ircd::magick: Add interface for shave operation.

include/ircd/magick.h

@@ -17,6 +17,7 @@ namespace ircd::magick
 	IRCD_EXCEPTION(ircd::error, error)
 
 	struct crop;
+	struct shave;
 	struct thumbnail;
 
 	std::tuple<ulong, string_view> version();
@@ -32,6 +33,18 @@ struct ircd::magick::thumbnail
 	          const result_closure &);
 };
 
+struct ircd::magick::shave
+{
+	using offset = std::pair<ssize_t, ssize_t>; // x, y
+	using dimensions = std::pair<size_t, size_t>; // x, y
+	using result_closure = std::function<void (const const_buffer &)>;
+
+	shave(const const_buffer &in,
+	      const dimensions &,
+	      const offset &,
+	      const result_closure &);
+};
+
 struct ircd::magick::crop
 {
 	using offset = std::pair<ssize_t, ssize_t>; // x, y

modules/media/magick.cc

@@ -180,6 +180,57 @@ ircd::magick::thumbnail::thumbnail(const const_buffer &in,
 	closure(result);
 }
 
+//
+// shave
+//
+
+ircd::magick::shave::shave(const const_buffer &in,
+                           const dimensions &dim,
+                           const offset &off,
+                           const result_closure &closure)
+{
+	const custom_ptr<::ImageInfo> input_info
+	{
+		::CloneImageInfo(nullptr), ::DestroyImageInfo
+	};
+
+	const custom_ptr<::ImageInfo> output_info
+	{
+		::CloneImageInfo(nullptr), ::DestroyImageInfo
+	};
+
+	const custom_ptr<::Image> input
+	{
+		callex<::Image *>(::BlobToImage, input_info.get(), data(in), size(in)), ::DestroyImage
+	};
+
+	const ::RectangleInfo geometry
+	{
+		dim.first,   // width
+		dim.second,  // height
+		off.first,   // x
+		off.second,  // y
+	};
+
+	const custom_ptr<::Image> output
+	{
+		callex<::Image *>(::ShaveImage, input.get(), &geometry), ::DestroyImage
+	};
+
+	size_t output_size(0);
+	const auto output_data
+	{
+		callex<void *>(::ImageToBlob, output_info.get(), output.get(), &output_size)
+	};
+
+	const const_buffer result
+	{
+		reinterpret_cast<char *>(output_data), output_size
+	};
+
+	closure(result);
+}
+
 //
 // crop
 //