html - 如何在 TImage 上显示 Div 背景图像

Question

我有一个应用程序可以从各个站点收集信息来填充我的数据库。我坚持这个 site有一个验证码。我需要为我的用户显示验证码。问题是图像位于 DIV 中的 background-image 中。

DIV id 是 captchaCodigo。

我知道如何通过 id 和名称获取元素，使用值等。但是我不知道如何获取这张图片或 url。

提前致谢

Answer 1

图像是 base64 编码 ，您需要将它从 html 代码中提取出来并将其转换为位图不要忘记发送 uuidCaptcha 与您的发布请求标识您在程序中输入的验证码的 ID。

uses Soap.EncdDecd, IdHTTP, System.StrUtils, pngimage;

Function _ExtractBetweenTags(Const s, LastTag, FirstTag: string; TrimTags: Boolean = True): string;
var
  pLast,pFirst,pNextFirst : Integer;
begin
  pFirst := Pos(FirstTag,s);
  pLast := Pos(LastTag,s);
  while (pLast > 0) and (pFirst > 0) do begin
    if (pFirst > pLast) then // Find next LastTag
      pLast := PosEx(LastTag,s,pLast+Length(LastTag))
    else
    begin
      pNextFirst := PosEx(FirstTag,s,pFirst+Length(FirstTag));
      if (pNextFirst = 0) or (pNextFirst > pLast) then begin
        if TrimTags then begin
          Result := Trim(StringReplace(Trim(Copy(s,pFirst,pLast-pFirst+Length(LastTag))), LastTag, '', [rfReplaceAll, rfIgnoreCase]));
          Result := Trim(StringReplace(Result, FirstTag, '', [rfReplaceAll, rfIgnoreCase]));
        end
        else
        Result := Trim(Copy(s,pFirst,pLast-pFirst+Length(LastTag)));
        Exit;
      end
      else
        pFirst := pNextFirst;
    end;
  end;
  Result := '';
end;

procedure TForm4.btn1Click(Sender: TObject);
var
  Input: TStringStream;
  Output: TBytesStream;
  sTmp, uuidCaptcha, captchaCodigo: string;
  IdHTTP: TIdHTTP;
  Graphic: TGraphic;
begin
  IdHTTP := TIdHTTP.Create(nil);
  try
    IdHTTP.AllowCookies := True;
    IdHTTP.HandleRedirects := True;
    IdHTTP.Request.Connection := 'keep-alive';
    IdHTTP.Request.UserAgent := 'Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/50.0.2661.102 Safari/537.36';
    sTmp := IdHTTP.Get('http://www.tjms.jus.br/cpopg5/imagemCaptcha.do');
    uuidCaptcha := _ExtractBetweenTags(sTmp, '"}', '"uuidCaptcha": "'); // You need this when you send the post request
    captchaCodigo := _ExtractBetweenTags(sTmp, '", "labelValorCaptcha":', 'base64,');
    mmo1.Lines.Add(captchaCodigo);
    Input := TStringStream.Create(captchaCodigo, TEncoding.ASCII);
    try
      Output := TBytesStream.Create;
      try
        Soap.EncdDecd.DecodeStream(Input, Output);
        Output.Position := 0;
        Graphic := TPngImage.Create;
        try
          Graphic.LoadFromStream(Output);
          img1.Picture.Bitmap.Assign(Graphic);  // Your Image loads here
        finally
          Graphic.Free;
        end;
      finally
        Output.Free;
      end;
    finally
      Input.Free;
    end;
  finally
    IdHTTP.Free;
  end;
end;