Mega Code Archive
A class to toggle image display in Internet Explorer 5
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Title: A class to toggle image display in Internet Explorer 5.
Question: Internet Explorer 5 (and others) allows you to toggle image displays. If you are using Twebbrowser this can speed up retrieving webpages as the graphics are not longer fetched.
Answer:
A class to toggle image display in Internet Explorer 5.
A year ago I had an article published in Delphi Developer on writing Web-robots using the twebbrowser that is part of Internet Explorer and which you can install in Delphi 3 or 4 and comes pre-installed in Delphi 5. This article is also on Borlands website at http://www.borland.com/delphi/news/delphi_developer/bolton/
My only gripes with using Twebbrowser are that there is a fair bit of baggage- it renders every web-page which slows things down (especially when it has to retrieve every image on the page). The class below implements a way of disabling image display (toggling the IE switch programmatically) in IE 5 to speed up web-robots written using it. It hasnt beeen tested in IE 4 or IE 5.5 though I suspect it will probably work.
type
TViewIEImage = class
private
fSavedimagesVisible: Boolean;
function GetState: Boolean;
procedure SetVisible(Visible: Boolean);
public
BroadcastChange: Boolean;
constructor Create;
destructor Destroy; override;
property ImagesVisible: Boolean read GetState write SetVisible;
property SavedImagesVisible: Boolean read fSavedimagesVisible write fSavedimagesVisible;
end;
constructor TViewIEImage.Create;
begin
fSavedimagesVisible := GetState;
BroadcastChange := True;
end;
destructor TViewIEImage.Destroy;
begin
SetVisible(fSavedimagesVisible);
end;
function TViewIEImage.GetState: Boolean;
begin
Result := GetRegistryValue = 'yes';
end;
procedure TViewIEImage.SetVisible(Visible: Boolean);
var
Reg: TRegistry;
Str: string;
begin
if Visible then
Str := 'yes'
else
Str := 'no';
Reg := TRegistry.Create;
try
Reg.RootKey := HKEY_CURRENT_USER;
if Reg.OpenKey('\Software\Microsoft\Internet Explorer\Main',
False) then
Reg.WriteString('Display Inline Images', Str);
finally
Reg.CloseKey;
Reg.Free;
inherited;
end;
if BroadcastChange or Visible then
PostMessage(
HWND_BROADCAST,
WM_WININICHANGE,
0,
Longint(pchar('HKEY_CURRENT_USER\Software\Microsoft\Internet
Explorer\Main')));
end;
In future articles I will look at writing web robots without using twebbrowser.
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