Develop Reference

Can't Center the scene to the screen in Godot?

I have few scenes in my project. I was able to center all of the other scenes. But i cannot center the main scene in my project. Its fine when it opened on a mobile device(probably because resolution matches i guess). but when i opened it in tablet(its an old tab "xiaomi tab 3") its always align to the right on the screen. I was able to center other scenes but i cant center the main scene to screen for some reason. project setting set as 2D and Expand. I also tried to use Control nod, canves layers, margine containers.. but nothing works. If someone can give any suggestions, Thank you in advance.
img1
https://i.stack.imgur.com/FJOHl.jpg
project
1920 x 1080

I have seen this problem, or similar, in windowed mode. I don't know if this is the exact case, but if it doesn't mess with your project, try full-screen mode.
If it's that, you can also take care of the window bar size (which is a problem because it can change from different devices), since godot will count its pixels too.
Notice that you're only having this problem in one axis.
Also, I think you could take a look into the Viewport Stretch Mode. It could mess your graphics depending of the intended result—but other projects won't even notice, so judge for yourself.
The viewport setting sets the root scene’s Viewport to the base resolution. The rendered output of the root Viewport is then scaled to the display resolution. [...]
The viewport setting is a better choice than the 2d setting when pixel-perfect precision is required, since primary rendering still occurs at the base resolution.
Support multiple devices
Scaling correctly for all devices could be an odyssey, so bon voyage.

How can I implement a ScreenViewport?

I'm new to libgdx and I have a question:
How can I implement a ScreenViewport? I created a new class but I think that is not enough. I'm developing a game and therefore I need the viewport so that every device is gets supported.
I also developed a score but without a viewport the texture will be on different positions on the screen. However, I want it on a certain position!
Hope someone can help me. Thanks!

World size of ScreenViewport is based on the size of the screen so for different screen size, you'll get different world size.
You should take a look of libgdx wiki, and choose appropriate viewport for your requirement.
I'll recommend you to use ExtendViewport because it keeps the world aspect ratio without black bars. Check this answer.

libgdx -> camera and viewports

I have made my game, which scaled accordingly to a % of the screen width with the Gdx.graphics.getWidth() method, and it works perfectly on all screens.
Now I am trying to learn viewports, but seems like there is a lot more trouble, like when does it take in world coordinated or when does it take actual screen pixels.
Do I have to constantly convert beetwen these two measurments? It seems like there is alot more trouble, than if I just scale it the old fasion way...
I can use the whole screen, and manually make the pictures non streched, if I used a FitViewport I would have like blackbars and the game would be totally different.
Any clear suggestions to why to use these ports, cause I cannot seem to understand them...

The thing is that you do not have to do anything especially making any conversion.
Viewport is a kind of tool that handling your app's rendering on many types of screens (I mean many other ratios) and you do not have to worry about it anymore.
Only thing you have to do is to "tell" viewport what is the size of your screen and to handle screen resizing by updateing the viewport. Then you are treating your app like it would be always for example 800 x 600px no matter how it looks actually.
The way your app will render depends on what viewport implementation you will use. For example:
FitViewport will fit your screen to device and add some black bars
FillViewport will fit your screen to device and cut off overflowing part
and so on...
The a look at official Viewport libGDX tutorial. Also you can take a look at this thread to get some information how to deal with viewports.

iOS) How to set image's size and coordinate as the same as android

I'm developing ios app for a service that already has android application.
I have psd files and png files corresponding android one.
But I don't know how to set image's size and coordinate as the same as android....
Is there a way to follow android's ratio constructively?
I'm just setting imageview by eye measurement...
By eye measurement, I calculated ratio, size(width,height) and coordinate...
I want to make images set as the same as the android's one.
I'm just using 'aspect to fit', that makes this problem less heavy but not perfect

Calculating everything manually will be horrible when you want to support multiple devices of different screen size. Use constraints if you want to scale the UIImageView to a certain ratio of another view.
Please refer to the auto layout guide at https://developer.apple.com/library/ios/documentation/UserExperience/Conceptual/AutolayoutPG/Introduction/Introduction.html

Android: Doing all my drawing on a SurfaceView; what's the proper way of making sure my drawing conforms to any screen size?

I'm making an app (a game, to be exact) where each activity uses a SurfaceView for the UI. All of the drawing is done through onDraw. I am also designing this to use no Bitmap assets, so everything that is drawn is produced directly by the app. I'm trying to design the app in such a way that it can easily be viewed on any screen size.
So here's how I'm accomplishing this: I'm doing my testing on a Galaxy S4, which has a screen size of 1080x1920. In the constructor for each activity, the width and height of the current screen are calculated and stored as ints "w" and "h" (the app is already locked in portrait). Then, whenever anything needs to be drawn onto the screen, I multiply the desired dimension (as seen on my 1080x1920 screen) by either w or h, and then divide by 1080 or 1920. Since I'm not using any Bitmap assets, I never need to worry about pixelated images or anything this way.
This gets the job done, but seems like a bit of a roundabout way of doing it. I figured there would be a better framework for getting this done, and I'm worried that these big calculations are eating into my drawing time (running at 30FPS can get a little jerky).
Is this is the customary way of doing it, or is there a better way out there?

There's a very simple yet effective way to do it, you can declare all your sizes in a dimen file for each specific density/size, as you usually do for layouts e.g:
values/dimens.xml <--- With default sizes
values-sw600dp/dimens.xml <-- Tablets sizes
(etc...)
Now before you start drawing, load all the values in your program only once, maybe onCreate of your drawing activity, using the following command:
float someItemSize = Context.getResources().getDimension(R.dimen.some_itemSize)
etc...
That way, you let the operating system do the pixels conversion for you, you should do it only once and most important, this will give alot of flexibility to your code because you will be able to change sizes from xml files without even touching your actual code, hence, the customization should be easier as well as future changes...
Hope it helps!
Regards!

There are two considerations: screen size and screen aspect ratio. If you simply scale everything to match the display, you will appear stretched a bit if you put a 4:3 device next to a 16:9 device.
You generally have two options for dealing with the aspect ratio: you can letterbox / pillarbox the output (which is fine for movies, but looks kinda lame for an app), or you can recognize that your output isn't always proportionately the same, and adjust the layout to fit nicely on the screen.
As far as size matching goes, when using a SurfaceView you can actually use a single size and then let the hardware scaler handle the rest. For an example of this, see the "Hardware scaler exerciser" in Grafika. I put a demo video here, though it's a bit hard to evaluate after getting rinsed through screenrecord + youtube. What you're seeing is the same couple of shapes rendered onto a Surface whose size has been set to an arbitrary value, and then scaled up to match the display. This is most obvious on the final setting, where it's drawing on a 106x64 surface.
With this, you could size your assets for 720p and always draw them the same way, and let the scaler deal with the stretching. See also this blog post.