Notice: Any messages purporting to come from this site telling you that your password has expired, or that you need to verify your details, confirm your email, resolve issues, making threats, or asking for money, are
spam. We do not email users with any such messages. If you have lost your password you can obtain a new one by using the
password reset link.
Due to spam on this forum, all posts now need moderator approval.
Entire forum
➜ MUSHclient
➜ General
➜ ColourNameToRGB
It is now over 60 days since the last post. This thread is closed.
Refresh page
| Posted by
| Tsunami
USA (204 posts) Bio
|
| Date
| Sun 03 Jun 2007 06:40 PM (UTC) |
| Message
| | world.Note(world.ColourNameToRGB('blue')) displays 16711680, or 0xFF0000. Shouldn't this be 0x0000FF or 255, in RGB order, or am I missing something? -Tsunami | | Top |
|
| Posted by
| Shaun Biggs
USA (644 posts) Bio
|
| Date
| Reply #1 on Sun 03 Jun 2007 08:34 PM (UTC) |
| Message
| 16711680 is the Lua colour code for blue (#0000FF). If you are using Lua as a script language, then that is the appropriate value returned. ColourNameToRGB just translates a word form of a colour to something that various functions can use.
I'm not sure where the 0xFF0000 came from. I just get the 16711680 when I run Note(ColourNameToRGB('blue')) |
It is much easier to fight for one's ideals than to live up to them. | | Top |
|
| Posted by
| Shaun Biggs
USA (644 posts) Bio
|
| Date
| Reply #2 on Sun 03 Jun 2007 08:37 PM (UTC) |
| Message
| | Bah, nevermind... I figured it out. Lua is backwards, it's using a BGR format instead of RGB like everything else does. world.Note(world.ColourNameToRGB('red')) printed out 255, and world.Note(world.ColourNameToRGB('green')) yielded a result of 32768. The colours come out correct though, which is the important part. Unless you are using a script to modify colours or something. |
It is much easier to fight for one's ideals than to live up to them. | | Top |
|
| Posted by
| Tsunami
USA (204 posts) Bio
|
| Date
| Reply #3 on Sun 03 Jun 2007 09:09 PM (UTC) |
| Message
| | I'm passing the information to Java, which is why it's annoying, to say the least. Is it only Lua that uses BGR? And why? | | Top |
|
| Posted by
| Shaun Biggs
USA (644 posts) Bio
|
| Date
| Reply #4 on Sun 03 Jun 2007 09:41 PM (UTC) |
| Message
| | Yes, it is the only one. And I have no idea why... Every example of colours in Lua I found using Google. had it RGB, except for links back to MUSHclient. |
It is much easier to fight for one's ideals than to live up to them. | | Top |
|
| Posted by
| Nick Gammon
Australia (23,140 posts) Bio
Forum Administrator |
| Date
| Reply #5 on Sun 03 Jun 2007 09:57 PM (UTC) |
| Message
|
Quote:
Lua is backwards, it's using a BGR format instead of RGB like everything else does.
It is nothing to do with Lua. In C, it will be the same.
RGB is red/green/blue, right?
So, red is the lower-order byte (it comes first).
Green is next, and is multiplied by 256.
Blue is last, and is multiplied by 65536.
Languages like Lua, Java, C, Fortran, etc. etc. will all represent (as hex codes) the colours in that order, that is:
0xBBGGRR
However in HTML they rearranged things to be in "human" order, and write it as:
#RRGGBB.
|
- Nick Gammon
www.gammon.com.au, www.mushclient.com | | Top |
|
| Posted by
| Nick Gammon
Australia (23,140 posts) Bio
Forum Administrator |
| Date
| Reply #6 on Sun 03 Jun 2007 10:04 PM (UTC) |
| Message
| The very first result I got when I Googled "rgb macro" is this page:
http://www.functionx.com/win32/Lesson12.htm
This explains quite well, that red is the low-order byte for a RGB colour, green is the middle-order byte, and blue is the high-order byte.
