Select like Opera

An userscript to provide Opera(old) like scrolling behavior.

Fra 23.12.2014. Se den seneste versjonen.

You will need to install an extension such as Tampermonkey, Greasemonkey or Violentmonkey to install this script.

You will need to install an extension such as Tampermonkey or Violentmonkey to install this script.

You will need to install an extension such as Tampermonkey or Violentmonkey to install this script.

You will need to install an extension such as Tampermonkey or Userscripts to install this script.

You will need to install an extension such as Tampermonkey to install this script.

You will need to install a user script manager extension to install this script.

(I already have a user script manager, let me install it!)

You will need to install an extension such as Stylus to install this style.

You will need to install an extension such as Stylus to install this style.

You will need to install an extension such as Stylus to install this style.

You will need to install a user style manager extension to install this style.

You will need to install a user style manager extension to install this style.

You will need to install a user style manager extension to install this style.

(I already have a user style manager, let me install it!)

// ==UserScript==
// @name        Select like Opera
// @description	An userscript to provide Opera(old) like scrolling behavior.
// @namespace   eight04.blogspot.com
// @include     http*
// @version     1.0.0
// @require 	https://greasyfork.org/scripts/1884-gm-config/code/GM_config.js?version=4836
// @require		https://greasyfork.org/scripts/7108-bezier-easing/code/bezier-easing.js?version=29098
// @grant       GM_setValue
// @grant		GM_getValue
// @grant       GM_registerMenuCommand
// ==/UserScript==

(function(){

	"use strict";

	var config = {
		scrollHorizontallyWithScrollbar: true,
		scrollOverflowHidden: false,
		alwaysUse: false,
		scrollDelay: 400,
		scrollOffset: 120
	};

	initConfig(config);

	/**
		Register event
	*/
	window.addEventListener("wheel", function(e){
		var q = getScrollInfo(e.target, e);

		if (q && (q.use || config.alwaysUse)) {
			e.preventDefault();
			scroll(q.element, q.offsetX, q.offsetY);
		}
	});

	/**
		Main logic
	*/
	function getInfo(element, e) {
		var rect, border;

		if (element != document.documentElement) {

			rect = element.getBoundingClientRect();
			border = getBorder(element);

			return {
				element: element,
				onScrollbarX: e.clientY >= rect.top + border.top + element.clientHeight && e.clientY <= rect.bottom - border.bottom,
				scrollableX: element.scrollWidth > element.clientWidth,
				scrollableY: element.scrollHeight > element.clientHeight,
				scrollerX: element.offsetHeight - border.top - border.bottom > element.clientHeight,
				scrollerY: element.offsetWidth - border.left - border.right > element.clientWidth
			};

		} else {

			return {
				element: element,
				onScrollBarX: e.clientY >= element.clientHeight && e.clientY <= window.innerHeight,
				scrollableX: element.scrollWidth > element.clientWidth,
				scrollableY: element.scrollHeight > element.clientHeight,
				scrollerX: window.innerHeight - element.clientHeight,
				scrollerY: window.innerWidth - element.clientWidth
			};
		}
	}

	function getScrollInfo(element, e) {
		var q;

		// Get scrollable parent
		while (element) {

			q = getInfo(element, e);

			if (e.deltaY && (q.onScrollbarX || useHorizontalScroll(q)) && scrollable(element, e.deltaY, 0)) {
				// Horizontal scroll
				q.offsetX = getOffset(e.deltaY);
				q.offsetY = 0;
				q.use = true;
				return q;
			}

			if ((e.deltaX && q.scrollableX || e.deltaY && q.scrollableY) && scrollable(element, e.deltaX, e.deltaY)) {
				if (e.deltaX && q.scrollerX || e.deltaY && q.scrollerY) {
					// Usual cases
					q.offsetX = getOffset(e.deltaX);
					q.offsetY = getOffset(e.deltaY);
					return q;
				}
				if (config.scrollOverflowHidden && (e.deltaX && !q.scrollerX || e.deltaY && !q.scrollerY)) {
					// Scroll hidden
					q.offsetX = getOffset(e.deltaX);
					q.offsetY = getOffset(e.deltaY);
					q.use = true;
					return q;
				}
			}

			element = element.parentNode;
			if (element == document) {
				return null;
			}
		}

		return null;
	}

	/**
		Scroll function. Should I put them into seperate library?
		Thanks to https://github.com/galambalazs/smoothscroll
	*/
	var animate = null;
	var que = [];
	function scroll(element, x, y) {
		var elapsed = config.scrollDelay;

