fix: make router socket non-blocking to prevent poll loop stalls

sketch/lib/examples/ASCIIDraw/ASCIIDraw.ino

@@ -0,0 +1,109 @@
+/*
+  ASCIIDraw
+
+  Use the ArduinoGraphics library to draw ASCII art on the Serial Monitor.
+
+  This is intended primarily to allow testing of the library.
+  See the Arduino_MKRRGB library for a more useful demonstration of the ArduinoGraphics library.
+
+  The circuit:
+  - Arduino board
+
+  This example code is in the public domain.
+*/
+
+#include <ArduinoGraphics.h>
+
+const byte fontSize = 3;
+const byte canvasWidth = fontSize * (5 * 7) + 26;
+const byte canvasHeight = fontSize * 7 + 20;
+
+class ASCIIDrawClass : public ArduinoGraphics {
+  public:
+    // can be used with an object of any class that inherits from the Print class
+    ASCIIDrawClass(Print &printObject = (Print &)Serial) :
+      ArduinoGraphics(canvasWidth, canvasHeight),
+      _printObject(&printObject) {}
+
+    // this function is called by the ArduinoGraphics library's functions
+    virtual void set(int x, int y, uint8_t r, uint8_t g, uint8_t b) {
+      // the r parameter is (mis)used to set the character to draw with
+      _canvasBuffer[x][y] = r;
+      // cast unused parameters to void to fix "unused parameter" warning
+      (void)g;
+      (void)b;
+    }
+
+    // display the drawing
+    void endDraw() {
+      ArduinoGraphics::endDraw();
+
+      for (byte row = 0; row < canvasHeight; row++) {
+        for (byte column = 0; column < canvasWidth; column++) {
+          // handle unset parts of buffer
+          if (_canvasBuffer[column][row] == 0) {
+            _canvasBuffer[column][row] = ' ';
+          }
+          _printObject->print(_canvasBuffer[column][row]);
+        }
+        _printObject->println();
+      }
+    }
+
+  private:
+    Print *_printObject;
+    char _canvasBuffer[canvasWidth][canvasHeight] = {{0}};
+};
+
+ASCIIDrawClass ASCIIDraw;
+
+void setup() {
+  Serial.begin(9600);
+  while (!Serial) {
+    ; // wait for serial port to connect. Needed for native USB port only
+  }
+
+  ASCIIDraw.beginDraw();
+
+  // configure the character used to fill the background. The second and third parameters are ignored
+  ASCIIDraw.background('+', 0, 0);
+  ASCIIDraw.clear();
+
+  // add the outer border
+  ASCIIDraw.stroke('-', 0, 0);
+  ASCIIDraw.fill('*', 0, 0);
+  const byte outerBorderThickness = 1;
+  ASCIIDraw.rect(outerBorderThickness, outerBorderThickness, canvasWidth - outerBorderThickness * 2, canvasHeight - outerBorderThickness * 2);
+
+  // add the inner border
+  ASCIIDraw.stroke('+', 0, 0);
+  ASCIIDraw.fill('O', 0, 0);
+  const byte borderThickness = outerBorderThickness + 6;
+  ASCIIDraw.rect(borderThickness, borderThickness, canvasWidth - borderThickness * 2, canvasHeight - borderThickness * 2);
+
+  // add the text
+  ASCIIDraw.background(' ', 0, 0);
+  ASCIIDraw.stroke('@', 0, 0);
+  const char text[] = "ARDUINO";
+  ASCIIDraw.textFont(Font_5x7);
+  ASCIIDraw.textSize(fontSize);
+  const byte textWidth = strlen(text) * ASCIIDraw.textFontWidth();
+  const byte textHeight = ASCIIDraw.textFontHeight();
+  const byte textX = (canvasWidth - textWidth) / 2;
+  const byte textY = (canvasHeight - textHeight) / 2;
+  ASCIIDraw.text(text, textX, textY);
+
+  // underline the text
+  ASCIIDraw.stroke('-', 0, 0);
+  ASCIIDraw.line(textX, textY + textHeight - 1, textX + textWidth - 1, textY + textHeight - 1);
+
+  // add some accents to the underline
+  ASCIIDraw.stroke('+', 0, 0);
+  ASCIIDraw.point(textX + 4, textY + textHeight - 1);
+  ASCIIDraw.point(textX + textWidth - 1 - 4, textY + textHeight - 1);
+
+  // print the drawing to the Serial Monitor
+  ASCIIDraw.endDraw();
+}
+
+void loop() {}