Using the LCD

The library provides an LCDGraphics class to deal with the LCD. But in this stage, the LCDGraphics class haven't implemented completely. This page is only for testing the features.

LCD lcd = new LCD(); //Creates an ev3dev LCD instance.

LCDGraphics g = new LCDGraphics(lcd); //Creates the LCDGraphics class

//The LCD only supports BLACK and WHITE. Specifying other colors
//will result an exception

//g.setColor(Color.WHITE); //Sets color to Color.WHITE
//g.setWhiteColor(); //Alternative
//g.setColor(Color.BLACK); //Sets color to Color.BLACK
g.setBlackColor(); //Alternative

//The library currently implements the drawLine() and fillRect() method
g.drawLine(0, 0, 100, 30); //Draws a line from (0,0) to (100,30)
g.fillRect(50, 50, 25, 25); //Draws a 25x25 rectangle at (50,50)

g.flush(); //Applies the graphics to the LCD

VirtualLCD for development

The library provides a VirtualLCD to emulate the graphics on the computer before the ev3.

VirtualLCD lcd = new VirtualLCD();
lcd.showVLCD(); //Shows an UI of the virtual LCD

LCDGraphics g = new LCDGraphics(lcd);
g.setBlackColor(); //Alternative
g.drawLine(0, 0, 100, 30); //Draws a line from (0,0) to (100,30)
g.flush(); //Applies the graphics to the LCD

It should be like this:

Advanced

The library also allows you to draw directly to the buffer. More details please refer to http://www.ev3dev.org/docs/tutorials/using-ev3-lcd/

LCD lcd = new LCD();

final int SCREEN_WIDTH = 178;
final int SCREEN_HEIGHT = 128;
final int LEN = 24;
final int SIZE = 3072;
byte[] arr = new byte[SIZE];

//0xff (1) = BLACK
//0x00 (0) = WHITE

//Draws a horizontal line to row 5 to the end of the screen
for (int i = 0; i < SCREEN_WIDTH; i++){
    arr[5 * LEN + i] = (byte) 0xff; //Fill with BLACK
}

lcd.draw(arr);

Development stage of LCDGraphics

The LCDGraphics class is in very very early development stage. Many methods are still not implemented. The problem behind is it requires high knowledge on pixel and a lot of time to develop. Contributions on this are welcome!

• All things marked with TODO in LCDGraphics.java
• Moving to Graphics2D

Mark down algorithm.