How to change the X view port!

[Carlos Eduardo Rodrigues Diogenes]

Bill Haneman wrote:

> Keith Packard wrote:
>
>> On Mon, 2005-06-27 at 12:49 -0300, Carlos Eduardo Rodrigues Diogenes
>> wrote:
>>
>>> So, what I want to know is if we have some way in X or if it can be 
>>> easely implemented to chage the part of the screen that is clipped 
>>> and send to display, so when the user move the pointer in direction 
>>> of the magnified screen, the pointer don't go in the magnified 
>>> screen, but the half screen start to appear? What I think that must 
>>> be done is change the origin clipping coordinate to be clipped foward.
>>>   
>>
>> Have you looked at my demonstration of a full-screen magnifier
>> application called 'diopter' in /cvs/xapps on freedesktop.org?  I built
>> this as a demonstration for the FSG accessibility workshop last January
>> in Hawaii.
>>
>> It shows a full-screen magnifier that passes input to the underlying
>> windows using an updated version of the Shape extension.
>>  
>>
> I think it might make more sense to put effort into a version of the X 
> magnifier that uses COMPOSITE, since there is work going on in this 
> area already (I believe by Gunnar SchmiDt).  COMPOSITE makes it 
> possible to get to the pixels 'underneath' an obscuring window.

Some magnifiers have the option that I sad, change the viewport, or 
scroll the 'underneath' screen, when the pointer goes near the magnified 
area and the users that I test it says that this resource is interesting 
and helps the localization of the magnified part in the entired 
screen... So, there is some way to do this???

Backing to 'diopter'... I find documentation about the XCreeateColormap 
function in http://tronche.com/gui/x/xlib/color/XCreateColormap.html, 
but what is beeing sad in Diagnostics is not clear for me... someone 
knows other place where I can find more documentation about this? And in 
what part o Xorg XCreateColormap is implemented?

Carlos.