Hello!
Have special chips for realize these functions with I2C interface, many laptop's LCD are TFT (Think film transistor), where the proper mode of operation and interface like VGA and others.
In moment, i design a project with convert the pattern VGA signal of the output card video computer and show in TFT colour LCD. For this function I used the Averlogic chips like AL300 and AL875; I contact the Averlogic company and received the applications notes and schematics of the development kits. See more details in Averlogic website.
gorkin