Support halfmaximizing using a keyboard shortcut

Setting width of the window to half the screen and setting horizontal align to left/right has (well, it is valid only for left alignment, right alignment seems ot be broken as it behave s like central) the same effect as half maximizing a window. It is sometimes handy to have a terminal side by side another window (say a browser with some information), if there were a keyboard shortcut that would accomplish this, it would be great. I would not mind some text configuration to precisely set the width and height of the window to allow better compatibility.