Merge pull request #8 from akash-akya/new-op

Add vips_image_new_from_image

c_src/vips_image.c

@@ -69,6 +69,66 @@ ERL_NIF_TERM nif_image_new_from_file(ErlNifEnv *env, int argc,
   return ret;
 }
 
+ERL_NIF_TERM nif_image_new_from_image(ErlNifEnv *env, int argc,
+                                     const ERL_NIF_TERM argv[]) {
+  assert_argc(argc, 2);
+
+  VipsImage *image;
+  VipsImage *copy;
+  ErlNifTime start;
+  ERL_NIF_TERM list, head;
+  double *array;
+  guint size;
+  ERL_NIF_TERM ret;
+
+  start = enif_monotonic_time(ERL_NIF_USEC);
+
+  if (!erl_term_to_g_object(env, argv[0], (GObject **)&image)) {
+    ret = make_error(env, "Failed to get VipsImage");
+    goto exit;
+  }
+
+  list = argv[1];
+
+  if (!enif_get_list_length(env, list, &size)) {
+    error("Failed to get list length");
+    ret = enif_make_badarg(env);
+    goto exit;
+  }
+
+  array = g_new(double, size);
+
+  for (guint i = 0; i < size; i++) {
+    if (!enif_get_list_cell(env, list, &head, &list)) {
+      ret = make_error(env, "Failed to get list entry");
+      goto free_and_exit;
+    }
+
+    if (!enif_get_double(env, head, &array[i])) {
+      ret = make_error(env, "Failed to get double");
+      goto free_and_exit;
+    }
+  }
+
+  copy = vips_image_new_from_image(image, array, size);
+
+  if (!copy) {
+    error("Failed to create new image. error: %s", vips_error_buffer());
+    vips_error_clear();
+    ret = make_error(env, "Failed to create new image");
+    goto free_and_exit;
+  }
+
+  ret = make_ok(env, g_object_to_erl_term(env, (GObject *)copy));
+
+free_and_exit:
+  g_free(array);
+
+exit:
+  notify_consumed_timeslice(env, start, enif_monotonic_time(ERL_NIF_USEC));
+  return ret;
+}
+
 ERL_NIF_TERM nif_image_copy_memory(ErlNifEnv *env, int argc,
                                    const ERL_NIF_TERM argv[]) {
   assert_argc(argc, 1);

c_src/vips_image.h

@@ -6,6 +6,9 @@
 ERL_NIF_TERM nif_image_new_from_file(ErlNifEnv *env, int argc,
                                      const ERL_NIF_TERM argv[]);
 
+ERL_NIF_TERM nif_image_new_from_image(ErlNifEnv *env, int argc,
+                                      const ERL_NIF_TERM argv[]);
+
 ERL_NIF_TERM nif_image_copy_memory(ErlNifEnv *env, int argc,
                                    const ERL_NIF_TERM argv[]);
 

c_src/vix.c

@@ -56,6 +56,8 @@ static ErlNifFunc nif_funcs[] = {
     /* VipsImage */
     {"nif_image_new_from_file", 1, nif_image_new_from_file,
      ERL_NIF_DIRTY_JOB_IO_BOUND},
+    {"nif_image_new_from_image", 2, nif_image_new_from_image,
+     ERL_NIF_DIRTY_JOB_IO_BOUND},
     {"nif_image_copy_memory", 1, nif_image_copy_memory,
      ERL_NIF_DIRTY_JOB_IO_BOUND},
     {"nif_image_write_to_file", 2, nif_image_write_to_file,

lib/vix/g_object/double.ex

@@ -17,14 +17,7 @@ defmodule Vix.GObject.Double do
   def to_nif_term(value, data) do
     case value do
       value when is_number(value) ->
-        value =
-          if !is_float(value) do
-            # convert to float
-            value * 1.0
-          else
-            value
-          end
-
+        value = normalize(value)
         validate_number_limits!(value, data)
         value
 
@@ -37,6 +30,9 @@ defmodule Vix.GObject.Double do
   @impl Type
   def to_erl_term(value), do: value
 
+  def normalize(num) when is_float(num), do: num
+  def normalize(num) when is_integer(num), do: num * 1.0
+
   defp validate_number_limits!(_value, nil), do: :ok
 
   defp validate_number_limits!(value, {min, max, _default}) do

lib/vix/nif.ex

@@ -8,17 +8,25 @@ defmodule Vix.Nif do
   end
 
   # GObject
-  def nif_g_object_type_name(_obj), do: :erlang.nif_error(:nif_library_not_loaded)
+  def nif_g_object_type_name(_obj),
+    do: :erlang.nif_error(:nif_library_not_loaded)
 
   # GType
-  def nif_g_type_from_instance(_instance), do: :erlang.nif_error(:nif_library_not_loaded)
+  def nif_g_type_from_instance(_instance),
+    do: :erlang.nif_error(:nif_library_not_loaded)
 
-  def nif_g_type_name(_type), do: :erlang.nif_error(:nif_library_not_loaded)
+  def nif_g_type_name(_type),
+    do: :erlang.nif_error(:nif_library_not_loaded)
 
   # VipsImage
-  def nif_image_new_from_file(_src), do: :erlang.nif_error(:nif_library_not_loaded)
+  def nif_image_new_from_file(_src),
+    do: :erlang.nif_error(:nif_library_not_loaded)
 
-  def nif_image_copy_memory(_vips_image), do: :erlang.nif_error(:nif_library_not_loaded)
+  def nif_image_new_from_image(_vips_image, _value),
+    do: :erlang.nif_error(:nif_library_not_loaded)
+
+  def nif_image_copy_memory(_vips_image),
+    do: :erlang.nif_error(:nif_library_not_loaded)
 
   def nif_image_write_to_file(_vips_image, _dst),
     do: :erlang.nif_error(:nif_library_not_loaded)

lib/vix/vips/image.ex

@@ -56,6 +56,15 @@ defmodule Vix.Vips.Image do
     Nif.nif_image_new_from_file(normalize_string(path))
   end
 
+  @doc """
+  Creates a new image with width, height, format, interpretation, resolution and offset taken from the input image, but with each band set from `value`.
+  """
+  @spec new_from_image(__MODULE__.t(), [float()]) :: {:ok, __MODULE__.t()} | {:error, term()}
+  def new_from_image(vips_image, value) do
+    float_value = Enum.map(value, &Vix.GObject.Double.normalize/1)
+    Nif.nif_image_new_from_image(vips_image, float_value)
+  end
+
   # Copy an image to a memory area.
   # If image is already a memory buffer, just ref and return. If it's
   # a file on disc or a partial, allocate memory and copy the image to

test/vix/vips/image_test.exs

@@ -115,4 +115,13 @@ defmodule Vix.Vips.ImageTest do
 
     assert <<_::binary-size(size), "\a">> = image_data
   end
+
+  test "new image from other image", %{dir: _dir} do
+    {:ok, im} = Image.new_from_file(img_path("puppies.jpg"))
+    {:ok, new_im} = Image.new_from_image(im, [250])
+
+    assert Image.width(im) == Image.width(new_im)
+    assert Image.height(im) == Image.height(new_im)
+    assert Image.bands(new_im) == 1
+  end
 end