Question:
I need to make screenshots of web pages. Can I do that elegantly with TWebBrowser?
Answer:
Have TWebBrowser load the page, then have a view object paint the page onto a TCanvas (of a TBitmap) which you then subsequently resize to your desired thumbnail dimension and save in JPEG format.
The example below does not reduce the picture, thus the JPEGs are about full screen size.
You can download a project which was compiled with Delphi 5 here: HTTPtoJPEG.zip (3 kB).
procedure GenerateJPEGfromBrowser(browser: iWebBrowser2;
jpegFQFilename: string; srcHeight:
integer; srcWidth: integer;
tarHeight: integer; tarWidth: integer);
var
sourceDrawRect: TRect;
targetDrawRect: TRect;
sourceBitmap : TBitmap;
targetBitmap : TBitmap;
aJPG : TJPEGImage;
aViewObject : IViewObject;
begin { GenerateJPEGfromBrowser }
sourceBitmap := TBitmap.Create;
targetBitmap := TBitmap.Create;
aJPG := TJPEGImage.Create;
try
try
sourceDrawRect := Rect(0, 0, srcWidth, srcHeight);
sourceBitmap.Width := srcWidth;
sourceBitmap.Height := srcHeight;
aViewObject := browser as IViewObject;
if aViewObject=nil then
Exit;
OleCheck(aViewObject.Draw(DVASPECT_CONTENT, 1, nil, nil,
Form1.Handle,
sourceBitmap.Canvas.Handle,
@sourceDrawRect, nil, nil, 0));
// Resize the src bitmap to the target bitmap
// Need to make thumbnails instead of full size?
// set the target size here..
targetDrawRect := Rect(0, 0, tarWidth, tarHeight);
targetBitmap.Height := tarHeight;
targetBitmap.Width := tarWidth;
targetBitmap.Canvas.StretchDraw(targetDrawRect, sourceBitmap);
// Create a JPEG from the Bitmap and save it
aJPG.Assign(targetBitmap);
aJPG.SaveToFile(jpegFQFilename)
finally
aJPG.Free;
sourceBitmap.Free;
targetBitmap.Free
end; { try }
except
// error handler code
end; { try }
end; { GenerateJPEGfromBrowser }
procedure TForm1.Button2Click(Sender: TObject);
var
IDoc1: IHTMLDocument2;
Web : iWebBrowser2;
tmpX,
tmpY : integer;
begin { TForm1.Button2Click }
with WebBrowser1 do
begin
Document.QueryInterface(IHTMLDocument2, IDoc1);
Web := ControlInterface;
tmpX := Height;
tmpY := Width;
Height := OleObject.Document.ParentWindow.Screen.Height;
Width := OleObject.Document.ParentWindow.Screen.Width;
GenerateJPEGfromBrowser(Web, '.\test.jpg',
Height, Width,
Height, Width);
Height := tmpX;
Width := tmpY;
Image1.Picture.LoadFromFile('.\test.jpg')
end; { with WebBrowser1 }
end; { TForm1.Button2Click }