remove magick variable, use convert for all platform

combine.lua

@@ -1,5 +1,5 @@
-local uuid      = require "resty.jit-uuid"
-local cjson     = require "cjson"
+local uuid = require "resty.jit-uuid"
+local cjson = require "cjson"
 uuid.seed()
 
 local file_dir = ngx.var.tmp_file_dir
@@ -12,27 +12,23 @@ local len = table.getn(data)
 if len == 0 then
     ngx.status = 500
     ngx.log(ngx.ERR, "No images to combine!")
-    return;
+    return ;
 end
 local origin = {}
 for i = 1, len do
-    ngx.log(ngx.INFO, "COMBINE FILE ->", data[i]) 
+    ngx.log(ngx.INFO, "COMBINE FILE ->", data[i])
     origin[i] = file_dir .. "/" .. data[i] .. " "
 end
 -- 从 nginx 变量取
-local magick = ngx.var.magick
 local convert = ngx.var.convert
 
-if not magick then
-    if not convert then
-        ngx.status = 500
-        ngx.log(ngx.ERR, "ImageMagick NOT FOUND.")
-        return
-    end
-    magick = ""
+if not convert then
+    ngx.status = 500
+    ngx.log(ngx.ERR, "ImageMagick NOT FOUND.")
+    return
 end
 
-local cmd = magick .. " " .. convert .. " -append " .. table.concat(origin, " ") .. " " .. combined  
+local cmd = convert .. " -append " .. table.concat(origin, " ") .. " " .. combined
 ngx.log(ngx.INFO, 'CMD -> ', cmd)
 local result, _, code = os.execute(cmd)
 if result and code == 0 then