[REBOL] Re: to-offset
From: greggirwin:mindspring at: 12-Apr-2002 11:32
Hi Romano,
<< What is the best way to find the offset of a pixel in an image given a
pair?
to-offet: func [image [image!] pos [pair!]][ ??? ]>>
I wrote an article for the latest 'zine on REBOLForces that deals with this.
Here are some relevant snippets.
to-index: func [pos [pair!] cols [integer!] ] [
pos/y - 1 * cols + pos/x
]
pick-xy: func [data [series!] pos [pair!] cols [integer!] ] [
pick data to-index pos cols
]
poke-xy: func [data [series!] pos [pair!] cols [integer!] value ] [
poke data to-index pos cols value
]
These wrappers just reduce the number of parameters we have to pass, and
make it clear exactly what we're doing. I.e. working with images and pixels.
pick-pixel: func [img [image!] pos [pair!]] [
pick-xy img pos img/size/x
]
poke-pixel: func [img [image!] pos [pair!] value [tuple!]] [
poke-xy img pos img/size/x value
]
HTH!
--Gregg
