From a0a707ac0e8c20d1095791773b5ab3ff370baa94 Mon Sep 17 00:00:00 2001
From: Adolfo Reyna <adolforeyna@Adolfos-MacBook-Air.local>
Date: Tue, 18 Nov 2025 13:36:39 -0500
Subject: [PATCH] marquee"

---
 hello_usb.cpp | 49 ++++++++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 44 insertions(+), 5 deletions(-)

diff --git a/hello_usb.cpp b/hello_usb.cpp
index d2acac5..5dfd059 100644
--- a/hello_usb.cpp
+++ b/hello_usb.cpp
@@ -20,16 +20,40 @@ static SSD1306 *g_display = nullptr;
 
 // Holds last echoed line for display
 static char g_last_echo[128] = "";
+// Scrolling state for last echo (marquee)
+static size_t g_last_echo_scroll_index = 0;
+static uint64_t g_last_echo_last_scroll_ms = 0;
+static const uint64_t SCROLL_INTERVAL_MS = 300; // milliseconds between scroll steps
+static const size_t LAST_ECHO_VISIBLE_CHARS = 10; // visible chars for 12x16 font on 128px width
 
 // Refresh OLED with current input (line 0) and last echoed text (line 2)
 static void refresh_display(const char *current_input, const char *last_echo) {
     if (!g_display) return;
     g_display->clear();
-    // Use next bigger font (12x16) to improve readability
-    // First line: current input
-    pico_ssd1306::drawText(g_display, font_12x16, current_input, 0, 0);
-    // Second line: last echoed text (start lower to avoid overlap)
-    pico_ssd1306::drawText(g_display, font_12x16, last_echo, 0, 20);
+
+    // If current input is longer than 10 chars, use smaller font to fit more text
+    size_t input_len = current_input ? strlen(current_input) : 0;
+    const unsigned char *input_font = (input_len > 10) ? font_5x8 : font_12x16;
+
+    // Draw current input using chosen font
+    pico_ssd1306::drawText(g_display, input_font, current_input, 0, 0);
+
+    // Draw last echoed text using the larger font for readability
+    // If the last echo is longer than visible chars, create a scrolling window
+    size_t last_len = last_echo ? strlen(last_echo) : 0;
+    if (last_len > LAST_ECHO_VISIBLE_CHARS) {
+        char window[LAST_ECHO_VISIBLE_CHARS + 1];
+        // copy up to visible chars starting at scroll index, wrapping as needed
+        for (size_t i = 0; i < LAST_ECHO_VISIBLE_CHARS; ++i) {
+            size_t src = (g_last_echo_scroll_index + i) % last_len;
+            window[i] = last_echo[src];
+        }
+        window[LAST_ECHO_VISIBLE_CHARS] = '\0';
+        pico_ssd1306::drawText(g_display, font_12x16, window, 0, 20);
+    } else {
+        pico_ssd1306::drawText(g_display, font_12x16, last_echo, 0, 20);
+    }
+
     g_display->sendBuffer();
 }
 
@@ -58,6 +82,9 @@ void echo_and_reset(char* buffer, int* index_ptr) {
             g_last_echo[i] = (char)toupper(buffer[i]);
         }
         g_last_echo[i] = '\0';
+        // reset scrolling state whenever last echo changes
+        g_last_echo_scroll_index = 0;
+        g_last_echo_last_scroll_ms = time_us_64() / 1000;
     }
 
     *index_ptr = 0;
@@ -116,6 +143,18 @@ void run_echo_session() {
             last_char_time = time_us_64();
         }
 
+        // Advance marquee for last echoed text if needed
+        size_t last_len = strlen(g_last_echo);
+        uint64_t now_ms = time_us_64() / 1000;
+        if (last_len > LAST_ECHO_VISIBLE_CHARS) {
+            if (now_ms - g_last_echo_last_scroll_ms >= SCROLL_INTERVAL_MS) {
+                g_last_echo_scroll_index = (g_last_echo_scroll_index + 1) % last_len;
+                g_last_echo_last_scroll_ms = now_ms;
+                // refresh display to show new window
+                refresh_display(input_buffer, g_last_echo);
+            }
+        }
+
         sleep_us(100);
     }