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examples/highdpi: Use a beautiful high-DPI image

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This commit is contained in:
Hajime Hoshi 2018-01-28 20:37:02 +09:00
parent 4f3682a130
commit 58997097d6
1 changed files with 37 additions and 16 deletions
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53
examples/highdpi/main.go
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@ -18,9 +18,10 @@ package main
import (
"fmt"
"image"
_ "image/jpeg"
"log"
"math"
"net/http"
"github.com/hajimehoshi/ebiten"
"github.com/hajimehoshi/ebiten/ebitenutil"
@ -28,42 +29,62 @@ import (
var (
count int
gophersImage *ebiten.Image
highDPIImage *ebiten.Image
)
func init() {
// licensed under Public Domain
// https://commons.wikimedia.org/wiki/File:As08-16-2593.jpg
const url = "https://upload.wikimedia.org/wikipedia/commons/1/1f/As08-16-2593.jpg"
res, err := http.Get(url)
if err != nil {
log.Fatal(err)
}
defer res.Body.Close()
img, _, err := image.Decode(res.Body)
if err != nil {
log.Fatal(err)
}
highDPIImage, err = ebiten.NewImageFromImage(img, ebiten.FilterLinear)
if err != nil {
log.Fatal(err)
}
}
func update(screen *ebiten.Image) error {
count++
if ebiten.IsRunningSlowly() {
return nil
}
scale := ebiten.DeviceScaleFactor()
sw, sh := screen.Size()
w, h := gophersImage.Size()
w, h := highDPIImage.Size()
op := &ebiten.DrawImageOptions{}
op.GeoM.Translate(-float64(w)/2, -float64(h)/2)
op.GeoM.Rotate(float64(count%360) * 2 * math.Pi / 360)
op.GeoM.Translate(float64(-w)/2, float64(-h)/2)
// The image is just too big. Adjust the scale.
op.GeoM.Scale(0.25, 0.25)
// Scale the image by the device ratio so that the rendering result can be same
// on various (diffrent-DPI) environments.
op.GeoM.Scale(scale, scale)
op.GeoM.Translate(float64(sw)/2, float64(sh)/2)
screen.DrawImage(gophersImage, op)
screen.DrawImage(highDPIImage, op)
ebitenutil.DebugPrint(screen, fmt.Sprintf("Scale: %0.2f", scale))
ebitenutil.DebugPrint(screen, fmt.Sprintf("Device Scale Ratio: %0.2f", scale))
return nil
}
func main() {
const (
screenWidth = 320
screenHeight = 240
screenWidth = 640
screenHeight = 480
)
var err error
gophersImage, _, err = ebitenutil.NewImageFromFile(ebitenutil.JoinStringsIntoFilePath("_resources", "images", "gophers.jpg"), ebiten.FilterLinear)
if err != nil {
log.Fatal(err)
}
s := ebiten.DeviceScaleFactor()
// Pass the invert of scale so that Ebiten's auto scaling by device scale is disabled.
s := ebiten.DeviceScaleFactor()
if err := ebiten.Run(update, int(screenWidth*s), int(screenHeight*s), 1/s, "High DPI (Ebiten Demo)"); err != nil {
log.Fatal(err)
}