Add abstracted functions for display - simplify code

Simple functions for printing a line normal, large or centered
using format string directly instead of having to use both
snprintf first and then display function all the time
This makes the code more readable and compact

Applied this optimization where applicable in manu.cpp and display.cpp

board_single/main/display.cpp

@@ -75,6 +75,74 @@ void display_init(){
 
 
 
+//===============================
+//======= displayTextLine =======
+//===============================
+//abstracted function for printing one line on the display, using a format string directly
+//and options: Large-font (3 lines, max 5 digits), or inverted color
+void displayTextLine(SSD1306_t *display, int line, bool isLarge, bool inverted, const char *format, ...)
+{
+	char buf[17];
+	int len;
+
+	// format string + arguments to string
+	va_list args;
+	va_start(args, format);
+	len = vsnprintf(buf, sizeof(buf), format, args);
+	va_end(args);
+
+	// show line on display
+	if (isLarge)
+		ssd1306_display_text_x3(display, line, buf, len, inverted);
+	else
+		ssd1306_display_text(display, line, buf, len, inverted);
+}
+
+
+
+//===================================
+//===== displayTextLineCentered =====
+//===================================
+//abstracted function for printing a string CENTERED on the display, using a format string
+//adds spaces left and right to fill the line (if not too long already)
+#define MAX_LEN_NORMAL 16 //count of available digits on display (normal/large font)
+#define MAX_LEN_LARGE 5
+void displayTextLineCentered(SSD1306_t *display, int line, bool isLarge, bool inverted, const char *format, ...)
+{
+	// variables
+	char buf[MAX_LEN_NORMAL*2 + 2];
+	char tmp[MAX_LEN_NORMAL + 1];
+	int len;
+
+	// format string + arguments to string (-> tmp)
+	va_list args;
+	va_start(args, format);
+	len = vsnprintf(tmp, sizeof(tmp), format, args);
+	va_end(args);
+
+	// define max available digits
+	int maxLen = MAX_LEN_NORMAL;
+	if (isLarge)
+		maxLen = MAX_LEN_LARGE;
+
+	// determine required spaces
+	int numSpaces = (maxLen - len) / 2;
+	if (numSpaces < 0) // limit to 0 in case string is too long already
+		numSpaces = 0;
+
+	// add certain spaces around string (-> buf)
+	snprintf(buf, MAX_LEN_NORMAL*2, "%*s%s%*s", numSpaces, "", tmp, maxLen - numSpaces - len, "");
+	ESP_LOGD(TAG, "print center - isLarge=%d, value='%s', needed-spaces=%d, resulted-string='%s'", isLarge, tmp, numSpaces, buf);
+
+	// show line on display
+	if (isLarge)
+		ssd1306_display_text_x3(display, line, buf, maxLen, inverted);
+	else
+		ssd1306_display_text(display, line, buf, maxLen, inverted);
+}
+
+
+
 //----------------------------------
 //------- getBatteryVoltage --------
 //----------------------------------
@@ -138,35 +206,32 @@ float getBatteryPercent(){
 //percentage, voltage, current, mode, rpm, speed
 void showScreen1()
 {
-	char buf[20];
-	char buf1[20];
-	int len, len1;
-
 	//-- battery percentage --
 	// TODO update when no load (currentsensors = ~0A) only
-	len1 = snprintf(buf1, sizeof(buf1), "B:%02.0f%%", getBatteryPercent());
+	//large
-	ssd1306_display_text_x3(&dev, 0, buf1, len1, false);
+	displayTextLine(&dev, 0, true, false, "B:%02.0f%%", getBatteryPercent());
 
 	//-- voltage and current --
-	len = snprintf(buf, sizeof(buf), "%04.1fV %04.1f:%04.1fA",
+	displayTextLine(&dev, 3, false, false, "%04.1fV %04.1f:%04.1fA",
 				   getBatteryVoltage(),
 				   fabs(motorLeft.getCurrentA()),
 				   fabs(motorRight.getCurrentA()));
-	ssd1306_display_text(&dev, 3, buf, len, false);
 
