'use strict';
var logMethods = require('../log');
var type = require('../type');
var when = require('../when');
var stitchingScripts = require('../scripts/stitching');
var PNGImage = require('pngjs-image');
module.exports = Stitching;
/**
* Stitching object
*
* @constructor
* @class Stitching
* @module WebDriver
* @submodule Helpers
* @param {Driver} driver
*/
function Stitching (driver) {
this._driver = driver;
}
/////////////////////
// Private Methods //
/////////////////////
/**
* Logs a method call by an event
*
* @param {object} event
* @method _logMethodCall
* @private
*/
Stitching.prototype._logMethodCall = function (event) {
event.target = 'Stitching';
this._driver._logMethodCall(event);
};
/**
* Performs a context dependent JSON request for the current session.
* The result is parsed for errors.
*
* @method _requestJSON
* @private
* @param {String} method
* @param {String} path
* @param {*} [body]
* @return {*}
*/
Stitching.prototype._requestJSON = function (method, path, body) {
return this._driver._requestJSON(method, path, body);
};
////////////////////
// Public Methods //
////////////////////
/**
* Gets the driver object.
* Direct-access. No need to wait.
*
* @return {Driver}
*/
Stitching.prototype.getDriver = function () {
return this._driver;
};
/**
* Is stitching needed for browser?
*
* Some browsers (i.e. Chrome) do only take a screenshot of the view-port instead of the whole document as per standard.
* This information will then be cached for each driver instance, determining this only once per instance.
*
* @method doesNeedStitching
* @param {object} [options]
* @param {int} [options.horizontalPadding=0] Padding of the document
* @return {number}
*/
Stitching.prototype.doesNeedStitching = function (options) {
var needsStitching = this.getDriver().getValue('needsStitching');
if (needsStitching === null) {
return when(this._determineNeedsStitching(options), function (value) {
this.getDriver().setValue('needsStitching', value); // Cache value
return value;
}.bind(this));
} else {
return this.getDriver().utils().resolve(needsStitching);
}
};
/**
* Determines if the browser needs stitching due to the fact of taking only view-port screenshots instead of
* whole document ones.
*
* Note:
* ```horizontalPadding``` is any element that extents horizontally
* outside of the document, i.e. negative absolute position.
*
* @method _determineNeedsStitching
* @param {object} [options]
* @param {int} [options.horizontalPadding=0] Padding of the document
* @return {boolean}
* @private
*/
Stitching.prototype._determineNeedsStitching = function (options) {
var Screenshot = require('./screenshot'),
screenshot = new Screenshot(this.getDriver()),
DevicePixelRatio = require('./devicePixelRatio'),
devicePixelRatio = new DevicePixelRatio(this.getDriver());
options = options || {};
// Determine device-pixel-ratio
return when(devicePixelRatio.getDevicePixelRatio(options), function (devicePixelRatio) {
// Reduce size of document to get a small screenshot for stitching determination
return when(this._execute(stitchingScripts.init, [options.horizontalPadding || 0]), function (initData) {
initData = JSON.parse(initData);
// Take screenshot (hopefully very small, but big enough to get the stitching info)
return when(screenshot.takeProcessedScreenshot(), function (image) {
// Revert document size
return when(this._execute(stitchingScripts.revert, [initData]), function () {
return this._needsStitchingExceptions(image, initData, devicePixelRatio);
}.bind(this));
}.bind(this));
}.bind(this));
}.bind(this));
};
/**
* Processes the exception handling of stitching determination
*
* Note:
* Overwrite this method if you want to change the stitching behavior of browsers.
*
* @param {PNGImage} image
* @param {object} initData
* @param {number} devicePixelRatio
* @returns {boolean}
* @private
*/
Stitching.prototype._needsStitchingExceptions = function (image, initData, devicePixelRatio) {
// If the screenshot width and the actual view-port width are pretty much the same (here 10px),
// even though the document is twice the view-port size, then we need stitching.
var expectedViewPortWidth = initData.viewPortWidth * 2 * devicePixelRatio,
actualViewPortWidth = image.getWidth(),
difference = actualViewPortWidth - expectedViewPortWidth,
delta = Math.abs(difference),
needsStitching,
browserName = this.getDriver().browserName().toLowerCase(),
browserVersion = this.getDriver().browserVersion();
// When actual is smaller than expected, then needs stitching
// When actual is bigger than expected and delta is not off for more than 2% (border issues), then no stitching needed
needsStitching = (difference <= 0) && (delta >= expectedViewPortWidth * 0.2);
if (!needsStitching) { // Exceptions
if ((browserName === 'internet explorer') && (browserVersion >= 10)) {
needsStitching = true;
}
}
return needsStitching
};
/**
* Executes a script in the browser and returns the result.
*
* This is a convenience method for accessing the execute method.
*
* @method _execute
* @param {String|Function} script
* @param {Array} [args]
* @return {*}
* @private
*/
Stitching.prototype._execute = function (script, args) {
if (script) {
return this.getDriver().browser().activeWindow().execute(script, args);
} else { // Ignore script if there is nothing - might happen with screenshot requests
return this.getDriver().utils().resolve(undefined);
}
};
logMethods(Stitching.prototype);
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