Center Image

Centers images (directly opened with browser)(firefox-like) with hotkeys (to resize or scroll)

Versión del día 23/4/2019. Echa un vistazo a la versión más reciente.

Tendrás que instalar una extensión para tu navegador como Tampermonkey, Greasemonkey o Violentmonkey si quieres utilizar este script.

Necesitarás instalar una extensión como Tampermonkey o Violentmonkey para instalar este script.

Necesitarás instalar una extensión como Tampermonkey o Violentmonkey para instalar este script.

Necesitarás instalar una extensión como Tampermonkey o Userscripts para instalar este script.

Necesitará instalar una extensión como Tampermonkey para instalar este script.

Necesitarás instalar una extensión para administrar scripts de usuario si quieres instalar este script.

(Ya tengo un administrador de scripts de usuario, déjame instalarlo)

Necesitará instalar una extensión como Stylus para instalar este estilo.

Necesitará instalar una extensión como Stylus para instalar este estilo.

Necesitará instalar una extensión como Stylus para instalar este estilo.

Necesitará instalar una extensión del gestor de estilos de usuario para instalar este estilo.

Necesitará instalar una extensión del gestor de estilos de usuario para instalar este estilo.

Necesitará instalar una extensión del gestor de estilos de usuario para instalar este estilo.

(Ya tengo un administrador de estilos de usuario, déjame instalarlo)

// ==UserScript==
// @name          Center Image
// @namespace     CenterImage
// @author        Owyn
// @version       1.91
// @description   Centers images (directly opened with browser)(firefox-like) with hotkeys (to resize or scroll)
// @homepage      https://greatest.deepsurf.us/scripts/110-center-image
// @run-at        document-end
// @noframes
// @grant         GM.getValue
// @grant         GM.setValue
// @grant         GM_registerMenuCommand
// @match         http://*/*
// @match         https://*/*
// @match         file://*/*
// ==/UserScript==

if (typeof GM_registerMenuCommand !== "undefined")
{
	GM_registerMenuCommand("Center Image Configuration", cfg, "n");
}

var images = document.images;
if (!images || images.length !== 1 || images[0].src !== location.href) 
{
	return false;
}

var rescaled = false;
var iot = 0, iol = 0;
var i = images[0];

var FireFox = ((navigator.userAgent.indexOf('Firefox') != -1) ? true : false);

function makeimage()
{
	if(cfg_bgclr)
	{
		document.body.bgColor = cfg_bgclr;
		if(document.head){document.head.innerHTML = "";} // remove FireFox background
	}
	document.body.innerHTML = "<style>img { position: absolute; top: 0; right: 0; bottom: 0; left: 0; }</style>"; // center image
	i.style = ""; // chrome has lots of crap there
	document.body.style = "";
	i.style.margin = "auto"; // center image
	document.body.style.margin = "0px";
	document.body.appendChild(i);
	i.addEventListener("mousedown", onmousedown, true);
	i.addEventListener("click", rescale, true);
	window.addEventListener("keydown", onkeydown, true);
	window.addEventListener("resize", onresize, true);
	autoresize();
}

function onresize()
{
	if(rescaled)
	{
		rescaled = false;
		rescale();
	}
}

function changecursor()
{
	i.style.margin = "auto";
	if(!rescaled && (((i.naturalHeight / window.devicePixelRatio).toFixed() == window.innerHeight && (i.naturalWidth / window.devicePixelRatio).toFixed() <= window.innerWidth) || ((i.naturalHeight / window.devicePixelRatio).toFixed() <= window.innerHeight && (i.naturalWidth / window.devicePixelRatio).toFixed() == window.innerWidth))) // one img dimension is equal to screen and other is the same or less than the screen
	{
		i.style.cursor = "";
	}
	else if((i.naturalHeight / window.devicePixelRatio).toFixed() > window.innerHeight || (i.naturalWidth / window.devicePixelRatio).toFixed() > window.innerWidth) // at least one img dimenion is bigger than the screen
	{
		if(rescaled)
		{
			i.style.cursor = "-moz-zoom-in";
			i.style.cursor = "-webkit-zoom-in";
		}
		else
		{
			i.style.cursor = "-moz-zoom-out";
			i.style.cursor = "-webkit-zoom-out";
			if((i.naturalHeight / window.devicePixelRatio).toFixed() > window.innerHeight) // image pushing out-of-screen fix
			{
				i.style.margin = "0px auto";
			}
		}
	}
	else
	{
		if(rescaled)
		{
			i.style.cursor = "-moz-zoom-out";
			i.style.cursor = "-webkit-zoom-out";
		}
		else
		{
			i.style.cursor = "-moz-zoom-in";
			i.style.cursor = "-webkit-zoom-in";
		}
	}
}

