Diff: N5110.cpp

Revision:

24:342bdb6679a1

Parent:

23:eb7e6632fc9e

Child:

26:36be85c20ef4

--- a/N5110.cpp	Wed Feb 01 16:26:22 2017 +0000
+++ b/N5110.cpp	Tue Feb 07 10:21:43 2017 +0000
@@ -12,16 +12,13 @@
 // to power LCD. Doesn't work well with K64F.
 N5110::N5110(PinName pwrPin, PinName scePin, PinName rstPin, PinName dcPin, PinName mosiPin, PinName sclkPin, PinName ledPin)
 {
-  spi = new SPI(mosiPin,NC,sclkPin); // create new SPI instance and initialise
-
-  // set up pins as required
-  led = new PwmOut(ledPin);
-  pwr = new DigitalOut(pwrPin);
-  sce = new DigitalOut(scePin);
-  rst = new DigitalOut(rstPin);
-  dc = new DigitalOut(dcPin);
-
-  clearBuffer();
+    spi = new SPI(mosiPin,NC,sclkPin); // create new SPI instance and initialise
+    // set up pins as required
+    led = new PwmOut(ledPin);
+    pwr = new DigitalOut(pwrPin);
+    sce = new DigitalOut(scePin);
+    rst = new DigitalOut(rstPin);
+    dc = new DigitalOut(dcPin);
 }
 
 // overloaded constructor does not include power pin - LCD Vcc must be tied to +3V3
@@ -29,121 +26,118 @@
 // drive the LCD.
 N5110::N5110(PinName scePin, PinName rstPin, PinName dcPin, PinName mosiPin, PinName sclkPin, PinName ledPin)
 {
-  spi = new SPI(mosiPin,NC,sclkPin); // create new SPI instance and initialise
-  // set up pins as required
-  pwr = NULL;
-  led = new PwmOut(ledPin);
-  sce = new DigitalOut(scePin);
-  rst = new DigitalOut(rstPin);
-  dc = new DigitalOut(dcPin);
-
-  clearBuffer();
-
+    spi = new SPI(mosiPin,NC,sclkPin); // create new SPI instance and initialise
+    // set up pins as required
+    pwr = NULL;  // pwr not needed so null it to be safe
+    led = new PwmOut(ledPin);
+    sce = new DigitalOut(scePin);
+    rst = new DigitalOut(rstPin);
+    dc = new DigitalOut(dcPin);
 }
 
 // initialise function - powers up and sends the initialisation commands
 void N5110::init()
 {
-  turnOn();     // power up
-  reset();      // reset LCD - must be done within 100 ms
+    turnOn();     // power up
+    reset();      // reset LCD - must be done within 100 ms
 
-  initSPI();
-  // function set - extended
-  sendCommand(0x20 | CMD_FS_ACTIVE_MODE | CMD_FS_HORIZONTAL_MODE | CMD_FS_EXTENDED_MODE);
-  //printf("*");
-  // Don't completely understand these parameters - they seem to work as they are
-  // Consult the datasheet if you need to change them
-  sendCommand(CMD_VOP_7V38);    // operating voltage - these values are from Chris Yan's Library
-  sendCommand(CMD_TC_TEMP_2);   // temperature control
-  sendCommand(CMD_BI_MUX_48);   // bias
+    initSPI();
+    // function set - extended
+    sendCommand(0x20 | CMD_FS_ACTIVE_MODE | CMD_FS_HORIZONTAL_MODE | CMD_FS_EXTENDED_MODE);
+    // Don't completely understand these parameters - they seem to work as they are
+    // Consult the datasheet if you need to change them
+    sendCommand(CMD_VOP_7V38);    // operating voltage - these values are from Chris Yan's Library
+    sendCommand(CMD_TC_TEMP_2);   // temperature control
+    sendCommand(CMD_BI_MUX_48);   // changing this can sometimes improve the contrast on some displays
 
-  // function set - basic
-  sendCommand(0x20 | CMD_FS_ACTIVE_MODE | CMD_FS_HORIZONTAL_MODE | CMD_FS_BASIC_MODE);
-  normalMode();  // normal video mode by default
-  sendCommand(CMD_DC_NORMAL_MODE);  // black on white
+    // function set - basic
+    sendCommand(0x20 | CMD_FS_ACTIVE_MODE | CMD_FS_HORIZONTAL_MODE | CMD_FS_BASIC_MODE);
+    normalMode();  // normal video mode by default
+    sendCommand(CMD_DC_NORMAL_MODE);  // black on white
 
