TFT_eSPI/Extensions/Touch.cpp
Bodmer 0e0fd75277 Raise to version 2.0.0
The library has been cleaned up as it has got a bit untidy due to the large number of small incremental changes.

4bit Sprite examples renaed to be consistent with others.

alphaBlend example moved to generic folder (alphaBlend fn was moved to TFT_eSPI class).
Added sections + explanatory comments to functions prototypes.

Temporary comments added for potential gotchas for noobs when using DMA.

spi_begin/end functions renamed to reflect functionality. Old fns  retained for backwards compatibility with user setup.h files.
2020-01-26 21:17:49 +00:00

306 lines
11 KiB
C++

// The following touch screen support code by maxpautsch was merged 1/10/17
// https://github.com/maxpautsch
// Define TOUCH_CS is the user setup file to enable this code
// A demo is provided in examples Generic folder
// Additions by Bodmer to double sample, use Z value to improve detection reliability
// and to correct rotation handling
// See license in root directory.
/***************************************************************************************
** Function name: getTouchRaw
** Description: read raw touch position. Always returns true.
***************************************************************************************/
uint8_t TFT_eSPI::getTouchRaw(uint16_t *x, uint16_t *y){
uint16_t tmp;
begin_touch_read_write();
// Start YP sample request for x position, read 4 times and keep last sample
spi.transfer(0xd0); // Start new YP conversion
spi.transfer(0); // Read first 8 bits
spi.transfer(0xd0); // Read last 8 bits and start new YP conversion
spi.transfer(0); // Read first 8 bits
spi.transfer(0xd0); // Read last 8 bits and start new YP conversion
spi.transfer(0); // Read first 8 bits
spi.transfer(0xd0); // Read last 8 bits and start new YP conversion
tmp = spi.transfer(0); // Read first 8 bits
tmp = tmp <<5;
tmp |= 0x1f & (spi.transfer(0x90)>>3); // Read last 8 bits and start new XP conversion
*x = tmp;
// Start XP sample request for y position, read 4 times and keep last sample
spi.transfer(0); // Read first 8 bits
spi.transfer(0x90); // Read last 8 bits and start new XP conversion
spi.transfer(0); // Read first 8 bits
spi.transfer(0x90); // Read last 8 bits and start new XP conversion
spi.transfer(0); // Read first 8 bits
spi.transfer(0x90); // Read last 8 bits and start new XP conversion
tmp = spi.transfer(0); // Read first 8 bits
tmp = tmp <<5;
tmp |= 0x1f & (spi.transfer(0)>>3); // Read last 8 bits
*y = tmp;
end_touch_read_write();
return true;
}
/***************************************************************************************
** Function name: getTouchRawZ
** Description: read raw pressure on touchpad and return Z value.
***************************************************************************************/
uint16_t TFT_eSPI::getTouchRawZ(void){
begin_touch_read_write();
// Z sample request
int16_t tz = 0xFFF;
spi.transfer(0xb0); // Start new Z1 conversion
tz += spi.transfer16(0xc0) >> 3; // Read Z1 and start Z2 conversion
tz -= spi.transfer16(0x00) >> 3; // Read Z2
end_touch_read_write();
return (uint16_t)tz;
}
/***************************************************************************************
** Function name: validTouch
** Description: read validated position. Return false if not pressed.
***************************************************************************************/
#define _RAWERR 20 // Deadband error allowed in successive position samples
uint8_t TFT_eSPI::validTouch(uint16_t *x, uint16_t *y, uint16_t threshold){
uint16_t x_tmp, y_tmp, x_tmp2, y_tmp2;
