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Example 1 - Hello

A simple example to show the basic setup and use of the SparkFun Qwiic OLED Library.

Key Demo Features

  • Declaring a Qwiic OLED device object.
  • Initializing the Qwiic OLED device
  • Drawing a simple graphic - a filled rectangle and a text string
  • Using the current font to center text on the screen.
  • Displaying the graphics on the screen

Setup

After installing this library in your local Arduino environment, begin with a standard Arduino sketch, and include the header file for this library. 

// Include the SparkFun qwiic OLED Library
#include <SparkFun_Qwiic_OLED.h>
The next step is to declare the object for the SparkFun qwiic OLED device used. Like most Arduino sketches, this is done at a global scope (after the include file declaration), not within the setup() or loop() functions.

The user selects from one of the following classes:

Class Qwiic OLED Device
QwiicMicroOLED SparkFun Qwiic Micro OLED
QwiicNarrowOLED SparkFun Qwiic OLED Display (128x32)
QwiicTransparentOLED SparkFun Transparent Graphical OLED
Qwiic1in3OLED SparkFun Qwiic OLED 1.3" Display (128x32)

The Example code supports all of the SparkFun Qwiic OLED boards. To select the board being used, uncomment the #define for the demo board.

For this example, the Qwiic Micro OLED is used. 

#define MICRO
//#define NARROW
//#define TRANSPARENT
Which results in myOLED being declared as:

QwiicMicroOLED myOLED;

Initialization

In the setup() function of this sketch, like all of the SparkFun qwiic libraries, the device is initialized by calling the begin() method. This method returns a value of true on success, or false on failure. 

void setup()
{

    delay(500);   //Give display time to power on

    // Serial on!
    Serial.begin(115200);

    Serial.println("\n\r-----------------------------------");

    Serial.print("Running Example 01 on: ");
    Serial.println(String(deviceName));

    // Initalize the OLED device and related graphics system
    if(!myOLED.begin()){

        Serial.println(" - Device Begin Failed");
        while(1);
    }

    Serial.println("- Begin Success");

Drawing Graphics

Once the device is enabled, the rest of the setup() function is devoted to drawing a simple graphic on the target device.

Filled Rectangle

First, draw a filled rectangle on the screen - leave a 4 pixel boarder at the end of the screen. Note that the getWidth() and getHeight() method are used to get the devices screen size.

    // fill a rectangle on the screen that has a 4 pixel board
    myOLED.rectangleFill(4, 4, myOLED.getWidth()-4, myOLED.getHeight()-4);

Centered Text

The next part of our graphic is a message centered in the drawn rectangle. To do the centering, the current font is accessed from the device, and the size of a character in the font is used to calculate the text position on the screen.

Once the position is determined, the message is drawn on the display in black (0 for a color value).

    String hello = "hello"; // our message

    // Lets center our message on the screen. We need to current font. 

    QwiicFont * pFont = myOLED.getFont();

    // starting x position - width minus string length (font width * number of characters) / 2
    int x0 = (myOLED.getWidth() - pFont->width * hello.length())/2;

    int y0 = (myOLED.getHeight() - pFont->height)/2;

    // Draw the text - color of black (0)
    myOLED.text(x0, y0, hello, 0);

Displaying the Graphics

The last step is sending the graphics to the device. This is accomplished by calling the display() method.

    // There's nothing on the screen yet - Now send the graphics to the device
    myOLED.display();

And that's in - the graphic is displayed on the OLED device.

Hello!