How can I wrap text using Imagick in PHP so that it is drawn as multiline text?

Question

The Imagick library in PHP allows you to draw text on top of an image.

How can I tell Imagick to wrap the text based upon some bounded text box, so that the words appear as multiline text rather than a single line?

Answer 1

Usage:

list($lines, $lineHeight) = wordWrapAnnotation($image, $draw, $msg, 140);
for($i = 0; $i < count($lines); $i++)
    $image->annotateImage($draw, $xpos, $ypos + $i*$lineHeight, 0, $lines[$i]);

Function:

/* Implement word wrapping... Ughhh... why is this NOT done for me!!!
    OK... I know the algorithm sucks at efficiency, but it's for short messages, okay?

    Make sure to set the font on the ImagickDraw Object first!
    @param image the Imagick Image Object
    @param draw the ImagickDraw Object
    @param text the text you want to wrap
    @param maxWidth the maximum width in pixels for your wrapped "virtual" text box
    @return an array of lines and line heights
*/
function wordWrapAnnotation(&$image, &$draw, $text, $maxWidth)
{
    $words = explode(" ", $text);
    $lines = array();
    $i = 0;
    $lineHeight = 0;
    while($i < count($words) )
    {
        $currentLine = $words[$i];
        if($i+1 >= count($words))
        {
            $lines[] = $currentLine;
            break;
        }
        //Check to see if we can add another word to this line
        $metrics = $image->queryFontMetrics($draw, $currentLine . ' ' . $words[$i+1]);
        while($metrics['textWidth'] <= $maxWidth)
        {
            //If so, do it and keep doing it!
            $currentLine .= ' ' . $words[++$i];
            if($i+1 >= count($words))
                break;
            $metrics = $image->queryFontMetrics($draw, $currentLine . ' ' . $words[$i+1]);
        }
        //We can't add the next word to this line, so loop to the next line
        $lines[] = $currentLine;
        $i++;
        //Finally, update line height
        if($metrics['textHeight'] > $lineHeight)
            $lineHeight = $metrics['textHeight'];
    }
    return array($lines, $lineHeight);
}

Answer 2

I have been using @Sarke's version successfully for a while, but I noticed there is an infinite loop if a word is longer than the $maxWidth. Here is a version that fixes the infinite loop:

function wordWrapAnnotation($image, $draw, $text, $maxWidth)
{   
    $text = trim($text);

    $words = preg_split('%\s%', $text, -1, PREG_SPLIT_NO_EMPTY);
    $lines = array();
    $i = 0;
    $lineHeight = 0;

    while (count($words) > 0)
    {   
        $metrics = $image->queryFontMetrics($draw, implode(' ', array_slice($words, 0, ++$i)));
        $lineHeight = max($metrics['textHeight'], $lineHeight);

        // check if we have found the word that exceeds the line width
        if ($metrics['textWidth'] > $maxWidth or count($words) < $i) 
        {   
            // handle case where a single word is longer than the allowed line width (just add this as a word on its own line?)
            if ($i == 1)
                $i++;

            $lines[] = implode(' ', array_slice($words, 0, --$i));
            $words = array_slice($words, $i);
            $i = 0;
        }   
    }   

    return array($lines, $lineHeight);
}