Enum CompositeOp 

#[repr(u32)]
pub enum CompositeOp {
    Over = 0,
    Under = 1,
    In = 2,
    Out = 3,
    Atop = 4,
    Xor = 5,
}

Porter-Duff alpha-compositing operator.

The discriminant is the value written into the shader’s composite uniform, so variants are only ever appended, never renumbered. Each doc comment gives the premultiplied output colour co and alpha ao.

Variants

Over = 0

Source over destination. co = s + d(1-sa), ao = sa + da(1-sa).

Under = 1

Destination over source. co = d + s(1-da), ao = da + sa(1-da).

In = 2

Source shown only where the destination is opaque. co = s·da, ao = sa·da.

Out = 3

Source shown only where the destination is transparent. co = s(1-da), ao = sa(1-da).

Atop = 4

Source atop the destination; the destination’s shape is kept. co = s·da + d(1-sa), ao = da.

Xor = 5

Whichever side the other does not cover. co = s(1-da) + d(1-sa), ao = sa(1-da) + da(1-sa).

Trait Implementations

impl Clone for CompositeOp

fn clone(&self) -> CompositeOp

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for CompositeOp

impl Debug for CompositeOp

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for CompositeOp

fn default() -> CompositeOp

Returns the “default value” for a type.

impl Eq for CompositeOp

impl PartialEq for CompositeOp

fn eq(&self, other: &CompositeOp) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for CompositeOp