Merged shapes anti-alias differently in Photoshop, any workaround?

Question

For some reason, when two shapes (in my case, lines) in different orientations are combined into one layer, they alias different than expected.

To present what my issue is, here is how to replicate the strange behavior:

• Start up Photoshop and create a basic blank document, I used 500x500.
• Grab the line tool, create a new layer, and begin drawing a diagonal line. Hold shift to align it at 45deg.
• Create another new layer, and draw a horizontal line. It should look like this:

• Now, select both layers, right click, and "Merge Shapes". To illustrate how it changes, I moved the diagonal line a bit – you can see how the vertical line (and the horizontal line) both have strange anti-aliasing now.

If anyone has any idea how to prevent this, that would be awesome. I'm looking to export a single layer of merged shapes as a vector for use on my website, but this issue prevents me from doing that.

All help is appreciated. Thanks!

Answer 1

The issue seems to have been caused by an option in Photoshop, Align Edges. It was turned on, and because it was actively trying to "align edges", edges of shapes that were within the same layer were modified in an odd way as shown in the question.

It should be noted that shapes do not need to be redrawn to fix the issue!

• Here, I have two line shapes on the same layer.

• Select a vector selection tool of your choice, I used the Direct Selection Tool (A), and select the shapes that you want to fix, if applicable.

• Find the Align Edges checkbox option in the tool-specific toolbar, located at the top of the Photoshop window by default.

  

• Turn off the option. Shapes that are drawn on the same layer should not interfere with eachothers edges now, and if you had shapes selected, they will no longer exhibit the issues anymore.

Here is an official blog post from Adobe detailing the different options, categorized under Pixel Grid alignment: Align and Snap to Pixel Grid in Photoshop