Add example 'hue'

_docs/gen.go

@@ -102,6 +102,7 @@ func main() {
 		panic(err)
 	}
 	examples := []example{
+		{Name: "hue"},
 		{Name: "mosaic"},
 		{Name: "perspective"},
 		{Name: "rotate"},

_docs/public/index.html

@@ -38,6 +38,55 @@ limitations under the License.-->
   <tr>
     <td><pre><code>package main
 
+import (
+	&#34;github.com/hajimehoshi/ebiten&#34;
+	&#34;github.com/hajimehoshi/ebiten/ebitenutil&#34;
+	_ &#34;image/jpeg&#34;
+	&#34;log&#34;
+	&#34;math&#34;
+)
+
+const (
+	screenWidth  = 320
+	screenHeight = 240
+)
+
+var (
+	count        int
+	gophersImage *ebiten.Image
+)
+
+func update(screen *ebiten.Image) error {
+	count&#43;&#43;
+	w, h := gophersImage.Size()
+	geo := ebiten.TranslateGeo(float64(screenWidth - w)/2, float64(screenHeight - h) / 2)
+	clr := ebiten.RotateHue(float64(count%360) * 2 * math.Pi / 360)
+	if err := screen.DrawImage(gophersImage, &amp;ebiten.DrawImageOptions{
+		GeoM: geo,
+		ColorM: clr,
+	}); err != nil {
+		return err
+	}
+	return nil
+}
+
+func main() {
+	var err error
+	gophersImage, _, err = ebitenutil.NewImageFromFile(&#34;images/gophers.jpg&#34;, ebiten.FilterNearest)
+	if err != nil {
+		log.Fatal(err)
+	}
+	if err := ebiten.Run(update, screenWidth, screenHeight, 2, &#34;Image (Ebiten Demo)&#34;); err != nil {
+		log.Fatal(err)
+	}
+}
+</code></pre></td>
+    <td><img src="hue.gif" width="320" height="240"></td>
+  </tr>
+  
+  <tr>
+    <td><pre><code>package main
+
 import (
 	&#34;github.com/hajimehoshi/ebiten&#34;
 	&#34;github.com/hajimehoshi/ebiten/ebitenutil&#34;
@@ -158,32 +207,14 @@ const (
 )
 
 var (
-	count           int
-	horizontalCount int
-	verticalCount   int
-	gophersImage    *ebiten.Image
+	count        int
+	gophersImage *ebiten.Image
 )
 
 func update(screen *ebiten.Image) error {
 	count&#43;&#43;
-	if ebiten.IsKeyPressed(ebiten.KeyLeft) {
-		horizontalCount--
-	}
-	if ebiten.IsKeyPressed(ebiten.KeyRight) {
-		horizontalCount&#43;&#43;
-	}
-	if ebiten.IsKeyPressed(ebiten.KeyDown) {
-		verticalCount--
-	}
-	if ebiten.IsKeyPressed(ebiten.KeyUp) {
-		verticalCount&#43;&#43;
-	}
-
 	w, h := gophersImage.Size()
 	geo := ebiten.TranslateGeo(-float64(w)/2, -float64(h)/2)
-	scaleX := math.Pow(1.05, float64(horizontalCount))
-	scaleY := math.Pow(1.05, float64(verticalCount))
-	geo.Concat(ebiten.ScaleGeo(scaleX, scaleY))
 	geo.Concat(ebiten.RotateGeo(float64(count%720) * 2 * math.Pi / 720))
 	geo.Concat(ebiten.TranslateGeo(screenWidth/2, screenHeight/2))
 	if err := screen.DrawImage(gophersImage, &amp;ebiten.DrawImageOptions{

example/hue/main.go

@@ -0,0 +1,58 @@
+// Copyright 2014 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 main
+
+import (
+	"github.com/hajimehoshi/ebiten"
+	"github.com/hajimehoshi/ebiten/ebitenutil"
+	_ "image/jpeg"
+	"log"
+	"math"
+)
+
+const (
+	screenWidth  = 320
+	screenHeight = 240
+)
+
+var (
+	count        int
+	gophersImage *ebiten.Image
+)
+
+func update(screen *ebiten.Image) error {
+	count++
+	w, h := gophersImage.Size()
+	geo := ebiten.TranslateGeo(float64(screenWidth-w)/2, float64(screenHeight-h)/2)
+	clr := ebiten.RotateHue(float64(count%360) * 2 * math.Pi / 360)
+	if err := screen.DrawImage(gophersImage, &ebiten.DrawImageOptions{
+		GeoM:   geo,
+		ColorM: clr,
+	}); err != nil {
+		return err
+	}
+	return nil
+}
+
+func main() {
+	var err error
+	gophersImage, _, err = ebitenutil.NewImageFromFile("images/gophers.jpg", ebiten.FilterNearest)
+	if err != nil {
+		log.Fatal(err)
+	}
+	if err := ebiten.Run(update, screenWidth, screenHeight, 2, "Image (Ebiten Demo)"); err != nil {
+		log.Fatal(err)
+	}
+}

readme.md

@@ -14,6 +14,7 @@
 
 ## Example
 
+* example/hue - Changes the hue of an image
 * example/mosaic - Mosaics an image
 * example/perspective - See an image in a perspective view
 * example/rotate - Rotates an image