Scale UI for multiple resolutions/different devices - user-interface

Question

I have a quite simple unity GUI that has the following scheme :
Where Brekt and so are buttons.
The GUI works just fine on PC and is on screen space : overlay so it is supposed to be adapted automatically to fit every screen.
But on tablet the whole GUI is smaller and reduced in the center of the screen, with huge margins around the elements (can't join a screenshot now)
What is the way to fix that? Is it something in player settings or in project settings?

Answer 1

Automatically scaling the UI requires using combination of anchor,pivot point of RecTransform and the Canvas Scaler component. It is hard to understand it without images or videos. It is very important that you thoroughly understand how to do this and Unity provided full video tutorial for this.You can watch it here.
Also, when using scrollbar, scrollview and other similar UI controls, the ContentSizeFitter component is also used to make sure they fit in that layout.

Answer 2

There is a problem with MovementRange. We must scale this value too.
I did it so:
public int MovementRange = 100;
public AxisOption axesToUse = AxisOption.Both; // The options for the axes that the still will use
public string horizontalAxisName = "Horizontal"; // The name given to the horizontal axis for the cross platform input
public string verticalAxisName = "Vertical"; // The name given to the vertical axis for the cross platform input
private int _MovementRange = 100;
Vector3 m_StartPos;
bool m_UseX; // Toggle for using the x axis
bool m_UseY; // Toggle for using the Y axis
CrossPlatformInputManager.VirtualAxis m_HorizontalVirtualAxis; // Reference to the joystick in the cross platform input
CrossPlatformInputManager.VirtualAxis m_VerticalVirtualAxis; // Reference to the joystick in the cross platform input
void OnEnable()
{
CreateVirtualAxes();
}
void Start()
{
m_StartPos = transform.position;
Canvas c = GetComponentInParent<Canvas>();
_MovementRange = (int)(MovementRange * c.scaleFactor);
Debug.Log("Range:"+ _MovementRange);
}
void UpdateVirtualAxes(Vector3 value)
{
var delta = m_StartPos - value;
delta.y = -delta.y;
delta /= _MovementRange;
if (m_UseX)
{
m_HorizontalVirtualAxis.Update(-delta.x);
}
if (m_UseY)
{
m_VerticalVirtualAxis.Update(delta.y);
}
}
void CreateVirtualAxes()
{
// set axes to use
m_UseX = (axesToUse == AxisOption.Both || axesToUse == AxisOption.OnlyHorizontal);
m_UseY = (axesToUse == AxisOption.Both || axesToUse == AxisOption.OnlyVertical);
// create new axes based on axes to use
if (m_UseX)
{
m_HorizontalVirtualAxis = new CrossPlatformInputManager.VirtualAxis(horizontalAxisName);
CrossPlatformInputManager.RegisterVirtualAxis(m_HorizontalVirtualAxis);
}
if (m_UseY)
{
m_VerticalVirtualAxis = new CrossPlatformInputManager.VirtualAxis(verticalAxisName);
CrossPlatformInputManager.RegisterVirtualAxis(m_VerticalVirtualAxis);
}
}
public void OnDrag(PointerEventData data)
{
Vector3 newPos = Vector3.zero;
if (m_UseX)
{
int delta = (int)(data.position.x - m_StartPos.x);
delta = Mathf.Clamp(delta, -_MovementRange, _MovementRange);
newPos.x = delta;
}
if (m_UseY)
{
int delta = (int)(data.position.y - m_StartPos.y);
delta = Mathf.Clamp(delta, -_MovementRange, _MovementRange);
newPos.y = delta;
}
transform.position = new Vector3(m_StartPos.x + newPos.x, m_StartPos.y + newPos.y, m_StartPos.z + newPos.z);
UpdateVirtualAxes(transform.position);
}