I'm given exact size .png renders from Application Design showing exactly what my app should look like on Retina 4", Retina 3.5", etc.
Would like to automate a comparison between these "golden master" renders and screenshots of what the app actually looks like when that screen is shown.
Ideally I would like to have something I can run via continuous integration so I can break the build if a .xib gets messed up.
How can I do this?
Already tried:
Used Command-S in iPhone simulator to grab a screenshot suitable for comparison
Used GitHub's excellent image diff interface to manually compare the images
Pulled them up side-by-side in Preview.app, in actual size (Command-0)
Did some research on ImageMagick's comparison capabilities (examples)
Possible approaches:
Getting a screenshot of the app in code is already implemented
Similarly, I'm pretty sure I can find code to simulate a tap on the screen
Might need some way to exclude a mask or bounding box of areas known to not match exactly
Take a look at ios-snapshot-test-case, which was built for something close to this.
It will take a reference image the first time a test is run and then compare subsequent test outputs to the reference image. You could essentially use this but instead of creating reference images from the tests, you supply your own reference images.
In practice, this will be extremely tricky to do correctly. There are subtle differences in how text, gradients, etc are rendered between iOS and whatever tool your designers are using.
I'd check out KIF for functional testing.
You can create a custom test (small example near the end of the readme just above "Use with other testing frameworks") that takes a screenshot and compares it to your expected screenshot for that view. Just call failWithException:stopTest: if it doesn't match.
As you mentioned, you will want to save a mask with each expected screenshot, and apply the mask before comparing. You will always have parts of the screen that won't match, like the time in the status bar at a minimum.
For the comparison itself, here are a couple links:
Building an image mask
Slow, straightforward way to compare two images
OpenCV: I've seen this recommended, but haven't tried it.
I know this is an older question, but it's worth pointing out that KIF has built a "Perceptual Difference Testing Framework" called Lela:
https://github.com/kif-framework/Lela
If you're already using KIF this is the way to go. I believe it uses somewhat fuzzy image diffing so it may be able to get around the text rendering issues David Grandinetti mentioned. I haven't tried using it against external comps though.
If you're more comfortable with BDD/Cucumber/Gherkin syntax, you should also check out Zucchini, which uses reference images:
http://zucchiniframework.org/
I haven't used it but it's well spoken of.
I suggest you take a look at Visual CI
It's a software built for Continuous integration image compare,
It has UI that allows you to control settings which also include which parts of your image to compare
It's kind of new, but may answer your requirements better.
Related
I am researching into the best way to detect test in a photo using open source libraries.
I think the standard way is as follows (note: steps 1 - 4 all use OpenCV):
1) detect outline of document
2) transform document so it's flat and cropped, using said outline
3) Make the background of document white, using a filter
4) Feed resulting image to Tesseract
Is this the optimum process, or is there a better way, or better tools?
Also, what happens for case if the photo doesn't have a document outline (It's possible that step 1 & 2 are redundant)?
Is there anyway to automatically detect document orientation (i.e. portrait / landscape)?
I think your process is fine. I've used a similar process for an Android project.
I think that the only way you can discover if a document is portrait/landscape is to reason with the length of the sides of the bounding box of your outline.
I don't think there's an automatic way to do this, maybe you can find the most external contour approximable with a 4 segment polyline (all doable in opencv). In order to get this you'll have to work with contour hierarchy and contous approximation (see cv2.approxPolyDP).
This is how I would go for automatic outline detection. As I said, the rest of your algorithm seems just fine to me.
PS. I'll leave my Android project GitHub link. I don't know if it can be useful to you, but here I specify the outline by dragging some handles, then transform the image and feed it to Tesseract, using Java and OpenCV. Yeah It's a very bad idea to do that in the main thread of an Android app and yeah, the app is not finished. I just wanted to experiment with OCR, so I didn't care much of performance and usability, since this was not intended to use, but just for studying.
Look up the uniform width transform.
What this does is detect edges which have more or less the same width with respect to their opposite edge. So things like drainpipes (which can be eliminated at a later pass) but also the majority of text. Whilst conceptually it's similar to a distance transform, the published method uses rather ad hoc normal projection methods and Canny edge detection.
let me start off by showing that I have this UIImageView set up in my ViewController:
Each one of the lines contains a UIButton for a body part. If I select a particular button, it will segue me appropriately.
What'd I like to do is, when the user taps (but doesn't release) the button, I'd like the appropriate body part to show like this:
I can achieve this using 2 options:
UIBuzierPath class to draw, but would take a lot of trial and error and many overlapping shapes per body part to get fitting nicely as similiar in a previous question: Create clickable body diagram with Swift (iOS)
Crop out the highlighted body parts from the original image and position it over the UIImageView depending on which UIButton selected. However there would only be one image per body part, but still less cumbersome then option 1.
Now, my question is not HOW to do it, but which would be a BETTER option for achieving this in terms of cpu processing and memory allocation?
In other words, I'm just concerned about my app lagging as well as taking up app size storage. I'm not concerned about how much time it takes to do it, I want to just make sure my app doesn't stutter when it tries to draw all the shapes.
Thanks.
It is very very very unlikely that either of those approaches would have any significant impact on CPU or memory. Particularly if in option 2, you just use the alpha channels of the cutout images and make them semitransparent tinted overlays. CPU/GPU-wise, neither of the approaches would drop you below the max screen refresh rate of 60fps (which is how users would notice a performance problem). Memory-wise, loading a dozen bezier paths or single-channel images into RAM should be a drop in the bucket compared to what you have available, particularly on any iOS device released in the last 5 years unless it's the Apple Watch.
