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From: brian@ut-sally.UUCP (Brian H. Powell)
Newsgroups: comp.sys.mac
Subject: Re: Tabs in TextEdit
Message-ID: <8730@ut-sally.UUCP>
Date: Thu, 13-Aug-87 13:14:22 EDT
Article-I.D.: ut-sally.8730
Posted: Thu Aug 13 13:14:22 1987
Date-Received: Sat, 15-Aug-87 09:40:37 EDT
References: <8681@ut-sally.UUCP>
Organization: U. Texas CS Dept., Austin, Texas
Lines: 53
Summary: small optimization to my code


     I noticed that my code was pretty slow drawing a line with several tabs
in it, so I made a simple optimization that makes it quite a bit faster.
tabTxMeas still isn't as fast as I want it.  If I optimize that much, I'll
post the changes to it, also.
     This change keeps tabText from calling tabTxMeas more than once.  It used
to call it to measure from the beginning of the line up to every tab.  I don't
know why I didn't do this in the first place.
     Insert this fragment into the proper place in tabText.  You should be
able to figure it out.  I put plus signs in front of the new code.  (I hope I
got all the plus signs right.)
     I pasted this in here, and our ethernet was running slow, so some char-
acters were lost.  I think I put them all back right, but no guarantees.

pascal void tabText(byteCount, textBuf, numer, denom)
...
+	register int line_length, line_dh;

...
     /* If this is the first tab we've found, we need to go back and find
        the beginning of the line so we can figure out how big the tab is
        supposed to be.  */
         if (line_start == NULL) {
            line_start = textBuf;
            start_limit = *((*current_textedit_hdl)->hText);
            while ((*(line_start - 1) != '\r') &&
            	   (line_start > start_limit))
               line_start--;
+           line_length = tabTxMeas(traverse_ptr - line_start, line_start,
+           			    &numer, &denom, &info);
+        } else
+           /* just add in the length of the text we just drew.  */
+	    line_length += StdTxMeas(traverse_ptr - start_ptr, start_ptr,
+	    			     &numer, &denom, &info);
+
+     /* find the length of the tab.  */
+     line_length += line_dh = compute_tab_length(line_length);
+
+     /* Call Move(dh,dv) to move the pen line_dh pixels to the right.  */
+        Move(line_dh, 0);
      }
...

Brian H. Powell
		UUCP:	{ihnp4,seismo,ctvax}!ut-sally!brian
		ARPA:	brian@sally.UTEXAS.EDU

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