tupali/milfs/addon/brigada/js/load-image-orientation.js

/*
 * JavaScript Load Image Orientation 1.1.0
 * https://github.com/blueimp/JavaScript-Load-Image
 *
 * Copyright 2013, Sebastian Tschan
 * https://blueimp.net
 *
 * Licensed under the MIT license:
 * http://www.opensource.org/licenses/MIT
 */

/*global define, window */

(function (factory) {
    'use strict';
    if (typeof define === 'function' && define.amd) {
        // Register as an anonymous AMD module:
        define(['load-image'], factory);
    } else {
        // Browser globals:
        factory(window.loadImage);
    }
}(function (loadImage) {
    'use strict';

    var originalHasCanvasOption = loadImage.hasCanvasOption,
        originalTransformCoordinates = loadImage.transformCoordinates,
        originalGetTransformedOptions = loadImage.getTransformedOptions;

    // This method is used to determine if the target image
    // should be a canvas element:
    loadImage.hasCanvasOption = function (options) {
        return originalHasCanvasOption.call(loadImage, options) ||
            options.orientation;
    };

    // Transform image orientation based on
    // the given EXIF orientation option:
    loadImage.transformCoordinates = function (canvas, options) {
        originalTransformCoordinates.call(loadImage, canvas, options);
        var ctx = canvas.getContext('2d'),
            width = canvas.width,
            height = canvas.height,
            orientation = options.orientation;
        if (!orientation || orientation > 8) {
            return;
        }
        if (orientation > 4) {
            canvas.width = height;
            canvas.height = width;
        }
        switch (orientation) {
        case 2:
            // horizontal flip
            ctx.translate(width, 0);
            ctx.scale(-1, 1);
            break;
        case 3:
            // 180° rotate left
            ctx.translate(width, height);
            ctx.rotate(Math.PI);
            break;
        case 4:
            // vertical flip
            ctx.translate(0, height);
            ctx.scale(1, -1);
            break;
        case 5:
            // vertical flip + 90 rotate right
            ctx.rotate(0.5 * Math.PI);
            ctx.scale(1, -1);
            break;
        case 6:
            // 90° rotate right
            ctx.rotate(0.5 * Math.PI);
            ctx.translate(0, -height);
            break;
        case 7:
            // horizontal flip + 90 rotate right
            ctx.rotate(0.5 * Math.PI);
            ctx.translate(width, -height);
            ctx.scale(-1, 1);
            break;
        case 8:
            // 90° rotate left
            ctx.rotate(-0.5 * Math.PI);
            ctx.translate(-width, 0);
            break;
        }
    };

    // Transforms coordinate and dimension options
    // based on the given orientation option:
    loadImage.getTransformedOptions = function (img, opts) {
        var options = originalGetTransformedOptions.call(loadImage, img, opts),
            orientation = options.orientation,
            newOptions,
            i;
        if (!orientation || orientation > 8 || orientation === 1) {
            return options;
        }
        newOptions = {};
        for (i in options) {
            if (options.hasOwnProperty(i)) {
                newOptions[i] = options[i];
            }
        }
        switch (options.orientation) {
        case 2:
            // horizontal flip
            newOptions.left = options.right;
            newOptions.right = options.left;
            break;
        case 3:
            // 180° rotate left
            newOptions.left = options.right;
            newOptions.top = options.bottom;
            newOptions.right = options.left;
            newOptions.bottom = options.top;
            break;
        case 4:
            // vertical flip
            newOptions.top = options.bottom;
            newOptions.bottom = options.top;
            break;
        case 5:
            // vertical flip + 90 rotate right
            newOptions.left = options.top;
            newOptions.top = options.left;
            newOptions.right = options.bottom;
            newOptions.bottom = options.right;
            break;
        case 6:
            // 90° rotate right
            newOptions.left = options.top;
            newOptions.top = options.right;
            newOptions.right = options.bottom;
            newOptions.bottom = options.left;
            break;
        case 7:
            // horizontal flip + 90 rotate right
            newOptions.left = options.bottom;
            newOptions.top = options.right;
            newOptions.right = options.top;
            newOptions.bottom = options.left;
            break;
        case 8:
            // 90° rotate left
            newOptions.left = options.bottom;
            newOptions.top = options.left;
            newOptions.right = options.top;
            newOptions.bottom = options.right;
            break;
        }
        if (options.orientation > 4) {
            newOptions.maxWidth = options.maxHeight;
            newOptions.maxHeight = options.maxWidth;
            newOptions.minWidth = options.minHeight;
            newOptions.minHeight = options.minWidth;
            newOptions.sourceWidth = options.sourceHeight;
            newOptions.sourceHeight = options.sourceWidth;
        }
        return newOptions;
    };

}));