AdafruitResistiveTouchScreen.h

 
#ifndef AdafruitResistiveTouchScreen_h
#define AdafruitResistiveTouchScreen_h
 
//Only create adapapter if Adafruit's TouchScreen is already included.
#ifdef _ADAFRUIT_TOUCHSCREEN_H_
 
#include <Arduino.h>
 
#include "TouchScreenAdapter.h"
 
 
class AdafruitResistiveTouchScreen : public TouchScreenAdapter {
 
public:
 
    AdafruitResistiveTouchScreen(uint8_t pinXPos, uint8_t pinYPos, uint8_t pinXNeg,uint8_t pinYNeg, uint16_t ohms=300, uint16_t displayWidth=240, uint16_t displayHeight=320 ) 
    {   
        DISPLAY_WIDTH = displayWidth;
        DISPLAY_HEIGHT = displayHeight;
        this->displayHeight = DISPLAY_HEIGHT;
        this->displayWidth = DISPLAY_WIDTH;
        touchscreen = new TouchScreen(pinXPos, pinYPos, pinXNeg, pinYNeg, ohms);
    }
 
    ~AdafruitResistiveTouchScreen() {
        delete touchscreen; //Safe to delete even if null;
    }
 
 
    TouchScreenAdapter::TouchPoint getTouchPoint(void) { 
        TSPoint tsPoint = touchscreen->getPoint();
        //Serial.printf("TSPoint X: %3i, Y: %3i, Z: %3i \n", tsPoint.x, tsPoint.y, tsPoint.x);
        TouchScreenAdapter::TouchPoint touchpoint;
        // The resistive touch panel will irregularly report touch when at rest
        // I suspect it is the flexible membrane 'relaxing' or a read error in the TouchScreen lib,
        // so we have to chck if Z, X and Y are within the expected resistance range.
        if ( tsPoint.z > (int16_t)minRawZ && tsPoint.z < (int16_t)maxRawZ
        && tsPoint.x > (int16_t)minRawX && tsPoint.x < (int16_t)maxRawX
        && tsPoint.y > (int16_t)minRawY && tsPoint.y < (int16_t)maxRawY ) {
            touchpoint.z = constrain(map(tsPoint.z, maxRawZ, minRawZ, 1, 255), 1, 255);
            uint16_t x = rotation % 2 ? tsPoint.y : tsPoint.x;
            uint16_t y = rotation % 2 ? tsPoint.x : tsPoint.y;
            if ( rotation == 2 || rotation == 3 ) {
                touchpoint.x = constrain(map(x, maxRawX, minRawX, 0, displayWidth), 0, displayWidth-1);
            } else {
                touchpoint.x = constrain(map(x, minRawX, maxRawX, 0, displayWidth), 0, displayWidth-1);
            }
            if ( rotation == 1 || rotation == 2 ) {
                touchpoint.y = constrain(map(y, maxRawY, minRawY, 0, displayHeight), 0, displayHeight-1);
            } else {
                touchpoint.y = constrain(map(y, minRawY, maxRawY, 0, displayHeight), 0, displayHeight-1);
            }
        }
        return touchpoint;
    }
 
 
    TouchScreenAdapter::TouchPoint getTouchPointRaw(void) {
        TSPoint tsPoint = touchscreen->getPoint();
        TouchScreenAdapter::TouchPoint touchpoint;
        touchpoint.x = tsPoint.x;
        touchpoint.y = tsPoint.y;
        touchpoint.z = tsPoint.z;
        return touchpoint;
    }
 
    bool begin(void) { return true; }
 
    // Not implemented becuse the Adfruit TouchScreen library doesn't use the pressueThreshold (or pressureThreshhold :-)
    // void setPressureThreshold(uint8_t pressure) {
    //     touchscreen->pressureThreshhold = pressure;
    // }
 
    void setMinRawY(uint16_t limit) { minRawY = limit; }
 
    void setMinRawX(uint16_t limit) { minRawX = limit; }
 
    void setMaxRawX(uint16_t limit) { maxRawX = limit; }
 
    void setMaxRawY(uint16_t limit) { maxRawY = limit; }
 
    void setMinRawZ(uint16_t limit) { minRawZ = limit; }
 
    void setMaxRawZ(uint16_t limit) { maxRawZ = limit; }
 
protected:
 
private:
 
    //Have to use heap or Teensy on PlatformIO will fail to link. :-/
    //https://forum.pjrc.com/index.php?threads/multiple-definition-of-error-when-using-std-function-with-argument-teensy41-platformio.74505/
    TouchScreen *touchscreen = nullptr;
 
    uint16_t minRawY = 100;
    uint16_t maxRawY = 900;
    uint16_t minRawX = 100;
    uint16_t maxRawX = 900;
    uint16_t minRawZ = 1;
    uint16_t maxRawZ = 1023;
    uint8_t zThreshold = 10;
};
 
 
#endif
#endif