
     }
     $frame->split(null, true);
     $this->_page_full = true;
     $frame->_already_pushed = true;
     return true;
 }