He needs 1,237 to win the nomination. He currently has 949 locked in. He needs 288 more to win, otherwise he will have trouble fighting things out at the convention.
There are about 500 delegates remaining. California being the main one with 172 delegates.
California awards its delegates by congressional district so it could easily be proportional amongst all the candidates. Most likely Trump will win the few large Congressional districts in the big cities but Cruz and Kashsish could win a lot of the farmland districts throughout the state.
Ok so he still needs more than 50% of the remaining delegates :/
Well, we just have to hope and count on the stupidity of Americans voters ^^