-  // RAM is undefined at power-up so clear
-  clearRAM();
-  clear();
-  setBrightness(0.5);
+    clearRAM();      // RAM is undefined at power-up so clear
+    clear();   // clear buffer
+    setBrightness(0.5);
 }
 
 // sets normal video mode (black on white)
 void N5110::normalMode()
 {
-  sendCommand(CMD_DC_NORMAL_MODE);
+    sendCommand(CMD_DC_NORMAL_MODE);
 }
 
 // sets normal video mode (white on black)
 void N5110::inverseMode()
 {
-  sendCommand(CMD_DC_INVERT_VIDEO);
+    sendCommand(CMD_DC_INVERT_VIDEO);
 }
 
-// function to power up the LCD and backlight
+// function to power up the LCD and backlight - only works when using GPIO to power
 void N5110::turnOn()
 {
-  if (pwr != NULL) {
-    pwr->write(1);  // apply power
-  }
+    if (pwr != NULL) {
+        pwr->write(1);  // apply power
+    }
 }
 
 // function to power down LCD
 void N5110::turnOff()
 {
-  setBrightness(0.0);  // turn backlight off
-  clearRAM();   // clear RAM to ensure specified current consumption
-  // send command to ensure we are in basic mode
-  sendCommand(0x20 | CMD_FS_ACTIVE_MODE | CMD_FS_HORIZONTAL_MODE | CMD_FS_BASIC_MODE);
-  // clear the display
-  sendCommand(CMD_DC_CLEAR_DISPLAY);
-  // enter the extended mode and power down
-  sendCommand(0x20 | CMD_FS_POWER_DOWN_MODE | CMD_FS_HORIZONTAL_MODE | CMD_FS_EXTENDED_MODE);
-  // small delay and then turn off the power pin
-  wait_ms(10);
+    clear(); // clear buffer
+    refresh();
+    setBrightness(0.0);  // turn backlight off
+    clearRAM();   // clear RAM to ensure specified current consumption
+    // send command to ensure we are in basic mode
+    sendCommand(0x20 | CMD_FS_ACTIVE_MODE | CMD_FS_HORIZONTAL_MODE | CMD_FS_BASIC_MODE);
+    // clear the display
+    sendCommand(CMD_DC_CLEAR_DISPLAY);
+    // enter the extended mode and power down
+    sendCommand(0x20 | CMD_FS_POWER_DOWN_MODE | CMD_FS_HORIZONTAL_MODE | CMD_FS_EXTENDED_MODE);
+    // small delay and then turn off the power pin
+    wait_ms(10);
 
-  // if we are powering the LCD using the GPIO then make it low to turn off
-  if (pwr != NULL) {
-    pwr->write(0);  // turn off power
-  }
+    // if we are powering the LCD using the GPIO then make it low to turn off
+    if (pwr != NULL) {
+        pwr->write(0);  // turn off power
+    }
 
 }
 
 // function to change LED backlight brightness
 void N5110::setBrightness(float brightness)
 {
-  // check whether brightness is within range
-  if (brightness < 0.0f)
-  brightness = 0.0f;
-  if (brightness > 1.0f)
-  brightness = 1.0f;
-  // set PWM duty cycle
-  led->write(brightness);
+    // check whether brightness is within range
+    if (brightness < 0.0f)
+        brightness = 0.0f;
+    if (brightness > 1.0f)
+        brightness = 1.0f;
+    // set PWM duty cycle
+    led->write(brightness);
 }
 
 
 // pulse the active low reset line
 void N5110::reset()
 {
-  rst->write(0);  // reset the LCD
-  rst->write(1);
+    rst->write(0);  // reset the LCD
+    rst->write(1);
 }
 
 // function to initialise SPI peripheral
 void N5110::initSPI()
 {
-  spi->format(8,1);    // 8 bits, Mode 1 - polarity 0, phase 1 - base value of clock is 0, data captured on falling edge/propagated on rising edge
-  spi->frequency(4000000);  // maximum of screen is 4 MHz
+    spi->format(8,1);    // 8 bits, Mode 1 - polarity 0, phase 1 - base value of clock is 0, data captured on falling edge/propagated on rising edge
+    spi->frequency(4000000);  // maximum of screen is 4 MHz
 }
 
