Aaron, I haven't even begun looking at your implementation, but I'm just going to say it: this is awesome!
First question: When Capturing a DOM element, can you capture 'body' to grab it&children for a "full content screenshot", or does it have to be a specific single element? -Michal On Tue, Mar 12, 2013 at 1:58 PM, Aaron Charbonneau <[email protected]>wrote: > Greetings! My name is Aaron Charbonneau, happy to be a new member of the > mailing list! > > I have been developing a sceenshot plugin for Cordova to help facilitate > automation testing and debugging of Cordova apps, and I would love some > feedback on it. Currently Cordova provides a bunch of native functions > that allow you to do some cool stuff, but not much functionality to test > the apps that make use of them. Being able to take a capture of the screen > from within you app is a great way to automate testing or get additional > information for debugging an issue. Since there is no > Javascript mechanism for taking screen captures the solution would have to > be native, which fits nicely into the "gap" that Cordova/Phonegap bridges. > Any medium to large scale app can benefit greatly from automation testing > and any app can benefit from an extra debugging tool, and that is what I > hope this screenshot plugin can help achieve. > > Currently the plugin offers 2 functions: > > Capture(): > * Take a capture of the current view, write that capture to a .png file > with the specified file name and sub directory of the sdcard (fallback to > emulated sdcard in the case there isn't an sdcard mounted) > * Able to create a sub-screenshot with a specified rectangle in order to > block out ui elements that may be variable, and also save space. > * Can take captures of images/dom elements (including canvas) that are > lager than the actual screen size > > CaptureAndCompare(): > * All the functionality of Capture() > * Perform a comparison between the captured image and a baseline image > located at the specified location in either the assets folder or the > sdcard. > * User can specify per color channel tolerances as well as total pixel > tolerances to avoid false positives for the inevitable rendering > differences across devices. > * Optionally output a png file that contains the differences between the > actual and the baseline for debugging/triage purposes, two modes: binary > diff (all failing pixels appear as solid white) or the true differences > between pixels. > > If you can spare some time, I would love it if you could take a look at the > api and parameters I have defined to make sure they adhere to Cordova > plugin best practices. The most crucial part would be in the plugin itself > at ScreenCapture.java: > > https://github.com/Charbs09/Cordova-Mobile-Spec-ScreenCapture/blob/master/src/org/apache/cordova/plugin/ScreenCapture.java(capture() > and captureAndCompare() are the two exposed functions) > > I'm also interested to know you thoughts on it's usage. I started with the > mobile-spec testing framework and put some quick rendering tests into the > Autotest section as a viable use case. In order to get the WebView into > the state I wanted to capture, I had to implement a wait timer to allow the > view to update before taking the capture. Once the wait function > completes, the capture can be taken and everything from there is callback > based. I use the Jasmine waitsFor()/runs() blocks to make the tests run > synchronously. For some validation testing I made a compare function in > Javascript to run against the native compare. Turns out Java runs alot > faster than Javascript (surprise!) thus the native compare is about 2-5x > faster. All in all the process is fairly quick, the full captureAndCompare > with 3 file io's takes about 233ms on a Nexus One, and ~100ms on a Nexus 10 > (256x256 image size). > > Anyways here is the usage: > > https://github.com/Charbs09/Cordova-Mobile-Spec-ScreenCapture/blob/master/assets/www/autotest/tests/rendering.tests.js > > And here's the JS wrapper for the plugin calls: > > https://github.com/Charbs09/Cordova-Mobile-Spec-ScreenCapture/blob/master/assets/www/screencapture.js > > Thanks for your time, and I look forward to ANY feedback positive or > negative. > > Thanks, > Aaron >
