gpt answer with sloped lines

draw_12_rects_and_send.py

@@ -1,108 +1,182 @@
 #!/usr/bin/env python3
 """
-draw_12_rects_thick_outline.py
+draw_12_slanted_top_bottom.py
 
-800 × 600 ARGB framebuffer.
+* 800 × 600 ARGB framebuffer (A,R,G,B each 1 byte)
-12 tall rectangles (aspect 1 : 12) placed side‑by‑side with a gap.
+* 12 rectangles, aspect 1 : 12, 5 px gap, 100 px empty margin at top & bottom
-Only the rectangle outline is drawn, the border thickness can be changed
+* each rectangle has an individual tilt angle (degrees) stored in
-with the constant LINE_THICKNESS (default = 3 pixels).
+  ROT_ANGLES_DEG[12]
-
+* the top and bottom edges are *slanted* while the left‑ and right‑hand
-The complete framebuffer is streamed to a TCP server listening on
+  edges remain perfectly vertical
-localhost:12345 (payload is prefixed with a 4‑byte big‑endian length).
+* outline colour = opaque white, thickness = LINE_THICKNESS (default = 3 px)
+* the raw buffer (with a 4‑byte length prefix) is streamed to a TCP server
+  listening on localhost:12345
 """
 
+import math
 import socket
 import sys
 
 # ----------------------------------------------------------------------
-# Frame‑buffer configuration
+# 1️⃣ Frame‑buffer configuration
 # ----------------------------------------------------------------------
 FB_WIDTH  = 800                # horizontal pixels
 FB_HEIGHT = 600                # vertical   pixels
 BPP       = 4                  # bytes per pixel (A,R,G,B)
 
 # ----------------------------------------------------------------------
-# Geometry of the 12 rectangles
+# 2️⃣ Margins & rectangle geometry (before slant)
 # ----------------------------------------------------------------------
-RECT_HEIGHT = 400                # fill the whole image vertically
+MARGIN_TOP    = 100            # empty band at the very top
-RECT_WIDTH  = RECT_HEIGHT // 12       # 600 / 12 = 50 px (maintains 1:12)
+MARGIN_BOTTOM = 300            # empty band at the very bottom
 
-SPACING = 10                            # pixels between two neighbours
+RECT_HEIGHT = FB_HEIGHT - MARGIN_TOP - MARGIN_BOTTOM   # usable height = 400 px
+RECT_WIDTH  = RECT_HEIGHT // 12                       # ≈ 33 px  (aspect 1 : 12)
+
+SPACING      = 10                                       # gap between rectangles
 TOTAL_RECT_W = 12 * RECT_WIDTH + 11 * SPACING
-X0_START = (FB_WIDTH - TOTAL_RECT_W) // 2   # centre the whole strip
+X0_START     = (FB_WIDTH - TOTAL_RECT_W) // 2          # centre the whole strip
 
 # ----------------------------------------------------------------------
-# Outline thickness (change this to whatever you need)
+# 3️⃣ Outline thickness (you may change it)
 # ----------------------------------------------------------------------
-LINE_THICKNESS = 4                     # >=1 ; thicker than 1 pixel
+LINE_THICKNESS = 5            # ≥ 1 pixel
 
 # ----------------------------------------------------------------------
-# Helper – write a pixel into the bytearray (no bounds check for speed)
+# 4️⃣ Per‑rectangle tilt angles (degrees)
+# ----------------------------------------------------------------------
+# You can generate these programmatically, read them from a file, etc.
+ROT_ANGLES_DEG = [
+    90,   5,  10,  15,  20,  25,
+    30, 35,  40,  45,  50,  85
+]
+assert len(ROT_ANGLES_DEG) == 12, "Exactly 12 angles are required."
+
+# ----------------------------------------------------------------------
+# Helper – write a single pixel (bounds‑checked)
 # ----------------------------------------------------------------------
 def set_pixel(buf: bytearray, x: int, y: int, color: tuple) -> None:
     """Write an ARGB pixel at (x, y).  `color` = (A,R,G,B)."""
-    offset = (y * FB_WIDTH + x) * BPP
+    if 0 <= x < FB_WIDTH and 0 <= y < FB_HEIGHT:
-    buf[offset:offset + 4] = bytes(color)      # A,R,G,B order
+        off = (y * FB_WIDTH + x) * BPP
+        buf[off:off + 4] = bytes(color)      # A,R,G,B order
 
