old-www/LDP/LG/issue43/gm/webwonderings.html

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<br><img SRC="images/webwonderings.jpg" height=50 width=245>
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<td ALIGN=RIGHT WIDTH="100%"><font size=-2>&copy; 1999 <a href="mailto:mjhammel@graphics-muse.org">Michael
J. Hammel</a></font></td>
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<font face="Arial,Helvetica"><font size=-1>With the grid turned on you
can create rectangular, oval or polygonal areas that are snapped to the
grid.&nbsp; With any of these shaped areas you can edit the attributes
of the area using the Edit->Edit Area Info menu option.&nbsp; This option
opens a dialog with three pages:&nbsp; Link, Shape, and JavaScript.&nbsp;
The Link page allows you to specify what URL the region should link to.&nbsp;
With the 1.1 release, you can now drag from Netscape's Location icon directly
into the URL field of this page and the link will be dropped in for you.</font></font>
<table ALIGN=LEFT BORDER=0 CELLSPACING=0 CELLPADDING=6 NOSAVE >
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<td NOSAVE><img SRC="images/imagemap-3.gif" height=261 width=209></td>
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<center><b><font face="Arial,Helvetica"><font size=-1>The Selection portion
of the main</font></font></b>
<br><b><font face="Arial,Helvetica"><font size=-1>dialog.&nbsp; Notice
the URL #'s.&nbsp; The</font></font></b>
<br><b><font face="Arial,Helvetica"><font size=-1>higher the number, the
higher the</font></font></b>
<br><b><font face="Arial,Helvetica"><font size=-1>precedence that area
takes for</font></font></b>
<br><b><font face="Arial,Helvetica"><font size=-1>regions that overlap.</font></font></b></center>
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<font face="Arial,Helvetica"><font size=-1>The Shape page will allow you
to edit attributes of the shape itself - height, width, location of vertices,
radius and so forth.&nbsp; The JavaScript page allows you to specify 4
types of JavaScript event handlers:&nbsp; onBlur, onFocus, onMouseOver
and onMouseOut.&nbsp; The text input regions for these is a little small
- only one text line.&nbsp;&nbsp; But the line can go on (apparently) indefinitely.</font></font>
<p><font face="Arial,Helvetica"><font size=-1>To create a new rectangular
or circular shaped area, click once to drag the shape then click again
to anchor it.&nbsp; Doing this opens the area settings dialog so you can
specify the URL to associate with the area.&nbsp; The polygonal area shape
works similarly, except that a double click is required to end the shape
and open the attributes dialog.&nbsp; Additionally, with polygonal shapes
a left mouse button click will anchor a new vertices for the shape.&nbsp;
A right mouse button click will delete the vertices in reverse order.</font></font>
<p><font face="Arial,Helvetica"><font size=-1>To edit the shapes, click
on their URLs in the Selection window or click on the shapes outline while
the Select Existing Area button (the button with the arrow along the left
side of the dialog window) is enabled.&nbsp; Note that when you edit the
shapes size by dragging one of the handles on the shapes outline that the
snap to grid function is no longer in effect.&nbsp; I don't know if this
was intentional or not, however.&nbsp; Don't be suprised to see this change
to match the current grid settings in later releases.</font></font>
<p><font face="Arial,Helvetica"><font size=-1>Once you've set the URLs
for shapes, you can change their positions in the map.&nbsp; The lower
in the list the higher precedence that area takes.&nbsp; This is important
for areas which overlap.&nbsp; Notice in the example of the Selection window
that there are 4 areas defined.&nbsp; Area 4 will take precedence over
area 3 any place the two areas overlap.</font></font>
<p><font face="Arial,Helvetica"><font size=-1>Now that you have a number
of areas defined, what does the HTML code for this image map look like?&nbsp;
Here is the source for the example at left:</font></font>
<blockquote><tt><font size=-1>&lt;IMG SRC="/home/mjhammel/src/graphics/scenes/stock/ttu-ontour-97.pnm"
WIDTH=300 HEIGHT=359 BORDER=0 USEMAP="#"></font></tt>
<p><tt><font size=-1>&lt;MAP NAME=""></font></tt>
<br><tt><font size=-1>&lt;!-- #$-:Image Map file created by GIMP Imagemap
Plugin --></font></tt>
<br><tt><font size=-1>&lt;!-- #$-:GIMP Imagemap Plugin by Maurits Rijk
--></font></tt>
<br><tt><font size=-1>&lt;!-- #$-:Please do not edit lines starting with
"#$" --></font></tt>
<br><tt><font size=-1>&lt;!-- #$VERSION:1.1 --></font></tt>
<br><tt><font size=-1>&lt;!-- #$AUTHOR:Michael J. Hammel --></font></tt>
