GetScreenResolution() returns wrong value?

[kitblackheart_1 (KitBlackheart)]

Hello and good morning,

I am currently displaying a widget to my game viewport using SCanvas, and setting the size of a SColorBlock inside of it according the the values returned by the function GetScreenResolution() found in the user game settings class, I am setting the values utilizing this:

//FOR WIDTH
GEngine->GetGameUserSettings()->GetScreenResolution().X
//FOR HEIGHT
GEngine->GetGameUserSettings()->GetScreenResolution().Y

However, it seems its returning the wrong size, as if the widget were being scaled down, because, even though, through those functions i do get the real resolution, the widget size is still only about 60% of the screen.
Also, the alignment of the SCanvas is set to VAlign_Fill and HAlign_Fill, for width and height respectively.

I want to know what have i been doing wrong, or if is there a scale ratio for widgets that is doing that to my game.
*PS: I want to know if its a bug or how to fix it, I dont want to use a workaround or SOverlay, because i have other classes depending on this and i do not wish to reformulate them.

HERE IS A SNIPPET OF MY CODE:

//RETURNS 1280 FOR WIDTH AND 720 FOR HEIGHT
float width = GEngine->GetGameUserSettings()->GetScreenResolution().X;
	float height = GEngine->GetGameUserSettings()->GetScreenResolution().Y;

	ChildSlot
		.VAlign(VAlign_Top)
		.HAlign(HAlign_Left)
		[
			SNew(SCanvas)
			+ SCanvas::Slot()
			.VAlign(VAlign_Fill)
			.HAlign(HAlign_Fill)
			.Position(FVector2D(0, height - (height*0.07)))
			.Size(FVector2D(width, height*0.07))
			[
				SNew(SColorBlock)
				.Color(FColor(0, 0, 0, 100))
				.Size(FVector2D(width, height*0.07))
				
			]	
		];

AND HERE IS THE RESULT ON SCREEN:

[Fiskislod (Fiskislóð)]

Hi. Sorry for the delay!

Everything is working as designed. However, it is not obvious why the design is so complicated. Let me explain.

Slate does everything in Slate Units or su instead of pixels. The reason for this is that display density varies, and you want to be able to write a UI once and have it work on many different display densities. Unreal will automatically change the ration of su to pixels as you change your resolution. This should produce the appearance of the UI getting bigger or smaller along with the 3D scene (as opposed to your UI reflowing kind of like a webpage does). Both UI scaling and reflowing can be desireable though.

So, if you want to arrange elements on the screen there are many different ways of doing that. You could use layout panels (e.g. like horizontal and vertical panels) to accomplish what you want. You don’t even need to know the resolution of the game; Slate will figure it out for you. You could just do something like:

ChildSlot
.VAlign(VAlign_Fill)
.HAlign(HAlign_Fill)
[
  SNew(SOverlay)
  +SOverlay::Slot()
  .VAlign(VAlign_Bottom)
  .HAlign(HAlign_Fill)
  [
      SNew(SColorBlock)
      .Color(FColor(0, 0, 0, 100))
      .Size(FVector2D(100, 20)) // width =100, height = 20
      // Note that `width` will be ignored because the parent overlay is going
      // to `HAlign_Fill` all the available space with the Block inside this slot.
      // The `height` will be respected. You don't need to multiply by resolution because
      // this size is in `su` and will be scaled with resolution automatically.
  ]
];

BTW, please take a look at this doc about DPI scaling in UE4:

DPI Scaling