/src/FrameReflower/Text.php

<?php
/**
 * @package dompdf
 * @link    http://dompdf.github.com/
 * @author  Benj Carson <benjcarson@digitaljunkies.ca>
 * @author  Fabien Ménager <fabien.menager@gmail.com>
 * @license http://www.gnu.org/copyleft/lesser.html GNU Lesser General Public License
 */
namespace Dompdf\FrameReflower;

use Dompdf\FrameDecorator\Block as BlockFrameDecorator;
use Dompdf\FrameDecorator\Text as TextFrameDecorator;
use Dompdf\FontMetrics;

/**
 * Reflows text frames.
 *
 * @package dompdf
 */
class Text extends AbstractFrameReflower
{

    /**
     * @var BlockFrameDecorator
     */
    protected $_block_parent; // Nearest block-level ancestor

    /**
     * @var TextFrameDecorator
     */
    protected $_frame;

    public static $_whitespace_pattern = "/[ \t\r\n\f]+/u";

    /**
     * @var FontMetrics
     */
    private $fontMetrics;

    /**
     * @param TextFrameDecorator $frame
     * @param FontMetrics $fontMetrics
     */
    public function __construct(TextFrameDecorator $frame, FontMetrics $fontMetrics)
    {
        parent::__construct($frame);
        $this->setFontMetrics($fontMetrics);
    }

    //........................................................................

    protected function _collapse_white_space($text)
    {
        //$text = $this->_frame->get_text();
//     if ( $this->_block_parent->get_current_line_box->w == 0 )
//       $text = ltrim($text, " \n\r\t");
        return preg_replace(self::$_whitespace_pattern, " ", $text);
    }

    //........................................................................

    protected function _line_break($text)
    {
        $style = $this->_frame->get_style();
        $size = $style->font_size;
        $font = $style->font_family;
        $current_line = $this->_block_parent->get_current_line_box();

        // Determine the available width
        $line_width = $this->_frame->get_containing_block("w");
        $current_line_width = $current_line->left + $current_line->w + $current_line->right;

        $available_width = $line_width - $current_line_width;

        // Account for word-spacing
        $word_spacing = $style->length_in_pt($style->word_spacing);
        $char_spacing = $style->length_in_pt($style->letter_spacing);

        // Determine the frame width including margin, padding & border
        $text_width = $this->getFontMetrics()->getTextWidth($text, $font, $size, $word_spacing, $char_spacing);
        $mbp_width =
            $style->length_in_pt(array($style->margin_left,
                $style->border_left_width,
                $style->padding_left,
                $style->padding_right,
                $style->border_right_width,
                $style->margin_right), $line_width);

        $frame_width = $text_width + $mbp_width;

// Debugging:
//    Helpers::pre_r("Text: '" . htmlspecialchars($text). "'");
//    Helpers::pre_r("width: " .$frame_width);
//    Helpers::pre_r("textwidth + delta: $text_width + $mbp_width");
//    Helpers::pre_r("font-size: $size");
//    Helpers::pre_r("cb[w]: " .$line_width);
//    Helpers::pre_r("available width: " . $available_width);
//    Helpers::pre_r("current line width: " . $current_line_width);

//     Helpers::pre_r($words);

        if ($frame_width <= $available_width)
            return false;

        // split the text into words
        $words = preg_split('/([\s-]+)/u', $text, -1, PREG_SPLIT_DELIM_CAPTURE);
        $wc = count($words);

        // Determine the split point
        $width = 0;
        $str = "";
        reset($words);

        // @todo support <shy>, <wbr>
        for ($i = 0; $i < $wc; $i += 2) {
            $word = $words[$i] . (isset($words[$i + 1]) ? $words[$i + 1] : "");
            $word_width = $this->getFontMetrics()->getTextWidth($word, $font, $size, $word_spacing, $char_spacing);
            if ($width + $word_width + $mbp_width > $available_width)
                break;

            $width += $word_width;
            $str .= $word;
        }

        $break_word = ($style->word_wrap === "break-word");

        // The first word has overflowed.   Force it onto the line
        if ($current_line_width == 0 && $width == 0) {

            $s = "";
            $last_width = 0;

            if ($break_word) {
                for ($j = 0; $j < strlen($word); $j++) {
                    $s .= $word[$j];
                    $_width = $this->getFontMetrics()->getTextWidth($s, $font, $size, $word_spacing, $char_spacing);
                    if ($_width > $available_width) {
                        break;
                    }

                    $last_width = $_width;
                }
            }

            if ($break_word && $last_width > 0) {
                $width += $last_width;
                $str .= substr($s, 0, -1);
            } else {
                $width += $word_width;
                $str .= $word;
            }
        }