<br><tt><font size=-1>&lt;AREA SHAPE="RECT" COORDS="15,15,285,135" HREF="mailto:thisguy@home.org"></font></tt>
<br><tt><font size=-1>&lt;AREA SHAPE="CIRCLE" COORDS="75,135,67" HREF="http://blah.org"></font></tt>
<br><tt><font size=-1>&lt;AREA SHAPE="RECT" COORDS="60,285,255,345" HREF="http://blah.blah.net"></font></tt>
<br><tt><font size=-1>&lt;AREA SHAPE="POLY" COORDS="285,15,195,15,195,60"
HREF="ftp://somewhere.com"></font></tt>
<br><tt><font size=-1>&lt;AREA SHAPE="DEFAULT" HREF="http://www.graphics-muse.org/blah/ttu-ontour-98.jpg"></font></tt>
<br><tt><font size=-1>&lt;/MAP></font></tt></blockquote>
<font face="Arial,Helvetica"><font size=-1>Notice that the source images
URL is taken to be the path to the image I've opened in the Gimp.&nbsp;
I looked around the plug-in but couldn't find a way to change this.&nbsp;
You apparently have to edit the HTML code manually.&nbsp; There is an option
to set a default URL, using the Info icon, but you can't change the source
reference for the image.&nbsp; One you have this HTML&nbsp;output to a
file you'll need to find some way of importing it into your real HTML&nbsp;file.&nbsp;
The Image Map plug-in does not currently allow you to place this code directly
into an existing HTML file.</font></font>
<p><font face="Arial,Helvetica"><font size=-1>Unfortunately, I found, along
with quite a few bugs with the 1.1.1 release, that the Image Map plug-in
doesn't do many of the things I would like.&nbsp; First, the polygonal
area tool is really difficult to use.&nbsp; For some reason, it won't accept
my double clicks to end a polygon shape definition unless I double click
and don't move my mouse for a split second afterwards.&nbsp; If I double
click and move too quickly I get all sorts of line drawings from the last
vertices created to the current mouse location.&nbsp; It looks something
like a star burst shape.&nbsp; In any case, it's not what was expected.&nbsp;
The unwanted star burst design will go away if you cover and then uncover
the Image Map window with another window (forcing a window update for the
Image Map plug-in).&nbsp; However, getting out of that mode seems to require
backing completely out of the polygon by right mouse clicking until all
vertices have been removed.&nbsp; At this point, the extra line drawing
seems to stop.</font></font><font face="Arial,Helvetica"><font size=-1></font></font>
<p><font face="Arial,Helvetica"><font size=-1>Another nit pick of mine
is that the up and down buttons for URLs moves the selected item to the
top or bottom of the list, not up or down one list item.&nbsp; I feel a
little like I'm playing the Towers of Hanoi trying to arrange the URLs.&nbsp;
And I can't specify the path to the image source without hand editing the
saved HTML that the plug-in outputs to file.</font></font><font face="Arial,Helvetica"><font size=-1></font></font>
<p><font face="Arial,Helvetica"><font size=-1>Zoom takes a little while
to work - it zooms the whole image and doesn't appear to let you specify
the area to focus in on.&nbsp; I suspect it uses it's own zooming algorithm
and not the Gimp's since the Gimp's zoom is considerably faster.&nbsp;
Or maybe it just takes longer to recompute image map area shapes.&nbsp;
I also don't like the fact that changes to width, height or other shape
attributes don't automatically update the display.&nbsp; I think automatic
updates should probably be a user configurable preference.</font></font><font face="Arial,Helvetica"><font size=-1></font></font>
<p><font face="Arial,Helvetica"><font size=-1>As for bugs, there were a
number that were difficult to recreate.&nbsp; Aside from the problem with
the polygons and double clicking, I&nbsp;noticed at one point that the
height of my first rectangular selection, as displayed in the settings
dialog, was only 1 pixel high.&nbsp; But most of the bugs I found were
minor and self correcting.&nbsp; None seemed to cause the final HTML&nbsp;output
to be corrupted in any way.</font></font><font face="Arial,Helvetica"><font size=-1></font></font>
<p><font face="Arial,Helvetica"><font size=-1>Although I might prefer changes
to certain aspects of the interface, I find Maurits' Image Map plug-in
for the Gimp to be stable, easy to use and produces syntactically correct
HTML.&nbsp; If you do a fair amount of image map work, or even if you'd
just like to create one just for grins, you owe it to yourself to take
a look at this plug-in.&nbsp; It may just easy your life just a bit.</font></font>
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<td ALIGN=RIGHT><font size=-2>&copy; 1999 by <a href="mailto:mjhammel@graphics-muse.org">Michael
J. Hammel</a></font></td>
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