4 files changed, 152 insertions(+), 0 deletions(-)

A midi2human/__init__.py
A midi2human/cli.py
A midi2human/helpers.py
A midi2human/piano.py

@@ 0,0 1,1 @@
+__version__ = "0.1.0"

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+"""
+Read a MIDI file, map notes to piano keys and draw a piano layout.
+
+See http://www.mathpages.com/home/kmath043.htm for the math behind the piano layout.
+"""
+from pathlib import Path
+
+import click
+import importlib_metadata as metadata
+import mido
+import piano
+
+
+@click.command()
+@click.version_option(version=metadata.version("midi2human"))
+@click.argument("filename", nargs=1, type=click.Path(exists=True))
+@click.option(
+    "--layout",
+    type=click.Choice(["classic", "pure"]),
+    default="classic",
+    show_default=True,
+    help="Choose layout style.",
+)
+@click.option(
+    "--color",
+    type=str,
+    default="grey",
+    show_default=True,
+    help="Choose color for marked piano keys.",
+)
+def cli(filename, layout, color):
+    """Map a notes from a MIDI file onto a piano layout."""
+    filename = Path(filename)
+    mid = mido.MidiFile(filename)
+
+    # Each message in a MIDI file has a delta time,
+    # which tells how many ticks have passed since the last message
+    # (Mido Documentation).
+
+    # Notes which are played at the same time
+    note_pairs = []
+    # All notes and note pairs
+    notes = []
+
+    for msg in mid:
+        if msg.time == 0:
+            if msg.type == "note_on":
+                note_pairs.append(msg.note)
+        else:
+            notes.append(note_pairs)
+            note_pairs = []
+            if msg.type == "note_on":
+                note_pairs.append(msg.note)
+
+    piano.draw(notes, filename, color, layout)

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+import sys
+
+
+def progress_bar(iteration, total):
+    """Print a progress bar to stdout.
+
+    Call from inside loops.
+    """
+    iteration = iteration + 1
+    percent = int(100 * (iteration / total))
+    length = int(100 * iteration // total)
+    bar = "#" * length + " " * (100 - length)
+    sys.stdout.write("\rProgress: |{0}| {1}%\r".format(bar, percent))
+    sys.stdout.flush()
+    if iteration == total:
+        sys.stdout.write("\n")

@@ 0,0 1,80 @@
+import sys
+from typing import List
+
+import svgwrite
+
+from midi2human.helpers import progress_bar
+
+
+def draw(notes, filename, color, layout):
+    """Create and save an SVG file to disk."""
+    sys.stdout.write("Start mapping notes and drawing keys.")
+    filename = filename.with_suffix(".svg")
+    dwg = svgwrite.Drawing(filename=filename, size=("100%", "100%"))
+    length = len(notes)
+    for step, note_pairs in enumerate(notes):
+        progress_bar(step, length)
+        dwg = draw_keys(dwg, note_pairs, step, layout)
+    sys.stdout.write("Save drawing to: {0}".format(filename))
+    dwg.save()
+    sys.stdout.write("Done! Enjoy.")
+
+
+def draw_keys(dwg, notes: List, step: int, layout: str):
+    """Draw piano keys as SVG."""
+    if layout in {"classic", "pure"}:
+        height = 120
+        stroke_color = "black"
+    elif layout == "minimal":
+        height = 80
+        stroke_color = "white"
+
+    y = step * height
+
+    number_of_white_keys = 52
+    # number_of_black_keys = 36  # noqa: E800
+
+    width_of_white_key = 23
+    width_of_black_key = 13
+
+    # MIDI numver 21 maps to lowest piano note (A0)
+    midi_number = 21
+    # Start with piano note A0 not with C (C+5=A)
+    for j, i in enumerate(range(5, number_of_white_keys + 5)):
+        # Draw white keys
+        if midi_number in notes:
+            fill_color = "grey"
+        else:
+            fill_color = "white"
+        if layout == "pure":
+            stroke_color = fill_color
+        x = j * width_of_white_key
+        dwg.add(dwg.rect((x, y), (23, height), fill=fill_color, stroke=stroke_color))
+
+        # Do not draw left and right outer black key
+        if j in {0, 52}:
+            continue
+
+        midi_number = midi_number + 1
+
+        # Draw black keys
+        if i % 7 in {1, 2}:
+            if midi_number in notes:
+                fill_color = "grey"
+            else:
+                fill_color = "black"
+            x = x - (width_of_white_key - (width_of_black_key * 2 / 3)) / 2
+        elif i % 7 in {4, 5, 6}:
+            if midi_number in notes:
+                fill_color = "grey"
+            else:
+                fill_color = "black"
+            x = x - (width_of_white_key - (width_of_black_key * 3 / 4)) / 2
+        else:
+            continue
+        if layout == "pure":
+            stroke_color = fill_color
+        dwg.add(dwg.rect((x, y), (13, 80), fill=fill_color, stroke=stroke_color))
+        midi_number = midi_number + 1
+
+    return dwg