Craig Evans / N5110

Library for interfacing to Nokia 5110 LCD display (as found on the SparkFun website).

Dependents:   LV7_LCDtest LV7_Grupa5_Tim003_Zadatak1 lv7_Grupa5_Tim008_zad1 LV7_PAI_Grupa5_tim10_Zadatak1 ... more

This library is designed to make it easy to interface an mbed with a Nokia 5110 LCD display.

These can be found at Sparkfun (https://www.sparkfun.com/products/10168) and Adafruit (http://www.adafruit.com/product/338).

The library uses the SPI peripheral on the mbed which means it is much faster sending data to the display than other libraries available on other platforms that use software SPI.

The library can print strings as well as controlling individual pixels, meaning that both text and primitive graphics can be displayed.

Diff: N5110.cpp

Revision:
43:c2598020fcac
Parent:
42:596c207519de
Child:
44:57f9d32fb521
--- a/N5110.cpp	Tue Mar 21 10:43:19 2017 +0000
+++ b/N5110.cpp	Tue Mar 21 11:46:14 2017 +0000
@@ -370,12 +370,13 @@
                      unsigned int const y1,
                      unsigned int const type)
 {
-    int y_range = y1-y0;  // calc range of y and x
-    int x_range = x1-x0;
-    int start,stop,step;
+    // Note that the ranges can be negative so we have to turn the input values
+    // into signed integers first
+    int const y_range = static_cast<int>(y1) - static_cast<int>(y0);
+    int const x_range = static_cast<int>(x1) - static_cast<int>(x0);
 
     // if dotted line, set step to 2, else step is 1
-    step = (type==2) ? 2:1;
+    unsigned int const 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
@@ -383,13 +384,14 @@
     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;
+        unsigned int const start = x_range > 0 ? x0:x1;
+        unsigned int const stop =  x_range > 0 ? x1:x0;
 
         // loop between x pixels
-        for (int x = start; x<= stop ; x+=step) {
+        for (unsigned int x = start; x<= stop ; x+=step) {
             // do linear interpolation
-            int y = y0 + (y1-y0)*(x-x0)/(x1-x0);
+            int const dx = static_cast<int>(x)-static_cast<int>(x0);
+            unsigned int const y = y0 + y_range * dx / x_range;
 
             // If the line type is '0', this will clear the pixel
             // If it is '1' or '2', the pixel will be set
@@ -398,12 +400,13 @@
     } 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;
+        unsigned int const start = y_range > 0 ? y0:y1;
+        unsigned int const stop =  y_range > 0 ? y1:y0;
 
-        for (int y = start; y<= stop ; y+=step) {
+        for (unsigned int y = start; y<= stop ; y+=step) {
             // do linear interpolation
-            int x = x0 + (x1-x0)*(y-y0)/(y1-y0);
+            int const dy = static_cast<int>(y)-static_cast<int>(y0);
+            unsigned int const x = x0 + x_range * dy / y_range;
 
             // If the line type is '0', this will clear the pixel
             // If it is '1' or '2', the pixel will be set
@@ -437,7 +440,7 @@
                        int nrows,
                        int ncols,
                        int *sprite)
-{ 
+{
     for (int i = 0; i < nrows; i++) {
         for (int j = 0 ; j < ncols ; j++) {