UI Image's alpha is not reflecting in the render

[LaMoustacho98]

I spent half an hour wondering what was wrong with my code until I realized it’s the engine itself creating this weird problem. Is there a reason why the UI image is either fully opaque or completely transparent when the alpha is at 0?

[PeasantProductions]

In Unity, when an alpha value of 0 (fully transparent) is used for a UI image, it means that pixel becomes invisible. Unity’s rendering system completely ignores pixels with an alpha of 0, showing whatever is behind them instead. On the other hand, when the alpha is 1 (fully opaque), the pixel is fully visible and its color shows up without any transparency.

If you’re seeing UI images that are either fully visible or completely invisible when they should be semi-transparent, it might be due to how Unity handles these alpha values. Check the shader settings, texture import settings, and make sure UI elements are layered correctly in the Canvas to resolve such issues. This ensures Unity renders your UI elements with the transparency levels you expect.

• Shader Settings:
• Ensure that the shader used by your UI image supports transparency. Unity’s default UI shaders (UI/Default, UI/DefaultETC1, etc.) should handle transparency correctly.
• If using a custom shader or modified shader, verify that it’s configured to correctly blend alpha values. Look for properties like Blend Mode or Rendering Mode in the shader’s settings.
• Texture Import Settings:
• If your UI image uses a texture (like a PNG file) with transparency, check the import settings of the texture in Unity (Texture Type, Alpha Source, Alpha Is Transparency, etc.).
• Ensure that Alpha Is Transparency is checked if your texture contains alpha transparency information.
• Canvas Render Mode:
• Depending on the Canvas render mode (Screen Space - Overlay, Screen Space - Camera, World Space), transparency and layering might behave differently.
• Adjust the Canvas render mode as per your project’s needs. For simple UI elements, Screen Space - Overlay is often sufficient.
• Layering and Sorting:
• Verify that UI elements are correctly layered and sorted within the Canvas hierarchy.
• Elements with lower Order in Layer values are rendered on top of elements with higher values. Ensure that elements requiring transparency are properly ordered relative to each other.
• Debugging Tools:
• Use Unity’s Scene view and Game view to inspect how UI elements are rendered. Turn on Gizmos in the Scene view to visualize UI elements and their transparency.
• Check for any warnings or errors related to shaders, materials, or textures in Unity’s Console window.

[LaMoustacho98]

I’m just using the solid colour and there are no other active UI elements. The render mode is screen space - overlay.