Class Image.Layer

Description

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

Method create

Image.Layer Image.Layer(object image, object alpha, string mode)
Image.Layer Image.Layer(mapping info)
Image.Layer Image.Layer()
Image.Layer Image.Layer(int xsize, int ysize, object color)
Image.Layer Image.Layer(object color)

Description

The Layer construct either three arguments, the image object, alpha channel and mode, or a mapping with optional elements:

"image":image,
        // default: black
 
"alpha":alpha,
        // alpha channel object
        // default: full opaque
 
"mode":string mode,
        // layer mode, see mode.
        // default: "normal"
 
"alpha_value":float(0.0-1.0),
        // layer general alpha value
        // default is 1.0; this is multiplied
        // with the alpha channel.
 
"xoffset":int,
"yoffset":int,
        // offset of this layer
 
"fill":Color,
"fill_alpha":Color,
        // fill color, ie what color is used
        // "outside" the image. default: black
        // and black (full transparency).
 
"tiled":int(0|1),
        // select tiling; if 1, the image
        // will be tiled. deafult: 0, off

The layer can also be created "empty", either giving a size and color - this will give a filled opaque square, or a color, which will set the "fill" values and fill the whole layer with an opaque color.

All values can be modified after object creation.

Note

image and alpha channel must be of the same size.