 
 # ----------------------------------------------------------------------
-# Fill a rectangular region (used for thick edges)
+# Helper – draw a thick line (Bresenham + square brush)
 # ----------------------------------------------------------------------
-def fill_rect(buf: bytearray, x0: int, y0: int, w: int, h: int, color: tuple) -> None:
+def draw_thick_line(buf: bytearray,
-    """Write a solid w × h block of `color` starting at (x0, y0)."""
+                    x0: int, y0: int,
-    # Clip to the frame buffer – safety net for very thick lines at the border
+                    x1: int, y1: int,
-    x0 = max(0, x0)
+                    color: tuple,
-    y0 = max(0, y0)
+                    thickness: int) -> None:
-    w = min(w, FB_WIDTH - x0)
+    """Draw a line from (x0,y0) to (x1,y1) using a square brush of `thickness`."""
-    h = min(h, FB_HEIGHT - y0)
+    dx = abs(x1 - x0)
+    dy = -abs(y1 - y0)
+    sx = 1 if x0 < x1 else -1
+    sy = 1 if y0 < y1 else -1
+    err = dx + dy                     # error term
 
-    row_bytes = w * BPP
+    while True:
-    pixel_bytes = bytes(color)
+        # paint a filled square centred on the current pixel
+        for ty in range(-thickness // 2, thickness // 2 + 1):
+            for tx in range(-thickness // 2, thickness // 2 + 1):
+                set_pixel(buf, x0 + tx, y0 + ty, color)
 
-    for y in range(y0, y0 + h):
+        if x0 == x1 and y0 == y1:
-        off = (y * FB_WIDTH + x0) * BPP
+            break
-        buf[off:off + row_bytes] = pixel_bytes * w
+        e2 = 2 * err
+        if e2 >= dy:
+            err += dy
+            x0 += sx
+        if e2 <= dx:
+            err += dx
+            y0 += sy
 
 
 # ----------------------------------------------------------------------
-# Build the framebuffer
+# 5️⃣ Build the framebuffer (background + white slanted‑top/bottom rectangles)
 # ----------------------------------------------------------------------
 def build_framebuffer() -> bytearray:
-    """Create an ARGB buffer, fill it black and draw the thick‑outline rectangles."""
+    """Create the ARGB buffer and draw the 12 rectangles with slanted top/bottom."""
-    # 1️⃣ background = opaque black (A,R,G,B)
+    # ----- background: opaque black -----
     fb = bytearray(FB_WIDTH * FB_HEIGHT * BPP)
-    bg_color = (255, 0, 0, 0)                # opaque black
+    bg = (255, 0, 0, 0)                # A,R,G,B = opaque black
-    fb[:] = bg_color * (FB_WIDTH * FB_HEIGHT)
+    fb[:] = bg * (FB_WIDTH * FB_HEIGHT)
+
+    WHITE = (255, 255, 255, 255)      # colour of the outlines
+
+    half_w = RECT_WIDTH // 2          # half the (un‑slanted) width
+
+    y_top    = MARGIN_TOP
+    y_bottom = FB_HEIGHT - MARGIN_BOTTOM - 1   # inclusive bottom row
 
-    # 2️⃣ draw each rectangle outline
     for idx in range(12):
-        # ── colour palette (feel free to change) ───────────────────────
+        # --------------------------------------------------------------
-        rect_color = (255, 255, 255, 255)         # opaque
+        # 1️⃣  Un‑slanted left edge of the rectangle (including spacing)
+        # --------------------------------------------------------------
+        orig_x0 = X0_START + idx * (RECT_WIDTH + SPACING)
 
