[feat] add CrossDesk MCP with remote desktop panels

libs/controller/src/frame_image.cpp

@@ -0,0 +1,85 @@
+#include "frame_image.h"
+#include <algorithm>
+#include <libyuv.h>
+#include <png.h>
+#include <stdexcept>
+
+namespace crossdesk {
+FrameImage EncodeFrameImage(const DecodedFrame &f, ImageRegion r, int max_edge,
+                            size_t max_bytes) {
+  if (!f.width || !f.height || f.width > 8192 || f.height > 8192 ||
+      (f.width & 1) || (f.height & 1) ||
+      uint64_t(f.width) * f.height > 16777216 ||
+      f.nv12.size() != size_t(f.width) * f.height * 3 / 2 || max_edge < 64 ||
+      max_edge > 2048 || max_bytes < 4096 || max_bytes > 2 * 1024 * 1024)
+    throw std::invalid_argument("INVALID_IMAGE_REQUEST");
+  if (!r.width && !r.height)
+    r = {0, 0, int(f.width), int(f.height)};
+  if (r.x < 0 || r.y < 0 || r.width < 1 || r.height < 1 ||
+      r.width > int(f.width) || r.height > int(f.height) ||
+      r.x > int(f.width) - r.width || r.y > int(f.height) - r.height)
+    throw std::invalid_argument("INVALID_REGION");
+  std::vector<uint8_t> argb(size_t(f.width) * f.height * 4);
+  if (libyuv::NV12ToARGB(f.nv12.data(), f.width,
+                         f.nv12.data() + size_t(f.width) * f.height, f.width,
+                         argb.data(), f.width * 4, f.width, f.height))
+    throw std::runtime_error("IMAGE_CONVERSION_FAILED");
+  FrameImage result;
+  result.region = r;
+  for (int edge = max_edge;; edge = std::max(32, edge * 3 / 4)) {
+    const double scale =
+        std::min(1.0, double(edge) / std::max(r.width, r.height));
+    result.width = std::max(1, int(r.width * scale));
+    result.height = std::max(1, int(r.height * scale));
+    std::vector<uint8_t> scaled(size_t(result.width) * result.height * 4);
+    std::vector<uint8_t> rgb(size_t(result.width) * result.height * 3);
+    if (libyuv::ARGBScale(argb.data() + (size_t(r.y) * f.width + r.x) * 4,
+                          f.width * 4, r.width, r.height, scaled.data(),
+                          result.width * 4, result.width, result.height,
+                          libyuv::kFilterBox) ||
+        libyuv::ARGBToRAW(scaled.data(), result.width * 4, rgb.data(),
+                          result.width * 3, result.width, result.height))
+      throw std::runtime_error("IMAGE_CONVERSION_FAILED");
+    png_image image{};
+    image.version = PNG_IMAGE_VERSION;
+    image.width = result.width;
+    image.height = result.height;
+    image.format = PNG_FORMAT_RGB;
+    png_alloc_size_t size = 0;
+    if (!png_image_write_to_memory(&image, nullptr, &size, 0, rgb.data(), 0,
+                                   nullptr)) {
+      png_image_free(&image);
+      throw std::runtime_error("IMAGE_ENCODING_FAILED");
+    }
+    if (size <= max_bytes) {
+      result.png.resize(size);
+      const auto ok = png_image_write_to_memory(
+          &image, result.png.data(), &size, 0, rgb.data(), 0, nullptr);
+      png_image_free(&image);
+      if (!ok)
+        throw std::runtime_error("IMAGE_ENCODING_FAILED");
+      result.png.resize(size);
+      return result;
+    }
+    png_image_free(&image);
+    if (edge == 32)
+      throw std::runtime_error("IMAGE_TOO_LARGE");
+  }
+}
+std::string ImageBase64(const std::vector<uint8_t> &data) {
+  constexpr char alphabet[] =
+      "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
+  std::string out;
+  out.reserve((data.size() + 2) / 3 * 4);
+  for (size_t i = 0; i < data.size(); i += 3) {
+    const uint32_t n = (uint32_t(data[i]) << 16) |
+                       (i + 1 < data.size() ? uint32_t(data[i + 1]) << 8 : 0) |
+                       (i + 2 < data.size() ? data[i + 2] : 0);
+    out += alphabet[n >> 18];
+    out += alphabet[(n >> 12) & 63];
+    out += i + 1 < data.size() ? alphabet[(n >> 6) & 63] : '=';
+    out += i + 2 < data.size() ? alphabet[n & 63] : '=';
+  }
+  return out;
+}
+} // namespace crossdesk