Very Computer

Hi!

I wonder how to print (on printer) some text and few 24bit bitmaps
(over that text) using alpha and transparent blits.

Without transparency and alpha, I'll do (I'm doing) something like
this:

//---cut---------------------------------------------------
// create and prepare printer DC
// StartDoc
// StartPage

... do pDC->TextOut
... do pDC->StretchDIBits (blit DIB to DC)

// EndPage
// EndDoc
//---cut---------------------------------------------------

The problem is when I want to do transparent blits or blits using
alpha =8-|. I did 24bit to 24bit (DIBs) transparent blit and alpha
blit routines, but I'm not sure whether rendering manually
such image for printer is a right way (i.e. - creating
A4-600x600-24bit image (95MB!) and then using my alpha
and transparent DIB stretching routines).

I've read that operations (TextOut, StretchDIBits) on printer DC are
saved in temporary Enhanced metafile, so, there is actually no
bitmap underneath printerDC (it will be created by printer driver,
later - and sometimes using bands?!).

Any tips?

-<<< Matija Tomaskovic >>>------------------------------------------------

-----------------------------------------------------------<<< Mataya >>>-

Quote:> Hi!

> I wonder how to print (on printer) some text and few 24bit bitmaps
> (over that text) using alpha and transparent blits.

[snip]

Quote:> I've read that operations (TextOut, StretchDIBits) on printer DC are
> saved in temporary Enhanced metafile, so, there is actually no
> bitmap underneath printerDC (it will be created by printer driver,
> later - and sometimes using bands?!).

1. You can't rely on doing StretchDIBits with other than SRCCOPY mode.
(SRCPAINT may not work.)
2. Therefore you should create a bitmap of the whole page and print that
bitmap with SRCCOPY
3. The bitmap will be too large :-)
4. Work with stripes - rule of thumb says to stay under 2MB size
5. Of course, sending truecolor data to a printer is an overkill, and may
stuff the print server when printing to network printer. Consider reducing
the number of colors.