 	//-- control state --
-	len = snprintf(buf, sizeof(buf), "%s ", control.getCurrentModeStr());
+	//print large line
-	ssd1306_display_text_x3(&dev, 4, buf, len, false);
+	displayTextLine(&dev, 4, true, false, "%s ", control.getCurrentModeStr());
 
 	//-- speed and RPM --
-	len = snprintf(buf, sizeof(buf), "%3.1fkm/h %03.0f:%03.0fR",
+	displayTextLine(&dev, 7, false, false, "%3.1fkm/h %03.0f:%03.0fR",
 				   fabs((speedLeft.getKmph() + speedRight.getKmph()) / 2),
 				   speedLeft.getRpm(),
 				   speedRight.getRpm());
-	ssd1306_display_text(&dev, 7, buf, len, false);
 
 	// debug speed sensors
-	ESP_LOGD(TAG, "%s", buf);
+	ESP_LOGD(TAG, "%3.1fkm/h %03.0f:%03.0fR",
+				   fabs((speedLeft.getKmph() + speedRight.getKmph()) / 2),
+				   speedLeft.getRpm(),
+				   speedRight.getRpm());
 }
 
 
@@ -176,22 +241,16 @@ void showScreen1()
 //------------------------
 //shows welcome message and information about current version
 void showStartupMsg(){
-	char buf[20];
-	int len;
 	const esp_app_desc_t * desc = esp_ota_get_app_description();
 
 	//show message
-	len = snprintf(buf, 20, "START");
+	displayTextLine(&dev, 0, true, false, "START");
-	ssd1306_display_text_x3(&dev, 0, buf, len, false);
 	//show git-tag
-	len = snprintf(buf, 20, "%s", desc->version);
+	displayTextLine(&dev, 4, false, false, "%s", desc->version);
-	ssd1306_display_text(&dev, 4, buf, len, false);
 	//show build-date (note: date,time of last clean build)
-	len = snprintf(buf, 20, "%s", desc->date);
+	displayTextLine(&dev, 6, false, false, "%s", desc->date);
-	ssd1306_display_text(&dev, 6, buf, len, false);
 	//show build-time
-	len = snprintf(buf, 20, "%s", desc->time);
+	displayTextLine(&dev, 7, false, false, "%s", desc->time);
-	ssd1306_display_text(&dev, 7, buf, len, false);
 }
 
 
@@ -212,6 +271,7 @@ void display_task(void *pvParameters)
 	// show startup message
 	showStartupMsg();
 	vTaskDelay(STARTUP_MSG_TIMEOUT / portTICK_PERIOD_MS);
+	ssd1306_clear_screen(&dev, false);
 
 	// repeatedly update display with content
 	while (1)

board_single/main/display.hpp

@@ -1,7 +1,10 @@
+#pragma once
+
 extern "C" {
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <stdarg.h>
 #include "freertos/FreeRTOS.h"
 #include "freertos/task.h"
 #include "esp_log.h"
@@ -16,3 +19,11 @@ extern "C" {
 //task that inititialized the display, displays welcome message 
 //and releatedly updates the display with certain content
 void display_task( void * pvParameters );
+
+//abstracted function for printing one line on the display, using a format string directly
+//and options: Large-font (3 lines, max 5 digits), or inverted color
+void displayTextLine(SSD1306_t *display, int line, bool large, bool inverted, const char *format, ...);
+
+//abstracted function for printing a string CENTERED on the display, using a format string
+//adds spaces left and right to fill the line (if not too long already)
+void displayTextLineCentered(SSD1306_t *display, int line, bool isLarge, bool inverted, const char *format, ...);

board_single/main/menu.cpp

@@ -64,8 +64,6 @@ void item_debugJoystick_action(int value, SSD1306_t * display)
     //--- variables ---
     bool running = true;
     rotary_encoder_event_t event;
-    char buf[20];
-    int len;
 
