From 13461aa45577938444600f780360bd24b27442a9 Mon Sep 17 00:00:00 2001
From: Hajime Hoshi <hajimehoshi@gmail.com>
Date: Mon, 7 Mar 2016 01:29:12 +0900
Subject: [PATCH] ebitenutil: Add OpenFile

---
 ebitenutil/file.go                         | 29 ++++++++++++++++++++++
 ebitenutil/{loadimage_js.go => file_js.go} | 28 ++++++++++-----------
 ebitenutil/loadimage.go                    |  8 +++---
 3 files changed, 46 insertions(+), 19 deletions(-)
 create mode 100644 ebitenutil/file.go
 rename ebitenutil/{loadimage_js.go => file_js.go} (78%)

diff --git a/ebitenutil/file.go b/ebitenutil/file.go
new file mode 100644
index 000000000..04c75c967
--- /dev/null
+++ b/ebitenutil/file.go
@@ -0,0 +1,29 @@
+// 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.
+
+// +build !js
+
+package ebitenutil
+
+import (
+	"io"
+	"os"
+)
+
+// OpenFile opens a file and returns a stream for its data.
+//
+// This function is available both on desktops and browsers.
+func OpenFile(path string) (io.ReadCloser, error) {
+	return os.Open(path)
+}
diff --git a/ebitenutil/loadimage_js.go b/ebitenutil/file_js.go
similarity index 78%
rename from ebitenutil/loadimage_js.go
rename to ebitenutil/file_js.go
index 364d9b079..20b9ff04b 100644
--- a/ebitenutil/loadimage_js.go
+++ b/ebitenutil/file_js.go
@@ -20,12 +20,20 @@ import (
 	"bytes"
 	"errors"
 	"fmt"
+	"io"
+
 	"github.com/gopherjs/gopherjs/js"
-	"github.com/hajimehoshi/ebiten"
-	"image"
 )
 
-func NewImageFromFile(path string, filter ebiten.Filter) (*ebiten.Image, image.Image, error) {
+type file struct {
+	*bytes.Reader
+}
+
+func (f *file) Close() error {
+	return nil
+}
+
+func OpenFile(path string) (io.ReadCloser, error) {
 	var err error
 	var content *js.Object
 	ch := make(chan struct{})
@@ -48,18 +56,10 @@ func NewImageFromFile(path string, filter ebiten.Filter) (*ebiten.Image, image.I
 	req.Call("send")
 	<-ch
 	if err != nil {
-		return nil, nil, err
+		return nil, err
 	}
 
 	data := js.Global.Get("Uint8Array").New(content).Interface().([]uint8)
-	b := bytes.NewBuffer(data)
-	img, _, err := image.Decode(b)
-	if err != nil {
-		return nil, nil, err
-	}
-	img2, err := ebiten.NewImageFromImage(img, filter)
-	if err != nil {
-		return nil, nil, err
-	}
-	return img2, img, nil
+	f := &file{bytes.NewReader(data)}
+	return f, nil
 }
diff --git a/ebitenutil/loadimage.go b/ebitenutil/loadimage.go
index 4a9408377..a58ce64a5 100644
--- a/ebitenutil/loadimage.go
+++ b/ebitenutil/loadimage.go
@@ -12,14 +12,12 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-// +build !js
-
 package ebitenutil
 
 import (
-	"github.com/hajimehoshi/ebiten"
 	"image"
-	"os"
+
+	"github.com/hajimehoshi/ebiten"
 )
 
 // NewImageFromFile loads the file path and returns ebiten.Image and image.Image.
@@ -27,7 +25,7 @@ import (
 // The current directory for path depends on your environment. This will vary on your desktop or web browser.
 // It'll be safer to embed your resource, e.g., with github.com/jteeuwen/go-bindata instead of using this function.
 func NewImageFromFile(path string, filter ebiten.Filter) (*ebiten.Image, image.Image, error) {
-	file, err := os.Open(path)
+	file, err := OpenFile(path)
 	if err != nil {
 		return nil, nil, err
 	}