delphi - 如何让TWebBrowser像Internet Explorer一样使用ctrl+鼠标滚轮缩放？

Question

根据

http://www.rendelmann.info/blog/CommentView,guid,356fbe68-3ed6-4781-90a4-57070a0141da.aspx和 http://msdn.microsoft.com/en-us/library/aa770056(v=vs.85).aspx

使用控制键和鼠标滚轮让托管的 WebBrowser 进行缩放应该只需要调用 IWebBrowser2.ExecWB(OLECMDID_OPTICAL_ZOOM, ...)，并将 pvaIn 值设置为100，
但调用后，ctrl+鼠标滚轮仍然无法缩放内容

我在 Delphi 2007 中使用的代码:

const
  OLECMDID_OPTICAL_ZOOM = 63;
var
  pvaIn, pvaOut: OleVariant;
begin
  pvaIn := 100;
  pvaOut := NULL;
  WebBrowser1.ControlInterface.ExecWB(OLECMDID_OPTICAL_ZOOM,
    OLECMDEXECOPT_DONTPROMPTUSER, pvaIn, pvaOut);
end;

Answer 1

杰森彭尼，

100 是默认值，如果要更改缩放比例，则必须增大或减小该值，从 10 到 1000。

我编写了一个测试，代码如下:

type
  TFormWebBrowserZoom = class(TForm)
    WebBrowser1: TWebBrowser;
    procedure FormMouseWheelDown(Sender: TObject; Shift: TShiftState; MousePos: TPoint; var Handled: Boolean);
    procedure FormMouseWheelUp(Sender: TObject; Shift: TShiftState; MousePos: TPoint; var Handled: Boolean);
    procedure FormShow(Sender: TObject);
  private
    FZoom: Integer;
    FLastZoom: Integer; 

    procedure ApplyZoom(ZoomValue: Integer);
    procedure DecZoom;
    procedure IncZoom;
  end;

implementation

const
  OLECMDID_OPTICAL_ZOOM = $0000003F;
  MinZoom = 10;
  MaxZoom = 1000;
  ZoomFactor = 20;
  DefaultZoom = 100;

procedure TFormWebBrowserZoom.FormShow(Sender: TObject);
begin
  WebBrowser1.Navigate('http://www.cesarromero.com.br');
  FZoom := DefaultZoom;
  FLastZoom := DefaultZoom;
end;

procedure TFormWebBrowserZoom.ApplyZoom(ZoomValue: Integer);
var
  pvaIn, pvaOut: OleVariant;
begin
  if ZoomValue = FLastZoom then
    Exit;
  FLastZoom := ZoomValue;
  pvaIn := ZoomValue;
  pvaOut := Null;
  WebBrowser1.ControlInterface.ExecWB(OLECMDID_OPTICAL_ZOOM, OLECMDEXECOPT_DONTPROMPTUSER, pvaIn, pvaOut);
end;

procedure TFormWebBrowserZoom.DecZoom;
begin
  System.Dec(FZoom, ZoomFactor);
  if FZoom < MinZoom then
    FZoom := MinZoom;
  ApplyZoom(FZoom);
end;

procedure TFormWebBrowserZoom.IncZoom;
begin
  System.Inc(FZoom, ZoomFactor);
  if FZoom > MaxZoom then
    FZoom := MaxZoom;
  ApplyZoom(FZoom);
end;

procedure TFormWebBrowserZoom.FormMouseWheelDown(Sender: TObject; Shift: TShiftState; MousePos: TPoint; var Handled: Boolean);
begin
  DecZoom;
end;

procedure TFormWebBrowserZoom.FormMouseWheelUp(Sender: TObject; Shift: TShiftState; MousePos: TPoint; var Handled: Boolean);
begin
  IncZoom;
end;