Develop Reference

libgdx resize image on multiple screens ratio

I know how to set Image width and height using pixel coords. Is there a way to set relative coords? I want to deal with multiple screens.
For example i have 1920x1080 screen size. And i have relative coords width (-100,100) and height = 200*1080/1920=112.5, height(-56.25, 56.25)
Can i use this relative coords to set width and height? and how to do it?
Is there any best practices to handle different screens ratio, handle orientation change correctly?
thanks in advance.
here is how i'm using it in my app:
create()
public void create() {
stage = new Stage();
Gdx.input.setInputProcessor(stage);
camera = new OrthographicCamera(Gdx.graphics.getWidth(), Gdx.graphics.getHeight());
camera.setToOrtho(true, Gdx.graphics.getWidth(), Gdx.graphics.getHeight());
camera.update();
Skin skinBackground = new Skin();
skinBackground.add("background", new Texture(Gdx.files.absolute(FilePathSlicer.preparePath(taskSheet.background.getPicUrl()))));
background=new Image(skinBackground,"background");
if(background!=null) {
background.setWidth(width);
background.setHeight(height);
stage.addActor(background);
}
}
render
public void render() {
Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);
Gdx.gl.glClearColor(255/255f, 255/255f, 255/255f, 1);
stage.getBatch().setProjectionMatrix(camera.combined);
stage.act(Gdx.graphics.getDeltaTime());
stage.draw();
}

that is what Viewports are for. Viewport is kind on flexible are connected with a stage (which is actually something like transparency that you are adding items [buttons, labels etc...] on).
It cares for scaling in a way you defined by creating a proper type of viewport.
Main steps are:
//create() method
stage = new Stage(); //creating a stage
viewport = new FillViewport( screenWidth, screenHeight ); //creating viewport choosing a proper Viewport class - for example Fill
stage.setViewport( viewport ); //applying actors (buttons, labels etc...) to a stage
//render() method
stage.act(); //acting a stage to calculate positions of actors etc
stage.draw(); //drawing it to render all
//resize(width, height) method
viewport.update(width, height); //updateing viewport that it scales in proper way
You have many types of vieports like just for example:
FillViewport - stretches graphics to fill the display
FitViewport - adding black stripes when screen is to wide
ExtendViewport - cutting what is out of the screen
etc.
Of course you can have many stages and others viewport for each of them.
To read more about stages, actors and viewports visit: https://github.com/libgdx/libgdx/wiki/Scene2d
You don't have to care about screen orientation - all you need to do is to define your app orientation in android Manifest

Libgdx, scale sizes based on device screen

I am working on my first libgdx app, a game. I have made some apps in IntelliJ before, but this is different. I am struggling with how my game will look over several devices, how to make everything scale appropriately.
If you can take a look at how I have it now, and maybe help me understand how it 'should' be to get the most out of it?
I have three classes, 'MyGame', 'MainMenuScreen' and 'GameScreen'.
// MyGame.java
WIDTH = Gdx.graphics.getWidth();
HEIGHT = Gdx.graphics.getHeight();
// MainMenuScreen
public void show(){
WIDTH = Gdx.graphics.getWidth();
HEIGHT = Gdx.graphics.getHeight();
camera = new OrthographicCamera();
camera.setToOrtho(false, 800, 480);
}
// GameScreen
public void show(){
camera = new OrthographicCamera();
camera.setToOrtho(false, 800, 480);
}
So, the 800, 480 is pixels, lets say I want to add something to this, and make it 32x32px (height, width), will it look the same on all devices? Bigger on large screens, and smaller on small screens, but always relevant to, lets say a background that is 800x480px?
I hope you understand what I am getting at. I posted the code I thought was relevant to the question, if u want more code, just say so, just tell me what you need.

Why is my sprite not being drawn correctly (libgdx)?

I have a 1024x1024 pixel image in a jpg file. I am trying to render it onscreen with libgdx such that it fills the whole screen. At this stage I am not concerned with the image preserving its aspect ratio.
In my show() method I parse the jpg and initialize the sprite thus:
mWidth = Gdx.graphics.getWidth();
mHeight = Gdx.graphics.getHeight();
mCamera = new OrthographicCamera(1, mHeight/mWidth);
mBatch = new SpriteBatch();
mTexture = new Texture(Gdx.files.internal("my jpg file"));
mTexture.setFilter(TextureFilter.Linear, TextureFilter.Linear);
TextureRegion region = new TextureRegion(mTexture);
mSprite = new Sprite(region);
mSprite.setSize(0.99f, 0.99f);
mSprite.setOrigin(mSprite.getWidth()/2, mSprite.getHeight()/2);
mSprite.setPosition(-mSprite.getWidth()/2, -mSprite.getHeight()/2);
and in the render() method, I draw the sprite thus
Gdx.gl.glClearColor(1, 1, 1, 1);
Gdx.gl.glClear(GL10.GL_COLOR_BUFFER_BIT);
mBatch.setProjectionMatrix(mCamera.combined);
mBatch.begin();
mSprite.draw(mBatch);
mBatch.end();
but all that is actually rendered is a blank white screen. What am I doing wrong?

