From c0dcb1f755012b844326956ea3dcd329b93c7384 Mon Sep 17 00:00:00 2001
From: Phil Howard <github@gadgetoid.com>
Date: Mon, 11 Nov 2024 13:56:31 +0000
Subject: [PATCH] Basic dual display example.

---
 examples/dual-displays.py | 122 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 122 insertions(+)
 create mode 100755 examples/dual-displays.py

diff --git a/examples/dual-displays.py b/examples/dual-displays.py
new file mode 100755
index 0000000..d385805
--- /dev/null
+++ b/examples/dual-displays.py
@@ -0,0 +1,122 @@
+#!/usr/bin/env python3
+import colorsys
+import math
+import sys
+import time
+
+from PIL import Image, ImageDraw, ImageOps
+
+import st7789
+
+print(
+    f"""
+dual-displays.py - A basic demo of driving two displays.
+
+If you're using Breakout Garden-
+
+- Plug a 1.3" ROUND LCD (SPI) breakout into the back slot.
+- Plug a SQUARE LCD (SPI) breakout into the front.
+
+Adjust the offset and settings below if you want to use
+two round and two square.
+
+Usage: {sys.argv[0]} <style>
+
+Where style is one of:
+
+ * dots - swirly swooshy dots
+ * lines - 3D depth effect lines
+
+The round (rear) LCD will be colour-inverted to
+distinguish the two. Don't be alarmed!
+"""
+)
+
+try:
+    style = sys.argv[1]
+except IndexError:
+    style = "dots"
+
+# Since we must share data/command between both displays
+# and because libgpiod does not support sharing pins,
+# we create it *once* here and pass the same pin *instance*
+# (rather than pin number) to each display class constructor.
+dc = st7789.ST7789.get_dc_pin(9)
+
+# Create ST7789 LCD display class.
+disp = st7789.ST7789(
+    port=0,
+    cs=st7789.BG_SPI_CS_FRONT,  # BG_SPI_CS_BACK or BG_SPI_CS_FRONT
+    dc=dc,
+    backlight=19,  # Breakout Garden: 18 for back slot, 19 for front slot.
+                   # NOTE: Change this to 13 for Pirate Audio boards
+    rotation=90,
+    spi_speed_hz=80 * 1000 * 1000,
+    offset_left=0,
+)
+
+disp2 = st7789.ST7789(
+    port=0,
+    cs=st7789.BG_SPI_CS_BACK,
+    dc=dc,
+    backlight=18,
+    rotation=90,
+    spi_speed_hz=80 * 1000 * 1000,
+    offset_left=40
+)
+
+# Initialize display.
+disp.begin()
+disp2.begin()
+
+RADIUS = disp.width // 2
+
+img = Image.new("RGB", (disp.width, disp.height), color=(0, 0, 0))
+draw = ImageDraw.Draw(img)
+
+
+while True:
+    t = time.time()
+    draw.rectangle((0, 0, disp.width, disp.height), (0, 0, 0))
+    angle = t % (math.pi * 2)
+
+    prev_x = RADIUS
+    prev_y = RADIUS
+
+    steps = 100.0
+    angle_step = 1.0
+
+    if style == "lines":
+        steps *= 5
+        angle_step = 0.1
+
+    for step in range(int(steps)):
+        angle += angle_step
+
+        distance = RADIUS / steps * step
+        distance += step * 0.2
+
+        r, g, b = [
+            int(c * 255)
+            for c in colorsys.hsv_to_rgb((t / 10.0) + distance / 120.0, 1.0, 1.0)
+        ]
+
+        x = RADIUS + int(distance * math.cos(angle))
+        y = RADIUS + int(distance * math.sin(angle))
+
+        line = ((math.sin(t + angle) + 1) / 2.0) * 10
+        if style == "lines":
+            draw.line(
+                (prev_x + line, prev_y + line, x - line, y - line), fill=(r, g, b)
+            )
+        else:
+            line += 1
+            draw.ellipse(
+                (x - line, y - line, x + (line * 2), y + (line * 2)), fill=(r, g, b)
+            )
+
+        prev_x = x
+        prev_y = y
+
+    disp.display(img)
+    disp2.display(ImageOps.invert(img))