# Unity UI Optimization Tool A Unity Editor tool that automatically optimizes selected UI game objects (including Prefabs) to save you time.

## 🖥️ How It Works For starters, import the package located in the [Releases](https://github.com/JoanStinson/UnityUIOptimizationTool/releases) section into your project. Now then, inside the Unity Editor, select any number of game objects anywhere: in the scene's Hierarchy, in the Project window or in Prefab Edit Mode. Next, go to Tools > JGM > Optimize Selected UI GameObjects and press it. It will automatically optimize the selected game objects (including Prefabs) with the supported techniques.

## 🛠️ Unity UI Optimization Techniques

🛠️ Using more Canvases

### Using more Canvases Every time a single UI element inside a Canvas changes (e.g. change 1 Text or Image), the whole Canvas has to generate the meshes and draw them all over again (very costly).

🛠️ Separating objects between static and dynamic Canvases

### Separating objects between static and dynamic Canvases * Static Canvas: contains UI elements that are never going to change; good examples of these are background images, labels, and so on. * Incidental Dynamic Canvas: contains UI elements that only change in response to something, such as a UI button press or hover action. * Continuous Dynamic Canvas: contains UI elements that change regularly, such as animated elements.

🛠️ Disabling Raycast Target for non-interactive elements

### Disabling Raycast Target for non-interactive elements For all Image components that are not part of a Button, disable the Raycast Target (basically disable it in all images except for buttons).

Each time there is a UI input (click, tap, scroll, etc.) Unity's GraphicsRaycaster iterates over all the Raycast Targets in the scene, so the less we have the more processing we save.

🛠️ Hiding UI elements by disabling the parent Canvas component

### Hiding UI elements by disabling the parent Canvas component To avoid the Canvas regeneration, it's good habit to split the UI into different Canvases, and instead of disabling a LayoutGroup, disable an entire Canvas.

🛠️ Avoiding Animator components

### Avoiding Animator components Unity's Animator components are meant for 3D avatar animations primarily. Using it for UI elements causes extra processing.

Instead, the best approach is to use a custom tweening tool such as DOTween.

🛠️ Explicitly defining the event camera for World Space Canvases

### Explicitly defining the event camera for World Space Canvases Always set the Event Camera in a World Space Canvas as if there is no Camera assigned, it will call FindObjectWithTag("Main Camera") on every single frame! ☠️

🛠️ Don't use alpha to hide UI elements

### Don't use alpha to hide UI elements Even though the Image's color property is set to alpha 0, it will still cause a draw call.

Instead, disable the game object itself, or set the alpha of a Canvas Group to 0. This will prevent any draw calls from this object and its childs (0 draw calls).

🛠️ Make sure to use a RectMask2D

### Make sure to use a RectMask2D Like this, any element that is not inside the Scroll Rect, will not be drawn saving plenty of draw calls.

🛠️ Disable Pixel Perfect for ScrollRects

### Disable Pixel Perfect for ScrollRects Pixel Perfect makes UI elements appear sharper, but since in a Scroll Rect there's going to be movement, we won't notice it and we'll save a lot of processing.

The Scroll Rect should be on a separate Canvas with this setting off and other UI elements appearing in the same screen, would be in another Canvas with this setting on.

🛠️ Manually stop ScrollRect motion

### Manually stop ScrollRect motion We can use ScrollRect.StopMovement() to stop the motion once the ScrollRect.velocity is below a certain threshold to reduce regeneration frequency.

🛠️ Using empty UIText elements for full-screen interaction

### Using empty UIText elements for full-screen interaction For a Button that's going to be interactable full-screen, for the Button's Target Graphic, don't use an Image that fills the whole screen and has a color alpha set to 0 (as transparency breaks batching processes).

Instead, for the Button's Target Graphic, use a Text with no Font or Text defined.

🛠️ Reduce game objects inside Prefabs

### Reduce game objects inside Prefabs Wherever possible, try to reduce the number of game objects inside of a Prefab, maybe in some occasions it's possible to merge 3 game objects with Images into 1 single game object with 1 Image.

🛠️ Avoid nested Layout Groups

### Avoid nested Layout Groups Wherever possible, try to reduce the amount of nested Layout Groups as it's very costly performance wise.

## 🧰 Tool Supported Techniques ✅ Disabling Raycast Target for non-interactive elements
✅ Avoiding Animator components
✅ Make sure to use a RectMask2D
✅ Disable Pixel Perfect for ScrollRects ## 📚 Bibliography * [Unite Europe 2017 - Squeezing Unity: Tips for raising performance](https://youtu.be/_wxitgdx-UI?t=1426) * [Unity Game Optimization: Enhance and extend the performance of all aspects of your Unity games](https://www.amazon.com/Unity-Game-Optimization-Enhance-performance/dp/1838556516) * [Unity Learn - Optimizing Unity UI](https://learn.unity.com/tutorial/optimizing-unity-ui)