     //-- pre loop instructions --
     if (!value) // dont open menu when value was set to 0
@@ -73,11 +71,9 @@ void item_debugJoystick_action(int value, SSD1306_t * display)
     ESP_LOGW(TAG, "showing joystick debug page");
     ssd1306_clear_screen(display, false);
     // show title
-    len = snprintf(buf, 19, " - debug stick - ");
+    displayTextLine(display, 0, false, true, " - debug stick - ");
-    ssd1306_display_text(display, 0, buf, len, true);
     // show info line
-    len = snprintf(buf, 20, "click to exit");
+    displayTextLineCentered(display, 7, false, true, "click to exit");
-    ssd1306_display_text(display, 7, buf, len, false);
 
     //-- show/update values --
     // stop when button pressed or control state changes (timeouts to IDLE)
@@ -85,16 +81,11 @@ void item_debugJoystick_action(int value, SSD1306_t * display)
     {
         // repeatedly print all joystick data
         joystickData_t data = joystick.getData();
-        len = snprintf(buf, 20, "x = %.3f", data.x);
+        displayTextLine(display, 1, false, false, "x = %.3f     ", data.x);
-        ssd1306_display_text(display, 1, buf, len, false);
+        displayTextLine(display, 2, false, false, "y = %.3f     ", data.y);
-        len = snprintf(buf, 20, "y = %.3f", data.y);
+        displayTextLine(display, 3, false, false, "radius = %.3f", data.radius);
-        ssd1306_display_text(display, 2, buf, len, false);
+        displayTextLine(display, 4, false, false, "angle = %-06.3f   ", data.angle);
-        len = snprintf(buf, 20, "radius = %.3f", data.radius);
+        displayTextLine(display, 5, false, false, "pos=%-12s ", joystickPosStr[(int)data.position]);
-        ssd1306_display_text(display, 3, buf, len, false);
-        len = snprintf(buf, 20, "angle = %06.3f   ", data.angle);
-        ssd1306_display_text(display, 4, buf, len, false);
-        len = snprintf(buf, 20, "pos=%-12s ", joystickPosStr[(int)data.position]);
-        ssd1306_display_text(display, 5, buf, len, false);
 
         // exit when button pressed
         if (xQueueReceive(encoderQueue, &event, 20 / portTICK_PERIOD_MS))
@@ -272,15 +263,10 @@ int itemCount = 6;
 #define SELECTED_ITEM_LINE 4
 #define FIRST_ITEM_LINE 1
 #define LAST_ITEM_LINE 7
-void showItemList(SSD1306_t *display,  int selectedItem)
+void showItemList(SSD1306_t *display, int selectedItem)
 {
-    //--- variables ---
-    char buf[20];
-    int len;
-
     //-- show title line --
-    len = snprintf(buf, 19, "  --- menu ---  ");
+    displayTextLine(display, 0, false, true, "  --- menu ---  "); //inverted
-    ssd1306_display_text(display, 0, buf, len, true);
 
     //-- show item list --
     for (int line = FIRST_ITEM_LINE; line <= LAST_ITEM_LINE; line++)
@@ -289,82 +275,60 @@ void showItemList(SSD1306_t *display,  int selectedItem)
         // TODO: when reaching end of items, instead of showing "empty" change position of selected item to still use the entire screen
         if (printItemIndex < 0 || printItemIndex >= itemCount) // out of range of available items
         {
-            len = snprintf(buf, 20, "  -- empty --   ");
+            // no item in this line
+            displayTextLine(display, line, false, false, "  -- empty --   ");
         }
         else
         {
             if (printItemIndex == selectedItem)
             {
-                // add '> <' when selected item
+                // selected item -> add '> ' and print inverted
-                len = snprintf(buf, 20, "> %-13s<", menuItems[printItemIndex].title);
+                displayTextLine(display, line, false, true, "> %-14s", menuItems[printItemIndex].title); // inverted
             }
             else
             {
-                len = snprintf(buf, 20, "%-16s", menuItems[printItemIndex].title);
+                // not the selected item -> print normal
+                displayTextLine(display, line, false, false, "%-16s", menuItems[printItemIndex].title);
             }
         }
-        // update display line
-        ssd1306_display_text(display, line, buf, len, line == SELECTED_ITEM_LINE);
         // logging
         ESP_LOGD(TAG, "showItemList: loop - line=%d, item=%d, (selected=%d '%s')", line, printItemIndex, selectedItem, menuItems[selectedItem].title);
     }
 }
 
