mirror of
https://github.com/hajimehoshi/ebiten.git
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118 lines
3.2 KiB
Go
118 lines
3.2 KiB
Go
// Copyright 2018 The Ebiten Authors
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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// +build example jsgo
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// This example is an experiment to minify images with various filters.
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// When linear filter is used, mipmap images should be used for high-quality rendering (#578).
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package main
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import (
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"bytes"
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"fmt"
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"image"
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_ "image/jpeg"
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"log"
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"math"
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"github.com/hajimehoshi/ebiten"
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"github.com/hajimehoshi/ebiten/ebitenutil"
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"github.com/hajimehoshi/ebiten/examples/resources/images"
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"github.com/hajimehoshi/ebiten/inpututil"
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)
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const (
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screenWidth = 800
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screenHeight = 480
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)
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var (
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gophersImage *ebiten.Image
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rotate = false
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clip = false
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counter = 0
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)
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func update(screen *ebiten.Image) error {
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counter++
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if counter == 480 {
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counter = 0
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}
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if inpututil.IsKeyJustPressed(ebiten.KeyR) {
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rotate = !rotate
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}
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if inpututil.IsKeyJustPressed(ebiten.KeyC) {
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clip = !clip
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}
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if ebiten.IsDrawingSkipped() {
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return nil
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}
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s := 1.5 / math.Pow(1.01, float64(counter))
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msg := fmt.Sprintf(`Minifying images (Nearest filter vs Linear filter):
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Press R to rotate the images.
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Press C to clip the images.
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Scale: %0.2f`, s)
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ebitenutil.DebugPrint(screen, msg)
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for i, f := range []ebiten.Filter{ebiten.FilterNearest, ebiten.FilterLinear} {
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w, h := gophersImage.Size()
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op := &ebiten.DrawImageOptions{}
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if rotate {
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op.GeoM.Translate(-float64(w)/2, -float64(h)/2)
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op.GeoM.Rotate(float64(counter) / 300 * 2 * math.Pi)
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op.GeoM.Translate(float64(w)/2, float64(h)/2)
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}
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op.GeoM.Scale(s, s)
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op.GeoM.Translate(32+float64(i*w)*s+float64(i*4), 64)
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op.Filter = f
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if clip {
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r := image.Rect(10, 10, 100, 100)
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op.SourceRect = &r
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}
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screen.DrawImage(gophersImage, op)
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}
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return nil
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}
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func main() {
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// Decode image from a byte slice instead of a file so that
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// this example works in any working directory.
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// If you want to use a file, there are some options:
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// 1) Use os.Open and pass the file to the image decoder.
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// This is a very regular way, but doesn't work on browsers.
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// 2) Use ebitenutil.OpenFile and pass the file to the image decoder.
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// This works even on browsers.
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// 3) Use ebitenutil.NewImageFromFile to create an ebiten.Image directly from a file.
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// This also works on browsers.
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img, _, err := image.Decode(bytes.NewReader(images.Gophers_jpg))
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if err != nil {
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log.Fatal(err)
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}
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// Specifying filter on NewImage[FromImage] is just for backward compatibility.
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// Now specifying filter at DrawImageOptions is recommended.
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// Specify FilterDefault here, that means to prefer filter specified at DrawImageOptions.
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gophersImage, _ = ebiten.NewImageFromImage(img, ebiten.FilterDefault)
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if err := ebiten.Run(update, screenWidth, screenHeight, 1, "Minify (Ebiten Demo)"); err != nil {
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log.Fatal(err)
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}
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}
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