How to change canvas' size in unity3d

Question

I can not change canvas' size when it's in Screen Space - Overlay Mode; After some research I found that the size of a canvas is determined by your game's screen size. The canvas just covers your screen. So I think I could change my camera's size to change canvas' size. But it does not work. Does anyone know how to set a specific size to a canvas?

Answer 1

So may be my question should be how to change the screen size showed in editor?

To change the screen size, go to the Game window (accessed by the menu "Window->General->Game"). At the top of the window will be a screen size menu (outlined in green, below) to change the screen size. When pressed, it will display the list of screen sizes that will be emulated. I say "emulated" instead of "displayed" because it is possible to have a screen size larger than the screen on which you are working. It is also possible to zoom into a screen. The "Scale" slider (to the right of the screen size menu) will allow you to scale up/down.

As a note, the list of screens and resolutions shown are related to the current build target (accessed by "File->Build Settings..."). For example, common iOS screen sizes are displayed in the list when the build target is iOS.

Answer 2

Use the Canvas Scaler Component

Unity3D Documentation: Canvas Scaler