4 columns for ticker tape

print_tape.py

@@ -4,9 +4,9 @@
 Reads a CSV of trades (timestamp, symbol, lots, price) and generates
 ESC/POS commands with 90° rotated text to emulate an old stock ticker tape.
 
-Each character gets its own printed row. When the receipt paper is turned
-sideways, symbol characters read across the top and price characters read
-across the bottom — just like a real ticker tape.
+Trades are distributed across 4 parallel columns. Each column independently
+prints symbol characters at the top of the tape and price/lot characters at
+the bottom — just like a real multi-track ticker tape.
 """
 
 import csv
@@ -19,32 +19,85 @@ from glyphs import price_to_fraction, upload_fractions
 # TM-T88V with 90° rotation: Font A chars are 24 dots wide (instead of 12),
 # so 512 printable dots / 24 = 21 chars fit across the 80mm paper width.
 LINE_WIDTH = 21
+NUM_COLUMNS = 4
+COL_WIDTH = LINE_WIDTH // NUM_COLUMNS  # 5
 
 
-def print_trade(p, symbol, lots, price):
-    """Print a single trade as ticker tape characters, one per row."""
+def format_price(lots, price):
+    """Format price/lots string for a trade."""
     frac = price_to_fraction(price)
     if lots > 1:
-        price_str = f"{lots}s{frac}"
-    else:
-        price_str = frac
+        return f"{lots}s{frac}"
+    return frac
 
-    # Symbol characters at the top (right-aligned)
-    for ch in symbol:
-        p.text(" " * (LINE_WIDTH - 1) + ch + "\n")
 
-    # Price characters at the bottom (left-aligned)
-    for ch in price_str:
-        p.text(ch + "\n")
+def trade_char_count(symbol, price_str):
+    """Total characters a trade occupies in a column (symbol + price + separator)."""
+    return len(symbol) + len(price_str) + 1
 
-    # Blank line separator between trades
-    p.text("\n")
+
+def assign_to_columns(trades):
+    """Assign trades to columns, always picking the column with the fewest chars."""
+    columns = [[] for _ in range(NUM_COLUMNS)]
+    lengths = [0] * NUM_COLUMNS
+
+    for symbol, lots, price in trades:
+        price_str = format_price(lots, price)
+        count = trade_char_count(symbol, price_str)
+        shortest = lengths.index(min(lengths))
+        columns[shortest].append((symbol, price_str))
+        lengths[shortest] += count
+
+    return columns
+
+
+def build_column_chars(trades_in_column):
+    """Build the character sequence for one column.
+
+    Each entry is ('top', ch), ('bottom', ch), or ('blank',) controlling
+    where the character is placed within the column width.
+    """
+    chars = []
+    for symbol, price_str in trades_in_column:
+        for ch in symbol:
+            chars.append(("top", ch))
+        for ch in price_str:
+            chars.append(("bottom", ch))
+        chars.append(("blank",))
+    return chars
+
+
+def print_all(p, trades):
+    """Print all trades across multiple columns, one row at a time."""
+    columns = assign_to_columns(trades)
+    col_chars = [build_column_chars(col) for col in columns]
+    max_len = max(len(cc) for cc in col_chars)
+
+    for row_idx in range(max_len):
+        row = [" "] * LINE_WIDTH
+        for col_idx in range(NUM_COLUMNS):
+            col_start = col_idx * COL_WIDTH
+            if row_idx < len(col_chars[col_idx]):
+                entry = col_chars[col_idx][row_idx]
+                if entry[0] == "top":
+                    row[col_start + COL_WIDTH - 1] = entry[1]
+                elif entry[0] == "bottom":
+                    row[col_start] = entry[1]
+        p.text("".join(row) + "\n")
 
 
 def main():
     csv_file = sys.argv[1] if len(sys.argv) > 1 else "trades_sample_sorted.csv"
     output_file = sys.argv[2] if len(sys.argv) > 2 else "ticker_tape.bin"
 
+    # Read all trades
+    trades = []
+    with open(csv_file) as f:
+        reader = csv.reader(f)
+        for row in reader:
+            _timestamp, symbol, lots_str, price_str = row
+            trades.append((symbol, int(lots_str), float(price_str)))
+
     p = Dummy(profile="TM-T88V")
     p.hw("INIT")
     # ESC V 1: 90° clockwise character rotation (not exposed by python-escpos)
@@ -55,15 +108,9 @@ def main():
     # Upload custom fraction glyphs (⅛ ¼ ⅜ ½ ⅝ ¾ ⅞)
     upload_fractions(p)
 
-    with open(csv_file) as f:
-        reader = csv.reader(f)
-        for row in reader:
-            _timestamp, symbol, lots_str, price_str = row
-            lots = int(lots_str)
-            price = float(price_str)
-            print_trade(p, symbol, lots, price)
+    print_all(p, trades)
 
-    # Feed past the cutter (~20mm above print head, ~12 lines at 12-dot spacing)
+    # Feed past the cutter (~20mm above print head)
     p.text("\n" * 16)
     p.cut()