-        # left‑most X coordinate of the *inner* rectangle (the border belongs to it)
+        # --------------------------------------------------------------
-        x0 = X0_START + idx * (RECT_WIDTH + SPACING)
+        # 2️⃣  Centre X coordinate (kept fixed while slanting)
-        y0 = 100
+        # --------------------------------------------------------------
-        w  = RECT_WIDTH
+        cx = orig_x0 + half_w
-        h  = RECT_HEIGHT
 
-        # ── thick edges ──────────────────────────────────────────────────
+        # --------------------------------------------------------------
+        # 3️⃣  Angle for this rectangle
+        # --------------------------------------------------------------
+        angle_rad = math.radians(ROT_ANGLES_DEG[idx])
+        sin_a = math.sin(angle_rad)
+
+        # --------------------------------------------------------------
+        # 4️⃣  Vertical offset applied to the *ends* of the top/bottom lines
+        #     (the spec says: sin(angle) * RECT_WITH / 2)
+        # --------------------------------------------------------------
+        offset = sin_a * half_w   # because RECT_WITH/2 == half_w
+
+        # --------------------------------------------------------------
+        # 5️⃣  Coordinates of the four line end‑points
+        # --------------------------------------------------------------
         # top edge
-        fill_rect(fb, x0, y0, w, LINE_THICKNESS, rect_color)
+        x0_top = cx - half_w
+        y0_top = int(round(y_top    + offset))
+
+        x1_top = cx + half_w
+        y1_top = int(round(y_top    - offset))
 
         # bottom edge
-        fill_rect(fb, x0, y0 + h - LINE_THICKNESS, w, LINE_THICKNESS, rect_color)
+        x0_bot = cx - half_w
+        y0_bot = int(round(y_bottom - offset))
 
-        # left edge
+        x1_bot = cx + half_w
-        fill_rect(fb, x0, y0, LINE_THICKNESS, h, rect_color)
+        y1_bot = int(round(y_bottom + offset))
 
-        # right edge
+        # --------------------------------------------------------------
-        fill_rect(fb, x0 + w - LINE_THICKNESS, y0, LINE_THICKNESS, h, rect_color)
+        # 6️⃣  Draw the four sides
+        # --------------------------------------------------------------
+        # top (slanted)
+        draw_thick_line(fb, x0_top, y0_top, x1_top, y1_top,
+                        WHITE, LINE_THICKNESS)
+
+        # bottom (slanted)
+        draw_thick_line(fb, x0_bot, y0_bot, x1_bot, y1_bot,
+                        WHITE, LINE_THICKNESS)
+
+        # left vertical side – from the *top‑left* endpoint down to the
+        # *bottom‑left* endpoint
+        draw_thick_line(fb, x0_top, y0_top, x0_bot, y0_bot,
+                        WHITE, LINE_THICKNESS)
+
+        # right vertical side – from the *top‑right* endpoint down to the
+        # *bottom‑right* endpoint
+        draw_thick_line(fb, x1_top, y1_top, x1_bot, y1_bot,
+                        WHITE, LINE_THICKNESS)
 
     return fb
 
 
 # ----------------------------------------------------------------------
-# Send the buffer to the TCP server
+# 6️⃣ Send the framebuffer to the TCP server (localhost:12345)
 # ----------------------------------------------------------------------
 def send_framebuffer(buf: bytearray,
                      host: str = "127.0.0.1",
@@ -110,7 +184,7 @@ def send_framebuffer(buf: bytearray,
     """Open a TCP socket, connect, and stream the whole framebuffer."""
     try:
         with socket.create_connection((host, port), timeout=5) as sock:
-            # optional length prefix (many protocols expect it)
+            # optional 4‑byte length prefix – many simple protocols expect it
             length_prefix = len(buf).to_bytes(4, byteorder="big")
             sock.sendall(length_prefix + buf)
             print(f"✔ Sent {len(buf)} bytes to {host}:{port}")
@@ -119,7 +193,7 @@ def send_framebuffer(buf: bytearray,
 
 
 # ----------------------------------------------------------------------
-# Main entry point
+# 7️⃣ Main entry point
 # ----------------------------------------------------------------------
 def main() -> None:
     fb = build_framebuffer()
@@ -128,3 +202,4 @@ def main() -> None:
 
 if __name__ == "__main__":
     main()
+