Graphics and touchscreen drivers for Waveshare 3.5" and 4.0" Shields
This is an Arduino library for the Waveshare ILI9486 SPI touch shield displays and is a re-implementation of the 'Adafruit_GFX' graphics API. This version is substantially faster than the original sample software and provides an integrated touchscreen interface.
The touch screen will also calibrate itself automatically, and provides access to the calibration data so that is can be stored (for example, in EEPROM) and then set, so that the touch screen will maintain its calibration across reboots.
Under examples there is:
TouchTest
GraphicsTest runs through the Adafruit_GFX test code, and gives a timing speed for it. This is about 25 seconds for the whole run. The original Waveshare library used a cut down version of the Adafruit tests - that has been replicated as well so that times can be compared. On a Mega 2560, the original library took about 70 seconds to complete. This library is down to just under 16 seconds.
TouchTest is a very simple 'painting' program. It shows how to read and normalize the touch points, and how the screen calibration is handled. When first started, the drawing will not occur under the stylus. Once the screen is calibrated, the drawng and stylus should be very closely aligned.
To calibrate the screen, simply run the stylus off all four edges of the screen a few
times. This calibration can be retrieved using getTsConfigData(), saved, and restored
later using setTsConfigData().
This library can be installed manually, or it is available from the Arduino IDE Library Manager. Search for "Waveshare ILI9486" in the Library Manager.
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