		que.push({
			offsetX: x,
			offsetY: y,
			lastX: 0,
			lastY: 0,
			element: element,
			timeStart: null
		});

		if (animate != null) {
			return;
		}

		function animation(timestamp){
			var i, j, len, q, time, offsetX, offsetY, process, swap;

			swap = [];

			for (i = 0, j = 0, len = que.length; i < len; i++) {
				q = que[i];
				if (q.timeStart == null) {
					q.timeStart = timestamp;
				}
				if (timestamp - q.timeStart >= elapsed || !scrollable(q.element, q.offsetX, q.offsetY)) {
					scrollBy(q.element, q.offsetX - q.lastX, q.offsetY - q.lastY);
				} else {
					time = (timestamp - q.timeStart) / elapsed;
					process = ease(time);
					offsetX = Math.floor(q.offsetX * process);
					offsetY = Math.floor(q.offsetY * process);

					scrollBy(q.element, offsetX - q.lastX, offsetY - q.lastY);

					q.lastX = offsetX;
					q.lastY = offsetY;
					swap[j++] = q;
				}
			}

			que = swap;
			if (!que.length) {
				animate = null;
				return;
			}

			animate = requestAnimationFrame(animation);
		}
		animate = requestAnimationFrame(animation);
	}

	/**
		Helpers
	*/
	function useHorizontalScroll(q) {
		if (!config.scrollHorizontallyWithScrollbar) {
			return false;
		}
		if (config.scrollOverflowHidden && !q.scrollerX && !q.scrollerY) {
			return q.scrollableX && !q.scrollableY;
		}
		return q.scrollerX && (!q.scrollerY || !q.scrollableY);
	}

	function getOffset(delta) {
		var direction = 0;
		if (delta > 0) {
			direction = 1;
		} else if (delta < 0) {
			direction = -1;
		}
		return direction * config.scrollOffset;
	}

	function ease(t){
		return BezierEasing.css.ease(t);
	}

	function getBorder(element){
		var css = getComputedStyle(element);

		return {
			top: parseInt(css.getPropertyValue("border-top-width"), 10),
			right: parseInt(css.getPropertyValue("border-right-width"), 10),
			bottom: parseInt(css.getPropertyValue("border-bottom-width"), 10),
			left: parseInt(css.getPropertyValue("border-left-width"), 10)
		};
	}

	function scrollable(element, offsetX, offsetY) {
		var top, left;
		if (element == document.documentElement) {
			top = window.scrollY;
			left = window.scrollX;
		} else {
			top = element.scrollTop;
			left = element.scrollLeft;
		}

		if (top == 0 && offsetY < 0) {
			return false;
		}
		if (left == 0 && offsetX < 0) {
			return false;
		}
		if (top + element.clientHeight >= element.scrollHeight && offsetY > 0) {
			return false;
		}
		if (left + element.clientWidth >= element.scrollWidth && offsetX > 0) {
			return false;
		}
		return true;
	}

	function scrollBy(element, x, y) {
		if (element != document.documentElement) {
			element.scrollLeft += x;
			element.scrollTop += y;
		} else {
			window.scrollBy(x, y);
		}
	}

	function initConfig(config) {
		GM_config.init(
			"Scroll like Opera",
			{
				scrollHorizontallyWithScrollbar: {
					label: "Scroll horizontally if only horizontal scrollbar presented.",
					type: "checkbox",
					default: true
				},
				scrollOverflowHidden: {
					label: "Make overflow:hidden element scrollable.",
					type: "checkbox",
					default: false
				},
				alwaysUse: {
					label: "Always use script's scrolling handler. Enable this if you want to use the script's smooth scrolling on chrome.",
					type: "checkbox",
					default: false
				},
				scrollDelay: {
					label: "Smooth scrolling dealy.",
					type: "text",
					default: 400
				},
				scrollOffset: {
					label: "Scrolling offset.",
					type: "text",
					default: 120
				}
			}
		);

		config.scrollHorizontallyWithScrollbar = GM_config.get("scrollHorizontallyWithScrollbar");
		config.scrollOverflowHidden = GM_config.get("scrollOverflowHidden");
		config.alwaysUse = GM_config.get("alwaysUse");
		config.scrollDelay = +GM_config.get("scrollDelay");
		config.scrollOffset = +GM_config.get("scrollOffset");

		GM_registerMenuCommand("Linkify Plus Plus - Configure", function(){
			GM_config.open();
		});
	}
})();