Set the background for the embed
, flatten
and extend
operations.
The default background is {r: 0, g: 0, b: 0, alpha: 1}
, black without transparency.
Delegates to the color module, which can throw an Error
but is liberal in what it accepts, clipping values to sensible min/max.
The alpha value is a float between 0
(transparent) and 1
(opaque).
Parameters
-
rgba
(String | Object) parsed by the color module to extract values for red, green, blue and alpha. -
Throws Error Invalid parameter
Returns Sharp
Convert to 8-bit greyscale; 256 shades of grey.
This is a linear operation. If the input image is in a non-linear colour space such as sRGB, use gamma()
with greyscale()
for the best results.
By default the output image will be web-friendly sRGB and contain three (identical) color channels.
This may be overridden by other sharp operations such as toColourspace('b-w')
,
which will produce an output image containing one color channel.
An alpha channel may be present, and will be unchanged by the operation.
Parameters
greyscale
Boolean (optional, defaulttrue
)
Returns Sharp
Alternative spelling of greyscale
.
Parameters
grayscale
Boolean (optional, defaulttrue
)
Returns Sharp
Set the output colourspace. By default output image will be web-friendly sRGB, with additional channels interpreted as alpha channels.
Parameters
-
colourspace
String? output colourspace e.g.srgb
,rgb
,cmyk
,lab
,b-w
... -
Throws Error Invalid parameters
Returns Sharp
Alternative spelling of toColourspace
.
Parameters
Returns Sharp