Improve drawProgressBar by using the new `drawCircleQuads` function

OLEDDisplay.cpp

@@ -161,6 +161,46 @@ void OLEDDisplay::drawCircle(int16_t x0, int16_t y0, int16_t radius) {
   setPixel(x0, y0 - radius);
 }
 
+void OLEDDisplay::drawCircleQuads(int16_t x0, int16_t y0, int16_t radius, uint8_t quads) {
+  int16_t x = 0, y = radius;
+  int16_t dp = 1 - radius;
+  while (x < y) {
+    if (dp < 0)
+      dp = dp + 2 * (++x) + 3;
+    else
+      dp = dp + 2 * (++x) - 2 * (--y) + 5;
+    if (quads & 0x1) {
+      setPixel(x0 + x, y0 - y);
+      setPixel(x0 + y, y0 - x);
+    }
+    if (quads & 0x2) {
+      setPixel(x0 - y, y0 - x);
+      setPixel(x0 - x, y0 - y);
+    }
+    if (quads & 0x4) {
+      setPixel(x0 - y, y0 + x);
+      setPixel(x0 - x, y0 + y);
+    }
+    if (quads & 0x8) {
+      setPixel(x0 + x, y0 + y);
+      setPixel(x0 + y, y0 + x);
+    }
+  }
+  if (quads & 0x1 && quads & 0x8) {
+    setPixel(x0 + radius, y0);
+  }
+  if (quads & 0x4 && quads & 0x8) {
+    setPixel(x0, y0 + radius);
+  }
+  if (quads & 0x2 && quads & 0x4) {
+    setPixel(x0 - radius, y0);
+  }
+  if (quads & 0x1 && quads & 0x2) {
+    setPixel(x0, y0 - radius);
+  }
+}
+
+
 void OLEDDisplay::fillCircle(int16_t x0, int16_t y0, int16_t radius) {
   int16_t x = 0, y = radius;
 	int16_t dp = 1 - radius;
@@ -289,19 +329,22 @@ void OLEDDisplay::drawVerticalLine(int16_t x, int16_t y, int16_t length) {
 
 void OLEDDisplay::drawProgressBar(uint16_t x, uint16_t y, uint16_t width, uint16_t height, uint8_t progress) {
   uint16_t radius = height / 2;
-  uint16_t innerRadius = radius - 3;
-  setColor(WHITE);
-  drawCircle(x + radius, y + radius, radius);
-  drawRect(x+radius, y, width - 2*radius, height);
-  drawCircle(x + width - radius, y + radius, radius);
-  setColor(BLACK);
-  fillRect(x+radius, y+1, width - 2*radius + 1, height - 1);
+  uint16_t xRadius = x + radius;
+  uint16_t yRadius = y + radius;
+  uint16_t doubleRadius = 2 * radius;
+  uint16_t innerRadius = radius - 2;
+
   setColor(WHITE);
-  uint16_t maxProgressWidth = (width - 2 * radius) * progress / 100;
-  for (uint16_t i = 0; i < maxProgressWidth; i++) {
-    fillCircle(x + radius + i, y + radius, innerRadius);
-  }
+  drawCircleQuads(xRadius, yRadius, radius, 0b00000110);
+  drawHorizontalLine(xRadius, y, width - doubleRadius + 1);
+  drawHorizontalLine(xRadius, y + height, width - doubleRadius + 1);
+  drawCircleQuads(x + width - radius, yRadius, radius, 0b00001001);
+
+  uint16_t maxProgressWidth = (width - doubleRadius - 1) * progress / 100;
 
+  fillCircle(xRadius, yRadius, innerRadius);
+  fillRect(xRadius + 1, y + 2, maxProgressWidth, height - 3);
+  fillCircle(xRadius + maxProgressWidth, yRadius, innerRadius);
 }
 
 void OLEDDisplay::drawFastImage(int16_t xMove, int16_t yMove, int16_t width, int16_t height, const char *image) {

OLEDDisplay.h

@@ -138,6 +138,9 @@ class OLEDDisplay : public Print {
     // Draw the border of a circle
     void drawCircle(int16_t x, int16_t y, int16_t radius);
 
+    // Draw all Quadrants specified in the quads bit mask
+    void drawCircleQuads(int16_t x0, int16_t y0, int16_t radius, uint8_t quads);
+
     // Fill circle
     void fillCircle(int16_t x, int16_t y, int16_t radius);