Added drawLogBuffer(0,0) and display() at end of write() (#389)

* Added drawLogBuffer(0,0) and display() at end of write()

Now print, println and printf "just work", while display not refreshed every character when a string of characters is written, only at the end.

* The assumption that chars are at most twice as high as they're wide was too optimistic

* Remove the now unnecessary commands from DrawingDemo

Author: ropg

examples/SSD1306DrawingDemo/SSD1306DrawingDemo.ino

@@ -171,10 +171,6 @@ void drawCircle(void) {
 }
 
 void printBuffer(void) {
-  // Initialize the log buffer
-  // allocate memory to store 8 lines of text and 30 chars per line.
-  display.setLogBuffer(5, 30);
-
   // Some test data
   const char* test[] = {
     "Hello",
@@ -189,15 +185,10 @@ void printBuffer(void) {
     "scrolling is",
     "working"
   };
-
+  display.clear();
   for (uint8_t i = 0; i < 11; i++) {
-    display.clear();
     // Print to the screen
     display.println(test[i]);
-    // Draw it to the internal screen buffer
-    display.drawLogBuffer(0, 0);
-    // Display it on the screen
-    display.display();
     delay(500);
   }
 }

src/OLEDDisplay.cpp

@@ -32,7 +32,6 @@
  /*
   * TODO Helmut
   * - test/finish dislplay.printf() on mbed-os
-  * - Finish _putc with drawLogBuffer when running display
   */
 
 #include "OLEDDisplay.h"
@@ -42,6 +41,7 @@ OLEDDisplay::OLEDDisplay() {
 	displayWidth = 128;
 	displayHeight = 64;
 	displayBufferSize = displayWidth * displayHeight / 8;
+  inhibitDrawLogBuffer = false;
 	color = WHITE;
 	geometry = GEOMETRY_128_64;
 	textAlignment = TEXT_ALIGN_LEFT;
@@ -879,53 +879,72 @@ bool OLEDDisplay::setLogBuffer(uint16_t lines, uint16_t chars){
 }
 
