> HTML files are optimized to one size. 800/600, or 1024/768.

Proper HTML files are rendering independent, and may be optimised for
a five minute speech!  HTML files "optimised" for full screen at particular
resolutions are usually badly designed.

> 
> But I think, that some Windows MetaFile - like operations are missing 
> from HTML.
> 
> <viewport width=100px height=100px canresize=True>
>  <line x1=10 y1=10 x2=50 y2=50>

Please see SVG which is the W3C standard for purely presentational
work.  Note though that the SVG group has wandered off into competing
with Flash and has forgotten the original purpose of simple WMF type
uses.  Although abused as a page description language, HTML is not, and
is not a good choice for pixel perfect layouts (it is a good choice for
end users and machine processing (e.g. search engines)).

If you do want to make use of the structural features of HTML as well, 
you need to use XHTML and namespaces, although note that the SVG working
group has been criticised for ignoring mixed namespace documents.

>  <box pos="10,10,20,20" fillcolor="red" fillstyle="thincross_left">
>  <text pos="80,80" text="Test" font="arial" size="8">

Ouch.  This sort of construct encourages a total failure to maintain
correct reading order in the source and to use consistent styling.