ebiten/docs/examples/hsv.html

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  <h2>Ebiten example - hsv</h2>
  <iframe src="hsv.content.html" width="640" height="480"></iframe>
  <pre><code class="language-go">// &#43;build example

package main

import (
        &#34;fmt&#34;
        _ &#34;image/jpeg&#34;
        &#34;log&#34;
        &#34;math&#34;

        &#34;github.com/hajimehoshi/ebiten&#34;
        &#34;github.com/hajimehoshi/ebiten/ebitenutil&#34;
)

const (
        screenWidth  = 320
        screenHeight = 240
)

var (
        hueInt        = 0
        saturationInt = 128
        valueInt      = 128
        gophersImage  *ebiten.Image
)

func clamp(v, min, max int) int {
        if min &gt; max {
                panic(&#34;min must &lt;= max&#34;)
        }
        if v &lt; min {
                return min
        }
        if max &lt; v {
                return max
        }
        return v
}

func update(screen *ebiten.Image) error {
        if ebiten.IsKeyPressed(ebiten.KeyQ) {
                hueInt--
        }
        if ebiten.IsKeyPressed(ebiten.KeyW) {
                hueInt&#43;&#43;
        }
        if ebiten.IsKeyPressed(ebiten.KeyA) {
                saturationInt--
        }
        if ebiten.IsKeyPressed(ebiten.KeyS) {
                saturationInt&#43;&#43;
        }
        if ebiten.IsKeyPressed(ebiten.KeyZ) {
                valueInt--
        }
        if ebiten.IsKeyPressed(ebiten.KeyX) {
                valueInt&#43;&#43;
        }
        hueInt = clamp(hueInt, -256, 256)
        saturationInt = clamp(saturationInt, 0, 256)
        valueInt = clamp(valueInt, 0, 256)

        w, h := gophersImage.Size()
        op := &amp;ebiten.DrawImageOptions{}
        op.GeoM.Translate(float64(screenWidth-w)/2, float64(screenHeight-h)/2)
        hue := float64(hueInt) * 2 * math.Pi / 128
        saturation := float64(saturationInt) / 128
        value := float64(valueInt) / 128
        op.ColorM.ChangeHSV(hue, saturation, value)
        if err := screen.DrawImage(gophersImage, op); err != nil {
                return err
        }

        msg := fmt.Sprintf(`Hue:        %0.2f [Q][W]
Saturation: %0.2f [A][S]
Value:      %0.2f [Z][X]`, hue, saturation, value)
        if err := ebitenutil.DebugPrint(screen, msg); err != nil {
                return err
        }
        return nil
}

func main() {
        var err error
        gophersImage, _, err = ebitenutil.NewImageFromFile(&#34;_resources/images/gophers.jpg&#34;, ebiten.FilterNearest)
        if err != nil {
                log.Fatal(err)
        }
        if err := ebiten.Run(update, screenWidth, screenHeight, 2, &#34;HSV (Ebiten Demo)&#34;); err != nil {
                log.Fatal(err)
        }
}
</code></pre>

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  <p>© 2013 Hajime Hoshi</p>
  <p>Code is licensed under <a href="https://github.com/hajimehoshi/ebiten/blob/master/LICENSE">the Apache License 2.0</a>.</p>
  <p>The content of this page is licensed under <a href="https://creativecommons.org/licenses/by/4.0/">the Creative Commons Attribution 4.0 License</a>.</p>
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doc: Add new examples 2016-04-13 18:26:31 +02:00			`<!DOCTYPE html>`
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			`<link rel="icon" href="../favicon.png" type="image/png" >`
			`<title>Ebiten example - hsv</title>`
doc: Use relative path 2016-08-27 17:48:15 +02:00			`<link rel="stylesheet" href="../stylesheets/bootstrap.min.css">`
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doc: Separate Google Analytics snippet in another file 2016-08-29 02:51:38 +02:00			`<script src="./scripts/googleanalytics.js"></script>`
doc: Apply bootstrap 2016-08-26 19:28:57 +02:00
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doc: Use relative path 2016-08-27 17:48:15 +02:00			`<a class="navbar-brand" href="..">Ebiten</a>`
doc: Apply bootstrap 2016-08-26 19:28:57 +02:00			`</div>`
doc: Fix thumbnail size 2016-08-26 19:37:08 +02:00			`<nav class="collapse navbar-collapse">`
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			`<li><a href="https://github.com/hajimehoshi/ebiten">GitHub</a></li>`
doc: Force HTTPS 2016-08-27 17:58:27 +02:00			`<li><a href="https://godoc.org/github.com/hajimehoshi/ebiten">GoDoc</a></li>`
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doc: Apply bootstrap 2016-08-26 19:28:57 +02:00			`</header>`
doc: Add new examples 2016-04-13 18:26:31 +02:00
doc: Apply bootstrap 2016-08-26 19:28:57 +02:00			`<main><div class="container">`

doc: Adjust fonts 2016-08-26 20:18:16 +02:00			`<h2>Ebiten example - hsv</h2>`
doc: Apply bootstrap 2016-08-26 19:28:57 +02:00			`<iframe src="hsv.content.html" width="640" height="480"></iframe>`
doc: Highlight code 2016-08-27 07:00:06 +02:00			`<pre><code class="language-go">// +build example`
doc: go generate; Add style.css 2016-08-26 16:33:36 +02:00
			`package main`
doc: Add new examples 2016-04-13 18:26:31 +02:00
			`import (`
doc: Change indent size 4 -> 8 2016-08-26 22:36:52 +02:00			`"fmt"`
			`_ "image/jpeg"`
			`"log"`
			`"math"`
doc: Add new examples 2016-04-13 18:26:31 +02:00
doc: Change indent size 4 -> 8 2016-08-26 22:36:52 +02:00			`"github.com/hajimehoshi/ebiten"`
			`"github.com/hajimehoshi/ebiten/ebitenutil"`
doc: Add new examples 2016-04-13 18:26:31 +02:00			`)`

