Shrink OLED driver code. (#296)

* Precompute command header.
* Update data header on-demand.
* Use more aggressive inlining.
* Do not clear number buffer twice.

workspace/TS100/inc/OLED.hpp

@@ -12,6 +12,7 @@
 #include <hardware.h>
 #include "stm32f1xx_hal.h"
 #include <stdbool.h>
+#include <string.h>
 #include "FRToSI2C.hpp"
 #include "Font.h"
 #ifdef __cplusplus
@@ -23,32 +24,63 @@ extern "C" {
 #endif
 #define DEVICEADDR_OLED   (0x3c<<1)
 #define OLED_WIDTH        96
+#define FRAMEBUFFER_START 17
+
 
 class OLED {
 public:
 	OLED(FRToSI2C* i2cHandle); // Initialize Driver and store I2C pointer
 	void initialize(); 	// Startup the I2C coms (brings screen out of reset etc)
-	void refresh(); 	// Draw the buffer out to the LCD using the DMA Channel
+	
+	// Draw the buffer out to the LCD using the DMA Channel
+	void refresh() {
+		i2c->Transmit( DEVICEADDR_OLED, screenBuffer, FRAMEBUFFER_START + (OLED_WIDTH * 2));
+	}
+
 	void drawChar(char c, char preCursorCommand = '\0'); // Draw a character to a specific location
-	void displayOnOff(bool on);				// Turn the screen on or not
+	// Turn the screen on or not
+	void displayOnOff(bool on) {
+		displayOnOffState = on;
+		screenBuffer[1] = on ? 0xAF : 0xAE;
+	}			
 	void setRotation(bool leftHanded);  	// Set the rotation for the screen
-	bool getRotation();					// Get the current rotation of the LCD
+	// Get the current rotation of the LCD
+	bool getRotation() const {
+		return inLeftHandedMode;
+	}					
 	void print(const char* string);	// Draw a string to the current location, with current font
-	void setCursor(int16_t x, int16_t y);   // Set the cursor location by pixels
+	// Set the cursor location by pixels
-	void setCharCursor(int16_t x, int16_t y); //Set cursor location by chars in current font
+	void setCursor(int16_t x, int16_t y) {
+		cursor_x = x;
+		cursor_y = y;		
+	}   
+	//Set cursor location by chars in current font
+	void setCharCursor(int16_t x, int16_t y) {
+		cursor_x = x * fontWidth;
+		cursor_y = y * fontHeight;
+	}
 	void setFont(uint8_t fontNumber); // (Future) Set the font that is being used
-	void drawImage(const uint8_t* buffer, uint8_t x, uint8_t width);
+	void drawImage(const uint8_t* buffer, uint8_t x, uint8_t width) {
+		drawArea(x, 0, width, 16, buffer);
+	}
 	// Draws an image to the buffer, at x offset from top to bottom (fixed height renders)
 	void printNumber(uint16_t number, uint8_t places);
 	// Draws a number at the current cursor location
-	void clearScreen();						// Clears the buffer
+	// Clears the buffer
-	void drawBattery(uint8_t state);		// Draws the battery level symbol
+	void clearScreen() {
-	void drawCheckbox(bool state);		// Draws a checkbox
+		memset(&screenBuffer[FRAMEBUFFER_START], 0, OLED_WIDTH * 2);
+	}					
+	// Draws the battery level symbol
+	void drawBattery(uint8_t state) {
+		drawSymbol(3 + (state > 10 ? 10 : state));
+	}		
+	// Draws a checkbox
+	void drawCheckbox(bool state) {
+		drawSymbol((state) ? 16 : 17);
+	}
 	void drawSymbol(uint8_t symbolID);//Used for drawing symbols of a predictable width
-	void drawArea(int16_t x, int8_t y, uint8_t wide, uint8_t height,
+	void drawArea(int16_t x, int8_t y, uint8_t wide, uint8_t height, const uint8_t* ptr); //Draw an area, but y must be aligned on 0/8 offset
-			const uint8_t* ptr);
+	void fillArea(int16_t x, int8_t y, uint8_t wide, uint8_t height, const uint8_t value); //Fill an area, but y must be aligned on 0/8 offset
-	void fillArea(int16_t x, int8_t y, uint8_t wide, uint8_t height,
-			const uint8_t value);
 	void drawFilledRect(uint8_t x0, uint8_t y0, uint8_t x1, uint8_t y1,bool clear);
 	void drawHeatSymbol(uint8_t state);
 private:
@@ -57,7 +89,6 @@ private:
 