 size_t OLEDDisplay::write(uint8_t c) {
-  if (this->logBufferSize > 0) {
-    // Don't waste space on \r\n line endings, dropping \r
-    if (c == 13) return 1;
-
-    // convert UTF-8 character to font table index
-    c = (this->fontTableLookupFunction)(c);
-    // drop unknown character
-    if (c == 0) return 1;
-
-    bool maxLineNotReached = this->logBufferLine < this->logBufferMaxLines;
-    bool bufferNotFull = this->logBufferFilled < this->logBufferSize;
-
-    // Can we write to the buffer?
-    if (bufferNotFull && maxLineNotReached) {
-      this->logBuffer[logBufferFilled] = c;
-      this->logBufferFilled++;
-      // Keep track of lines written
-      if (c == 10) this->logBufferLine++;
-    } else {
-      // Max line number is reached
-      if (!maxLineNotReached) this->logBufferLine--;
-
-      // Find the end of the first line
-      uint16_t firstLineEnd = 0;
-      for (uint16_t i=0;i<this->logBufferFilled;i++) {
-        if (this->logBuffer[i] == 10){
-          // Include last char too
-          firstLineEnd = i + 1;
-          break;
-        }
-      }
-      // If there was a line ending
-      if (firstLineEnd > 0) {
-        // Calculate the new logBufferFilled value
-        this->logBufferFilled = logBufferFilled - firstLineEnd;
-        // Now we move the lines infront of the buffer
-        memcpy(this->logBuffer, &this->logBuffer[firstLineEnd], logBufferFilled);
-      } else {
-        // Let's reuse the buffer if it was full
-        if (!bufferNotFull) {
-          this->logBufferFilled = 0;
-        }// else {
-        //  Nothing to do here
-        //}
+  if (!fontData)
+		return 1;
+    
+  // Create a logBuffer if there isn't one
+	if (!logBufferSize) {
+		uint8_t textHeight = pgm_read_byte(fontData + HEIGHT_POS);
+		uint16_t lines =  this->displayHeight / textHeight;
+		uint16_t chars =   3 * (this->displayWidth / textHeight);
+
+		if (this->displayHeight % textHeight)
+			lines++;
+		if (this->displayWidth % textHeight)
+			chars++;
+		setLogBuffer(lines, chars);
+	}
+
+  // Don't waste space on \r\n line endings, dropping \r
+  if (c == 13) return 1;
+
+  // convert UTF-8 character to font table index
+  c = (this->fontTableLookupFunction)(c);
+  // drop unknown character
+  if (c == 0) return 1;
+
+  bool maxLineNotReached = this->logBufferLine < this->logBufferMaxLines;
+  bool bufferNotFull = this->logBufferFilled < this->logBufferSize;
+
+  // Can we write to the buffer?
+  if (bufferNotFull && maxLineNotReached) {
+    this->logBuffer[logBufferFilled] = c;
+    this->logBufferFilled++;
+    // Keep track of lines written
+    if (c == 10) this->logBufferLine++;
+  } else {
+    // Max line number is reached
+    if (!maxLineNotReached) this->logBufferLine--;
+
+    // Find the end of the first line
+    uint16_t firstLineEnd = 0;
+    for (uint16_t i=0;i<this->logBufferFilled;i++) {
+      if (this->logBuffer[i] == 10){
+        // Include last char too
+        firstLineEnd = i + 1;
+        break;
       }
-      write(c);
     }
+    // If there was a line ending
+    if (firstLineEnd > 0) {
+      // Calculate the new logBufferFilled value
+      this->logBufferFilled = logBufferFilled - firstLineEnd;
+      // Now we move the lines infront of the buffer
+      memcpy(this->logBuffer, &this->logBuffer[firstLineEnd], logBufferFilled);
+    } else {
+      // Let's reuse the buffer if it was full
+      if (!bufferNotFull) {
+        this->logBufferFilled = 0;
+      }// else {
+      //  Nothing to do here
+      //}
+    }
+    write(c);
+  }
+  if (!this->inhibitDrawLogBuffer) {
+    clear();
+    drawLogBuffer(0, 0);
+    display();
   }
   // We are always writing all uint8_t to the buffer
   return 1;
@@ -934,29 +953,20 @@ size_t OLEDDisplay::write(uint8_t c) {
 size_t OLEDDisplay::write(const char* str) {
   if (str == NULL) return 0;
   size_t length = strlen(str);
+  // If we write a string, only do the drawLogBuffer at the end, not every time we write a char
+  this->inhibitDrawLogBuffer = true;
   for (size_t i = 0; i < length; i++) {
     write(str[i]);
   }
+  this->inhibitDrawLogBuffer = false;
+  clear();
+  drawLogBuffer(0, 0);
+  display();
   return length;
 }
 
 #ifdef __MBED__
 int OLEDDisplay::_putc(int c) {
-
-	if (!fontData)
-		return 1;
-	if (!logBufferSize) {
-		uint8_t textHeight = pgm_read_byte(fontData + HEIGHT_POS);
-		uint16_t lines =  this->displayHeight / textHeight;
-		uint16_t chars =   2 * (this->displayWidth / textHeight);
-
-		if (this->displayHeight % textHeight)
-			lines++;
-		if (this->displayWidth % textHeight)
-			chars++;
-		setLogBuffer(lines, chars);
-	}
-
 	return this->write((uint8_t)c);
 }
 #endif

src/OLEDDisplay.h

@@ -364,6 +364,7 @@ class OLEDDisplay : public Stream {
     uint16_t   logBufferLine;
     uint16_t   logBufferMaxLines;
     char      *logBuffer;
+    bool      inhibitDrawLogBuffer;
 
 
 	// the header size of the buffer used, e.g. for the SPI command header