Building Layouts - Unity 3D UI Essentials - page 54

° Event Camera ( World Space only ): This identifies which camera
should be used to render and receive events on (same as the Render
Camera for Screen Space - Camera ).
° Sorting Layer ( Screen Space - Camera and World Space only ): When
the Canvas is used with other Sprite Rendering components in a
scene (such as the 2D rendering system and Sprites), this sets which
Sprite Sorting Layer the canvas renders on.
° Order in Layer ( Screen Space - Camera and World Space only ):
The draw order on the selected Sprite Sorting Layer .
• Canvas Scaler (the Script component): Defines how the canvas resolution
and positioning units are measured. For more details, see the Resolution and
scaling section later in this chapter.
• Graphics Raycaster (the Script component): This component is part of a
new Raycasting framework delivered with the new UnityEvent system.
(See the following UnityEvent system section later in this chapter). Events
and human interaction are derived through a new and efficient Raycasting
system (which the Graphics Raycaster is one implementation of). This
provides hit tests from the user's current input position through the Unity UI
layer and feeding back information to the UnityEvent system. The settings
here provide configurations to drive how the raycast functions will react;
they are as follows:
° Ignore Reversed Graphics : If a UI element is reversed (seen from the
back), then this setting will define if a raycast hit will qualify as a hit
or not and generate an event (basically does what it says on the tin).
° Blocking Objects : Allows you to block raycast hit tests from 2D, 3D,
Everything or None (allowing hit tests from everything).
Note: By default, raycasts will pass though the UI layer in to your
scene, so this setting can be very useful. But you can also control
this behavior with a Canvas Group (see the Canvas Group section
later in this chapter).
° Blocking Mask : Allows you to restrict the rendering layers
that raycasts will operate on: you can select multiple layers,
a single layer, or all layers.