在Golang draw2d包中填充一个像素

Question

Is there a way to draw an image by filling one pixel at a time in Golang, preferably using the draw2d package?

For example, one can draw a line by using the stroke() command as such (from their getting started page):

 package main

impenter code hereort (
        "bufio"
        "fmt"
        "log"
        "os"

        "code.google.com/p/draw2d/draw2d"
        "image"
        "image/png"
)

func saveToPngFile(filePath string, m image.Image) {
        f, err := os.Create(filePath)
        if err != nil {
                log.Println(err)
                os.Exit(1)
        }
        defer f.Close()
        b := bufio.NewWriter(f)
        err = png.Encode(b, m)
        if err != nil {
                log.Println(err)
                os.Exit(1)
        }
        err = b.Flush()
        if err != nil {
                log.Println(err)
                os.Exit(1)
        }
        fmt.Printf("Wrote %s OK.
", filePath)
}

func main() {
        i := image.NewRGBA(image.Rect(0, 0, 200, 200))
        gc := draw2d.NewGraphicContext(i)
        gc.MoveTo(10.0, 10.0)
        gc.LineTo(100.0, 10.0)
        gc.Stroke()
        saveToPngFile("TestPath.png", i)
}

But how could I fill just one pixel, instead of connecting the 2 points? Draw2d is not a necessity, it is simply what I thought would be easiest.

Answer 1

In a vector graphics library like draw2d or Cairo, there is rarely pixel addressing because the model is not a raster of bits. Instead, the vector graphics model has you do things like draw lines in an abstract Euclidean space. This allows device independent drawing and prevents pixel addressing because there are no pixels.

However, draw2d has the standard Package image underlying it, which does allow pixel addressing as with the function Set.

If you are doing many pixels, expect it to be slow. And maybe learn about raster operations.