			`const (`
doc: Change indent size 4 -> 8 2016-08-26 22:36:52 +02:00			`screenWidth = 320`
			`screenHeight = 240`
doc: Add new examples 2016-04-13 18:26:31 +02:00			`)`

			`var (`
doc: Change indent size 4 -> 8 2016-08-26 22:36:52 +02:00			`hueInt = 0`
			`saturationInt = 128`
			`valueInt = 128`
			`gophersImage *ebiten.Image`
doc: Add new examples 2016-04-13 18:26:31 +02:00			`)`

			`func clamp(v, min, max int) int {`
doc: Change indent size 4 -> 8 2016-08-26 22:36:52 +02:00			`if min > max {`
			`panic("min must <= max")`
			`}`
			`if v < min {`
			`return min`
			`}`
			`if max < v {`
			`return max`
			`}`
			`return v`
doc: Add new examples 2016-04-13 18:26:31 +02:00			`}`

			`func update(screen *ebiten.Image) error {`
doc: Change indent size 4 -> 8 2016-08-26 22:36:52 +02:00			`if ebiten.IsKeyPressed(ebiten.KeyQ) {`
			`hueInt--`
			`}`
			`if ebiten.IsKeyPressed(ebiten.KeyW) {`
			`hueInt++`
			`}`
			`if ebiten.IsKeyPressed(ebiten.KeyA) {`
			`saturationInt--`
			`}`
			`if ebiten.IsKeyPressed(ebiten.KeyS) {`
			`saturationInt++`
			`}`
			`if ebiten.IsKeyPressed(ebiten.KeyZ) {`
			`valueInt--`
			`}`
			`if ebiten.IsKeyPressed(ebiten.KeyX) {`
			`valueInt++`
			`}`
			`hueInt = clamp(hueInt, -256, 256)`
			`saturationInt = clamp(saturationInt, 0, 256)`
			`valueInt = clamp(valueInt, 0, 256)`

			`w, h := gophersImage.Size()`
			`op := &ebiten.DrawImageOptions{}`
			`op.GeoM.Translate(float64(screenWidth-w)/2, float64(screenHeight-h)/2)`
			`hue := float64(hueInt) * 2 * math.Pi / 128`
			`saturation := float64(saturationInt) / 128`
			`value := float64(valueInt) / 128`
			`op.ColorM.ChangeHSV(hue, saturation, value)`
			`if err := screen.DrawImage(gophersImage, op); err != nil {`
			`return err`
			`}`

			msg := fmt.Sprintf(`Hue: %0.2f [Q][W]
doc: Add new examples 2016-04-13 18:26:31 +02:00			`Saturation: %0.2f [A][S]`
			Value: %0.2f [Z][X]`, hue, saturation, value)
doc: Change indent size 4 -> 8 2016-08-26 22:36:52 +02:00			`if err := ebitenutil.DebugPrint(screen, msg); err != nil {`
			`return err`
			`}`
			`return nil`
doc: Add new examples 2016-04-13 18:26:31 +02:00			`}`

			`func main() {`
doc: Change indent size 4 -> 8 2016-08-26 22:36:52 +02:00			`var err error`
			`gophersImage, _, err = ebitenutil.NewImageFromFile("_resources/images/gophers.jpg", ebiten.FilterNearest)`
			`if err != nil {`
			`log.Fatal(err)`
			`}`
			`if err := ebiten.Run(update, screenWidth, screenHeight, 2, "HSV (Ebiten Demo)"); err != nil {`
			`log.Fatal(err)`
			`}`
doc: Add new examples 2016-04-13 18:26:31 +02:00			`}`
			`</code></pre>`

doc: Apply bootstrap 2016-08-26 19:28:57 +02:00			`</div></main>`

			`<footer><div class="container">`
			`<p>© 2013 Hajime Hoshi</p>`
doc: Add 'the' 2016-08-28 00:10:41 +02:00			`<p>Code is licensed under <a href="https://github.com/hajimehoshi/ebiten/blob/master/LICENSE">the Apache License 2.0</a>.</p>`
doc: Apply bootstrap 2016-08-26 19:28:57 +02:00			`<p>The content of this page is licensed under <a href="https://creativecommons.org/licenses/by/4.0/">the Creative Commons Attribution 4.0 License</a>.</p>`
			`</div></footer>`
doc: Add new examples 2016-04-13 18:26:31 +02:00
doc: Use relative path 2016-08-27 17:48:15 +02:00			`<script src="../scripts/highlight.pack.js"></script>`
doc: Highlight code 2016-08-27 07:00:06 +02:00			`<script>hljs.initHighlightingOnLoad();</script>`