Background image size Sprite Kit Game

Question

i just started a new Sprite Kit project to learn how to use it. I watched and read a lot of tutorials but no tutorial has a answer for my question/problem.

I want to

Answer 1

The short answer to your immediate problem:

background.size = self.frame.size;

The long answer, and discussion about other methods...

The scene works in Logical Units, not physical pixels (as mentioned in other posts).

1 Logical Unit is typically 1 pixel on older kit, and 2 pixels on newer kit/iPads. This maybe 4 pixels in 5 years time.

Working in Logical Units protects you from sizes changing in future, and is supposed to help the programmer - although this often confuses newbies.

The simplest way to get an image to fill the current scene is to set its size in 'logical units' no matter what size it is originally.

This is better than using SKActions (because the user might end up seeing them, and any calculations based on the dimensions of the node can't be relied upon until the action has completed), and it's better than scaling because scaling requires you to know the original image dimensions.

You can do this via the size property, or through an action if you really want to make an animation.

In the scene simply....

-(void)didMoveToView:(SKView *)view
{
    [super didMoveToView:view];

    SKSpriteNode* background = [SKSpriteNode spriteNodeWithImageNamed:@"myBackground"];
    background.size = self.frame.size;
    background.position = CGPointMake(CGRectGetMidX(self.frame), CGRectGetMidY(self.frame));
    [self addChild:background];
} 

Alternatively, if your image works well, as is, on higher resolutions, you can rename your image to myBackground@2x.png, add that to your project and you probably won't need to resize at all, but you'll also need to shrink it by 50% for the lower resolution devices, and save that as myBackground.png.

I always set the size of an imported image to exactly the logical units I want (or a percentage of the screen dimensions) to preserve my sanity.