// Wait until pressure stops increasing to debounce pressure
uint16_t z1 = 1;
uint16_t z2 = 0;
while (z1 > z2)
{
z2 = z1;
z1 = getTouchRawZ();
delay(1);
}
// Serial.print("Z = ");Serial.println(z1);
if (z1 <= threshold) return false;
getTouchRaw(&x_tmp,&y_tmp);
// Serial.print("Sample 1 x,y = "); Serial.print(x_tmp);Serial.print(",");Serial.print(y_tmp);
// Serial.print(", Z = ");Serial.println(z1);
delay(1); // Small delay to the next sample
if (getTouchRawZ() <= threshold) return false;
delay(2); // Small delay to the next sample
getTouchRaw(&x_tmp2,&y_tmp2);
// Serial.print("Sample 2 x,y = "); Serial.print(x_tmp2);Serial.print(",");Serial.println(y_tmp2);
// Serial.print("Sample difference = ");Serial.print(abs(x_tmp - x_tmp2));Serial.print(",");Serial.println(abs(y_tmp - y_tmp2));
if (abs(x_tmp - x_tmp2) > _RAWERR) return false;
if (abs(y_tmp - y_tmp2) > _RAWERR) return false;
*x = x_tmp;
*y = y_tmp;
return true;
}
/***************************************************************************************
** Function name: getTouch
** Description: read callibrated position. Return false if not pressed.
***************************************************************************************/
#define Z_THRESHOLD 350 // Touch pressure threshold for validating touches
uint8_t TFT_eSPI::getTouch(uint16_t *x, uint16_t *y, uint16_t threshold){
uint16_t x_tmp, y_tmp;
if (threshold<20) threshold = 20;
if (_pressTime > millis()) threshold=20;
uint8_t n = 5;
uint8_t valid = 0;
while (n--)
{
if (validTouch(&x_tmp, &y_tmp, threshold)) valid++;;
}
if (valid<1) { _pressTime = 0; return false; }
_pressTime = millis() + 50;
convertRawXY(&x_tmp, &y_tmp);
if (x_tmp >= _width || y_tmp >= _height) return false;
_pressX = x_tmp;
_pressY = y_tmp;
*x = _pressX;
*y = _pressY;
return valid;
}
/***************************************************************************************
** Function name: convertRawXY
** Description: convert raw touch x,y values to screen coordinates
***************************************************************************************/
void TFT_eSPI::convertRawXY(uint16_t *x, uint16_t *y)
{
uint16_t x_tmp = *x, y_tmp = *y, xx, yy;
if(!touchCalibration_rotate){
xx=(x_tmp-touchCalibration_x0)*_width/touchCalibration_x1;
yy=(y_tmp-touchCalibration_y0)*_height/touchCalibration_y1;
if(touchCalibration_invert_x)
xx = _width - xx;
if(touchCalibration_invert_y)
yy = _height - yy;
} else {
xx=(y_tmp-touchCalibration_x0)*_width/touchCalibration_x1;
yy=(x_tmp-touchCalibration_y0)*_height/touchCalibration_y1;
if(touchCalibration_invert_x)
xx = _width - xx;
if(touchCalibration_invert_y)
yy = _height - yy;
}
*x = xx;
*y = yy;
}
/***************************************************************************************
** Function name: calibrateTouch
** Description: generates calibration parameters for touchscreen.
***************************************************************************************/
void TFT_eSPI::calibrateTouch(uint16_t *parameters, uint32_t color_fg, uint32_t color_bg, uint8_t size){
int16_t values[] = {0,0,0,0,0,0,0,0};
uint16_t x_tmp, y_tmp;
for(uint8_t i = 0; i<4; i++){
fillRect(0, 0, size+1, size+1, color_bg);
fillRect(0, _height-size-1, size+1, size+1, color_bg);
fillRect(_width-size-1, 0, size+1, size+1, color_bg);
fillRect(_width-size-1, _height-size-1, size+1, size+1, color_bg);
if (i == 5) break; // used to clear the arrows
switch (i) {
case 0: // up left
drawLine(0, 0, 0, size, color_fg);
drawLine(0, 0, size, 0, color_fg);
drawLine(0, 0, size , size, color_fg);
break;
case 1: // bot left
drawLine(0, _height-size-1, 0, _height-1, color_fg);
drawLine(0, _height-1, size, _height-1, color_fg);
