Why does this code to center text in PDF format using the PHP Zend_Pdf library not work?

Question

I am trying to dynamically create PDF documents on the server and send them to the client using the Zend_Pdf library. All text in PDF format should be centered on the page, which will have the size of the letters, landscape. Using the functions that I found several times on different sites, I had a problem - the excuse of the center is disabled. All text appears too far to the left. Here is my code:

<? require('Zend/Pdf.php'); $font = Zend_Pdf_Font::fontWithName(Zend_Pdf_Font::FONT_HELVETICA); $pdf = new Zend_Pdf(); // Create a new page, add to page listing $pdfPage = $pdf->newPage(Zend_Pdf_Page::SIZE_LETTER_LANDSCAPE); $pdf->pages[] = $pdfPage; // Add certify that $pdfPage->setFont($font, 15.75); drawCenteredText($pdfPage, "THIS IS TO CERTIFY THAT", 378); // Add name $pdfPage->setFont($font, 39.75); drawCenteredText($pdfPage, "Example Name", 314.25); // Headers header("Content-type: application/pdf"); header("Content-Disposition: inline; filename=\"cert.pdf\""); header('Content-Transfer-Encoding: binary'); header('Accept-Ranges: bytes'); // Output PDF echo $pdf->render(); function drawCenteredText($page, $text, $bottom) { $text_width = getTextWidth($text, $page->getFont(), $page->getFontSize()); $box_width = $page->getWidth(); $left = ($box_width - $text_width) / 2; $page->drawText($text, $left, $bottom, 'UTF-8'); } function getTextWidth($text, $font, $font_size) { $drawing_text = iconv('', 'UTF-8', $text); $characters = array(); for ($i = 0; $i < strlen($drawing_text); $i++) { $characters[] = (ord($drawing_text[$i++]) << 8) | ord ($drawing_text[$i]); } $glyphs = $font->glyphNumbersForCharacters($characters); $widths = $font->widthsForGlyphs($glyphs); $text_width = (array_sum($widths) / $font->getUnitsPerEm()) * $font_size; return $text_width; } ?> 

... and this is the result.

Answer 1

If someone else encounters a similar problem, the problem is here:

 function getTextWidth($text, $font, $font_size) { $drawing_text = iconv('', 'UTF-8', $text); $characters = array(); for ($i = 0; $i < strlen($drawing_text); $i++) { $characters[] = (ord($drawing_text[$i++]) << 8) | ord ($drawing_text[$i]); } $glyphs = $font->glyphNumbersForCharacters($characters); $widths = $font->widthsForGlyphs($glyphs); $text_width = (array_sum($widths) / $font->getUnitsPerEm()) * $font_size; return $text_width; } 

When creating an array of characters, characters are loaded incorrectly - 8 bits, not 16.

 $characters[] = ord ($drawing_text[$i]); 

This solves the problem and correctly calculates the width of the text.

Answer 2

try using this function:

 /** * Return length of generated string in points * * @param string $text * @param Zend_Pdf_Resource_Font|Zend_Pdf_Page $font * @param int $fontSize * @return double */ public static function getTextWidth($text, $resource, $fontSize = null/*, $encoding = null*/) { //if( $encoding == null ) $encoding = 'UTF-8'; if( $resource instanceof Zend_Pdf_Page ){ $font = $resource->getFont(); $fontSize = $resource->getFontSize(); }elseif( $resource instanceof Zend_Pdf_Resource_Font ){ $font = $resource; if( $fontSize === null ) throw new Exception('The fontsize is unknown'); } if( !$font instanceof Zend_Pdf_Resource_Font ){ throw new Exception('Invalid resource passed'); } $drawingText = $text;//iconv ( '', $encoding, $text ); $characters = array (); for($i = 0; $i < strlen ( $drawingText ); $i ++) { $characters [] = ord ( $drawingText [$i] ); } $glyphs = $font->glyphNumbersForCharacters ( $characters ); $widths = $font->widthsForGlyphs ( $glyphs ); $textWidth = (array_sum ( $widths ) / $font->getUnitsPerEm ()) * $fontSize; return $textWidth; } 

and name it the rendering function, for example:

 if ($this->getAlign() == self::TEXT_ALIGN_CENTER) { $x = ($currentPage->getWidth() - $this->getTextWidth($text, $currentPage)) / 2; } ... $currentPage->drawText($text, $x, $y, ...);