For loop and boolean expression in it and other troubles..

[hwnd]

Nice idea, but im not sure if it helps. I will try of course.
I actually even got it to work for both left and right of X.
But if i do negative selection with mouse, ex: from right to left. They still appear and limiting is buggy.
So there are somewhere problems with negative numbers, either in rendering or limiting code, or in both..
If selection goes from left to right, limiting works fine. Everywhere.

There are just so many things to check for. Ex: if selection is negative or positive, how many selector blocks there are in total etc..

Btw, the total nr of blocks that are selected do not depend on this "limitation". Its just visual thingy, If some of the selector blocks are outside the camera, these blocks will be taken into account anyway, just like in original editor. They just are not drawn. But the map array contents will be modified at this location anyway. Which is fine.

Its just the visual side of things that must be "good".
Here is the selectorblocks without left side limit:
http://i.minus.com/ityQSjPUTELoh.JPG

Here is the selectorblocks with left side limited, it means, i moved camera to the right for 1 step (column). Camera X incremented by 1.
http://i.minus.com/igCMGYgji107s.JPG

Because one column of blocks is outside the cameras left border, its now only 3 columns left.

The blue "ER" tiles from word "DINER" are rendered for whole camera range. So blue tiles show exactly the camera viewport or drawing range.

EDIT
Ok, here is better view of "floating" selectorblocks: Look how its limited from left, but NOT from the BOTTOM.
http://i.minus.com/ichfPhVMiUDbF.JPG


This of course is Y coordinate, but anyway it shows clearly how bad it looks when it goes off the camera range.