The Rect Transform Scaler requires a Rect Transform component, and automatically updates its X and Y scale, or, its width and height, based on the active Scale Profile, and its current interpolation value. 

When Scaling Mode is set to Scale, this component should only be added to Game Objects whose Rect Transforms’ scale won’t be manipulated by any other component.

The Sliced Image Scaler adjusts its required Image component’s Pixels Per Unity Multiplier to the active Scale Profile, and its current interpolation value. It is recommended to add this component to UI elements that have outlines, and use the Rect Transform Scaler with Scaling Mode set to Size. When an Image’s size changes, it will – by default – retain its Pixels Per Unity Multiplier, and will therefore look different compared to Images whose scale is adjusted by the Rect Transform Scaler.

The Image component’s Image Type must be set to Sliced to enable scaling. The Sliced Image Scaler only displays a message or a warning, letting you know if it will or will not have any effect on the Game Object’s visuals.

The Stretching Grid Layout Group is an extension of the Grid Layout Group that can calculate the Cell Size value for you, based on your preference. Its primary purpose is to automatically stretch the cells to fill the bounds of the Rect Transform, while taking Padding and Spacing into consideration.

Just like Scaling Horizontal and Vertical Layout Groups, this component can also update Padding and Spacing values based on the active Scale Profile, and its current interpolation value.

When Stretch Cells is toggled off, the component functions exactly like a Grid Layout Group. To enable automatic Cell Size calculation, check the Stretch Cells box, select the Constraint type, and set the following values that will appear based on your selection.

When Constraint is set to Flexible, the component will try to match your Preferred Cell Size by setting Cell Size to a value closest to your preference.

When Constraint is set to Expanded, the component will allow you to set the width-to-height ratio of your cells. Setting the Match slider to the Width end (0) will make the cells stretch across the Rect Transform’s width (minus Left and Right Padding), whereas setting it to the Height end (1) will make them match its height (minus Top and Bottom Padding).

The Match slider allows you to turn a Grid Layout Group into a Horizontal or Vertical Layout Group – at least visually.

While an Expanded Constraint will fit all children of the Rect Transform (that doesn’t have a Layout Element with Ignore Layout set to true) into the layout, Fixed Cell Count allows you to set the number of cells that should appear within its bounds. If there are more children, however, they will appear outside the Rect Transform’s bounds.

When Constraint is set to Fixed Column Count, Cell Size will be calculated based on the number of columns the layout should be divided into (Constraint Count), and the preferred height of each cell.

The Stretching Grid Layout Group will, as always, try to match the Cell Size as closely as possible based on these preferences, while considering the Rect Transform’s size, as well as Padding and Spacing values.

The Fixed Row Count Constraint type is the same as Fixed Column Count, but rotated by 90 degrees. Horizontal and vertical values are swapped; Constraint Count refers to the number of rows division will be based on, and cells’ preferred width will be matched as closely as possible.

Scale Profiles contain data used by Rect Transform Scalers, Scaling Horizontal Layout Groups, Scaling Vertical Layout Groups, Stretching Grid Layout Groups, Scaling Layout Elements, Sliced Image Scalers, and Text Stylers to set values that influence the size of your UI. While it is possible to create several Scale Profiles, only one of them can be active at any given time. Active Scale Profile can be changed during runtime, updating all relevant components.

Click on the “Edit” button (gear icon) next to a Scale Profile to open its editor, or, click on the “New Scale Profile” button to create a new one – this will automatically open the editor.