How do I scroll the viewport on mouse near screen edge?

So I can make a transparent sprite that the viewport always scrolls to and make some sprites on the edge of my project top, left, bottom, right that make the center sprite scroll too +/- 10 lets say and it works OK. But can someone point me in a direction of what function I should be using to make this more fluid? The current thing I'm using - on cursor over the "side" sprites is sluggish and probably wont work on every screen possibility.

How can I detect the mouse hitting the screen edge and then scroll in that direction? Preferably at the angle its hitting. So 45 at corners and 90 in the dead center + all the iterations in between.

Note I'm thinking the functionality seen in StarCraft and Civ - lots of games have this but I', not happy with my above mentioned solution.

Don't waste time please just send me to the function I should be using VS sprite collision :)

I've never done it, but for a smooth camera movement I would track mouse.x/mouse.y and when they get to the edge (Compare X/Y vs the LayoutWidth/Height) and I'd scroll lerp to a new position.

Also you can change the mouse cursor when it gets to the edge of the screen to show the player they are going to start moving the screen.

Thanks Jobel,

Got your version and the original working well. I found in full screen the performance is so much better (for both versions)