A problem with this approach is that it magnifies aliasing from the pixels, so your outset lines are all lined up with the raster grid or running along diagonals like on a subway map. That said, I don't know much about Photoshop so I don't know how you would do it properly there. Inkscape's "Outset" tool works reasonably well.
You can also use the 'outer glow' layer style - it's not as precise but very fast to do.
Yes i tried it too But the problem with this way is that u cant edit the bush form ( or i dont know how to do it)
I forgot to say the reasons that i tried it =/
Contract/ Expanding way I generated a work path, able to stroke any form of brush, like i did in my picture. That is why i want a parallel and editable line
Hi aqartis, I guess you could merge down to an empty layer to rasterise the layer style to make the lines editable...I think your way is more flexible
Ravells, do you mean "create layer" with the effect? That's one of my favorite tricks—right (mac: control) click on the effect in Photoshop and select "Create Layer" which moves each of the effects to their own layer. It allows you to apply multiple instances of an effect. For example, you could add thin strokes to fat strokes, or multiple strokes, or you could choose to apply your gradient overlay to your original layer (by merging the two) while leaving other effects still editable.
Sorry artearth, just seen this...not sure what you mean! Can you give me an example file to look at? I think I might learn something new here!
1.) basic photoshop image - background has the blue water, with the land mass on it's own layer
2.) apply a bunch of layer effects. In this case, a drop shadow, outer stroke, bevel/emboss and gradient overlay
3.) In the layer menu, right/control click on the list of effects (not the name of the layer, which brings up a different menu) and select "Create Layers."
4.) Woah! Any layer effect which affects the interior of the layer (so an inner shadow, inner glow, bevel, overlay, inner stroke) will appear above the original layer using the layer as a clipping mask. Any layer effect which is external (outer shadow/glow, outer stroke) will appear as it's own layer below the original layer.
5.) Keep playing - here I added an inside stroke to the original layer (thin black line to the inside) and a new outside stroke to the layer "Layer 1's Outer Stroke" which gives me three strokes in a row, any one or more or which I can disable. The original stroke has been rasterized and is no longer editable. I also created a very subtle effect where I used the new drop shadow layer as a mask revealing a cloud render, which would create a slightly less uniform drop shadow.
Hope that makes sense, and is useful. Here's also a use on a retro t-shirt design for our local brew pub (called Short's Brewing), where multiple strokes came in handy, and gave me a chance to play around with the balance and color before committing too deeply.