microbit: Use default constructor for MatrixPoint so data is ROMable.

Previous to this patch an explicit constructor was provided for creating
MatrixPoint instances, which meant that such objects could not be put in
ROM (since they needed to be constructed at runtime).

By using the defualt construction method for structs the MatrixPoint map
is now compiled into the rodata section, hence freeing up RAM.

Saves: 4 bytes data, 56 bytes bss, 148 bytes code.

inc/MicroBitDisplay.h

@@ -85,8 +85,6 @@ enum DisplayMode {
 struct MatrixPoint {
     uint8_t x;
     uint8_t y;
-
-    MatrixPoint(uint8_t x, uint8_t y);
 };
 
 /**

inc/MicroBitMatrixMaps.h

@@ -19,50 +19,50 @@
 
 #if MICROBIT_DISPLAY_TYPE == MICROBUG_REFERENCE_DEVICE
     const MatrixPoint MicroBitDisplay::matrixMap[MICROBIT_DISPLAY_COLUMN_COUNT][MICROBIT_DISPLAY_ROW_COUNT] = 
-    {   {MatrixPoint(0,0),MatrixPoint(0,1),MatrixPoint(0,2), MatrixPoint(0,3), MatrixPoint(0,4)},
-        {MatrixPoint(1,0),MatrixPoint(1,1),MatrixPoint(1,2), MatrixPoint(1,3), MatrixPoint(1,4)},
-        {MatrixPoint(2,0),MatrixPoint(2,1),MatrixPoint(2,2), MatrixPoint(2,3), MatrixPoint(2,4)},
-        {MatrixPoint(3,0),MatrixPoint(3,1),MatrixPoint(3,2), MatrixPoint(3,3), MatrixPoint(3,4)},
-        {MatrixPoint(4,0),MatrixPoint(4,1),MatrixPoint(4,2), MatrixPoint(4,3), MatrixPoint(4,4)} 
+    {   {{0,0},{0,1},{0,2},{0,3},{0,4}},
+        {{1,0},{1,1},{1,2},{1,3},{1,4}},
+        {{2,0},{2,1},{2,2},{2,3},{2,4}},
+        {{3,0},{3,1},{3,2},{3,3},{3,4}},
+        {{4,0},{4,1},{4,2},{4,3},{4,4}}
     };
 #endif
 
 #if MICROBIT_DISPLAY_TYPE == MICROBIT_3X9
     const MatrixPoint MicroBitDisplay::matrixMap[MICROBIT_DISPLAY_COLUMN_COUNT][MICROBIT_DISPLAY_ROW_COUNT] = 
     {   
-        {MatrixPoint(0,4),MatrixPoint(0,3),MatrixPoint(1,1)},
-        {MatrixPoint(1,4),MatrixPoint(4,2),MatrixPoint(0,1)},
-        {MatrixPoint(2,4),MatrixPoint(3,2),MatrixPoint(4,0)},  
-        {MatrixPoint(3,4),MatrixPoint(2,2),MatrixPoint(3,0)},
-        {MatrixPoint(4,4),MatrixPoint(1,2),MatrixPoint(2,0)},
-        {MatrixPoint(4,3),MatrixPoint(0,2),MatrixPoint(1,0)},
-        {MatrixPoint(3,3),MatrixPoint(4,1),MatrixPoint(0,0)},
-        {MatrixPoint(2,3),MatrixPoint(3,1),MatrixPoint(NO_CONN,NO_CONN)},
-        {MatrixPoint(1,3),MatrixPoint(2,1),MatrixPoint(NO_CONN,NO_CONN)}
+        {{0,4},{0,3},{1,1}},
+        {{1,4},{4,2},{0,1}},
+        {{2,4},{3,2},{4,0}},
+        {{3,4},{2,2},{3,0}},
+        {{4,4},{1,2},{2,0}},
+        {{4,3},{0,2},{1,0}},
+        {{3,3},{4,1},{0,0}},
+        {{2,3},{3,1},{NO_CONN,NO_CONN}},
+        {{1,3},{2,1},{NO_CONN,NO_CONN}}
     };
 #endif
 
