Created
April 15, 2011 13:14
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PCの傾き具合によりページをスクロールするGreasemonkeyスクリプト。MacBookやThinkPadで動くと思います。
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// ==UserScript== | |
// @name Scroll by orientation | |
// @namespace jp.mumoshu.scroll_by_orientation | |
// @include * | |
// ==/UserScript== | |
(function() { | |
/** | |
* 傾きの絶対値(0から1.0)がこの値より大きいときにスクロールをはじめる | |
*/ | |
var ORIENTATION_THRESHOLD = 0.1; | |
/** | |
* 加速度の倍率。加速度は傾き(-1.0 ~ +1.0) * 倍率 px/sec^2 | |
*/ | |
var ACCELERATION_BIAS = 20; | |
/** | |
* 速度の減衰率を表す。1.0近いほど減衰しない(端末を水平にしてもずっとスクロールしつづける) | |
* 逆に0.0に近いほど、端末を水平にしたとき時間経過に伴いスクロールが止まる。 | |
*/ | |
var VELOCITY_DECAY = 0.0; | |
function vectorLength(x, y) { | |
return Math.sqrt(Math.pow(x, 2) + Math.pow(y, 2)); | |
} | |
/** | |
* 2次元ベクトル。わざわざクラスにしない方が高速なんですけどね。。 | |
* @param x | |
* @param y | |
*/ | |
function Vector2D(x, y) { | |
this.x = x; | |
this.y = y; | |
} | |
Vector2D.prototype.multiplyBy = function(number) { | |
this.x *= number; | |
this.y *= number; | |
}; | |
Vector2D.prototype.add = function(vector) { | |
this.x += vector.x; | |
this.y += vector.y; | |
}; | |
Vector2D.prototype.len = function() { | |
return vectorLength(this.x, this.y); | |
}; | |
/** | |
* 再利用しないのでただのオブジェクトにしておきますね | |
*/ | |
var state = { | |
orientationx: 0, | |
orientationY: 0, | |
acceleration: new Vector2D(0, 0), | |
velocity: new Vector2D(0, 0), | |
handleOrientation: function(orientation) { | |
var ox = orientation.x; | |
var oy = orientation.y; | |
ox = Math.abs(ox) < ORIENTATION_THRESHOLD ? 0.0 : ox; | |
oy = Math.abs(oy) < ORIENTATION_THRESHOLD ? 0.0 : oy; | |
this.velocity.multiplyBy(VELOCITY_DECAY); | |
this.acceleration.x = ox * ACCELERATION_BIAS; | |
this.acceleration.y = oy * ACCELERATION_BIAS; | |
this.velocity.add(this.acceleration); | |
} | |
}; | |
setInterval(function() { | |
window.scrollBy(state.velocity.x, state.velocity.y); | |
}, 16); | |
window.addEventListener("MozOrientation", function(orientation) { state.handleOrientation(orientation); }, true); | |
})(); |
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