graphics: Bug fix: NewImageFromImage with ebiten.Image froze (#212)

image.go

@@ -338,6 +338,11 @@ func NewImage(width, height int, filter Filter) (*Image, error) {
 //
 // This function is concurrent-safe.
 func NewImageFromImage(img image.Image, filter Filter) (*Image, error) {
+	// Can't call (*ebiten.Image).At here because of the lock.
+	if _, ok := img.(*Image); ok {
+		return nil, errors.New("ebiten: NewImageFromImage can't take *ebiten.Image")
+	}
+
 	imageM.Lock()
 	defer imageM.Unlock()
 	size := img.Bounds().Size()

image_test.go

@@ -0,0 +1,84 @@
+// Copyright 2016 Hajime Hoshi
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package ebiten_test
+
+import (
+	"image"
+	_ "image/png"
+	"testing"
+
+	. "github.com/hajimehoshi/ebiten"
+)
+
+var ebitenImageBin = ""
+
+func openImage(path string) (image.Image, error) {
+	file, err := readFile(path)
+	if err != nil {
+		return nil, err
+	}
+
+	img, _, err := image.Decode(file)
+	if err != nil {
+		return nil, err
+	}
+	return img, nil
+}
+
+func openEbitenImage(path string) (*Image, image.Image, error) {
+	img, err := openImage(path)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	eimg, err := NewImageFromImage(img, FilterNearest)
+	if err != nil {
+		return nil, nil, err
+	}
+	return eimg, img, nil
+}
+
+func TestImageSelf(t *testing.T) {
+	img, _, err := openEbitenImage("testdata/ebiten.png")
+	if err != nil {
+		t.Fatal(err)
+		return
+	}
+	if err := img.DrawImage(img, nil); err == nil {
+		t.Fatalf("img.DrawImage(img, nil) doesn't return error; an error should be returned")
+	}
+}
+
+func TestImageDispose(t *testing.T) {
+	img, err := NewImage(16, 16, FilterNearest)
+	if err != nil {
+		t.Fatal(err)
+		return
+	}
+	if err := img.Dispose(); err != nil {
+		t.Errorf("img.Dipose() returns error: %v", err)
+	}
+}
+
+func TestNewImageFromEbitenImage(t *testing.T) {
+	img, _, err := openEbitenImage("testdata/ebiten.png")
+	if err != nil {
+		t.Fatal(err)
+		return
+	}
+	if _, err := NewImageFromImage(img, FilterNearest); err == nil {
+		t.Errorf("NewImageFromImage with an *ebiten.Image must return an error")
+	}
+}