function onmousedown(event)
{
	if(i.offsetLeft > 0){iol = i.offsetLeft;}
	if(i.offsetTop > 0){iot = i.offsetTop;}
}

function rescale(event)
{
	if(rescaled)
	{
		rescaled = false;
		var scale;
		if(event)
		{
			if (typeof event.y === "undefined") // Firefox
			{
				ex = event.clientX;
				ey = event.clientY;
			}
			else
			{
				ex = event.x;
				ey = event.y;
			}
			ex -= iol;
			ey -= iot;
			scale = Math.min((window.innerWidth / (i.naturalWidth / window.devicePixelRatio).toFixed()), (window.innerHeight / (i.naturalHeight / window.devicePixelRatio).toFixed()));
		}
		i.removeAttribute("width");
		i.removeAttribute("height");
		i.style.width = (i.naturalWidth / window.devicePixelRatio).toFixed() + "px";
		i.style.height = (i.naturalHeight / window.devicePixelRatio).toFixed() + "px";
		changecursor();
		if(event)
		{
			window.scrollTo(ex / scale - window.innerWidth / 2, ey / scale - window.innerHeight / 2);
		}
	}
	else
	{
		i.removeAttribute("width");
		i.removeAttribute("height");
		i.style.width = (i.naturalWidth / window.devicePixelRatio).toFixed() + "px";
		i.style.height = (i.naturalHeight / window.devicePixelRatio).toFixed() + "px";
		if((i.naturalWidth / window.devicePixelRatio).toFixed() != window.innerWidth)
		{
			i.style.width = window.innerWidth + "px";
			i.style.height = "";
			rescaled = true;
		}
		
		if((i.height > window.innerHeight) || (i.width > window.innerWidth))
		{
			i.style.width = (i.naturalWidth / window.devicePixelRatio).toFixed() + "px";
			i.style.height = (i.naturalHeight / window.devicePixelRatio).toFixed() + "px";
			if((i.naturalHeight / window.devicePixelRatio).toFixed() != window.innerHeight)
			{
				i.style.height = window.innerHeight + "px";
				i.style.width = "";
				rescaled = true;
			}
		}
		changecursor();
	}
}

function autoresize()
{
	if(!document.head) // old fix for old chrome - let it be
	{
		document.lastChild.insertBefore(document.createElement("head"), document.body);
	}
	var link = document.createElement('link');
	link.type = 'image/x-icon';
	link.rel = 'shortcut icon';
	link.href = i.src;
	document.head.appendChild(link); // favicon
	var title = i.src.substr(i.src.lastIndexOf("/")+1);
	if(title.indexOf("?") != -1)
	{
		title = title.substr(0, title.indexOf("?"));
	}
	document.title = title + " (" + i.naturalWidth + "x" + i.naturalHeight + ")"; // title
	
	rescaled = true;rescale(0); // to original size in pixels
	if(cfg_fitWH && i.height > window.innerHeight && i.width > window.innerWidth) // both scrollbars
	{
		rescale(0);
	}
	else if(cfg_fitB && (i.height > window.innerHeight || i.width > window.innerWidth)) // one scrollbar
	{
		rescale(0);
	}
	else if(cfg_fitS && i.height <= window.innerHeight && i.width <= window.innerWidth) // no scrollbars
	{
		rescale(0);
	}
	if(cfg_js){eval(cfg_js);}
}

// hotkeys
if (typeof KeyEvent === "undefined")
{
	var KeyEvent = {
		DOM_VK_SPACE: 32,
		DOM_VK_LEFT: 37,
		DOM_VK_UP: 38,
		DOM_VK_RIGHT: 39,
		DOM_VK_DOWN: 40,
		DOM_VK_A: 65,
		DOM_VK_D: 68,
		DOM_VK_P: 80,
		DOM_VK_Q: 81,
		DOM_VK_S: 83,
		DOM_VK_W: 87,
		DOM_VK_NUMPAD2: 98,
		DOM_VK_NUMPAD4: 100,
		DOM_VK_NUMPAD5: 101,
		DOM_VK_NUMPAD6: 102,
		DOM_VK_NUMPAD8: 104
	};
}

function cancelEvent(a)
{
	a = a ? a : window.event;
	if (a.stopPropagation)
	{
		a.stopPropagation();
	}
	if (a.preventDefault)
	{
		a.preventDefault();
	}
	a.cancelBubble = true;
	a.cancel = true;
	a.returnValue = false;
	return false;
}

function scroll_space(a, b)
{
	var by = Math.round((b ? window.innerHeight : window.innerWidth) * 0.50 * (a ? -1 : 1));
	if(!b)
	{
		window.scrollBy(0, by);
	}
	else
	{
		window.scrollBy(by, 0);
	}
}

