These were wide-leg jeans with back pockets
big enough to hold my Kindle Fire.
Here is how I did it:
First, I measured how long the tote would have to be
to fit my laptop and cut off the legs about an inch
below that to allow for the seams.
I cut the seams from the inside of the pant legs
and pinned the seams together.
Next, I marked the new seam as an extension
of the top, so the seam would be straight:
Then I sewed the seams, first with a straight stitch then a
zig zag to enforce it (can't have my laptop falling out!).
Next, I folded the sides and sewed across it,
creating some width to the bottom of the bag:
Here is what it looks like so far:
Now, for the straps. I cut the bottom hems off the jeans and removed one of them seams to create a long, wide strap.
I sewed the straps on and -viola! DONE!