--- The purpose of this module is to show pieces of an image file instead of the whole image.
 --- One intended use is within other templates, such as a template to return flags of many
 --- countries, so that you need to load only ONE image to produce all the flags on the page
 --- This should produce - but is not actually known to - some increase in performance.
 --- It might also be useful for pulling out entries from very large tables of graphics, such
 --- as one character from a font.

 --- This module accepts a filename, and uses Template:Sprite/filename (or parameter spritedefs)
 --- to identify sprites within the image at filename.
 --- it locates a given name for a sprite within the file and scales it to the desired width


local p={}

function spritedraw(left,right,top,bottom,name,imagewidth,spritewidth,scalewidth,float)
    if (left==nil or right==nil or top==nil or bottom==nil or name==nil or imagewidth==nil or spritewidth==nil or scalewidth==nil) then return tostring(left) .. tostring(right)..tostring(top)..tostring(bottom)..tostring(name)..tostring(imagewidth)..tostring(spritewidth)..tostring(scalewidth) end
    if float then float="float:"..float..";" else float="" end
    local scale=scalewidth/spritewidth
    top=math.floor(top*scale)
    bottom=math.floor(bottom*scale)
    left=math.floor(left*scale)
    right=math.floor(right*scale)
    local scalestring=""
    if scalewidth~=spritewidth then scalestring=math.floor(imagewidth*scale)..'px|' end
    output='<div style="position:relative;'..float..'width:'..scalewidth..'px;height:'..(bottom-top)..'px;"><div style="position:absolute;'..float..'top:'..(-1*top)..'px;left:'..(-1*left)..'px;clip:rect('..top..'px,'..right..'px,'..bottom..'px,'..left..'px);">[[Image:Flag sprite demo.png|'..scalestring..'link=http://en.wikipedia.org/wiki/'..name..']]</div></div>'
          
    return output
end

function p.sprite(frame)
   local args=frame.args
   local parent=frame.getParent(frame)
   local pargs=parent.args
   local imagewidth=args.imagewidth or pargs.imagewidth or 360
   local spritewidth=args.spritewidth or pargs.spritewidth or 120
   local scalewidth=args.width or pargs.width or 120
   local leftcol=0;local midcol=120;local rightcol=240
   local filename=args.filename or pargs.filename or ""
   if filename=="" then return "error: Sprite needs filename= parameter" end
   local spritedefs=args.spritedefs or pargs.spritedefs or ("Module:Sandbox/Wnt/Sprite/"..filename)
   local sfile=mw.loadData(spritedefs)
   local name=args[1] or pargs[1] or "0"
   local top,bottom,left,right
   local count=-4;debuglog=""
   local float=args.float or pargs.float --string like "left", "right", or nil=no float
   repeat
      count=count+5
      local n=sfile[count];local l=sfile[count+1];local r=sfile[count+2];local t=sfile[count+3];local b=sfile[count+4]
      debuglog="n"..tostring(n).."l="..tostring(l).."r=" ..tostring(r).."t="..tostring(t).."b="..tostring(b)
      if not(n and l and r and t and b) then return "error: sprite not found"..debuglog end
      if n==name or count==tonumber(name) then top=tonumber(t);bottom=tonumber(b);left=tonumber(l);right=tonumber(r);break end
   until false
   if args.nowiki or pargs.nowiki then return frame:preprocess("<nowiki>"..spritedraw(left,right,top,bottom,name,imagewidth,spritewidth,scalewidth,float).."</nowiki>") end
   return spritedraw(left,right,top,bottom,name,imagewidth,spritewidth,scalewidth,float)
end

return p