DELPHI AREA Forum

Hello
I have read in the TPrintPreview documentaton that there are the
function BeginEdit and the procedure EndEdit in order to edit an existing page.

Is there available some simple code snippet to see how to use these feature?

thank you

There's nothing particular. Just inside BeginEdit/EndEdit block, use PrintPreview.Canvas to update the page.

Hi Kambiz thank you again
so it's better to use BeginEdit/EndEdit to edit items in a page instead of recreate a page (within the BeginDoc/EndDoc block)?

It depends on what you are going to modify.

Hello Kambiz
let's say some graphical items drawn by the user on a drawing canvas

for example imagine the user moving a rectangle over a panel on the left and wishing to get the print preview on the right immediately updated to watch how looks the "real page" paper preview as he moves the shapes around.

for similar purposes could be used the BeginEdit/EndEdit block?

thanks again

In your example, you have to consider that the BeginEdit/EndEdit block doesn't cause the old drawn rectangle be erased.

Hi Kambiz
ok, so basically with the BeginEdit/EndEdit I can use the canvas of an existing page to add new items (for example draw new rectangle, some text out ecc.).

As a test I have tried the following

Code: Select all

 with PrintPreview do
  for PageNo := 1 to TotalPages do
    if BeginEdit(PageNo) then
      try
        // write a simple test text
        Canvas.TextOut(10,10,'EDITING PAGE: '+IntToStr(PageNo));
      finally
        EndEdit;
      end;


Yes, this is exactly what BeginEdit/EndEdit block is supposed to do.

Hi Kambiz thank you
well now I got the correct purpose of a BeginEdit/EndEdit block