Rotate a circular image

[Phil Oldroyd]

I would like to be able to display a circular image, which can then be rotated. The image is typically of a valve for controlling the flow of liquid. I need to be able to display its current position between 0 and 359 degrees with respect to its input/output ports. As most images are rectangular, can a image be laid onto a circular tool such as a dial so as to only display the circular section. I understand it is possible to rotate tools. I am currently using LabView 8.5.

Has anyone any experience of rotating images or masking an image for a circular representation?

[Ben]

In reply #14 of the Picture Control thread Christian showed us how to rotate an image.

Rather than deal with the tedious work of masking around the circle I suggest you place a decoration with a transparent center region over the rotated image and just let the region of interest show through.

Ben

[altenbach]

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Ben wrote:

Rather than deal with the tedious work of masking around the circle I suggest you place a decoration with a transparent center region over the rotated image and just let the region of interest show through.

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It's not very tedious. 🙂 Simply check for the radius and substitute the background color if a pixel is outside the circle.

Here's a very rough draft modification of my old VI. Modify as needed.

Message Edited by altenbach on 06-03-2008 06:45 AM

[Ben]

Yeeeeshhh....

Reminds me of the first time I road out a huricane and we came up with the bright idea (NOT) of measuring the ships angle of rocking by hanging a pendulum from the ceiling. I had never been sea-sick before that or since (amusement rides excluded).

Ben

[Phil Brooks]

Ben, you're  not the only one to use this pendulum idea!

Phoenix Lander - Telltale (or jokingly a weather rock)


Message Edited by pbrooks100 on 06-03-2008 09:11 AM

[Phil Oldroyd]

Hi,

Many thanks for your suggestion I will try it. What package did you use to create a transparent centre circle?

[Ben]

PowerPoint or any other package that will save as ".wmf", but first try Christian's example.

Ben