Imagick::getImageHistogram

array Imagick::getImageHistogram ( void )

<?php
function?getColorStatistics($histogramElements,?$colorChannel)?{
????$colorStatistics?=?[];

????foreach?($histogramElements?as?$histogramElement)?{
????????$color?=?$histogramElement->getColorValue($colorChannel);
????????$color?=?intval($color?*?255);
????????$count?=?$histogramElement->getColorCount();

????????if?(array_key_exists($color,?$colorStatistics))?{
????????????$colorStatistics[$color]?+=?$count;
????????}
????????else?{
????????????$colorStatistics[$color]?=?$count;
????????}
????}

????ksort($colorStatistics);
????
????return?$colorStatistics;
}
????


function?getImageHistogram($imagePath)?{

????$backgroundColor?=?'black';

????$draw?=?new?\ImagickDraw();
????$draw->setStrokeWidth(0);?//make?the?lines?be?as?thin?as?possible

????$imagick?=?new?\Imagick();
????$imagick->newImage(500,?500,?$backgroundColor);
????$imagick->setImageFormat("png");
????$imagick->drawImage($draw);

????$histogramWidth?=?256;
????$histogramHeight?=?100;?//?the?height?for?each?RGB?segment

????$imagick?=?new?\Imagick(realpath($imagePath));
????//Resize?the?image?to?be?small,?otherwise?PHP?tends?to?run?out?of?memory
????//This?might?lead?to?bad?results?for?images?that?are?pathologically?'pixelly'
????$imagick->adaptiveResizeImage(200,?200,?true);
????$histogramElements?=?$imagick->getImageHistogram();

????$histogram?=?new?\Imagick();
????$histogram->newpseudoimage($histogramWidth,?$histogramHeight?*?3,?'xc:black');
????$histogram->setImageFormat('png');

????$getMax?=?function?($carry,?$item)??{
????????if?($item?>?$carry)?{
????????????return?$item;
????????}
????????return?$carry;
????};

????$colorValues?=?[
????????'red'?=>?getColorStatistics($histogramElements,?\Imagick::COLOR_RED),
????????'lime'?=>?getColorStatistics($histogramElements,?\Imagick::COLOR_GREEN),
????????'blue'?=>?getColorStatistics($histogramElements,?\Imagick::COLOR_BLUE),
????];

????$max?=?array_reduce($colorValues['red']?,?$getMax,?0);
????$max?=?array_reduce($colorValues['lime']?,?$getMax,?$max);
????$max?=?array_reduce($colorValues['blue']?,?$getMax,?$max);

????$scale?=??$histogramHeight?/?$max;

????$count?=?0;
????foreach?($colorValues?as?$color?=>?$values)?{
????????$draw->setstrokecolor($color);

????????$offset?=?($count?+?1)?*?$histogramHeight;

????????foreach?($values?as?$index?=>?$value)?{
????????????$draw->line($index,?$offset,?$index,?$offset?-?($value?*?$scale));
????????}
????????$count++;
????}

????$histogram->drawImage($draw);
????
????header(?"Content-Type:?image/png"?);
????echo?$histogram;
}

?>

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