 	FRToSI2C* i2c;					//i2c Pointer
 	const uint8_t* currentFont;	// Pointer to the current font used for rendering to the buffer
-	uint8_t screenBuffer[16 + 96 + 96 + 10];    // The data buffer
 	uint8_t* firstStripPtr; // Pointers to the strips to allow for buffer having extra content
 	uint8_t* secondStripPtr;	//Pointers to the strips
 	bool inLeftHandedMode; // Whether the screen is in left or not (used for offsets in GRAM)
@@ -65,6 +96,7 @@ private:
 	uint8_t fontWidth, fontHeight;
 	int16_t cursor_x, cursor_y;
 	uint8_t displayOffset;
+	uint8_t screenBuffer[16 + (OLED_WIDTH * 2) + 10];    // The data buffer
 };
 
 #endif /* OLED_HPP_ */

workspace/TS100/src/OLED.cpp

@@ -13,7 +13,6 @@
 /*http://www.displayfuture.com/Display/datasheet/controller/SSD1307.pdf*/
 /*All commands are prefixed with 0x80*/
 /*Data packets are prefixed with 0x40*/
-const uint8_t configLength = 50;
 uint8_t OLED_Setup_Array[] = { /**/
 0x80, 0xAE,/*Display off*/
 0x80, 0xD5,/*Set display clock divide ratio / osc freq*/
@@ -43,54 +42,42 @@ uint8_t OLED_Setup_Array[] = { /**/
 };
 //Setup based on the SSD1307 and modified for the SSD1306
 
+const uint8_t REFRESH_COMMANDS[17] = {
+	0x80, 0xAF,
+	0x80, 0x21,
+	0x80, 0x20,
+	0x80, 0x7F,
+	0x80, 0xC0,
+	0x80, 0x22,
+	0x80, 0x00,
+	0x80, 0x01,
+	0x40
+};
+
 OLED::OLED(FRToSI2C* i2cHandle) {
 	i2c = i2cHandle;
 	cursor_x = cursor_y = 0;
 	currentFont = FONT_12;
 	fontWidth = 12;
 	inLeftHandedMode = false;
-	firstStripPtr = &screenBuffer[16 + 1];
+	firstStripPtr = &screenBuffer[FRAMEBUFFER_START];
-	secondStripPtr = &screenBuffer[16 + 1 + 96];
+	secondStripPtr = &screenBuffer[FRAMEBUFFER_START + OLED_WIDTH];
 	fontHeight = 16;
-	fontWidth = 12;
 	displayOffset = 0;
 	displayOnOffState = true;
-
 }
 
 void OLED::initialize() {
+	memcpy(&screenBuffer[0], &REFRESH_COMMANDS[0], sizeof(REFRESH_COMMANDS));
+
 	HAL_Delay(5);
 	HAL_GPIO_WritePin(OLED_RESET_GPIO_Port, OLED_RESET_Pin, GPIO_PIN_SET);
 	HAL_Delay(10);
 	//Send the setup settings
-	i2c->Transmit( DEVICEADDR_OLED, (uint8_t*) OLED_Setup_Array, configLength);
+	i2c->Transmit( DEVICEADDR_OLED, (uint8_t*) OLED_Setup_Array, sizeof(OLED_Setup_Array));
 	displayOnOff(true);
 }
 
-//Write out the buffer to the OLEd & call any rendering objects
-void OLED::refresh() {
-	screenBuffer[0] = 0x80;
-	screenBuffer[1] = displayOnOffState ? 0xAF : 0xAE;
-	screenBuffer[2] = 0x80;
-	screenBuffer[3] = 0x21;
-	screenBuffer[4] = 0x80;
-	screenBuffer[5] = inLeftHandedMode ? 0 : 32; //display is shifted by 32 in left handed mode as driver ram is 128 wide
-	screenBuffer[6] = 0x80;
-	screenBuffer[7] = inLeftHandedMode ? 95 : 0x7F; //End address of the ram segment we are writing to (96 wide)
-	screenBuffer[8] = 0x80; /*Set COM Scan direction*/
-	screenBuffer[9] = inLeftHandedMode ? 0xC8 : 0xC0;
-	screenBuffer[10] = 0x80;    //Set pages to rollover after 2
-	screenBuffer[11] = 0x22;
-	screenBuffer[12] = 0x80;
-	screenBuffer[13] = 0x00;    //start page 0
-	screenBuffer[14] = 0x80;
-	screenBuffer[15] = 0x01;
-	screenBuffer[16] = 0x40;    //start of data marker
-
-	i2c->Transmit( DEVICEADDR_OLED, screenBuffer, 16 + (96 * 2) + 1);
-
-}
-
 /*
  * Prints a char to the screen.
  * UTF font handling is done using the two input chars.
@@ -151,25 +138,26 @@ void OLED::drawChar(char c, char PrecursorCommand) {
 	cursor_x += fontWidth;
 }
 
