Best way divide a circle - Adobe Photoshop

This is a discussion on Best way divide a circle - Adobe Photoshop ; In have a white circle on a black background which I need to divide into 8 equal pie selections to post pictures into...whats the best way to do this please? Thanks so much Emma...

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Best way divide a circle

  1. Default Best way divide a circle

    In have a white circle on a black background which I need to divide into 8 equal pie selections to post pictures into...whats the best way to do this please? Thanks so much
    Emma

  2. Default Re: Best way divide a circle

    It is easy to chop anything vertically and horizontally. Once you do that, rotate all the art 45 degrees and chop again.

    I'd do this in a page layout application though so I can't imagine which of the 20 ways to do this in Photoshop would be most ideal.

  3. Default Re: Best way divide a circle

    If the placement of the circle is not critical, and you can make a new one on a blank (transparent) layer, make one, and skip to step 2.

    1) Double-click the background layer (white circle on black background) and name it layer 0. Then double click to the right of the name (layer 0). Up should pop the blending dialog. Pull the black "blend if" slider at the bottom of the dialog under "this layer" to somewhere near the middle of the slider bar (you should see the black bg vanish). Now with the alt key pressed, break the black slider apart the two sections apart. Where they end up is not critical, just make them separate. Hit ok. Then, use the key command ctrl-j to dupe the layer. Then hit ctrl-e to merge it down. You should now have your white circle (with a black fringe) over transparent checkerboard.

    2) Make sure View menu... snap is checked. Now draw guides that bound the circle (top bottom left right) and put two intersecting in the center of the circle. These guides should "snap" into place.

    3) With the polygon lasso tool, you should now be able to draw triangles that are precisely 1/8 of the circle. Draw one triangle, then with ctrl-alt-shift held down, click on the layer icon in the layers palette (you should see an x in a box next to your cursor as you hover over the icon). This should clip your selection. Now just open the pic you like, select all copy and go back to your new circle doc and edit... paste into. Repeat for all 8 pie pieces.

    4) Make a new layer, move it underneath your circle layer and fill it with black.

    <http://www.pixentral.com/show.php?picture=1tHMruqWn2okMPQyxftxgFTc3tgpM0>

    <http://www.pixentral.com/show.php?picture=1qUbgUBPqoSQEOLcZIbU945yIXmSL>

  4. Default Re: Best way divide a circle

    The tricky part is making a dead-accurate 360/x pie wedge. I'd do it in illustrator.

    But I'd want to do it with a vector shape, however I get there, and use the shape as a mask.

    After that, then, and by copying and rotating I'd create a separate layer + mask for each image. That way each image could be moved and resized independently from the others, retaining the pie-shaped outline.

    Similar to this mask-layer example I showed somebody last year, only with vector masks instead of letters.

    (Click image for full size version)
    <http://www.pixentral.com/show.php?picture=1L0he0TcEqWbfITy3Q2HQI18YgdGZ>

  5. Default Re: Best way divide a circle

    Thank-you so much, it did the trick wonderfully
    Emma

  6. Default Re: Best way divide a circle

    Sorry for the broken record, but I can't resist once again advocating Filter Factory (FF) for tasks such as this.

    To divide a circle into 8 equal pie sections, select the circle and put it on a separate layer via CTRL-J. With that layer highlighted invoke FF and enter the following in the R G and B boxes:

    R: d%128==0?0:255

    G: 255

    B: 255

    FF splits the circle into 1024 angles. d is the angle

    The R code says "If the angle divided by 128 leaves zero remainder, set R =0, else set R=255.

    Thus, where d is a multiple of 128, the color is cyan (blue and green). Elsewhere it is white.

    What could be cleaner?

  7. Default Re: Best way divide a circle

    Despite Filter Factory's agility (or the even more versatile Filter Foundry <http://www.telegraphics.com.au/svn/filterfoundry/trunk/dist/README.html>) I'd still want to do it with vector masks.

    But that's just me, and my famous pickiness.



  8. Default Re: Best way divide a circle

    Phos

    Correct me if I'm not following you. I think you are referring to what you do with the eight pie sections after they have been formed, and using them as masks is one way to go. How you delineate them is one thing, and how you make masks of them and deploy the masks is another. Using FF to form the pie sections to begin with and then selecting each piece of pie, in turn, as a mask seems as good a way to go as any.

    George

  9. Default Re: Best way divide a circle

    I'm saying I'd create the pie wedges as vector objects, and keep and use them as vectors so they'd re-render as cleanly as possible if I decided I wanted to move, rotate or resize them. Once you've created a pixel-based selection or mask, you're kind of limited in what you can do with them and still maintain original quality.

    I've learned the hard way too many times about trying to tweak pixel-based objects and not having them meet the quality standards I enjoy, so I do what I can to use vectors wherever possible.

  10. Default Re: Best way divide a circle

    Can you create a vectorized circular section in PS?

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