Please explain this curved line tool

In photoshop, one can used a certain tool to create a curved line. Can someone please explain.
Source: http://thinkvitamin.com/code/html5/html5-canvas-tutorial/

Is this what you mean?

Yes, well, that helps but I was hoping for something more specific in terms of the tangent lines

They are really just handles. What do you mean by more specific? I find the best way to learn how they work is to play around with them, just by experimenting with the pen tool. I prefer to do it in Illustrator, though, as that’s better suited to vector stuff like this.

Are you trying to create a visible line with the pen tool? Since it usually just puts out shape layers (filled in) or paths that are invisible until you apply them to a photo or fill, that’s what I find most people have trouble with. In Photoshop the pen tool is used more for cutting out shapes than creating lines. As the names imply, Illustrator is great for creating lineart and your own images, Photoshop is great for image editing.

A quick Google search turned up this tutorial on deviantArt that explains how to create lines with the pen tool: http://acaraluv.deviantart.com/art/lineart-with-the-pen-tool-21814747

Nice post, huit. Thanks for the link, as I do need to learn more about this myself.

Haha, yeah, I need to keep reminding myself how to do stuff like that too. Only for Photoshop though. I can do the same thing in two seconds using Illustrator.

Yep, I find Illustrator very intuitive, but with Ps I’m always grinding my teeth.