-
-
-
 //---------------------------
 //----- showValueSelect -----
 //---------------------------
-//function that renders value-select screen to display (one update)
+// function that renders value-select screen to display (one update)
-//shows configured text of selected item and currently selected value
+// shows configured text of selected item and currently selected value
 // TODO show previous value in one line?
 // TODO update changed line only (value)
 void showValueSelect(SSD1306_t *display, int selectedItem)
 {
-    //--- variables ---
-    char buf[20];
-    int len;
-
     //-- show title line --
-    len = snprintf(buf, 19, " -- set value -- ");
+    displayTextLine(display, 0, false, true, " -- set value -- "); // inverted
-    ssd1306_display_text(display, 0, buf, len, true);
 
     //-- show text above value --
-    len = snprintf(buf, 20, "%-16s", menuItems[selectedItem].line1);
+    displayTextLine(display, 1, false, false, "%-16s", menuItems[selectedItem].line1);
-    ssd1306_display_text(display, 1, buf, len, false);
+    displayTextLine(display, 2, false, false, "%-16s", menuItems[selectedItem].line2);
-    len = snprintf(buf, 20, "%-16s", menuItems[selectedItem].line2);
-    ssd1306_display_text(display, 2, buf, len, false);
 
     //-- show value and other configured lines --
     // print value large, if 2 description lines are empty
-    if (strlen(menuItems[selectedItem].line4) == 0 && strlen(menuItems[selectedItem].line5) == 0 )
+    if (strlen(menuItems[selectedItem].line4) == 0 && strlen(menuItems[selectedItem].line5) == 0)
     {
-        //print large value + line5 and line6
+        // print large value + line5 and line6
-        len = snprintf(buf, 20, " %d   ", value);
+        displayTextLineCentered(display, 3, true, false, "%d", value); //large centered
-        ssd1306_display_text_x3(display, 3, buf, len, false);
+        displayTextLine(display, 6, false, false, "%-16s", menuItems[selectedItem].line6);
-        len = snprintf(buf, 20, "%-16s", menuItems[selectedItem].line6);
+        displayTextLine(display, 7, false, false, "%-16s", menuItems[selectedItem].line7);
-        ssd1306_display_text(display, 6, buf, len, false);
-        len = snprintf(buf, 20, "%-16s", menuItems[selectedItem].line7);
-        ssd1306_display_text(display, 7, buf, len, false);
     }
     else
     {
-        // print value centered
+        displayTextLineCentered(display, 3, false, false, "%d", value); //centered
-        int numDigits = snprintf(NULL, 0, "%d", value);
-        int numSpaces = (16 - numDigits) / 2;
-        snprintf(buf, sizeof(buf), "%*s%d%*s", numSpaces, "", value, 16 - numSpaces - numDigits, "");
-        ESP_LOGD(TAG, "showValueSelect: center number - value=%d, needed-spaces=%d, resulted-string='%s'", value, numSpaces, buf);
-        ssd1306_display_text(display, 3, buf, len, false);
         // print description lines 4 to 7
-        len = snprintf(buf, 20, "%-16s", menuItems[selectedItem].line4);
+        displayTextLine(display, 4, false, false, "%-16s", menuItems[selectedItem].line4);
-        ssd1306_display_text(display, 4, buf, len, false);
+        displayTextLine(display, 5, false, false, "%-16s", menuItems[selectedItem].line5);
-        len = snprintf(buf, 20, "%-16s", menuItems[selectedItem].line5);
+        displayTextLine(display, 6, false, false, "%-16s", menuItems[selectedItem].line6);
-        ssd1306_display_text(display, 5, buf, len, false);
+        displayTextLine(display, 7, false, false, "%-16s", menuItems[selectedItem].line7);
-        len = snprintf(buf, 20, "%-16s", menuItems[selectedItem].line6);
-        ssd1306_display_text(display, 6, buf, len, false);
-        len = snprintf(buf, 20, "%-16s", menuItems[selectedItem].line7);
-        ssd1306_display_text(display, 7, buf, len, false);
     }
 }