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фон webp

27 июля 2021 Написать комментарий К комментариям

javascript:

function canUseWebp(){
	let elem=document.createElement('canvas');
	if(!!(elem.getContext&&elem.getContext('2d'))){
		return elem.toDataURL('image/webp').indexOf('data:image/webp')==0;
	}
	return false;
}
window.onload=function(){
	let images=document.querySelectorAll('[data-bg]');
	for(let i=0;i<images.length;i++){
		let image=images[i].getAttribute('data-bg');
		images[i].style.backgroundImage='url('+image+')';
	}
	let isitFirefox=window.navigator.userAgent.match(/Firefox\/([0-9]+)\./);
	let firefoxVer=isitFirefox?parseInt(isitFirefox[1]):0;
	if(canUseWebp()||firefoxVer>=65){
		let imagesWebp=document.querySelectorAll('[data-bg-webp]');
		for(let i=0;i<imagesWebp.length;i++){
			let imageWebp=imagesWebp[i].getAttribute('data-bg-webp');
			imagesWebp[i].style.backgroundImage='url('+imageWebp+')';
		}
	}
};

html:

<div class="item" style="background-image:url('/img/banners/banner2.webp');" data-bg="/img/banners/banner2.jpg" data-bg-webp="/img/banners/banner2.webp"></div>

пример программного вывода:

function attr_background_image($image,$dir,$add=''){
	$html='';
	$image_path=ROOT_HTTP.$dir.$image;
	$image_pathinfo=pathinfo($image_path);
	$ext=($image_pathinfo['extension']=='jpg')?'jpeg':$image_pathinfo['extension'];
	if(USE_WEBP==1&&$ext!='svg'&&file_exists(ROOT_DIR.$dir.$image_pathinfo['filename'].'.webp')){
		$html.=' style="background-image:url(\''.ROOT_HTTP.$dir.$image_pathinfo['filename'].'.webp\');" data-bg="'.ROOT_HTTP.$dir.$image.'" data-bg-webp="'.ROOT_HTTP.$dir.$image_pathinfo['filename'].'.webp"';
	}
	else{
		$html.=' style="background-image:url(\''.ROOT_HTTP.$dir.$image.'\');'.$add.'"';
	}
	return $html;
}
$block_bg='';
if($block['photo']||$block['bgcolor']){
	if($block['photo']){
		$bgcolor='';
		if($block['bgcolor']){
			$bgcolor.='background-color:'.$block['bgcolor'].';';
		}
		$block_bg=attr_background_image($block["photo"],IMAGES_BLOCKS_DIR,$bgcolor);
	}
	elseif($block['bgcolor']){
		$block_bg.=' style="';
		$block_bg.='background-color:'.$block['bgcolor'].';';
		$block_bg.='"';
	}
}

или

<div class="item"<?=attr_background_image($item["photo"],IMAGES_BANNERS_DIR)?>>

https://webinmind.ru/javascript/webp-to-background-image

Categories: Javascript, PHP Tags: , ,
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