        $offset = mb_strlen($str);

// More debugging:
//     var_dump($str);
//     print_r("Width: ". $width);
//     print_r("Offset: " . $offset);

        return $offset;

    }

    //........................................................................

    protected function _newline_break($text)
    {

        if (($i = mb_strpos($text, "\n")) === false)
            return false;

        return $i + 1;

    }

    //........................................................................

    protected function _layout_line()
    {
        $frame = $this->_frame;
        $style = $frame->get_style();
        $text = $frame->get_text();
        $size = $style->font_size;
        $font = $style->font_family;

        // Determine the text height
        $style->height = $this->getFontMetrics()->getFontHeight($font, $size);

        $split = false;
        $add_line = false;

        // Handle text transform:
        // http://www.w3.org/TR/CSS21/text.html#propdef-text-transform
        switch (strtolower($style->text_transform)) {
            default:
                break;
            case "capitalize":
                $text = mb_convert_case($text, MB_CASE_TITLE);
                break;
            case "uppercase":
                $text = mb_convert_case($text, MB_CASE_UPPER);
                break;
            case "lowercase":
                $text = mb_convert_case($text, MB_CASE_LOWER);
                break;
        }

        // Handle white-space property:
        // http://www.w3.org/TR/CSS21/text.html#propdef-white-space
        switch ($style->white_space) {

            default:
            case "normal":
                $frame->set_text($text = $this->_collapse_white_space($text));
                if ($text == "")
                    break;

                $split = $this->_line_break($text);
                break;

            case "pre":
                $split = $this->_newline_break($text);
                $add_line = $split !== false;
                break;

            case "nowrap":
                $frame->set_text($text = $this->_collapse_white_space($text));
                break;

            case "pre-wrap":
                $split = $this->_newline_break($text);

                if (($tmp = $this->_line_break($text)) !== false) {
                    $add_line = $split < $tmp;
                    $split = min($tmp, $split);
                } else
                    $add_line = true;

                break;

            case "pre-line":
                // Collapse white-space except for \n
                $frame->set_text($text = preg_replace("/[ \t]+/u", " ", $text));

                if ($text == "")
                    break;

                $split = $this->_newline_break($text);

                if (($tmp = $this->_line_break($text)) !== false) {
                    $add_line = $split < $tmp;
                    $split = min($tmp, $split);
                } else
                    $add_line = true;

                break;

        }

        // Handle degenerate case
        if ($text === "")
            return;

        if ($split !== false) {

            // Handle edge cases
            if ($split == 0 && $text === " ") {
                $frame->set_text("");
                return;
            }

            if ($split == 0) {

                // Trim newlines from the beginning of the line
                //$this->_frame->set_text(ltrim($text, "\n\r"));

                $this->_block_parent->add_line();
                $frame->position();

                // Layout the new line
                $this->_layout_line();

            } else if ($split < mb_strlen($frame->get_text())) {
                // split the line if required
                $frame->split_text($split);

                $t = $frame->get_text();

                // Remove any trailing newlines
                if ($split > 1 && $t[$split - 1] === "\n" && !$frame->is_pre())
                    $frame->set_text(mb_substr($t, 0, -1));

                // Do we need to trim spaces on wrapped lines? This might be desired, however, we
                // can't trim the lines here or the layout will be affected if trimming the line
                // leaves enough space to fit the next word in the text stream (because pdf layout
                // is performed elsewhere).
                /*if (!$this->_frame->get_prev_sibling() && !$this->_frame->get_next_sibling()) {
                  $t = $this->_frame->get_text();
                  $this->_frame->set_text( trim($t) );
                }*/
            }

            if ($add_line) {
                $this->_block_parent->add_line();
                $frame->position();
            }

        } else {

            // Remove empty space from start and end of line, but only where there isn't an inline sibling
            // and the parent node isn't an inline element with siblings
            // FIXME: Include non-breaking spaces?
            $t = $frame->get_text();
            $parent = $frame->get_parent();
            $is_inline_frame = get_class($parent) === 'Inline_Frame_Decorator';

            if ((!$is_inline_frame && !$frame->get_next_sibling()) /* ||
          ( $is_inline_frame && !$parent->get_next_sibling())*/
            ) { // fails <b>BOLD <u>UNDERLINED</u></b> becomes <b>BOLD<u>UNDERLINED</u></b>
                $t = rtrim($t);
            }

            if ((!$is_inline_frame && !$frame->get_prev_sibling()) /* ||
          ( $is_inline_frame && !$parent->get_prev_sibling())*/
            ) { //  <span><span>A<span>B</span> C</span></span> fails (the whitespace is removed)
                $t = ltrim($t);
            }