You should use
mCamera = new OrthographicCamera(mWidth, mHeight);
in stead of
mCamera = new OrthographicCamera(1, mHeight/mWidth);
in most cases, unless you want to scale things in a different way.
Check if your code has actually found and read the file successfully. If not, check things like full path, file extension, intermediate spaces etc.
In resize method, try adding following
mBatch.getProjectionMatrix().setToOrtho2D(0, 0, mWidth, mHeight);
If it isn't working even then, I'd recommend falling back to the working libgdx logo sprite being drawn when you create a new project with setup ui. Change things slowly from there.
For reference, use https://code.google.com/p/libgdx-users/wiki/Sprites
Good luck.

To the best of my knowledge, mSprite.setSize(0.99f, 0.99f); sets the pixel width and height of a sprite whereas setScale scales the sprite's dimensions. Setting setSize to something larger such as 256 x 256 should make your sprite visible and setting it to the resolution of the screen should make it fill the screen if all goes well. The examples linked by Tanmay Patil are great so look into them if you're having trouble.

How to correct aspect ratio of tiled map rendering in libgdx?

First of all, some explanation of situation.
Init tiled map code:
map = new TmxMapLoader().load("maps/map.tmx");
mapRenderer = new OrthogonalTiledMapRenderer(map, 1f / 32f);
Rendering code:
mapRenderer.setView(cam);
mapRenderer.render();
The problem. I have square map and non-square screen. Map fills whole screen. Because of that map scales incorrectly (32x32 cells transform to 32x40 cells according to X and Y scaling of screen). How can I render map without filling whole screen?

Based on the comments on the question...
You are using a square camera on a non-square screen and ignoring the aspect ratio. To take into account the aspect ratio, do something like this:
float w = Gdx.graphics.getWidth();
float h = Gdx.graphics.getHeight();
MyWorld.CAMERA_HEIGHT = 10; // Fill the height of the screen
MyWorld.CAMERA_WIDTH = 10 * (w / h); // Account for the aspect ratio
camera = new OrthographicCamera(MyWorld.CAMERA_WIDTH, MyWorld.CAMERA_HEIGHT);

Andengine Android Game resizing sprites with respect to screen size?

So I need to resize my sprites with respect to the phones screen size,
I do the following:
final Display display = getWindowManager().getDefaultDisplay();
cameraWidth = display.getWidth();
cameraHeight = display.getHeight();
//check to load male or female
Intent sender=getIntent();
String extraData=sender.getExtras().getString("char");
if(extraData.contains("1"))
{
isMale = 1;
}
else
{
isMale = 0;
}
mCamera = new Camera(0, 0, cameraWidth, cameraHeight);
return new Engine(new EngineOptions(true, ScreenOrientation.LANDSCAPE,
new RatioResolutionPolicy(cameraWidth, cameraHeight), mCamera)
.setNeedsMusic(true).setNeedsSound(true));
However, for sprites, ie the player and enemies, I give them an arbitrary size such as 50 pix by 50pix - Now on small screens they appear really large! how can I resize them with respect to the screen size?
Also, These images are loaded from assets folder, so they have nothing to do with HDPI and LHPI image folders.
Thanks in advance community.

You should either use SVG graphics that are scalable on different device screens.
What i would suggest is you set the CAMERA_WIDTH and HEIGHT to a screen size no matter what size device it is on.
For example, for a project i am making i have a camera width and height of 800x480.
This way you dont have to worry about resizing any sprites. They all appear the same on each device while scaling up by the engine with the RationResolutionPolicy.
This is the best way to go about this.
If you set the screens size based on the device you will have to supple different graphics for each.
So i would recommend using SVG graphics so that when the images are scaled up automatically by the engine they dont loose quality. OR you can use png's and make them large, that way they will only be scaled down. And as you know they wont lose image quality by scaling down.