FontBase:getAdvanceX question

antix

Hey all. Can anyone clarify what the parameters for this function actually do? I understand what the first parameter is (text) but the others are a mystery.

Parameters:
text: (string)
letterSpacing: (number, default = 0)
size: (number, optional)

Return value:

number: The width of the first size characters of text.

ar2rsawseen

So I think the purpose of this function is to know how much space would the text use up, or more properly, where to place next character after this string
and text is obviously text to use
letterSpacing is amount of pixels between letters in the text
and size I think is a font size to use, but now I'm not sure

antix

Thanks ar2rsawseen, thats close enough

I'm trying to get some text to print across multiple lines. I have the following code and would appreciate if anyone can suggest any optimizations...

local myFont = Font.new("ocr_s.fnt", "ocr_s.png")   local myString = "The quick brown fox jumps over the lazy dog.|Once the quick brown fox jumped over the lazy dog, it fell down a hole, got skewered on some bunjee stakes, and bled to death.|It turns out that the lazy dog was actually quite the enterprising chap. He had dug a pit, filled it with stakes, and then concealed it with leaves and twigs.|Then he just had to wait for the quick (but quite stupid) brown fox to come around prancing and dancing and kill himself in the pit.|Yay, fox for dinner!!!"   local function create_lines(text, font, maxWidth) local function split(input, char) -- SPLIT FUNCTION FROM STACK EXCHANGE <a href="http://bit.ly/1iXGtNN" rel="nofollow">http://bit.ly/1iXGtNN</a> local match = string.gmatch local pattern = '([^'..char..']+)' -- OPTIMIZED SLIGHTLY BY ANTIX local output = {} for str in match(input, pattern) do -- MORE OPTIMIZATIONS AFTER FULLY READING THREAD output[#output + 1] = str -- THIS IS FASTER THAN TABLE.INSERT end return output end   local paragraphs = split(text, "\n") -- SPLIT TEXT INTO PARAGRAPHS   local lines = {}   for p = 1, #paragraphs do local words = split(paragraphs[p], " ") -- SPLIT PARAGRAPH INTO WORDS local word = 1 local line = "" local lineWidth = 0 local done = false   repeat local wordWidth = font:getAdvanceX(words[word] .. " ") -- GET PIXEL WIDTH OF NEXT WORD if lineWidth + wordWidth >= maxWidth then -- IF ABOUT TO EXCEED MAXIMUM WIDTH, ADD LINE TO LINES AND START A NEW LINE table.insert(lines, line) line = "" lineWidth = 0 end line = line .. " " .. words[word] -- ADD WORD TO LINE, PLUS SPACE CHAR THAT WAS STRIPPED IN SPLIT FUNCTION lineWidth = lineWidth + wordWidth word = word + 1 if word > #words then -- IF ALL WORDS PROCESSED, ADD LAST LINE TO LINES AND SET FLAG TO BEGIN NEXT PARAGRAPH table.insert(lines, line) done = true end until done end line = nil words = nil paragraphs = nil   return lines end   local myLines = create_lines(myString, myFont, 352)

ar2rsawseen

Btw, you can also search forum for TextWrap, which does a similar thing. But your solution might even be better.
Does it work too slow for you?

antix

@ar2rsawseen - I have only just got this working and its not tested for speed as of yet. I need to decide which method I will use to actually draw the text to screen now.

I did grab TextWrap but I'm a bit stupid and found the code very hard to follow L-)

antix

I modified the spilt function and it performs slightly faster now..

local function split(input, char) -- SPLIT FUNCTION FROM STACK EXCHANGE <a href="http://bit.ly/1iXGtNN" rel="nofollow">http://bit.ly/1iXGtNN</a> local match = string.gmatch local pattern = '([^'..char..']+)' -- OPTIMIZED SLIGHTLY BY ANTIX local output = {} local i = 1 for str in match(input, pattern) do output[i] = str i = i + 1 end return output end

I edited my original post to reflect changes.

antix

Final optimizations and I'm happy with it now

local function split(input, char) -- SPLIT FUNCTION FROM STACK EXCHANGE <a href="http://bit.ly/1iXGtNN" rel="nofollow">http://bit.ly/1iXGtNN</a> local match = string.gmatch local pattern = '([^'..char..']+)' -- OPTIMIZED SLIGHTLY BY ANTIX local output = {} for str in match(input, pattern) do -- MORE OPTIMIZATIONS AFTER FULLY READING THREAD output[#output + 1] = str -- THIS IS FASTER THAN TABLE.INSERT end return output end