 #if MICROBIT_DISPLAY_TYPE == MICROBIT_SB1
     const MatrixPoint MicroBitDisplay::matrixMap[MICROBIT_DISPLAY_COLUMN_COUNT][MICROBIT_DISPLAY_ROW_COUNT] = 
     {   
-        {MatrixPoint(0,4), MatrixPoint(1,4), MatrixPoint(2,4), MatrixPoint(3,4), MatrixPoint(4,4), MatrixPoint(4,3), MatrixPoint(3,3), MatrixPoint(2,3), MatrixPoint(1,3)},
-        {MatrixPoint(0,3), MatrixPoint(4,2), MatrixPoint(3,2), MatrixPoint(2,2), MatrixPoint(1,2), MatrixPoint(0,2), MatrixPoint(4,1), MatrixPoint(3,1), MatrixPoint(2,1)},
-        {MatrixPoint(1,1), MatrixPoint(0,1), MatrixPoint(4,0), MatrixPoint(3,0), MatrixPoint(2,0), MatrixPoint(1,0), MatrixPoint(0,0), MatrixPoint(NO_CONN,NO_CONN), MatrixPoint(NO_CONN,NO_CONN)}        
+        {{0,4},{1,4},{2,4},{3,4},{4,4},{4,3},{3,3},{2,3},{1,3}},
+        {{0,3},{4,2},{3,2},{2,2},{1,2},{0,2},{4,1},{3,1},{2,1}},
+        {{1,1},{0,1},{4,0},{3,0},{2,0},{1,0},{0,0},{NO_CONN,NO_CONN},{NO_CONN,NO_CONN}}
     };
 #endif
 
 #if MICROBIT_DISPLAY_TYPE == MICROBIT_SB2
     const MatrixPoint MicroBitDisplay::matrixMap[MICROBIT_DISPLAY_COLUMN_COUNT][MICROBIT_DISPLAY_ROW_COUNT] = 
     {   
-        {MatrixPoint(0,0),MatrixPoint(4,2),MatrixPoint(2,4)},
-        {MatrixPoint(2,0),MatrixPoint(0,2),MatrixPoint(4,4)},
-        {MatrixPoint(4,0),MatrixPoint(2,2),MatrixPoint(0,4)},  
-        {MatrixPoint(4,3),MatrixPoint(1,0),MatrixPoint(0,1)},
-        {MatrixPoint(3,3),MatrixPoint(3,0),MatrixPoint(1,1)},
-        {MatrixPoint(2,3),MatrixPoint(3,4),MatrixPoint(2,1)},
-        {MatrixPoint(1,3),MatrixPoint(1,4),MatrixPoint(3,1)},
-        {MatrixPoint(0,3),MatrixPoint(NO_CONN,NO_CONN),MatrixPoint(4,1)},
-        {MatrixPoint(1,2),MatrixPoint(NO_CONN,NO_CONN),MatrixPoint(3,2)}
+        {{0,0},{4,2},{2,4}},
+        {{2,0},{0,2},{4,4}},
+        {{4,0},{2,2},{0,4}},
+        {{4,3},{1,0},{0,1}},
+        {{3,3},{3,0},{1,1}},
+        {{2,3},{3,4},{2,1}},
+        {{1,3},{1,4},{3,1}},
+        {{0,3},{NO_CONN,NO_CONN},{4,1}},
+        {{1,2},{NO_CONN,NO_CONN},{3,2}}
     };
     
 #endif

source/MicroBitDisplay.cpp

@@ -10,17 +10,6 @@
 
 const float timings[MICROBIT_DISPLAY_GREYSCALE_BIT_DEPTH] = {0.000010, 0.000047, 0.000094, 0.000187, 0.000375, 0.000750, 0.001500, 0.003000};
 
-/**
-  * Constructor.
-  * Create a Point representation of an LED on a matrix
-  * Used to handle non-linear matrix layouts.
-  */
-MatrixPoint::MatrixPoint(uint8_t x, uint8_t y)
-{
-    this->x = x;
-    this->y = y;
-}
-
 /**
   * Constructor.
   * Create a representation of a display of a given size.