From: Michal Mertl Newsgroups: comp.os.msdos.djgpp Subject: Re: Background colour for text using Allegro Date: Wed, 22 Apr 1998 17:41:47 +0200 Organization: Prague University of Economics Lines: 30 Message-ID: References: <6h50av$f3s AT news DOT network DOT com> NNTP-Posting-Host: manes.vse.cz Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII In-Reply-To: <6h50av$f3s@news.network.com> To: djgpp AT delorie DOT com DJ-Gateway: from newsgroup comp.os.msdos.djgpp Precedence: bulk On 16 Apr 1998, Mike Collins wrote: > I am trying to use Allegro to write a simple typing tutor. > > Initially, the screen is white with black text on it that has to be > read and typed. To show at what speed a line should be typed, a > coloured bar moves along the text line making a background for the > text, changing the original white background to, for example, > green. I would like to do this without rewriting the text, but > everything I have tried simply hides the text under my colour bar. > Do you mean to draw the text only once? If so you can't do that with any Allegro function. If the bar moves in jumps long as the character width (e.g. 8 for fixed width font (the default one)) you can redraw always only two characters, the one you are moving the bar from with white background and the one you are moving to with green background. You set the background of characters with text_mode(background_color). If the bar moves by say 1 pixel it would be a bit more difficult, you would first have to draw backgrounds (first bigger white rectangle and than smaller green), call text_mode(-1) to draw the characters without affecting the background. HTH Michal "MiMe" Mertl xmerm05 AT vse DOT cz