Subversion-Projekte lars-tiefland.php_share

<?php

// $Header: /cvsroot/html2ps/box.br.php,v 1.31 2006/11/11 13:43:51 Konstantin Exp $

require_once(HTML2PS_DIR.'layout.vertical.php');

/**

 * @package HTML2PS

 * @subpackage Document

 *

 * Class defined in this file handles the layout of "BR" HTML elements

 */

/**

 * @package HTML2PS

 * @subpackage Document

 *

 * The BRBox class dessribed the behavior of the BR HTML elements

 *

 * @link http://www.w3.org/TR/html4/struct/text.html#edef-BR HTML 4.01 Forcing a line break: the BR element

 */

class BRBox extends GenericBox {

  /**

   * Create new BR element

   */

  function BRBox() {

    $this->GenericBox();

  }

  function apply_clear($y, &$context) {

    return LayoutVertical::apply_clear($this, $y, $context);

  }

  function out_of_flow() {

    return true;

  }

  function readCSS(&$state) {

    parent::readCSS($state);

    /**

     * We treat BR as a block box; as default value of 'display' property is not 'block', we should

     * set it up manually.

     */

    $this->setCSSProperty(CSS_DISPLAY, 'block');

    $this->_readCSS($state,

                    array(CSS_CLEAR));

    $this->_readCSSLengths($state,

                           array(CSS_MARGIN,

                                 CSS_LINE_HEIGHT));

  }

  /**

   * Create new BR element

   *

   * @return BRBox new BR element object

   */

  function &create(&$pipeline) {

    $box =& new BRBox();

    $box->readCSS($pipeline->get_current_css_state());

    return $box;

  }

  /**

   * BR tags do not take any horizontal space, so if minimal width is zero.

   *

   * @param FlowContext $context The object containing auxiliary flow data; not used here/

   *

   * @return int should always return constant zero.

   */

  function get_min_width(&$context) {

    return 0;

  }

  /**

   * BR tags do not take any horizontal space, so if maximal width is zero.

   *

   * @param FlowContext $context The object containing auxiliary flow data; not used here.

   *

   * @return int should always return constant zero.

   */

  function get_max_width(&$context) {

    return 0;

  }

  /**

   * Layout current BR element. The reflow routine is somewhat similar to the block box reflow routine.

   * As most CSS properties do not apply to BR elements, and BR element always have parent element,

   * the routine is much simpler.

   *

   * @param GenericContainerBox $parent The document element which should be treated as the parent of current element

   * @param FlowContext $context The flow context containing the additional layout data

   *

   * @see FlowContext

   * @see GenericContainerBox

   */

  function reflow(&$parent, &$context) {

    parent::reflow($parent, $context);

    /**

     * Apply 'clear' property; the current Y coordinate can be modified as a result of 'clear'.

     */

    $y = $this->apply_clear($parent->_current_y, $context);

    /**

     * Move current "box" to parent current coordinates. It is REQUIRED, in spite of the generated

     * box itself have no dimensions and will never be drawn, as several other routines uses box coordinates.

     */

    $this->put_left($parent->_current_x);

    $this->put_top($y);

    /**

     * If we met a sequence of BR tags (like <BR><BR>), we'll have an only one item in the parent's

     * line box - whitespace; in this case we'll need to additionally offset current y coordinate by the font size,

     * as whitespace alone does not affect the Y-coordinate.

     */

    if ($parent->line_box_empty()) {

      /**

       * There's no elements in the parent line box at all (e.g in the following situation:

       * <div><br/> .. some text here...</div>); thus, as we're initiating

       * a new line, we need to offset current Y coordinate by the font-size value.

       */

      // Note that _current_y should be modified before 'close_line' call, as it checks for

      // left-floating boxes, causing an issues if line bottom will be placed below

      // float while line top is above float bottom margin

      $font = $this->get_css_property(CSS_FONT);

      $fs = $font->size;

      $parent->_current_y = min($this->get_bottom(),

                                $parent->_current_y - $font->line_height->apply($fs->getPoints()));

      $parent->close_line($context, true);

    } else {

     /**

       * There's at least 1 non-whitespace element in the parent line box, we do not need to use whitespace

       * height; the bottom of the line box is defined by the non-whitespace elements. Top of the new line

       * should be equal to that value.

       */

      $parent->close_line($context, true);

    };

    /**

     * We need to explicitly extend the parent's height, to make it contain the generated line,

     * as we don't know if it have any children _after_ this BR box. If we will not do it,

     * the following code will be rendred incorrectly:

     * <div>...some text...<br/></div>

     */

    $parent->extend_height($parent->_current_y);

  }

  /**

   * Render the BR element; as BR element is non-visual, we do nothing here.

   *

   * @param OutputDriver $driver Current output device driver object.

   *

   * @return boolean true in case the box was successfully rendered

   */

  function show(&$driver) {

    return true;

  }

  /**

   * As BR element generated a line break, it means that a new line box will be started

   * (thus, any whitespaces immediately following the BR tag should not be rendered).

   * To indicate this, we reset the linebox_started flag to 'false' value.

   *

   * @param boolean $linebox_started Flag indicating that a new line box have just started and it already contains

   * some inline elements

   * @param boolean $previous_whitespace Flag indicating that a previous inline element was an whitespace element.

   *

   * @see GenericFormattedBox::reflow_whitespace()

   */

  function reflow_whitespace(&$linebox_started, &$previous_whitespace) {

    $linebox_started = false;

  }

  function get_height() {

    return 0;

  }

  function get_width() {

    return 0;

  }

  /**

   * BRBox may be placed inside InlineBox (white-space: pre)

   */

  function get_ascender() {

    return 0;

  }

  function get_descender() {

    return 0;

  }

  function isLineBreak() {

    return true;

  }

}

?>