From 35ec1107b6e7eec6ee65e6a9cbd36d49543d7d38 Mon Sep 17 00:00:00 2001
From: Kirill Osipov <querielo@protonmail.com>
Date: Tue, 30 Jun 2026 17:08:18 +0200
Subject: [PATCH] Add PixelBuffer#to_bytes for zero-overhead RGBA pixel access

Exposes a GSI method on tl::PixelBuffer that returns the raw ARGB32
contents as a byte vector (4 bytes per pixel, row-major, top to bottom)
via a single memcpy. Unlike to_png_data this skips all image encoding,
which is useful when the caller just wants direct pixel data.
---
 src/gsi/gsi/gsiDeclTlPixelBuffer.cc | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/src/gsi/gsi/gsiDeclTlPixelBuffer.cc b/src/gsi/gsi/gsiDeclTlPixelBuffer.cc
index c78cd1b1d..a0fae9f7a 100644
--- a/src/gsi/gsi/gsiDeclTlPixelBuffer.cc
+++ b/src/gsi/gsi/gsiDeclTlPixelBuffer.cc
@@ -126,6 +126,14 @@ static std::vector<char> pixel_buffer_to_png (const tl::PixelBuffer *pb)
 #endif
 }
 
+//  Returns the raw ARGB32 pixel data as a byte vector (no encoding overhead)
+static std::vector<char> pixel_buffer_to_bytes (const tl::PixelBuffer *pb)
+{
+  const char *p = (const char *) pb->data ();
+  size_t n = (size_t) pb->width () * (size_t) pb->height () * 4;
+  return std::vector<char> (p, p + n);
+}
+
 
 Class<tl::PixelBuffer> decl_PixelBuffer ("lay", "PixelBuffer",
   gsi::constructor ("new", &create_pixel_buffer, gsi::arg ("width"), gsi::arg ("height"),
@@ -188,6 +196,14 @@ Class<tl::PixelBuffer> decl_PixelBuffer ("lay", "PixelBuffer",
     "\n"
     "This method may not be available if PNG support is not compiled into KLayout."
   ) +
+  gsi::method_ext ("to_bytes", &pixel_buffer_to_bytes,
+    "@brief Converts the pixel buffer to a raw byte stream\n"
+    "\n"
+    "Returns the raw ARGB32 pixel data with 4 bytes per pixel in row-major order, "
+    "top to bottom. Unlike \\to_png_data this method has zero encoding overhead.\n"
+    "\n"
+    "This method has been added in version 0.30.9."
+  ) +
   gsi::method ("patch", &tl::PixelBuffer::patch, gsi::arg ("other"),
     "@brief Patches another pixel buffer into this one\n"
     "\n"