Got it almost working...

src/graphics/Monochrome.cpp

@@ -21,7 +21,8 @@
 
 #include <cmath>
 
-#include <cstdint>
+#include <cstdio>
+#include <cstdlib>
 #include <iostream>
 #include <vector>
 
@@ -57,4 +58,20 @@ std::vector<uint8_t> Monochrome::get() {
     }
     return outPixels;
 }
+
+void Monochrome::visualize() {
+    auto mono = get();
+    for (unsigned char pix : mono) {
+        std::cout << ((pix & (1 << 7)) == 0 ? "." : "x");
+        std::cout << ((pix & (1 << 6)) == 0 ? "." : "x");
+        std::cout << ((pix & (1 << 5)) == 0 ? "." : "x");
+        std::cout << ((pix & (1 << 4)) == 0 ? "." : "x");
+        std::cout << ((pix & (1 << 3)) == 0 ? "." : "x");
+        std::cout << ((pix & (1 << 2)) == 0 ? "." : "x");
+        std::cout << ((pix & (1 << 1)) == 0 ? "." : "x");
+        std::cout << ((pix & (1 << 0)) == 0 ? "." : "x");
+    }
+    std::cout << std::endl;
+}
+
 }  // namespace ptprnt::graphics