mirror of
https://github.com/hajimehoshi/ebiten.git
synced 2024-12-27 04:08:53 +01:00
121 lines
2.8 KiB
Go
121 lines
2.8 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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package main
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import (
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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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"net/http"
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"github.com/hajimehoshi/ebiten"
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"github.com/hajimehoshi/ebiten/ebitenutil"
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)
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var (
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count int
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highDPIImage *ebiten.Image
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highDPIImageCh = make(chan *ebiten.Image)
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)
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func init() {
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// Licensed under Public Domain
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// https://commons.wikimedia.org/wiki/File:As08-16-2593.jpg
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const url = "https://upload.wikimedia.org/wikipedia/commons/1/1f/As08-16-2593.jpg"
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// Load the image asynchronously.
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go func() {
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res, err := http.Get(url)
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if err != nil {
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log.Fatal(err)
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}
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defer res.Body.Close()
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img, _, err := image.Decode(res.Body)
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if err != nil {
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log.Fatal(err)
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}
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eimg, err := ebiten.NewImageFromImage(img, ebiten.FilterDefault)
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if err != nil {
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log.Fatal(err)
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}
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highDPIImageCh <- eimg
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close(highDPIImageCh)
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}()
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}
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func update(screen *ebiten.Image) error {
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if highDPIImage == nil {
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// Use select and 'default' clause for non-blocking receiving.
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select {
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case img := <-highDPIImageCh:
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highDPIImage = img
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default:
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}
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}
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if ebiten.IsRunningSlowly() {
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return nil
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}
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if highDPIImage == nil {
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ebitenutil.DebugPrint(screen, "Loading the image...")
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return nil
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}
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scale := ebiten.DeviceScaleFactor()
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sw, sh := screen.Size()
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w, h := highDPIImage.Size()
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op := &ebiten.DrawImageOptions{}
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// Move the images's center to the upper left corner.
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op.GeoM.Translate(float64(-w)/2, float64(-h)/2)
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// The image is just too big. Adjust the scale.
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op.GeoM.Scale(0.25, 0.25)
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// Scale the image by the device ratio so that the rendering result can be same
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// on various (diffrent-DPI) environments.
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op.GeoM.Scale(scale, scale)
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// Move the image's center to the screen's center.
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op.GeoM.Translate(float64(sw)/2, float64(sh)/2)
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op.Filter = ebiten.FilterLinear
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screen.DrawImage(highDPIImage, op)
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ebitenutil.DebugPrint(screen, fmt.Sprintf("Device Scale Ratio: %0.2f", scale))
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return nil
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}
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func main() {
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const (
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screenWidth = 640
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screenHeight = 480
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)
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// Pass the invert of scale so that Ebiten's auto scaling by device scale is disabled.
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s := ebiten.DeviceScaleFactor()
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if err := ebiten.Run(update, int(screenWidth*s), int(screenHeight*s), 1/s, "High DPI (Ebiten Demo)"); err != nil {
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log.Fatal(err)
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}
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}
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