function onkeydown (b)
{
	var a = (window.event) ? b.keyCode : b.which;
	
	if (a != KeyEvent.DOM_VK_SPACE && (b.altKey || b.ctrlKey || b.metaKey))
	{
		return;
	}
	
	var by = Math.round(window.innerHeight * 0.10);
	
	switch (a)
	{
	case KeyEvent.DOM_VK_RIGHT:
	case KeyEvent.DOM_VK_D:
	case KeyEvent.DOM_VK_NUMPAD6:
		window.scrollBy(by, 0);
		cancelEvent(b);
		break;
	case KeyEvent.DOM_VK_LEFT:
	case KeyEvent.DOM_VK_A:
	case KeyEvent.DOM_VK_NUMPAD4:
		window.scrollBy(by * -1, 0);
		cancelEvent(b);
		break;
	case KeyEvent.DOM_VK_W:
	case KeyEvent.DOM_VK_NUMPAD8:
		window.scrollBy(0, by * -1);
		cancelEvent(b);
		break;
	case KeyEvent.DOM_VK_S:
	case KeyEvent.DOM_VK_NUMPAD2:
		window.scrollBy(0, by);
		cancelEvent(b);
		break;
	case KeyEvent.DOM_VK_SPACE:
		scroll_space(b.shiftKey, b.ctrlKey);
		cancelEvent(b);
		break;
	case KeyEvent.DOM_VK_Q:
	case KeyEvent.DOM_VK_NUMPAD5:
		rescale(0);
		cancelEvent(b);
		break;
	case KeyEvent.DOM_VK_P:
		cfg();
		cancelEvent(b);
	}
}

var cfg_bgclr;
var cfg_fitWH;
var cfg_fitB;
var cfg_fitS;
var cfg_js;

async function loadCfg()
{
	if (typeof GM.getValue !== "undefined")
	{
		cfg_bgclr = await GM.getValue("bgColor", "grey");
		cfg_fitWH = await GM.getValue("fitWH", true);
		cfg_fitB = await GM.getValue("fitB", false);
		cfg_fitS = await GM.getValue("fitS", true);
		cfg_js = await GM.getValue("js", "");
	}
	makeimage();
}
loadCfg();

function $(id) {return document.getElementById(id);}

function cfg()
{
	if (typeof GM.setValue !== "undefined")
	{
		function saveCfg()
		{
			GM.setValue("bgColor", $("ci_cfg_2_bgclr").value);
			GM.setValue("fitWH", $("ci_cfg_3_fitWH").checked);
			GM.setValue("fitB", $("ci_cfg_4_fitB").checked);
			GM.setValue("fitS", $("ci_cfg_5_fitS").checked);
			GM.setValue("js", $("ci_cfg_6_js").value);
			alert("Configuration Saved");
			if($("ci_cfg_2_bgclr").value){document.body.bgColor = $("ci_cfg_2_bgclr").value;}else{document.body.removeAttribute("bgColor");}
		}
		if(i){i.removeEventListener("click", rescale, true);}
		window.removeEventListener("keydown", onkeydown, true);
		if(document.head){document.head.innerHTML = "";}
		document.body.innerHTML = "";
		var div = document.createElement("div");
		div.style.margin = "11% auto";
		div.style.width = "444px";
		div.style.border = "solid 1px black";
		div.style.background = "silver";
		div.innerHTML = "<b><center>Configuration</center></b>"
		+ "<br><input id='ci_cfg_2_bgclr' type='text' size='6'> Background color (empty = default)"
		+ "<br><br>Fit to window images:"
		+ "<br><br><input id='ci_cfg_3_fitWH' type='checkbox'> Larger than window both vertically and horizontally"
		+ "<br><br><input id='ci_cfg_4_fitB' type='checkbox'> Larger than window either vertically or horizontally"
		+ "<br><br><input id='ci_cfg_5_fitS' type='checkbox'> Smaller than window"
		+ "<br><br><center>Custom JS Action:<textarea id='ci_cfg_6_js' style='margin: 0px; width: 400px; height: 50px;'></textarea>"
		+ "<br><input id='ci_cfg_save' type='button' value='Save configuration'></center>";
		document.body.appendChild(div);
		$("ci_cfg_2_bgclr").value = cfg_bgclr;
		$("ci_cfg_3_fitWH").checked = cfg_fitWH;
		$("ci_cfg_4_fitB").checked = cfg_fitB;
		$("ci_cfg_5_fitS").checked = cfg_fitS;
		$("ci_cfg_6_js").value = cfg_js;
		$("ci_cfg_save").addEventListener("click", saveCfg, true);
	}
	else
	{
		alert("Sorry, Chrome userscripts in native mode can't have configurations! Install TamperMonkey (Beta) extension. (it's very good)");
	}
}