primo::codecs::AlphaCompositingMode Namespace Reference

Defines the way a foreground image will be combined with background video. More...

Enumerations
enum	Enum {   Over = 1,   In = 2,   Out = 3,   Atop = 4,   Xor = 5,   Plus = 6 }

Detailed Description

Defines the way a foreground image will be combined with background video.

Enumeration Type Documentation

enum Enum

Enumerator
Over	Foreground over Background - in effect, normal painting operation. Remarks If Fa is foreground alpha, Frgb is foreground RGB, Ba is background alpha, Brgb is background RGB, then Rrgb is the compositing result: Rrgb = (Fa * Frgb) + (1 - Fa ) * (Ba * Brgb) Normally, alpha blending implies a background alpha of 1.0 (Ba = 1.0), so the compositing result Rrgb becomes: Rrgb = (Fa * Frgb) + (1 - Fa) * Brgb Fa and Ba are alpha density value with range from 0.0 to 1.0
In	Foreground in Background - the alpha compositing equivalent of clipping / itersection. Remarks If Fa is foreground alpha, Frgb is foreground RGB, Ba is background alpha, Brgb is background RGB, then Rrgb is the compositing result: Rrgb = (Fa * Frgb) * Ba Fa and Ba are alpha density value with range from 0.0 to 1.0
Out	Foreground outside Background. Remarks If Fa is foreground alpha, Frgb is foreground RGB, Ba is background alpha, Brgb is background RGB, then Rrgb is the compositing result: Rrgb = (Fa * Frgb) * (1 - Ba) Fa and Ba are alpha density value with range from 0.0 to 1.0
Atop	Foreground atop Background. Remarks If Fa is foreground alpha, Frgb is foreground RGB, Ba is background alpha, Brgb is background RGB, then Rrgb is the compositing result: Rrgb = (Fa * Frgb) * Ba + (1 - Fa) * (Ba * Brgb) Fa and Ba are alpha density value with range from 0.0 to 1.0
Xor	Foreground xor Background. Remarks If Fa is foreground alpha, Frgb is foreground RGB, Ba is background alpha, Brgb is background RGB, then Rrgb is the compositing result: Rrgb = (Fa * Frgb) * (1 - Ba) + (1 - Fa) * (Ba * Brgb) Fa and Ba are alpha density value with range from 0.0 to 1.0
Plus	Foreground plus Background. Remarks If Fa is foreground alpha, Frgb is foreground RGB, Ba is background alpha, Brgb is background RGB, then Rrgb is the compositing result: Rrgb = (Fa * Frgb) + (Ba * Brgb) Fa and Ba are alpha density value with range from 0.0 to 1.0