Anonymous user
Grayscale image: Difference between revisions
Added R code
(different structure for grayscale, bug fixes) |
(Added R code) |
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Line 487:
exit 0;</lang>
=={{header|R}}==
{{libheader|pixmap}}
<lang r>
# Conversion from Grey to RGB uses the following code
setAs("pixmapGrey", "pixmapRGB",
function(from, to){
z = new(to, as(from, "pixmap"))
z@red = from@grey
z@green = from@grey
z@blue = from@grey
z@channels = c("red", "green", "blue")
z
})
# Conversion from RGB to grey uses built-in coefficients of 0.3, 0.59, 0.11. To see this, type
getMethods(addChannels)
# We can override this behaviour with
setMethod("addChannels", "pixmapRGB",
function(object, coef=NULL){
if(is.null(coef)) coef = c(0.2126, 0.7152, 0.0722)
z = new("pixmapGrey", object)
z@grey = coef[1] * object@red + coef[2] * object@green +
coef[3] * object@blue
z@channels = "grey"
z
})
# Colour image
plot(p1 <- pixmapRGB(c(c(1,0,0,0,0,1), c(0,1,0,0,1,0), c(0,0,1,1,0,0)), nrow=6, ncol=6))
#Convert to grey
plot(p2 <- as(p1, "pixmapGrey"))
# Convert back to "colour"
plot(p3 <- as(p2, "pixmapRGB"))
</lang>
=={{header|Tcl}}==
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