Centering X-axis text on a monitor - ComputerCraft Forums (archive)

Yoshi18 #1

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7 posts

Posted 30 March 2014 - 04:41 AM

I'm needing help on centering text on a 2x5 monitor. I've used the code that has been posted on other related topics but none seem to work. I want it to say on line 1: "Welcome To" and on line 2: "Town". Any help will be greatly appreciated.

Bomb Bloke #2

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7083 posts

Location Tasmania (AU)

Posted 30 March 2014 - 07:59 AM

local mon = peripheral.wrap("top")       -- Or whatever direction the monitor is in.
local xSize, ySize = mon.getSize()       -- We need to know how many columns exist on the display.
local myMessages = {"Welcome To","Town"}  -- Cram our strings in a table.

mon.clear()

for i=1,#myMessages do  -- For every index in the "myMessages" table, ...
	mon.setCursorPos(math.floor((xSize-#myMessages[i])/2), i)  -- Position the cursor.
	mon.write(myMessages[i])  -- Write the current table entry.
end

Sticking a # symbol in front of a given variable generally gives you the "length" of that variable. In the case of a table (eg "myMessages")you get back the number of entries in it - in the case of a string, you get back the number of characters (eg, "myMessages[1]" represents the string "Welcome To").

math.floor() rounds down to the nearest integer. To go up instead, use math.ceil().

Edited on 30 March 2014 - 06:00 AM

Yoshi18 #3

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7 posts

Posted 30 March 2014 - 04:20 PM

It returns '=' expected on line 7. I typed everything on that line.

TheOddByte #4

1852 posts

Location Sweden

Posted 30 March 2014 - 05:03 PM

Yoshi18, on 30 March 2014 - 04:20 PM said:
It returns '=' expected on line 7. I typed everything on that line.

Post your current code, Bomb Blokes code seems correct so you must have messed up something

Yoshi18 #5

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7 posts

Posted 30 March 2014 - 05:34 PM


local mon = peripheral.wrap("back")
local xSize, ySize = mon.getSize()
local myMessages = {"Welcome To","Town"}
mon.clear
for i=1,#myMessages do
          mon.setCursorPos(math.floor((xSize-myMessages[i])/2, i)
          mon.write(myMessages[i])
end

Edited on 30 March 2014 - 03:53 PM

CometWolf #6

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1281 posts

Posted 30 March 2014 - 05:58 PM


mon.clear


mon.clear()

See the difference?

Yoshi18 #7

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7 posts

Posted 30 March 2014 - 06:53 PM

CometWolf, on 30 March 2014 - 05:58 PM said:
mon.clear
mon.clear()
See the difference?

Ok i fixed that, but now I have an error saying "startup:8: attempt to preform arithmetic __sub on nil and string"

CometWolf #8

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1281 posts

Posted 30 March 2014 - 07:06 PM


mon.setCursorPos(math.floor((xSize-#myMessages[i])/2), i)


mon.setCursorPos(math.floor((xSize-myMessages[i])/2, i)

We're gonna be doing this all day aren't we… Take a look at the line yourself next time, please.

Also, this


xSize-myMessages

is the only subtraction in your entire code, however xSize should not be nil because


local xSize, ySize = mon.getSize()

So i'd suggest you take a look at that line aswell.

Yoshi18 #9

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7 posts

Posted 30 March 2014 - 07:55 PM

CometWolf, on 30 March 2014 - 07:06 PM said:
mon.setCursorPos(math.floor((xSize-#myMessages[i])/2), i)
mon.setCursorPos(math.floor((xSize-myMessages[i])/2, i)
We're gonna be doing this all day aren't we… Take a look at the line yourself next time, please.

Also, this
xSize-myMessages
is the only subtraction in your entire code, however xSize should not be nil because
local xSize, ySize = mon.getSize()
So i'd suggest you take a look at that line aswell.

Oh dang….. I didn't see that there… It's working now. Thanks for all the help.