Image Radial Fill Incorrect

Questions & Answers
1

Hi all,

I’m trying to display a hexagonal power meter that fills radially.
To do this, I have an image of a pointy top hexagon with Radial 360 fill with an origin at the bottom filling clockwise.
However some of the angles of this fill are incorrect.

For example, if I want to fill up to 120 degrees from the bottom (the north west corner of the hexagon), the fill does not align with the corner.
I’ve set the fill amount to 120 / 360 = 0.333

186127-heximageat120.png
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To show what the correct angle should be I’ve added a line image with its rotation set to -120 degrees.
This lines up perfectly where I want the fill to line up. The line is correctly at the north west corner of the hexagon, but the fill is off.

186129-incorrectangleat120.png
186129-incorrectangleat120.png857×991 48.2 KB

The fill is incorrect at most angles, but it is correct at 90 degree increments (0, 90, 180, 270). It is just between those angles where the fill does not line up correctly.

I’m trying to write some code to add an offset to correctly line up the fill, but I would rather fix the root cause. Have I made an incorrect assumption? The fact that 90 degree angles work makes me think radians are involved, but I’m not sure how. Any help is much appreciated.

Thanks!

2

Well, the issue is most likely that your image is not square, so there will be all sorts of scaling issues. I just did some measurements in gimp and the visible area is about “3° larger” but only because of the aspect ratio issue. When you take the tan of 30° and multiply it by half the width of your image you get the pixel offset on your desired line. However if you “correct” the value by the aspect ratio of your image (which is 812 / 707 == 1.1485) You get exactly the area visible. So when you want to do any radial things, you should make sure your image is actually square and is not stretched nonuniformly.