Method Image.Layer()->mode()

Method set_mode
Method mode
Method available_modes

object set_mode(string mode)
string mode()
array(string) available_modes()

Description

Set/get layer mode. Mode is one of these:

All channels are calculated separately, if nothing else is specified.

top layer
bottom layer
normal
	D=L applied with alpha: D=(L*aL+S*(1-aL)*aS) / (aL+(1-aL)*aS), aD=(aL+(1-aL)*aS)
add
	D=L+S applied with alpha, aD=aS
subtract
	D=S-L applied with alpha, aD=aS
multiply
	D=S*L applied with alpha, aD=aS
divide
	D=S/L applied with alpha, aD=aS
negdivide
	D=1.0-S/L applied with alpha, aD=aS
modulo
	D=S%L applied with alpha, aD=aS
invsubtract
	D=L-S applied with alpha, aD=aS
invdivide
	D=L/S applied with alpha, aD=aS
invmodulo
	D=L%S applied with alpha, aD=aS
imultiply
	D=(1-L)*S applied with alpha, aD=aS
idivide
	D=S/(1-L) applied with alpha, aD=aS
invidivide
	D=L/(1-S) applied with alpha, aD=aS
difference
	D=abs(L-S) applied with alpha, aD=aS
max
	D=max(L,S) applied with alpha, aD=aS
min
	D=min(L,S) applied with alpha, aD=aS
bitwise_and
	D=L&S applied with alpha, aD=aS
bitwise_or
	D=L|S applied with alpha, aD=aS
bitwise_xor
	D=L^S applied with alpha, aD=aS
replace
	D=(L*aL+S*(1-aL)*aS) / (aL+(1-aL)*aS), aD=aS
red
	Dr=(Lr*aLr+Sr*(1-aLr)*aSr) / (aLr+(1-aLr)*aSr), Dgb=Sgb, aD=aS
green
	Dg=(Lg*aLg+Sg*(1-aLg)*aSg) / (aLg+(1-aLg)*aSg), Drb=Srb, aD=aS
blue
	Db=(Lb*aLb+Sb*(1-aLb)*aSb) / (aLb+(1-aLb)*aSb), Drg=Srg, aD=aS
hardlight
	Like photoshop hardlight layer mode, aD=aS
replace_hsv
	Dhsv=Lhsv apply with alpha, aD=aS
hue
	Dh=Lh apply with alpha, Dsv=Lsv, aD=aS
saturation
	Ds=Ls apply with alpha, Dhv=Lhv, aD=aS
value
	Dv=Lv apply with alpha, Dhs=Lhs, aD=aS
color
	Dhs=Lhs apply with alpha, Dv=Lv, aD=aS
value_mul
	Dv=Lv*Sv apply with alpha, Dhs=Lhs, aD=aS
darken
	Dv=min(Lv,Sv) apply with alpha, Dhs=Lhs, aD=aS
lighten
	Dv=max(Lv,Sv) apply with alpha, Dhs=Lhs, aD=aS
saturate
	Ds=max(Ls,Ss) apply with alpha, Dhv=Lhv, aD=aS
desaturate
	Ds=min(Ls,Ss) apply with alpha, Dhv=Lhv, aD=aS
hls_replace
	Dhls=Lhls apply with alpha, aD=aS
hls_hue
	Dh=Lh apply with alpha, Dsv=Lsv, aD=aS
hls_saturation
	Ds=Ls apply with alpha, Dhv=Lhv, aD=aS
hls_lightness
	Dl=Ll apply with alpha, Dhs=Lhs, aD=aS
hls_color
	Dhs=Lhs apply with alpha, Dl=Ll, aD=aS
hls_lightness_mul
	Dl=Ll*Sl apply with alpha, Dhs=Lhs, aD=aS
hls_darken
	Dl=min(Ll,Sl) apply with alpha, Dhs=Lhs, aD=aS
hls_lighten
	Dl=max(Ll,Sl) apply with alpha, Dhs=Lhs, aD=aS
hls_saturate
	Ds=max(Ls,Ss) apply with alpha, Dhl=Lhl, aD=aS
hls_desaturate
	Ds=min(Ls,Ss) apply with alpha, Dhl=Lhl, aD=aS
dissolve
	i=random 0 or 1, D=i?L:S, aD=i+aS
behind
	D=(S*aS+L*(1-aS)*aL) / (aS+(1-aS)*aL), aD=(aS+(1-aS)*aL); simply swap S and L
erase
	D=S, aD=aS*(1-aL)
screen
	1-(1-S)*(1-L) applied with alpha, aD=aS
overlay
	(1-(1-a)*(1-b)-a*b)*a+a*b applied with alpha, aD=aS
burn_alpha
	aD=aL+aS applied with alpha, D=L+S; experimental, may change or be removed
equal
	each channel D=max if L==S, 0 otherwise, apply with alpha
not_equal
	each channel D=max if L!=S, 0 otherwise, apply with alpha
less
	each channel D=max if L<S, 0 otherwise, apply with alpha
more
	each channel D=max if L>S, 0 otherwise, apply with alpha
less_or_equal
	each channel D=max if L<=S, 0 otherwise, apply with alpha
more_or_equal
	each channel D=max if L>=S, 0 otherwise, apply with alpha
logic_equal
	logic: D=white and opaque if L==S, black and transparent otherwise
logic_not_equal
	logic: D=white and opaque if any L!=S, black and transparent otherwise
logic_strict_less
	logic: D=white and opaque if all L<S, black and transparent otherwise
logic_strict_more
	logic: D=white and opaque if all L>S, black and transparent otherwise
logic_strict_less_equal
	logic: D=white and opaque if all L<=L, black and transparent otherwise
logic_strict_more_equal
	logic: D=white and opaque if all L>=L, black and transparent otherwise

available_modes() simply gives an array containing the names of these modes.

Note

image and alpha channel must be of the same size, or canceled.