in2
The in2 attribute identifies the second input for the given filter primitive. It works exactly like the in attribute.
You can use this attribute with the following SVG elements:
feBlend
For <feBlend>, in2 defines the second input image to the blending operation.
| Value | SourceGraphic|SourceAlpha|BackgroundImage|BackgroundAlpha|FillPaint|StrokePaint|<filter-primitive-reference> | 
|---|---|
| Default value | SourceGraphicfor first filter primitive, otherwise result
        of previous filter primitive | 
| Animatable | Yes | 
feComposite
For <feComposite>, in2 defines the second input image to the compositing operation.
| Value | SourceGraphic|SourceAlpha|BackgroundImage|BackgroundAlpha|FillPaint|StrokePaint|<filter-primitive-reference> | 
|---|---|
| Default value | SourceGraphicfor first filter primitive, otherwise result
        of previous filter primitive | 
| Animatable | Yes | 
feDisplacementMap
For <feDisplacementMap>, in2 defines the second input image, which is used to displace the pixels in the image defined in the in attribute.
| Value | SourceGraphic|SourceAlpha|BackgroundImage|BackgroundAlpha|FillPaint|StrokePaint|<filter-primitive-reference> | 
|---|---|
| Default value | SourceGraphicfor first filter primitive, otherwise result
        of previous filter primitive | 
| Animatable | Yes |