Thus an "all red" code would be: 0x0000FF
An "all green" code would be: 0x00FF00
An "all blue" code would be: 0xFF0000
You can also look at various page which describes how the Windows "RGB" macro works:
#define RGB(r, g ,b) ((DWORD) (((BYTE) (r) | \
((WORD) (g) << 8)) | \
(((DWORD) (BYTE) (b)) << 16)))
Again, you can see that red is in the low-order byte, green is shifted left by 8 bits, and blue is shifted left by 16 bits.
All this shows that it is nothing to do with Lua. |
- Nick Gammon
www.gammon.com.au, www.mushclient.com | | Top |
|
| Posted by
| Shaun Biggs
USA (644 posts) Bio
|
| Date
| Reply #7 on Sun 03 Jun 2007 10:10 PM (UTC) |
| Message
| | That does make a good deal of sense, since that's how I figured out what was going on. The ColourNameToRGB function return whatever is appropriate to the language calling it, right? The only complication that should come in is if you are passing colours back and forth between plugins which use different languages. |
It is much easier to fight for one's ideals than to live up to them. | | Top |
|
| Posted by
| David Haley
USA (3,881 posts) Bio
|
| Date
| Reply #8 on Sun 03 Jun 2007 10:13 PM (UTC) |
| Message
| | I don't think different languages would use different conventions. That would be extremely strange. R is the low byte, G is middle, B is high, end of story (according to the standard). The only problem I could see would be if you were passing these numbers to machines architectures with different endianness, but somehow I doubt that would be an issue with MUSHclient... :-) |
David Haley aka Ksilyan
Head Programmer,
Legends of the Darkstone
http://david.the-haleys.org | | Top |
|
| Posted by
| Nick Gammon
Australia (23,140 posts) Bio
Forum Administrator |
| Date
| Reply #9 on Sun 03 Jun 2007 10:33 PM (UTC) |
| Message
|
Quote:
The ColourNameToRGB function return whatever is appropriate to the language calling it, right?
No, it returns a number along the lines of what I described. The language is irrelevant. Try this line of code and it will work in all languages, after adjusting for language syntax:
ColourNote (RGBColourToName (16711680), "", "test")
This displays "test" in blue. That exact example works in Lua and JScript, and you remove the brackets for VBscript:
ColourNote RGBColourToName (16711680), "", "test"
The point is, the number 16711680 is "blue", regardless of language. If you use the MUSHclient colour picker, it simply represents that number in different ways:
MXP (ie. HTML format): #0000FF
VBscript: &hFF0000
JScript: 0xFF0000
Lua: 16711680
The difference between VBscript and Jscript is just the way they represent hex numbers, and since Lua doesn't have a way of (simply) using hex literals, we have to use the decimal format.
You could represent it other ways too:
Octal: 77600000
Binary: 111111110000000000000000
Individual bytes: red: 0, green: 0, blue: 255
It is all the same number, it is just the way you look at it.
|
- Nick Gammon
www.gammon.com.au, www.mushclient.com | | Top |
|
| Posted by
| Shaun Biggs
USA (644 posts) Bio
|
| Date
| Reply #10 on Sun 03 Jun 2007 11:13 PM (UTC) |
| Message
| | I thought that if you used ColourNameToRGB with VBscript or Jscript, it returned a hex value instead of decimal. Since Lua doesn't have hex as a default number format, it can't show hex. I hadn't read the helpfile which shows that it just returns the number in decimal for all of them. The part that I was getting confused with was allowing to have HTML colour codes allowed in as a colour name. |
It is much easier to fight for one's ideals than to live up to them. | | Top |
|
| Posted by
| Tsunami
USA (204 posts) Bio
|
| Date
| Reply #11 on Mon 04 Jun 2007 03:22 PM (UTC) |
| Message
| | So the problem is really that the function outputs the code as the computer expects it, BGR, while the Java function expects human input, RGB. Ok, thanks! Just switched the high and low bits, and all is working as expected. | | Top |
|
The dates and times for posts above are shown in Universal Co-ordinated Time (UTC).
To show them in your local time you can join the forum, and then set the 'time correction' field in your profile to the number of hours difference between your location and UTC time.
32,291 views.
It is now over 60 days since the last post. This thread is closed.
Refresh page
![[Go to top]](/images/gototop.gif)
top