ebiten/examples/minify/main.go

125 lines
3.5 KiB
Go

// Copyright 2018 The Ebiten Authors
//
// 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 example jsgo
// This example is an experiment to minify images with various filters.
// When linear filter is used, mipmap images should be used for high-quality rendering (#578).
package main
import (
"bytes"
"fmt"
"image"
_ "image/jpeg"
"log"
"math"
"github.com/hajimehoshi/ebiten/v2"
"github.com/hajimehoshi/ebiten/v2/ebitenutil"
"github.com/hajimehoshi/ebiten/v2/examples/resources/images"
"github.com/hajimehoshi/ebiten/v2/inpututil"
)
const (
screenWidth = 800
screenHeight = 480
)
var (
gophersImage *ebiten.Image
)
type Game struct {
rotate bool
clip bool
counter int
}
func (g *Game) Update() error {
g.counter++
if g.counter == 480 {
g.counter = 0
}
if inpututil.IsKeyJustPressed(ebiten.KeyR) {
g.rotate = !g.rotate
}
if inpututil.IsKeyJustPressed(ebiten.KeyC) {
g.clip = !g.clip
}
return nil
}
func (g *Game) Draw(screen *ebiten.Image) {
s := 1.5 / math.Pow(1.01, float64(g.counter))
msg := fmt.Sprintf(`Minifying images (Nearest filter vs Linear filter):
Press R to rotate the images.
Press C to clip the images.
Scale: %0.2f`, s)
ebitenutil.DebugPrint(screen, msg)
clippedGophersImage := gophersImage.SubImage(image.Rect(100, 100, 200, 200)).(*ebiten.Image)
for i, f := range []ebiten.Filter{ebiten.FilterNearest, ebiten.FilterLinear} {
w, h := gophersImage.Size()
op := &ebiten.DrawImageOptions{}
if g.rotate {
op.GeoM.Translate(-float64(w)/2, -float64(h)/2)
op.GeoM.Rotate(float64(g.counter) / 300 * 2 * math.Pi)
op.GeoM.Translate(float64(w)/2, float64(h)/2)
}
op.GeoM.Scale(s, s)
op.GeoM.Translate(32+float64(i*w)*s+float64(i*4), 64)
op.Filter = f
if g.clip {
screen.DrawImage(clippedGophersImage, op)
} else {
screen.DrawImage(gophersImage, op)
}
}
}
func (g *Game) Layout(outsideWidth, outsideHeight int) (int, int) {
return screenWidth, screenHeight
}
func main() {
// Decode image from a byte slice instead of a file so that
// this example works in any working directory.
// If you want to use a file, there are some options:
// 1) Use os.Open and pass the file to the image decoder.
// This is a very regular way, but doesn't work on browsers.
// 2) Use ebitenutil.OpenFile and pass the file to the image decoder.
// This works even on browsers.
// 3) Use ebitenutil.NewImageFromFile to create an ebiten.Image directly from a file.
// This also works on browsers.
img, _, err := image.Decode(bytes.NewReader(images.Gophers_jpg))
if err != nil {
log.Fatal(err)
}
// Specifying filter on NewImage[FromImage] is just for backward compatibility.
// Now specifying filter at DrawImageOptions is recommended.
// Specify FilterDefault here, that means to prefer filter specified at DrawImageOptions.
gophersImage, _ = ebiten.NewImageFromImage(img)
ebiten.SetWindowSize(screenWidth, screenHeight)
ebiten.SetWindowTitle("Minify (Ebiten Demo)")
if err := ebiten.RunGame(&Game{}); err != nil {
log.Fatal(err)
}
}