            $frame->set_text($t);

        }

        // Set our new width
        $width = $frame->recalculate_width();
    }

    //........................................................................

    function reflow(BlockFrameDecorator $block = null)
    {
        $frame = $this->_frame;
        $page = $frame->get_root();
        $page->check_forced_page_break($this->_frame);

        if ($page->is_full())
            return;

        $this->_block_parent = /*isset($block) ? $block : */
            $frame->find_block_parent();

        // Left trim the text if this is the first text on the line and we're
        // collapsing white space
//     if ( $this->_block_parent->get_current_line()->w == 0 &&
//          ($frame->get_style()->white_space !== "pre" ||
//           $frame->get_style()->white_space !== "pre-wrap") ) {
//       $frame->set_text( ltrim( $frame->get_text() ) );
//     }

        $frame->position();

        $this->_layout_line();

        if ($block) {
            $block->add_frame_to_line($frame);
        }
    }

    //........................................................................

    // Returns an array(0 => min, 1 => max, "min" => min, "max" => max) of the
    // minimum and maximum widths of this frame
    function get_min_max_width()
    {
        /*if ( !is_null($this->_min_max_cache)  )
          return $this->_min_max_cache;*/
        $frame = $this->_frame;
        $style = $frame->get_style();
        $this->_block_parent = $frame->find_block_parent();
        $line_width = $frame->get_containing_block("w");

        $str = $text = $frame->get_text();
        $size = $style->font_size;
        $font = $style->font_family;

        $word_spacing = $style->length_in_pt($style->word_spacing);
        $char_spacing = $style->length_in_pt($style->letter_spacing);

        switch ($style->white_space) {

            default:
            case "normal":
                $str = preg_replace(self::$_whitespace_pattern, " ", $str);
            case "pre-wrap":
            case "pre-line":

                // Find the longest word (i.e. minimum length)

                // This technique (using arrays & an anonymous function) is actually
                // faster than doing a single-pass character by character scan.  Heh,
                // yes I took the time to bench it ;)
                $words = array_flip(preg_split("/[\s-]+/u", $str, -1, PREG_SPLIT_DELIM_CAPTURE));
                $root = $this;
                array_walk($words, function(&$val, $str) use ($font, $size, $word_spacing, $char_spacing, $root) {
                    $val = $root->getFontMetrics()->getTextWidth($str, $font, $size, $word_spacing, $char_spacing);
                });

                arsort($words);
                $min = reset($words);
                break;

            case "pre":
                $lines = array_flip(preg_split("/\n/u", $str));
                $root = $this;
                array_walk($lines, function(&$val, $str) use ($font, $size, $word_spacing, $char_spacing, $root) {
                    $val = $root->getFontMetrics()->getTextWidth($str, $font, $size, $word_spacing, $char_spacing);
                });

                arsort($lines);
                $min = reset($lines);
                break;

            case "nowrap":
                $min = $this->getFontMetrics()->getTextWidth($this->_collapse_white_space($str), $font, $size, $word_spacing, $char_spacing);
                break;

        }

        switch ($style->white_space) {

            default:
            case "normal":
            case "nowrap":
                $str = preg_replace(self::$_whitespace_pattern, " ", $text);
                break;

            case "pre-line":
                //XXX: Is this correct?
                $str = preg_replace("/[ \t]+/u", " ", $text);

            case "pre-wrap":
                // Find the longest word (i.e. minimum length)
                $lines = array_flip(preg_split("/\n/", $text));
                $root = $this;
                array_walk($lines, function(&$val, $str) use ($font, $size, $word_spacing, $char_spacing, $root) {
                    $val = $root->getFontMetrics()->getTextWidth($str, $font, $size, $word_spacing, $char_spacing);
                });
                arsort($lines);
                reset($lines);
                $str = key($lines);
                break;

        }

        $max = $this->getFontMetrics()->getTextWidth($str, $font, $size, $word_spacing, $char_spacing);

        $delta = $style->length_in_pt(array($style->margin_left,
            $style->border_left_width,
            $style->padding_left,
            $style->padding_right,
            $style->border_right_width,
            $style->margin_right), $line_width);
        $min += $delta;
        $max += $delta;

        return $this->_min_max_cache = array($min, $max, "min" => $min, "max" => $max);

    }

    /**
     * @param FontMetrics $fontMetrics
     * @return $this
     */
    public function setFontMetrics(FontMetrics $fontMetrics)
    {
        $this->fontMetrics = $fontMetrics;
        return $this;
    }

    /**
     * @return FontMetrics
     */
    public function getFontMetrics()
    {
        return $this->fontMetrics;
    }
}