VulpesOS/assets/webapps/camera.gaiamobile.org/shared/js/media/downsample.js

(function (exports) {
    'use strict';
    function round(x) {
        return Math.round(x * 100) / 100;
    }
    function MozSampleSize(n, scale) {
        return Object.freeze({
            dimensionScale: round(scale),
            areaScale: round(scale * scale),
            toString: function () {
                return '#-moz-samplesize=' + n;
            },
            scale: function (x) {
                return Math.ceil(x * scale);
            }
        });
    }
    var NONE = Object.freeze({
        dimensionScale: 1,
        areaScale: 1,
        toString: function () {
            return '';
        },
        scale: function (x) {
            return x;
        }
    });
    var fragments = [
        NONE,
        MozSampleSize(2, 1 / 2),
        MozSampleSize(3, 3 / 8),
        MozSampleSize(4, 1 / 4),
        MozSampleSize(8, 1 / 8)
    ];
    function sizeAtLeast(scale) {
        scale = round(scale);
        for (var i = 0; i < fragments.length; i++) {
            var f = fragments[i];
            if (f.dimensionScale <= scale) {
                return f;
            }
        }
        return fragments[fragments.length - 1];
    }
    function sizeNoMoreThan(scale) {
        scale = round(scale);
        for (var i = fragments.length - 1; i >= 0; i--) {
            var f = fragments[i];
            if (f.dimensionScale >= scale) {
                return f;
            }
        }
        return NONE;
    }
    function areaAtLeast(scale) {
        scale = round(scale);
        for (var i = 0; i < fragments.length; i++) {
            var f = fragments[i];
            if (f.areaScale <= scale) {
                return f;
            }
        }
        return fragments[fragments.length - 1];
    }
    function areaNoMoreThan(scale) {
        scale = round(scale);
        for (var i = fragments.length - 1; i >= 0; i--) {
            var f = fragments[i];
            if (f.areaScale >= scale) {
                return f;
            }
        }
        return NONE;
    }
    exports.Downsample = {
        sizeAtLeast: sizeAtLeast,
        sizeNoMoreThan: sizeNoMoreThan,
        areaAtLeast: areaAtLeast,
        areaNoMoreThan: areaNoMoreThan,
        NONE: NONE,
        MAX_SIZE_REDUCTION: 1 / fragments[fragments.length - 1].dimensionScale,
        MAX_AREA_REDUCTION: 1 / fragments[fragments.length - 1].areaScale
    };
}(window));