 // send a command to the display
 void N5110::sendCommand(unsigned char command)
 {
-  dc->write(0);  // set DC low for command
-  sce->write(0); // set CE low to begin frame
-  spi->write(command);  // send command
-  dc->write(1);  // turn back to data by default
-  sce->write(1); // set CE high to end frame (expected for transmission of single byte)
+    dc->write(0);  // set DC low for command
+    sce->write(0); // set CE low to begin frame
+    spi->write(command);  // send command
+    dc->write(1);  // turn back to data by default
+    sce->write(1); // set CE high to end frame (expected for transmission of single byte)
 
 }
 
@@ -152,29 +146,29 @@
 // be the default mode.
 void N5110::sendData(unsigned char data)
 {
-  sce->write(0);   // set CE low to begin frame
-  spi->write(data);
-  sce->write(1);  // set CE high to end frame (expected for transmission of single byte)
+    sce->write(0);   // set CE low to begin frame
+    spi->write(data);
+    sce->write(1);  // set CE high to end frame (expected for transmission of single byte)
 }
 
 // this function writes 0 to the 504 bytes to clear the RAM
 void N5110::clearRAM()
 {
-  sce->write(0);  //set CE low to begin frame
-  for(int i = 0; i < WIDTH * HEIGHT; i++) { // 48 x 84 bits = 504 bytes
-    spi->write(0x00);  // send 0's
-  }
-  sce->write(1); // set CE high to end frame
+    sce->write(0);  //set CE low to begin frame
+    for(int i = 0; i < WIDTH * HEIGHT; i++) { // 48 x 84 bits = 504 bytes
+        spi->write(0x00);  // send 0's
+    }
+    sce->write(1); // set CE high to end frame
 
 }
 
 // function to set the XY address in RAM for subsequenct data write
 void N5110::setXYAddress(int x, int y)
 {
-  if (x>=0 && x<WIDTH && y>=0 && y<HEIGHT) {  // check within range
-    sendCommand(0x80 | x);  // send addresses to display with relevant mask
-    sendCommand(0x40 | y);
-  }
+    if (x>=0 && x<WIDTH && y>=0 && y<HEIGHT) {  // check within range
+        sendCommand(0x80 | x);  // send addresses to display with relevant mask
+        sendCommand(0x40 | y);
+    }
 }
 
 // These functions are used to set, clear and get the value of pixels in the display
@@ -182,47 +176,52 @@
 // function must be called after set and clear in order to update the display
 void N5110::setPixel(int x, int y)
 {
-  if (x>=0 && x<WIDTH && y>=0 && y<HEIGHT) {  // check within range
-    // calculate bank and shift 1 to required position in the data byte
-    buffer[x][y/8] |= (1 << y%8);
-  }
+    if (x>=0 && x<WIDTH && y>=0 && y<HEIGHT) {  // check within range
+        // calculate bank and shift 1 to required position in the data byte
+        buffer[x][y/8] |= (1 << y%8);
+    }
 }
 
 void N5110::clearPixel(int x, int y)
 {
-  if (x>=0 && x<WIDTH && y>=0 && y<HEIGHT) {  // check within range
-    // calculate bank and shift 1 to required position (using bit clear)
-    buffer[x][y/8] &= ~(1 << y%8);
-  }
+    if (x>=0 && x<WIDTH && y>=0 && y<HEIGHT) {  // check within range
+        // calculate bank and shift 1 to required position (using bit clear)
+        buffer[x][y/8] &= ~(1 << y%8);
+    }
 }
 
 int N5110::getPixel(int x, int y)
 {
-  if (x>=0 && x<WIDTH && y>=0 && y<HEIGHT) {  // check within range
-    // return relevant bank and mask required bit
-    return (int) buffer[x][y/8] & (1 << y%8);
-    // note this does not necessarily return 1 - a non-zero number represents a pixel
-  } else {
+    if (x>=0 && x<WIDTH && y>=0 && y<HEIGHT) {  // check within range
+        // return relevant bank and mask required bit
+
+        int pixel = (int) buffer[x][y/8] & (1 << y%8);
+
+        if (pixel)
+            return 1;
+        else
+            return 0;
+    }
+
     return 0;
-  }
+
 }
 
 // function to refresh the display
 void N5110::refresh()
 {
+    setXYAddress(0,0);  // important to set address back to 0,0 before refreshing display
+    // address auto increments after printing string, so buffer[0][0] will not coincide
+    // with top-left pixel after priting string
 
