I am trying to use golang.org/x/exp/shiny/screen to create a windows and then paint a buffer on the screen.

I have assigned same bounds (height and width) to the window and the buffer I am publishing on the window, but there seems to be a mismatch when I see the results.

You can see in the picture, that the blue buffer which is uploaded to the window is not covering it completely.

package main

import (
    "image"
    "image/color"
    "log"

    "golang.org/x/exp/shiny/driver"
    "golang.org/x/exp/shiny/screen"
    "golang.org/x/mobile/event/key"
    "golang.org/x/mobile/event/lifecycle"
)

const (
    Row = 32
    Col = 64
)

// Colors
var (
    Black = color.RGBA{0, 0, 0, 1.0}
    White = color.RGBA{255, 255, 255, 1.0}
    Blue  = color.RGBA{0, 0, 255, 1.0}
)

func main() {

    go driver.Main(func(s screen.Screen) {
        opts := screen.NewWindowOptions{
            Height: Row,
            Width:  Col,
            Title:  "Chip-8 VM",
        }

        window, err := s.NewWindow(&opts)
        if err != nil {
            log.Print("Unable to create display window: ")
            log.Fatal(err)
            return
        }

        defer window.Release()

        dim := image.Point{Col, Row}
        drawBuff, err := s.NewBuffer(dim)
        if err != nil {
            log.Fatal(err)
        }

        defaultDrawToBuffer(drawBuff.RGBA())

        log.Print("Window bounds: ", opts)
        log.Printf("Buffer bounds: %s", drawBuff.Bounds())
        log.Printf("Buffer size: %s", drawBuff.Size())

        window.Upload(image.Point{}, drawBuff, drawBuff.Bounds())
        window.Publish()

        for {
            e := window.NextEvent()
            switch e := e.(type) {

            case lifecycle.Event:
                if e.To == lifecycle.StageDead {
                    return
                } else if e.To == lifecycle.StageFocused {
                    log.Print("Focus back on the screen!")
                }

            case key.Event:
                log.Print("pressed key: ", e.Code)
                // exit game
                if e.Code == key.CodeEscape {
                    return
                }
            case error:
                log.Print(e)
            }

        }
    })

    for {
    }

}

// Bounds: (0,0)-(64,32)
func defaultDrawToBuffer(img *image.RGBA) {
    b := img.Bounds()

    log.Printf("Bounds: %s", b.String())

    for x := b.Min.X; x < b.Max.X; x++ {
        for y := b.Min.Y; y < b.Max.Y; y++ {
            img.SetRGBA(x, y, Blue)
        }
    }
}

publishing的问题,解释图片上的slide

weixin_41335120

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