Slow PrintPreview

HighTower · Post by **HighTower** » Wed Oct 12, 2005 9:10 am

Is it normal, that print previre renerates too slow?

       if ( !RVPrint->Ready )
         RVPrint->FormatPages(TRVDisplayOptions());

       PrintPreview->UpdateView();

       PrintPreview->SetFocus();

and RVPrint->FormatPages takes a lot of time, ~5 sec for 3 pages with text and tables (without pictures)!!! on P4 1.6, 512Mb

is it normal?

Post by **Sergey Tkachenko** » Wed Oct 12, 2005 2:36 pm

The first call may be slower than others (a printing system is initialized)

HighTower · Post by **HighTower** » Wed Oct 12, 2005 2:40 pm

is it possible to preinitialize printing system [in background]?

Post by **Sergey Tkachenko** » Wed Oct 12, 2005 2:49 pm

So do you confirm - it's the first call of FormatPages() which may take a lot of time, and subsequent calls are not slower than reformatting on the screen?

TRichView does nothing special but reads printer properties from the system and creates device context compatible to the printer. The initialization is performed by Windows.

Well, I do not know, you can try to create a hidden preview of empty document when the application is idle...

HighTower · Post by **HighTower** » Thu Oct 13, 2005 9:49 am

I've found the source of problem - tables drawing!!!
If document doesnt containt tables - previewing of 15 pages takes less than 1 second, but if it does - a lot of time!!!

Post by **Sergey Tkachenko** » Sat Oct 15, 2005 7:33 am

Please send me RVF document for testing

HighTower · Post by **HighTower** » Mon Oct 17, 2005 12:48 pm

here they are:

Создана ссылка на файл!
webfile.ru/578079
Имя файла - test_rvf.rar , размер 15 Кбайт. Файлу присвоен номер 578079, он будет доступен до 24.10.2005 16:46.

2 files in rar archive:

fast_13pages_text.rvf - 13 pages text with formatting only
slow_3pages_tables.rvf - 3 pages with tables

Post by **Sergey Tkachenko** » Mon Oct 17, 2005 3:46 pm

Downloaded. Will be tested tomorrow.

HighTower · Post by **HighTower** » Tue Oct 18, 2005 2:13 pm

and what about results and comments?

Post by **Sergey Tkachenko** » Tue Oct 18, 2005 9:37 pm

It's no surprise that the second document's preview redrawing is slower. It has a complex layout with a lot of tables and small text.

There is a way to speed up the preview: set RVPrintPreview.CachePageImage to True (but do it only when running on WinXP, problems were reported on some Win9x computers).
In this mode, the page image is rendered in a metafile, and this metafile is shown in preview.

HighTower · Post by **HighTower** » Wed Oct 19, 2005 1:25 pm

set RVPrintPreview.CachePageImage to True

If the difference also is, it imperceptible (for me) undex WinXP

As I understood, the preview is generated for all pages. Mey be it'ld be better to generate preview for each page separately when it is neded?

Benoit B. · Post by **Benoit B.** » Wed Oct 19, 2005 1:43 pm

HighTower wrote:I've found the source of problem - tables drawing!!!
If document doesnt containt tables - previewing of 15 pages takes less than 1 second, but if it does - a lot of time!!!

I use RichView for tables me too, and it's very slow :

for a file with 500 pages of tables, it works 5 minutes.

Post by **Sergey Tkachenko** » Wed Oct 19, 2005 5:00 pm

To HighTower:
If RVPrintPreview.CachePageImage=False, no caching is used, and a trichview page-painting procedure is called on each repainting of the preview.
If RVPrintPreview.CachePageImage=True, the current page is rendered into a metafile, and then this metafile is drawn, so the trichview page-painting procedure is called only one time per page, when this page is shown for the first time. Only one page is cached. When you switch the preview to another page, a metafile is recreated. This metafile is also recreated after changing zooming percent.
So the initial displaying of each page in the caching mode may be even slower (time for creating metafile + time for drawing metafile), but scrolling will be faster.

To Benoit B.:
Try to optimize your document. For example, instead of using one huge table, try to use several smaller tables.

HighTower · Post by **HighTower** » Fri Oct 21, 2005 9:40 am

so, as I understud - slow print [preview] of documents with tables - is a feature (or bug) of TRichView.
I've downloaded demos of WPTools http://www.wpcubed.com/ftp/wp5demo.zip
and DevExpress PrintingSystem http://www.devexpress.com/downloads/VCL ... S3Demo.zip
and they makes preview very, very fast!!!
and their speed doesn't depend on pages count and content...

Post by **Sergey Tkachenko** » Fri Oct 21, 2005 11:41 am

It's possible to make a very fast preview by drawing a page image in bitmap, and then showing this bitmap.
You can do it yourself, using RVPrint.MakeScaledPreview method.