// +build example

package main

import (
        _ "image/png"
        "log"

        "github.com/hajimehoshi/ebiten"
        "github.com/hajimehoshi/ebiten/ebitenutil"
)

const (
        screenWidth  = 640
        screenHeight = 480
)

var (
        ebitenImage *ebiten.Image
)

func update(screen *ebiten.Image) error {
        if ebiten.IsRunningSlowly() {
                return nil
        }

        ebitenutil.DebugPrint(screen, "Nearest Filter (default) VS Linear Filter")

        op := &ebiten.DrawImageOptions{}
        op.GeoM.Scale(4, 4)
        op.GeoM.Translate(64, 64)
        // By default, nearest filter is used.
        screen.DrawImage(ebitenImage, op)

        op = &ebiten.DrawImageOptions{}
        op.GeoM.Scale(4, 4)
        op.GeoM.Translate(64, 64+240)
        // Specify linear filter.
        op.Filter = ebiten.FilterLinear
        screen.DrawImage(ebitenImage, op)

        return nil
}

func main() {
        var err error
        // 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.
        ebitenImage, _, err = ebitenutil.NewImageFromFile("_resources/images/ebiten.png", ebiten.FilterDefault)
        if err != nil {
                log.Fatal(err)
        }
        if err := ebiten.Run(update, screenWidth, screenHeight, 1, "Filter (Ebiten Demo)"); err != nil {
                log.Fatal(err)
        }
}