Thanks to Visio's Mark Nelson for the following tip:
You can add the User.visEquivTitle cell to your shape and provide a string that will display as a tooltip in the web output. The shape must also have at least one custom property for the tooltip to be visible.
1) Select the shape in your drawing that you want to add a web tooltip for
2) Go to Window > Show Shapesheet
3) Go to Insert > Section, check User-defined cells and click OK
4) In the newly created section, click on the row name User.Row_1 to select the title of the row
5) Type visEquivTitle and press Enter - you should now see User.visEquivTitle for the row
6) In the Value cell of that row, enter the text you want to display surrounded by quotes (e.g. "Hello World")
7) If you instead want to display the same tooltip as the Shape ScreenTip enter =Comment (no quotes)
8) Go to Insert > Section, check Custom properties and click OK
9) You can fill in the custom property Label and Value if you want this information to be visible
10) If you don't want the custom property to be visible, enter TRUE in the Invisible cell
11) Close the Shapesheet window and repeat for any other shape you like
12) Choose File > Save as Web Page to create the HTML output
As you can see this is a bit involved. The capability was designed more as a developer feature than an end user feature. I recommend tying the Shape ScreenTip to the User cell so that you see the same tooltip in both Visio and the web output. It should also be possible to use Macro Recorder to automate these steps. If your shape has a custom property but does not have the User.visEquivTitle cell, Visio will display the shape's text in a tooltip instead.
Last month, Tsung-Yuan Liu reported that he was getting inconsistent results with DistanceFrom. DistanceFrom A->B was not the same as DistanceFrom B->A.
If you create two identical squares seperated by a gap,
DistanceFrom A->B = DistanceFrom B->A = the value of the gap
If you change one of the squares to a rectangle by reducing the hieght and maintain the gap, as long as the tops or the bottoms are aligned, the above relationship still holds.
Maintaining the gap, move the smaller rectangle (shape A), so that it's top is below the top of the larger shape (shape B) and it's bottom is above the bottom of the larger shape, DistanceFrom A->B is still the size of the gap, but DistanceFrom B->A is now larger than the gap. The width of the shapes has no effect on DistanceFrom and as long as the gap is maintained, the width of either shape can be reduced to almost nil and the values for DistanceFrom will not change. The maximum difference for a specific pair of shapes and a given gap is obtained by aligning the shapes vertically along their center lines.
So what does this larger number represent? Take the difference in the hieght of the tops of the two shapes (or the bottoms if that value is smaller) add the square of the gap and take the square root. This will give yo the larger number. In other words, if shape A is on the left and it's center is higher, the larger DistanceFrom value is the distance from the top right corner of shape A to the top left corner of shape B.
So the work around to minimize this problem is to do both calculations and use the smaller value.
Yoda has reported a similar effect with a trapezoid and a circle, but I have been unable to determine what the larger value represents. The smaller one does appear to be the shortest distance.