drawLine(size, _height-size-1, 0, _height-1 , color_fg);
break;
case 2: // up right
drawLine(_width-size-1, 0, _width-1, 0, color_fg);
drawLine(_width-size-1, size, _width-1, 0, color_fg);
drawLine(_width-1, size, _width-1, 0, color_fg);
break;
case 3: // bot right
drawLine(_width-size-1, _height-size-1, _width-1, _height-1, color_fg);
drawLine(_width-1, _height-1-size, _width-1, _height-1, color_fg);
drawLine(_width-1-size, _height-1, _width-1, _height-1, color_fg);
break;
}
// user has to get the chance to release
if(i>0) delay(1000);
for(uint8_t j= 0; j<8; j++){
// Use a lower detect threshold as corners tend to be less sensitive
while(!validTouch(&x_tmp, &y_tmp, Z_THRESHOLD/2));
values[i*2 ] += x_tmp;
values[i*2+1] += y_tmp;
}
values[i*2 ] /= 8;
values[i*2+1] /= 8;
}
// from case 0 to case 1, the y value changed.
// If the measured delta of the touch x axis is bigger than the delta of the y axis, the touch and TFT axes are switched.
touchCalibration_rotate = false;
if(abs(values[0]-values[2]) > abs(values[1]-values[3])){
touchCalibration_rotate = true;
touchCalibration_x0 = (values[1] + values[3])/2; // calc min x
touchCalibration_x1 = (values[5] + values[7])/2; // calc max x
touchCalibration_y0 = (values[0] + values[4])/2; // calc min y
touchCalibration_y1 = (values[2] + values[6])/2; // calc max y
} else {
touchCalibration_x0 = (values[0] + values[2])/2; // calc min x
touchCalibration_x1 = (values[4] + values[6])/2; // calc max x
touchCalibration_y0 = (values[1] + values[5])/2; // calc min y
touchCalibration_y1 = (values[3] + values[7])/2; // calc max y
}
// in addition, the touch screen axis could be in the opposite direction of the TFT axis
touchCalibration_invert_x = false;
if(touchCalibration_x0 > touchCalibration_x1){
values[0]=touchCalibration_x0;
touchCalibration_x0 = touchCalibration_x1;
touchCalibration_x1 = values[0];
touchCalibration_invert_x = true;
}
touchCalibration_invert_y = false;
if(touchCalibration_y0 > touchCalibration_y1){
values[0]=touchCalibration_y0;
touchCalibration_y0 = touchCalibration_y1;
touchCalibration_y1 = values[0];
touchCalibration_invert_y = true;
}
// pre calculate
touchCalibration_x1 -= touchCalibration_x0;
touchCalibration_y1 -= touchCalibration_y0;
if(touchCalibration_x0 == 0) touchCalibration_x0 = 1;
if(touchCalibration_x1 == 0) touchCalibration_x1 = 1;
if(touchCalibration_y0 == 0) touchCalibration_y0 = 1;
if(touchCalibration_y1 == 0) touchCalibration_y1 = 1;
// export parameters, if pointer valid
if(parameters != NULL){
parameters[0] = touchCalibration_x0;
parameters[1] = touchCalibration_x1;
parameters[2] = touchCalibration_y0;
parameters[3] = touchCalibration_y1;
parameters[4] = touchCalibration_rotate | (touchCalibration_invert_x <<1) | (touchCalibration_invert_y <<2);
}
}
/***************************************************************************************
** Function name: setTouch
** Description: imports calibration parameters for touchscreen.
***************************************************************************************/
void TFT_eSPI::setTouch(uint16_t *parameters){
touchCalibration_x0 = parameters[0];
touchCalibration_x1 = parameters[1];
touchCalibration_y0 = parameters[2];
touchCalibration_y1 = parameters[3];
if(touchCalibration_x0 == 0) touchCalibration_x0 = 1;
if(touchCalibration_x1 == 0) touchCalibration_x1 = 1;
if(touchCalibration_y0 == 0) touchCalibration_y0 = 1;
if(touchCalibration_y1 == 0) touchCalibration_y1 = 1;
touchCalibration_rotate = parameters[4] & 0x01;
touchCalibration_invert_x = parameters[4] & 0x02;
touchCalibration_invert_y = parameters[4] & 0x04;
}