[Mellfee]

I work with LED a lot and am experimenting with Omnigraffle to see how easy it is to create pixel accurate pixel maps for lining up our screens. All the screens are made up of different modules but for the purpose of my questions lets say that the module I am working with is 16 x 16 pixels.

Is it possible to change the anchor point which is used to calculate the shapes position? At the moment it always seems to use the top left corner but I'm sure you can change that...I just can't find where.

Also, if I draw a 16 x 16 rectangle with a stroke thickness of 1 px and then display that on a module 16 x 16 pixels in size, am I likely to only see half of the line? I'm trying to discern where the line originates from; whether it starts from the middle and grows out, or in, or what....


Thanks

[john.gersh]

Shapes' positions are calculated relative to the zero point of the rulers. That's controlled through the box in the upper left of the drawing where the rulers meet. (Rulers have to be visible, of course: View>Rulers or command-R.) Drag out of the box to move the zero point. The new axes will show up as blue lines; their intersection is draggable for further changes. Double-click on the control box to reset them.

See this thread for discussion of stroke vs. shape boundary:
http://forums.omnigroup.com/showthread.php?t=18719

The stroke is centered on the shape boundary. The control handles remain on the boundary, so you can see the relationship by zooming in far enough.

[Mellfee]

Hi John, thanks for your help.

My explanation wasn't great. What I mean is, I know the shape is measured from the 0 points, but at the shape it is measured from it's top left corner. I thought I remembered that you could change which point on the shape the reading came from.

I want to do this because I am making a lot of rectangles which need to be lined up next to each other accurately. I wanted to take the reading from the top right corner of the rectangle so I can stack the next one to the right of it in the right place by typing it in manually.

[MatthewS]

You might want to look at CAD tools if high-fidelity measuring is required.

I personally like Omni for it's distance from CAD tools, and its effort to include design and UX into the software philosophy. If you're trying to get pixel accuracy then you might want to use something that has tools for just that, such as Autodesk Inventor

[Mellfee]

Thanks for that reply. I wonder if I'm getting a memory of something else mixed up with Omni. I was sure it was possible to change the points.

I've tried a few different maps and it works well enough but I'm going to follow up on your suggestion to see if it improves the work rate.

[MatthewS]

I don't know why I didn't mention this before, but graphic design apps are also good at pixel accuracy (better in some ways) Adobe's Photoshop and Illustrator have highly evolved diagram to pixel tools.