-  setXYAddress(0,0);  // important to set address back to 0,0 before refreshing display
-  // address auto increments after printing string, so buffer[0][0] will not coincide
-  // with top-left pixel after priting string
-
-  sce->write(0);  //set CE low to begin frame
+    sce->write(0);  //set CE low to begin frame
 
-  for(int j = 0; j < BANKS; j++) {  // be careful to use correct order (j,i) for horizontal addressing
-    for(int i = 0; i < WIDTH; i++) {
-      spi->write(buffer[i][j]);  // send buffer
+    for(int j = 0; j < BANKS; j++) {  // be careful to use correct order (j,i) for horizontal addressing
+        for(int i = 0; i < WIDTH; i++) {
+            spi->write(buffer[i][j]);  // send buffer
+        }
     }
-  }
-  sce->write(1); // set CE high to end frame
+    sce->write(1); // set CE high to end frame
 
 }
 
@@ -230,199 +229,172 @@
 // The rand() function isn't seeded so it probably creates the same pattern everytime
 void N5110::randomiseBuffer()
 {
-  int i,j;
-  for(j = 0; j < BANKS; j++) {  // be careful to use correct order (j,i) for horizontal addressing
-    for(i = 0; i < WIDTH; i++) {
-      buffer[i][j] = rand()%256;  // generate random byte
+    int i,j;
+    for(j = 0; j < BANKS; j++) {  // be careful to use correct order (j,i) for horizontal addressing
+        for(i = 0; i < WIDTH; i++) {
+            buffer[i][j] = rand()%256;  // generate random byte
+        }
     }
-  }
 
 }
 
 // function to print 5x7 font
 void N5110::printChar(char c,int x,int y)
 {
-  if (y>=0 && y<BANKS) {  // check if printing in range of y banks
+    if (y>=0 && y<BANKS) {  // check if printing in range of y banks
 
-    for (int i = 0; i < 5 ; i++ ) {
-      int pixel_x = x+i;
-      if (pixel_x > WIDTH-1)  // ensure pixel isn't outside the buffer size (0 - 83)
-      break;
-      buffer[pixel_x][y] = font5x7[(c - 32)*5 + i];
-      // array is offset by 32 relative to ASCII, each character is 5 pixels wide
+        for (int i = 0; i < 5 ; i++ ) {
+            int pixel_x = x+i;
+            if (pixel_x > WIDTH-1)  // ensure pixel isn't outside the buffer size (0 - 83)
+                break;
+            buffer[pixel_x][y] = font5x7[(c - 32)*5 + i];
+            // array is offset by 32 relative to ASCII, each character is 5 pixels wide
+        }
+        
     }
-
-    refresh();  // this sends the buffer to the display and sets address (cursor) back to 0,0
-  }
 }
 
 // function to print string at specified position
 void N5110::printString(const char * str,int x,int y)
 {
-  if (y>=0 && y<BANKS) {  // check if printing in range of y banks
+    if (y>=0 && y<BANKS) {  // check if printing in range of y banks
 
-    int n = 0 ; // counter for number of characters in string
-    // loop through string and print character
-    while(*str) {
+        int n = 0 ; // counter for number of characters in string
+        // loop through string and print character
+        while(*str) {
 
-      // writes the character bitmap data to the buffer, so that
-      // text and pixels can be displayed at the same time
-      for (int i = 0; i < 5 ; i++ ) {
-        int pixel_x = x+i+n*6;
-        if (pixel_x > WIDTH-1) // ensure pixel isn't outside the buffer size (0 - 83)
-        break;
-        buffer[pixel_x][y] = font5x7[(*str - 32)*5 + i];
-      }
-
-      str++;  // go to next character in string
-
-      n++;    // increment index
-
+            // writes the character bitmap data to the buffer, so that
+            // text and pixels can be displayed at the same time
+            for (int i = 0; i < 5 ; i++ ) {
+                int pixel_x = x+i+n*6;
+                if (pixel_x > WIDTH-1) // ensure pixel isn't outside the buffer size (0 - 83)
+                    break;
+                buffer[pixel_x][y] = font5x7[(*str - 32)*5 + i];
+            }
+            str++;  // go to next character in string
+            n++;    // increment index
+        }
     }
-
-    refresh();  // this sends the buffer to the display and sets address (cursor) back to 0,0
-  }
 }
 
