Imagine watermark example Imagine: http://imagine.readthedocs.org/ https://github.com/avalanche123/Imagine Color Contrast based on: http://www.had2know.com/technology/color-contrast-calculator-web-design.html

watermark.php

$imagine = new Imagine\Gd\Imagine();

$pathPhoto = 'photo.jpg';
$pathThumbnail = 'thumb.jpg';

$watermarkText = 'My watermark text';

// thumb config
$thumbQuality = 75;
$thumbSize    = new \Imagine\Image\Box(800, 600);
$thumbMode    = \Imagine\Image\ImageInterface::THUMBNAIL_OUTBOUND;

// build font
$watermarkFontFile  = 'font.ttf';
$watermarkFontSize  = 14;
$watermarkFontColor = new Imagine\Image\Color('#fff'); // use white as default color

$watermarkFont = new Imagine\Gd\Font($watermarkFontFile, $watermarkFontSize, $watermarkFontColor);

// get watermark dimensions
$watermarkBox = $watermarkFont->box($watermarkText);

try {
    // try to open photo & build thumbnail
    $photo = $imagine->open($path)
                     ->thumbnail($size, $mode);
    
    
    // calc watermark position
    // display on bottom right with a 10 px padding
    $watermarkPadding = 10;
    $photoSize = $photo->getSize();                
    $watermarkPosition = new Imagine\Image\Point($photoSize->getWidth() - $watermarkBox->getWidth() - $watermarkPadding, 
                            $photoSize->getHeight() - $watermarkBox->getHeight() - $watermarkPadding);
    
    // test color
    $photoColor = $photo->getColorAt($watermarkPosition);
    
    // color brightness formula
    // ( 299*R + 587*G + 114*B ) / 1000
    // is sufficient if brightness diff > 125
    $brightnessBreakpoint   = 125;
    $brightnessWatermark    = (299 * $watermarkFontColor->getRed() + 587 * $watermarkFontColor->getGreen() + 114 * $watermarkFontColor->getBlue()) / 1000;
    $brightnessPhoto        = (299 * $photoColor->getRed() + 587 * $photoColor->getGreen() + 114 * $photoColor->getBlue()) / 1000;
    $brightnessDiff         = $brightnessWatermark - $brightnessPhoto;
    
    // use black text if brightness difference is not sufficient
    if ($brightnessDiff < $brightnessBreakpoint) {
        $watermarkFontColor = new Imagine\Image\Color('#000');
        $watermarkFont      = new Imagine\Gd\Font($watermarkFontFile, $watermarkFontSize, $watermarkFontColor);
    }
    
    // draw watermark
    $photo->draw()->text(
        $watermarkText,
        $watermarkFont,
        $watermarkPosition
    );

    // save thumb
    $photo->save($pathThumbnail, array(
        'quality' => $quality,
        'format'  => 'jpg'
    ));
    
} catch(Exception $e) {
  // oh noes
}