ebiten/docs/examples/alphablending.html

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

package main

import (
        &#34;image/color&#34;
        _ &#34;image/png&#34;
        &#34;log&#34;

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

const (
        screenWidth  = 320
        screenHeight = 240
)

var (
        count       int
        ebitenImage *ebiten.Image
)

type imageParts struct {
        diff float64
}

func (p *imageParts) Src(i int) (int, int, int, int) {
        w, h := ebitenImage.Size()
        return 0, 0, w, h
}

func (p *imageParts) Dst(i int) (int, int, int, int) {
        x := int(float64(i%10)*p.diff &#43; 15)
        y := int(float64(i/10)*p.diff &#43; 20)
        w, h := ebitenImage.Size()
        return x, y, x &#43; w, y &#43; h
}

func (p *imageParts) Len() int {
        return 10 * 10
}

func update(screen *ebiten.Image) error {
        count&#43;&#43;
        count %= ebiten.FPS * 10
        diff := float64(count) * 0.2
        switch {
        case 480 &lt; count:
                diff = 0
        case 240 &lt; count:
                diff = float64(480-count) * 0.2
        }

        if err := screen.Fill(color.NRGBA{0x00, 0x00, 0x80, 0xff}); err != nil {
                return err
        }
        op := &amp;ebiten.DrawImageOptions{}
        op.ColorM.Scale(1.0, 1.0, 1.0, 0.5)
        op.ImageParts = &amp;imageParts{
                diff: diff,
        }
        if err := screen.DrawImage(ebitenImage, op); err != nil {
                return err
        }
        return nil
}

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

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  <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 and remove examples 2016-02-15 16:52:45 +01:00			`<!DOCTYPE html>`
doc: Force HTTPS 2016-08-27 17:58:27 +02:00			`<script src="../scripts/force-https.js"></script>`
doc: Add and remove examples 2016-02-15 16:52:45 +01:00			`<link rel="shortcut icon" href="../favicon.png" type="image/png" >`
			`<link rel="icon" href="../favicon.png" type="image/png" >`
			`<title>Ebiten example - alphablending</title>`
doc: Use relative path 2016-08-27 17:48:15 +02:00			`<link rel="stylesheet" href="../stylesheets/bootstrap.min.css">`
			`<link rel="stylesheet" href="../stylesheets/highlight-github.css">`
			`<link rel="stylesheet" href="../stylesheets/ebiten.css">`
doc: Bug fix: wrong path 2016-09-02 18:55:07 +02:00			`<script src="../scripts/googleanalytics.js"></script>`
doc: Apply bootstrap 2016-08-26 19:28:57 +02:00
			`<header class="navbar"><div class="container">`
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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">`
			`<ul class="nav navbar-nav navbar-right">`
			`<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>`
doc: Fix thumbnail size 2016-08-26 19:37:08 +02:00			`<li><a href="https://github.com/hajimehoshi/ebiten/wiki">Wiki</a>`
			`</ul>`
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doc: Apply bootstrap 2016-08-26 19:28:57 +02:00			`</header>`
doc: Add and remove examples 2016-02-15 16:52:45 +01:00
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 - alphablending</h2>`
doc: Apply bootstrap 2016-08-26 19:28:57 +02:00			`<iframe src="alphablending.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 and remove examples 2016-02-15 16:52:45 +01:00
			`import (`
doc: Change indent size 4 -> 8 2016-08-26 22:36:52 +02:00			`"image/color"`
			`_ "image/png"`
			`"log"`
Swap import order 2016-02-15 17:13:04 +01:00
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 and remove examples 2016-02-15 16:52:45 +01:00			`)`

			`const (`
doc: Change indent size 4 -> 8 2016-08-26 22:36:52 +02:00			`screenWidth = 320`
			`screenHeight = 240`
doc: Add and remove examples 2016-02-15 16:52:45 +01:00			`)`

			`var (`
doc: Change indent size 4 -> 8 2016-08-26 22:36:52 +02:00			`count int`
			`ebitenImage *ebiten.Image`
doc: Add and remove examples 2016-02-15 16:52:45 +01:00			`)`

doc: Generate 2016-04-22 18:44:52 +02:00			`type imageParts struct {`
doc: Change indent size 4 -> 8 2016-08-26 22:36:52 +02:00			`diff float64`
doc: Generate 2016-04-22 18:44:52 +02:00			`}`

			`func (p *imageParts) Src(i int) (int, int, int, int) {`
doc: Change indent size 4 -> 8 2016-08-26 22:36:52 +02:00			`w, h := ebitenImage.Size()`
			`return 0, 0, w, h`
doc: Generate 2016-04-22 18:44:52 +02:00			`}`

			`func (p *imageParts) Dst(i int) (int, int, int, int) {`
doc: Change indent size 4 -> 8 2016-08-26 22:36:52 +02:00			`x := int(float64(i%10)*p.diff + 15)`
			`y := int(float64(i/10)*p.diff + 20)`
			`w, h := ebitenImage.Size()`
			`return x, y, x + w, y + h`
doc: Generate 2016-04-22 18:44:52 +02:00			`}`

			`func (p *imageParts) Len() int {`
doc: Change indent size 4 -> 8 2016-08-26 22:36:52 +02:00			`return 10 * 10`
doc: Generate 2016-04-22 18:44:52 +02:00			`}`

doc: Add and remove examples 2016-02-15 16:52:45 +01:00			`func update(screen *ebiten.Image) error {`
doc: Change indent size 4 -> 8 2016-08-26 22:36:52 +02:00			`count++`
			`count %= ebiten.FPS * 10`
			`diff := float64(count) * 0.2`
			`switch {`
			`case 480 < count:`
			`diff = 0`
			`case 240 < count:`
			`diff = float64(480-count) * 0.2`
			`}`

			`if err := screen.Fill(color.NRGBA{0x00, 0x00, 0x80, 0xff}); err != nil {`
			`return err`
			`}`
			`op := &ebiten.DrawImageOptions{}`
			`op.ColorM.Scale(1.0, 1.0, 1.0, 0.5)`
			`op.ImageParts = &imageParts{`
			`diff: diff,`
			`}`
			`if err := screen.DrawImage(ebitenImage, op); err != nil {`
			`return err`
			`}`
			`return nil`
doc: Add and remove examples 2016-02-15 16:52:45 +01:00			`}`

			`func main() {`
doc: Change indent size 4 -> 8 2016-08-26 22:36:52 +02:00			`var err error`
			`ebitenImage, _, err = ebitenutil.NewImageFromFile("_resources/images/ebiten.png", ebiten.FilterNearest)`
			`if err != nil {`
			`log.Fatal(err)`
			`}`
			`if err := ebiten.Run(update, screenWidth, screenHeight, 2, "Alpha Blending (Ebiten Demo)"); err != nil {`
			`log.Fatal(err)`
			`}`
doc: Add and remove examples 2016-02-15 16:52:45 +01:00			`}`
			`</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>`
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doc: Add and remove examples 2016-02-15 16:52:45 +01:00
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