+ Added with_image_from_memory. (sumbach)

[git-p4: depot-paths = "//src/image_science/dev/": change = 4791]

lib/image_science.rb

@@ -19,6 +19,12 @@ class ImageScience
   def self.with_image(path) # :yields: image
   end
 
+  ##
+  # The top-level image loader, opens an image from the string +data+ and then yields the image.
+
+  def self.with_image_from_memory(data) # :yields: image
+  end
+
   ##
   # Crops an image to +left+, +top+, +right+, and +bottom+ and then
   # yields the new image.
@@ -158,6 +164,36 @@ def cropped_thumbnail(size) # :yields: image
       }
     END
 
+    builder.c_singleton <<-"END"
+      VALUE with_image_from_memory(VALUE image_data) {
+        FREE_IMAGE_FORMAT fif = FIF_UNKNOWN;
+
+        Check_Type(image_data, T_STRING);
+        BYTE *image_data_ptr    = (BYTE*)RSTRING(image_data)->ptr;
+        DWORD image_data_length = RSTRING(image_data)->len;
+        FIMEMORY *stream = FreeImage_OpenMemory(image_data_ptr, image_data_length);
+
+        if (NULL == stream) {
+          rb_raise(rb_eTypeError, "Unable to open image_data");
+        }
+
+        fif = FreeImage_GetFileTypeFromMemory(stream, 0);
+        if ((fif == FIF_UNKNOWN) || !FreeImage_FIFSupportsReading(fif)) {
+          rb_raise(rb_eTypeError, "Unknown file format");
+        }
+
+        FIBITMAP *bitmap = NULL;
+        VALUE result = Qnil;
+        int flags = fif == FIF_JPEG ? JPEG_ACCURATE : 0;
+        bitmap = FreeImage_LoadFromMemory(fif, stream, flags);
+        FreeImage_CloseMemory(stream);
+        if (bitmap) {
+          result = wrap_and_yield(bitmap, self, fif);
+        }
+        return result;
+      }
+    END
+
     builder.c <<-"END"
       VALUE with_crop(int l, int t, int r, int b) {
         FIBITMAP *copy;

test/test_image_science.rb

@@ -46,6 +46,33 @@ def test_class_with_image_missing_with_img_extension
     end
   end
 
+  def test_class_with_image_from_memory
+    data = File.new(@path).binmode.read
+
+    ImageScience.with_image_from_memory data do |img|
+      assert_kind_of ImageScience, img
+      assert_equal @h, img.height
+      assert_equal @w, img.width
+      assert img.save(@tmppath)
+    end
+
+    assert File.exists?(@tmppath)
+
+    ImageScience.with_image @tmppath do |img|
+      assert_kind_of ImageScience, img
+      assert_equal @h, img.height
+      assert_equal @w, img.width
+    end
+  end
+
+  def test_class_with_image_from_memory_empty_string
+    assert_raises TypeError do
+      ImageScience.with_image_from_memory "" do |img|
+        flunk
+      end
+    end
+  end
+
   def test_resize
     ImageScience.with_image @path do |img|
       img.resize(25, 25) do |thumb|