How to make ImageGadget image into base64 JPEG data?

[stmdbe2019]

How to make `SetGadgetState(1,pic2)` pic2 into a base64 JPEG data for `pictures.s = "data:image/jpeg;base64,"`?
So that i can, upload the JPEG via POST method. (Everything is working except cant find how to convert ImageGadget images into base64 data string)

Code: Select all

InitNetwork()
IncludeFile "libcurl.pbi"; Download https://raw.githubusercontent.com/deseven/pbsamples/master/crossplatform/libcurl/libcurl.pbi

; Upload JPEG via CURL POST method
pictures.s = "data:image/jpeg;base64,"

; JPEG image uploader
Procedure iCurl()
  curl = curl_easy_init()
  url.s = str2curl("https://imgur.com/upload")
  agent.s = str2curl("pbcurl/1.0")
  cookie.s = str2curl("agent=purebasic;")
    
  post.s = str2curl("userid=1&preview=" + pictures)
  header.s = str2curl("Cache-Control: no-cache")
    
  If curl
    curl_easy_setopt(curl,#CURLOPT_URL,@url)
    curl_easy_setopt(curl,#CURLOPT_IPRESOLVE,#CURL_IPRESOLVE_V4)
    curl_easy_setopt(curl,#CURLOPT_COOKIE,@cookie)
    curl_easy_setopt(curl,#CURLOPT_POSTFIELDS,@post)
    curl_easy_setopt(curl,#CURLOPT_USERAGENT,@agent)
    curl_easy_setopt(curl,#CURLOPT_TIMEOUT,30)
    curl_easy_setopt(curl,#CURLOPT_FOLLOWLOCATION,1)
    *header = curl_slist_append(0,header)
    curl_easy_setopt(curl,#CURLOPT_HTTPHEADER,*header)
    curl_easy_setopt(curl,#CURLOPT_WRITEFUNCTION,@curlWriteData())
    res = curl_easy_perform(curl)
    resData.s = curlGetData()
    curl_easy_getinfo(curl,#CURLINFO_RESPONSE_CODE,@resHTTP)
    Debug "result: " + Str(res)
    If Not res
      Debug "HTTP code: " + Str(resHTTP)
      Debug "HTTP data: " + #CRLF$ + resData
    EndIf
    curl_easy_cleanup(curl)
  Else
    Debug "can't init curl!"
  EndIf  
EndProcedure


If OpenWindow(0,300,200,300,200,"test",#PB_Window_SystemMenu)
  pic1=CreateImage(1,50,50)
  pic2=CreateImage(2,100,100)
  StartDrawing(ImageOutput(2))
  Box(0,0,100,100,#Red)
  StopDrawing()
  ImageGadget(1,20,20,100,100,pic1)
  ButtonGadget(2,20,130,130,25,"Click to switch images")
  Repeat
    ev=WaitWindowEvent()
    If ev=#PB_Event_Gadget And EventGadget()=2
      count+1
      If count=1                
        ; === HELLO === HERE 
        ; How to make the pic2 as "data:image/jpeg;base64...." ?
        ;
        pictures.s = "data:image/jpeg;base64," 
        
        ; === HELLO === HERE
        
        iCurl()
        SetGadgetState(1,pic2)
        SetGadgetText(2,"Click to clear image")
      ElseIf count=2
        SetGadgetState(1,0)
      EndIf
    EndIf
  Until ev=#PB_Event_CloseWindow
EndIf