Lcd oop extensions - Githubissues

From @manfredjonsson on May 28, 2012 15:31

This Version of the Liquid Crystal Library can be inherited from other classes. A possible usage is outlined in http://github.com/manfredjonsson/LiquidCrystalAddons

Because of the many changes, each commit contains one step of the improvements.

Commit 1: Fixes

Remove unneeded variables.
Make setCursor work for 16x2 and 16x4 displays.
I consider LCD_ENTRYSHIFTINCREMENT etc to be a missnomer. Use ...ENABLE and ...DISABLE instead.
Different variable names were used in definition and declaration of begin(). Use the name "row" instead of "line" in all places to have a consistent wording.
Remove the begin() call from init() because some transport may not be initialized in a global constructor (Some versions of the Wire (I2C) library don't work when their begin() method is called inside a constructor of a global object).

Commit 2: Minimal set of changes for inheritance

Move functions and variables from private to protected.
Add the virtual keyword to all functions which may need an override in an derived class.

Commit 3: Make it smaller

Use the "-1" trick from rw for the data lines too. This enables the use of one writebits() function instead of two. Pay attention to the fact that pinMode is still in writebits(), this slows down each write to the LCD but code is smaller compared to an additional initialization loop.
Use the 4 upper bits of a byte in writebits() instead of the 4 lower bits for 4 bit writes. Leads to an almost identical initialization for 4 and 8 bit mode.
Use the same code in 4 and 8 bit mode to force display to 8 bit mode and use a loop instead of three distinct calls to writebits().

Copied from original issue: arduino/Arduino/pull/87

arduino-libraries / LiquidCrystal