-// function to clear the screen
+// function to clear the screen buffer
 void N5110::clear()
 {
-  clearBuffer();  // clear the buffer then call the refresh function
-  refresh();
-}
-
-// function to clear the buffer
-void N5110::clearBuffer()
-{
-  memset(buffer,0,sizeof(buffer));
-
-  /*int i,j;
-  for (i=0; i<WIDTH; i++) {  // loop through the banks and set the buffer to 0
-    for (j=0; j<BANKS; j++) {
-      buffer[i][j]=0;
-    }
-  }
-  */
+    memset(buffer,0,sizeof(buffer));
 }
 
 // function to plot array on display
 void N5110::plotArray(float array[])
 {
-
-  for (int i=0; i<WIDTH; i++) {  // loop through array
-    // elements are normalised from 0.0 to 1.0, so multiply
-    // by 47 to convert to pixel range, and subtract from 47
-    // since top-left is 0,0 in the display geometry
-    setPixel(i,47 - int(array[i]*47.0f));
-  }
-
-  refresh();
+    for (int i=0; i<WIDTH; i++) {  // loop through array
+        // elements are normalised from 0.0 to 1.0, so multiply
+        // by 47 to convert to pixel range, and subtract from 47
+        // since top-left is 0,0 in the display geometry
+        setPixel(i,47 - int(array[i]*47.0f));
+    }
 
 }
 
 // function to draw circle
 void N5110:: drawCircle(int x0,int y0,int radius,int fill)
 {
-  // from http://en.wikipedia.org/wiki/Midpoint_circle_algorithm
-  int x = radius;
-  int y = 0;
-  int radiusError = 1-x;
+    // from http://en.wikipedia.org/wiki/Midpoint_circle_algorithm
+    int x = radius;
+    int y = 0;
+    int radiusError = 1-x;
 
-  while(x >= y) {
+    while(x >= y) {
 
-    // if transparent, just draw outline
-    if (fill == 0) {
-      setPixel( x + x0,  y + y0);
-      setPixel(-x + x0,  y + y0);
-      setPixel( y + x0,  x + y0);
-      setPixel(-y + x0,  x + y0);
-      setPixel(-y + x0, -x + y0);
-      setPixel( y + x0, -x + y0);
-      setPixel( x + x0, -y + y0);
-      setPixel(-x + x0, -y + y0);
-    } else {  // drawing filled circle, so draw lines between points at same y value
+        // if transparent, just draw outline
+        if (fill == 0) {
+            setPixel( x + x0,  y + y0);
+            setPixel(-x + x0,  y + y0);
+            setPixel( y + x0,  x + y0);
+            setPixel(-y + x0,  x + y0);
+            setPixel(-y + x0, -x + y0);
+            setPixel( y + x0, -x + y0);
+            setPixel( x + x0, -y + y0);
+            setPixel(-x + x0, -y + y0);
+        } else {  // drawing filled circle, so draw lines between points at same y value
 
-      int type = (fill==1) ? 1:0;  // black or white fill
+            int type = (fill==1) ? 1:0;  // black or white fill
 
-      drawLine(x+x0,y+y0,-x+x0,y+y0,type);
-      drawLine(y+x0,x+y0,-y+x0,x+y0,type);
-      drawLine(y+x0,-x+y0,-y+x0,-x+y0,type);
-      drawLine(x+x0,-y+y0,-x+x0,-y+y0,type);
-    }
-
+            drawLine(x+x0,y+y0,-x+x0,y+y0,type);
+            drawLine(y+x0,x+y0,-y+x0,x+y0,type);
+            drawLine(y+x0,-x+y0,-y+x0,-x+y0,type);
+            drawLine(x+x0,-y+y0,-x+x0,-y+y0,type);
+        }
 
-    y++;
-    if (radiusError<0) {
-      radiusError += 2 * y + 1;
-    } else {
-      x--;
-      radiusError += 2 * (y - x) + 1;
+        y++;
+        if (radiusError<0) {
+            radiusError += 2 * y + 1;
+        } else {
+            x--;
+            radiusError += 2 * (y - x) + 1;
+        }
     }
-  }
 
 }
 
 void N5110::drawLine(int x0,int y0,int x1,int y1,int type)
 {
-  int y_range = y1-y0;  // calc range of y and x
-  int x_range = x1-x0;
-  int start,stop,step;
+    int y_range = y1-y0;  // calc range of y and x
+    int x_range = x1-x0;
+    int start,stop,step;
 
