Re: graphics/WebWorks question

[jeremy@xxxxxxxxx (Jeremy H. Griffith)]

On Wed, 7 Feb 2001 09:30:44 +0100, Jan Henning <henning@r-l.de> wrote:

>Your problem is caused by the fact that HTML does not scale bitmap
>graphics - every pixel in the graphic is mapped to one pixel on screen. 

That's just plain wrong.  In HTML, graphics are specified by
the <img> tag, which has both width and height attributes
(among others).  That provides any scaling you please.  The
values (in pixels) of those attributes specify the display
size on screen, regardless of the original pixel size of the
referenced image.  This also holds true in XHTML.

Iff (if and only if) both of these attributes are not given, 
then the original pixel size is used to determine display size.
Iff one is given and the other is not, only the missing value
is taken from the image.  It's bad practice to do this, as it
slows down the page display; the browser cannot do its layout
until after the actual graphic file has been retreived.

We make use of this scaling in Mif2Go for indenting tables and 
graphics to match their Frame indents (or any other setting
you want).  We use a transparent one-pixel GIF image (*not*
covered by the Unisys patent, as it doesn't use LZW compression),
and set up a tag like this:

  <img src="1p.gif" alt="" height="10" width="150" >

immediately before the <table> or other tag, to give a 150 pixel
indent.  Since the "image" is transparent, it doesn't interfere
with the page background.  And the .gif file is all of 43 bytes.

-- Jeremy H. Griffith, at Omni Systems Inc.
  (jeremy@omsys.com)  http://www.omsys.com/

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