Keep in mind that "premature optimization is the root of all evil". Unless you have seen performance issues or have good reason to believe they would exist, your time is probably better spent on other concerns like making the code more readable, concise, reusable, etc. See this brief section in Wikipedia on "When to Optimize": https://en.wikipedia.org/wiki/Program_optimization#When_to_optimize
Xcode have tests functionality built in(and performance tests too), so the best way is to try both methods for one body part and compare the results.
You may find the second method to be a bit slower, but not enough to be noticed by the user and at the same time a lot more easier to implement.
For quick start on tests here.
Performance tests here.
Before clarifying my question, please just consider these two generative portraits by Sergio Albiac:
Since I really like this kind of portraits I wanted to find a way of producing them myself.
I don't have much for now, the only things I can deduce from these examples are:
each portrait takes at least two inputs, one target image (the
portrait) and one or more source images (pictures of text) whose parts are used to
generate a stylized portrait
matching the parts from source images with the target image is
done using template matching
What I'd like to know is how to proceed, what things to learn and look for? What other concepts should I consider before trying to make this work?
Cheers
The Cover Maker plugin for Fiji/ImageJ does a similar thing.
It first builds a database from your source images indexed according to color/intensity. These source images are then used to build your target image. (Contrary to your example images, it only works with a constant tile size throughout the image, though.)
Have a look at the python source code for details.
EDIT: If you want to avoid the constant tile size, you could use e.g. a quadtree segmentation or a k-means segmentation to get regions of similiar intensity/texture in your target image, and then do the template matching for the segmented regions.
A little background: I'm working on an iOS app that has a variety of status icons for various states. These icons are used in a variety of places and sizes including as UITableViewCell imageViews, as custom MKMapAnnotations and a few other spots. I actually have a couple sets which include a more static status icon as well as ones that have dynamic text injected into the design.
So at first I went the conventional route of using static raster assets, but because the sizes were dynamic this wasn't always the best solution and I wasn't thrilled with the quality of the scaling using CGAffineTransforms. So instead I changed gears a bit and tried something else:
Created a custom UIView subclass for each high level class of icon. It takes as input the model object that derives the status from (I suppose I could have also just used an enum and loaded this into some kind of model constructor but this is how I did it) so it can decide what it needs to draw, then does the necessary drawing in drawRect. Since all of the drawing is based on the view bounds it scales to any reasonable dimensions.
Created a Category which has class method constructors that take the model inputs as well as the size you want to use and constructs the custom views.
Since I also wanted the option to have rasterized versions of these icons to plug into certain places (such as a UITableViewCell imageView) I also created constructors that build the view and return a UIImage using the fast iOS7 snapshotting functions.
So what does this give me? Well here's the pros/cons that I can see.
Pros
Completely scalable graphics that can easily be used in a variety of different scenarios and contexts.
Easy compatibility with adding dynamic info to the graphics such as text. Because I have the exact shape data on everything I'm drawing I don't need to guesstimate on the bounds for a text box since I know how everything is laid out.
Compatibility with situations where I might want a rasterized asset but I still get all the advantages of the dynamic view since I'm not rasterizing it till I need it.
Reduces the size of the application since I don't need to include raster assets.
Cons
The workflow for creating the draw code in the first place isn't ideal. For simple stuff I can do it straight in code but for more complex things I'll need to create the vector asset in Illustrator or Sketch then bring it into PaintCode and clean up the generated draw code into something more streamlined. This is not the most ideal process.
So the question is: does anyone have any better suggestions for how to deal with this sort of situation? I haven't found an enormous amount of material on techniques for this sort of thing and I'm wondering if I'm missing a better way of handling this or if there are any hidden gotchas here...performance doesn't seem to be an issue from my testing with my approach but I haven't tested it on the iPad3 or iPhone 4 yet so there could still be some unknowns.
You could try SVGKit, which draws SVG files, and can export to a UIImage, if desired.
I would like to create custom tabbar items similar to the ones shown here:
I assume these have to be designed and created first in Photoshop or a similar application. Are there any resources or tutorials available that demonstrate the creation of such items in Photoshop and how these are then used in MonoTouch?
Creating and bundling bitmaps is one option - and likely the most common one (for which googling should turn up several tutorials). Now in order to get optimal quality you need to supply multiple sets for the old iPhone/iPod, the newer retina iPhone/iPod, the iPad (1,2) and the retina iPad 3. This can takes a lot of space to cover each case with beautiful icons (or it won't look as good).
An alternative is to create the bitmaps at runtime, e.g. using the CoreGraphics API. This might seems counterproductive (and can surely be in many cases) but it has the advantage of requiring less (storage) space and/or getting better quality (see note).
Why ? because if you create them at runtime then you'll only create the ones for the specific device you're executing on. You can even cache them and re-create them when missing (e.g. if iOS flush your application cache).
If you're not an artist (and I'm not) you might want to look at easily licensable vector icons. The ones from your screenshot looks monochrome and could even use (bundle or extra the outlines from a) custom font - like the one provided by FontAwesome (CC BY 3.0) or similar sources.
Note: Maybe you noticed (I know I did) that some iPad applications looked beautiful (compared to others) on the iPad3 even if they were released months before the hardware become available. Vector graphics wins ;-)
UPDATE: Someone already made a script to convert the FontAwesome characters to iOS tab bar icons. However since it's done outside the app you'll need multiple versions of each bitmap to get the best look on every devices.