Re: Word Capture

From:

"David Ching" <dc@remove-this.dcsoft.com>

Newsgroups:

microsoft.public.vc.mfc

Date:

Wed, 18 Feb 2009 12:42:08 -0800

Message-ID:

<A50E9CDA-D1BC-4883-9D95-21DAA1EEDEB9@microsoft.com>

"Joseph M. Newcomer" <newcomer@flounder.com> wrote in message
news:p7pop4tp8kabt14one2k3cnl80rhcv99h2@4ax.com...

Hooking can work only if you can figure out what pixels are going to be
produced, which
means you need to know the font that is selected into the DC. For
example, Unicode fonts,
use of code pages, multiple languages, etc.

In general, simplistic assumptions can work, but consider a case where I
have PowerPoint
with two overlapping text boxes, one with red text and one with green
text, with multiple
sizes. OCR won't hack it, and TextOut/DrawText occur in several different
events.

Most of the efforts that capture generic screen output are actually very
complex programs.
They are not programs that you can write in a few days.
joe

For API hooking, I don't believe you care about the font used, you simply
hook the TextOut/DrawText API's and grab the strings of text out of them.
By noting the coordinates that they are being written to, you should be able
to map those to screen coordinates so when the user hovers the mouse over
the drawn text, you know what text was written there. For sure it is not
trivial, it is actually probably one of the most dificult things to do
correctly.

OCR surely would hack it since it works by analyzing the screen pixels the
same as the human eye. If you can read it on the screen, OCR can also get
the string.

-- David