-  // if dotted line, set step to 2, else step is 1
-  step = (type==2) ? 2:1;
+    // if dotted line, set step to 2, else step is 1
+    step = (type==2) ? 2:1;
 
-  // make sure we loop over the largest range to get the most pixels on the display
-  // for instance, if drawing a vertical line (x_range = 0), we need to loop down the y pixels
-  // or else we'll only end up with 1 pixel in the x column
-  if ( abs(x_range) > abs(y_range) ) {
+    // make sure we loop over the largest range to get the most pixels on the display
+    // for instance, if drawing a vertical line (x_range = 0), we need to loop down the y pixels
+    // or else we'll only end up with 1 pixel in the x column
+    if ( abs(x_range) > abs(y_range) ) {
 
-    // ensure we loop from smallest to largest or else for-loop won't run as expected
-    start = x1>x0 ? x0:x1;
-    stop =  x1>x0 ? x1:x0;
+        // ensure we loop from smallest to largest or else for-loop won't run as expected
+        start = x1>x0 ? x0:x1;
+        stop =  x1>x0 ? x1:x0;
 
-    // loop between x pixels
-    for (int x = start; x<= stop ; x+=step) {
-      // do linear interpolation
-      int y = y0 + (y1-y0)*(x-x0)/(x1-x0);
+        // loop between x pixels
+        for (int x = start; x<= stop ; x+=step) {
+            // do linear interpolation
+            int y = y0 + (y1-y0)*(x-x0)/(x1-x0);
 
-      if (type == 0)   // if 'white' line, turn off pixel
-      clearPixel(x,y);
-      else
-      setPixel(x,y);  // else if 'black' or 'dotted' turn on pixel
-    }
-  } else {
+            if (type == 0)   // if 'white' line, turn off pixel
+                clearPixel(x,y);
+            else
+                setPixel(x,y);  // else if 'black' or 'dotted' turn on pixel
+        }
+    } else {
 
-    // ensure we loop from smallest to largest or else for-loop won't run as expected
-    start = y1>y0 ? y0:y1;
-    stop =  y1>y0 ? y1:y0;
+        // ensure we loop from smallest to largest or else for-loop won't run as expected
+        start = y1>y0 ? y0:y1;
+        stop =  y1>y0 ? y1:y0;
 
-    for (int y = start; y<= stop ; y+=step) {
-      // do linear interpolation
-      int x = x0 + (x1-x0)*(y-y0)/(y1-y0);
+        for (int y = start; y<= stop ; y+=step) {
+            // do linear interpolation
+            int x = x0 + (x1-x0)*(y-y0)/(y1-y0);
 
-      if (type == 0)   // if 'white' line, turn off pixel
-      clearPixel(x,y);
-      else
-      setPixel(x,y);  // else if 'black' or 'dotted' turn on pixel
+            if (type == 0)   // if 'white' line, turn off pixel
+                clearPixel(x,y);
+            else
+                setPixel(x,y);  // else if 'black' or 'dotted' turn on pixel
 
+        }
     }
-  }
 
 }
 
 void N5110::drawRect(int x0,int y0,int width,int height,int fill)
 {
-
-  if (fill == 0) { // transparent, just outline
-    drawLine(x0,y0,x0+width,y0,1);  // top
-    drawLine(x0,y0+height,x0+width,y0+height,1);  // bottom
-    drawLine(x0,y0,x0,y0+height,1);  // left
-    drawLine(x0+width,y0,x0+width,y0+height,1);  // right
-  } else { // filled rectangle
-    int type = (fill==1) ? 1:0;  // black or white fill
-    for (int y = y0; y<= y0+height; y++) {  // loop through rows of rectangle
-      drawLine(x0,y,x0+width,y,type);  // draw line across screen
+    if (fill == 0) { // transparent, just outline
+        drawLine(x0,y0,x0+width,y0,1);  // top
+        drawLine(x0,y0+height,x0+width,y0+height,1);  // bottom
+        drawLine(x0,y0,x0,y0+height,1);  // left
+        drawLine(x0+width,y0,x0+width,y0+height,1);  // right
+    } else { // filled rectangle
+        int type = (fill==1) ? 1:0;  // black or white fill
+        for (int y = y0; y<= y0+height; y++) {  // loop through rows of rectangle
+            drawLine(x0,y,x0+width,y,type);  // draw line across screen
+        }
     }
-  }
-
 }