-void OLED::displayOnOff(bool on) {
-	displayOnOffState = on;
-}
-
 void OLED::setRotation(bool leftHanded) {
-	if (inLeftHandedMode != leftHanded) {
+	if (inLeftHandedMode == leftHanded) {
+		return;
+	}
+
 	//send command struct again with changes
-		if (leftHanded == 1) {
+	if (leftHanded) {
 			OLED_Setup_Array[11] = 0xC8;    //c1?
 			OLED_Setup_Array[19] = 0xA1;
-		} else if (leftHanded == 0) {
+	} else {
 			OLED_Setup_Array[11] = 0xC0;
 			OLED_Setup_Array[19] = 0xA0;
 		}
-		i2c->Transmit( DEVICEADDR_OLED, (uint8_t*) OLED_Setup_Array,
+	i2c->Transmit( DEVICEADDR_OLED, (uint8_t*) OLED_Setup_Array, sizeof(OLED_Setup_Array));
-				configLength);
 		inLeftHandedMode = leftHanded;
+
+	screenBuffer[5] = inLeftHandedMode ? 0 : 32; //display is shifted by 32 in left handed mode as driver ram is 128 wide
+	screenBuffer[7] = inLeftHandedMode ? 95 : 0x7F; //End address of the ram segment we are writing to (96 wide)
+	screenBuffer[9] = inLeftHandedMode ? 0xC8 : 0xC0;
 	}
-}
 
 //print a string to the current cursor location
 void OLED::print(const char* str) {
@@ -183,14 +171,6 @@ void OLED::print(const char* str) {
 	}
 }
 
-void OLED::setCursor(int16_t x, int16_t y) {
-	cursor_x = x;
-	cursor_y = y;
-}
-void OLED::setCharCursor(int16_t x, int16_t y) {
-	cursor_x = x * fontWidth;
-	cursor_y = y * fontHeight;
-}
 void OLED::setFont(uint8_t fontNumber) {
 	if (fontNumber == 1) {
 		//small font
@@ -208,58 +188,35 @@ void OLED::setFont(uint8_t fontNumber) {
 	}
 }
 
-void OLED::drawImage(const uint8_t* buffer, uint8_t x, uint8_t width) {
-	drawArea(x, 0, width, 16, buffer);
-}
-
 //maximum places is 5
 void OLED::printNumber(uint16_t number, uint8_t places) {
-	char buffer[6];
+	char buffer[6] = { 0 };
-	buffer[5] = 0;    //null
+	
 	if (places == 5) {
 		buffer[4] = '0' + number % 10;
 		number /= 10;
-	} else
+	}
-		buffer[4] = 0;
 
 	if (places > 3) {
 		buffer[3] = '0' + number % 10;
 		number /= 10;
-	} else
+	}
-		buffer[3] = 0;
 
 	if (places > 2) {
 		buffer[2] = '0' + number % 10;
 		number /= 10;
-	} else
+	}
-		buffer[2] = 0;
 
 	if (places > 1) {
 		buffer[1] = '0' + number % 10;
 		number /= 10;
-	} else
+	}
-		buffer[1] = 0;
+
 	buffer[0] = '0' + number % 10;
 	number /= 10;
 	print(buffer);
 }
 
-void OLED::clearScreen() {
-	memset(firstStripPtr, 0, 96);
-	memset(secondStripPtr, 0, 96);
-}
-
-bool OLED::getRotation() {
-	return inLeftHandedMode;
-}
-void OLED::drawBattery(uint8_t state) {
-	if (state > 10)
-		state = 10;
-	drawSymbol(3 + state);
-}
-void OLED::drawCheckbox(bool state) {
-	drawSymbol((state) ? 16 : 17);
-}
 void OLED::drawSymbol(uint8_t symbolID) {
 	//draw a symbol to the current cursor location
 	setFont(2);