集中線GIFメーカー in Golang

http://hitode909.hatenablog.com/entry/2015/09/13/205925

I wrote @hitode909's 集中線GIFメーカー(Awesome Web application) in Golang. This is command line application and you can use this as below.

Repository

https://github.com/syohex/speedline

Sample Output

Code

package main

import (
    "flag"
    "fmt"
    "math"
    "math/rand"

    "github.com/gographics/imagick/imagick"
)

var (
    output = flag.String("o", "output.gif", "output filename")
    color  = flag.String("color", "black", "background color")
)

func speedLine(mw *imagick.MagickWand, aw *imagick.MagickWand) error {
    cols, rows := mw.GetImageHeight(), mw.GetImageWidth()

    dw := imagick.NewDrawingWand()
    defer dw.Destroy()
    cw := imagick.NewPixelWand()
    cw.SetColor(*color)
    dw.SetFillColor(cw)

    center := []float64{float64(cols) / 2.0, float64(rows) / 2.0}
    const radiusCenter float64 = 0.75
    const step float64 = 0.02
    const bold float64 = 1.0
    var theeta float64

    for theeta < math.Pi*2 {
        stepNoise := rand.Float64() + 0.5
        theeta += step * stepNoise
        radiusCenterNoise := rand.Float64()*0.3 + 1.0
        boldNoise := rand.Float64() + 0.7 + 0.3

        point0 := imagick.PointInfo{
            X: math.Sin(theeta)*center[0]*radiusCenter*radiusCenterNoise + center[0],
            Y: math.Cos(theeta)*center[1]*radiusCenter*radiusCenterNoise + center[1],
        }
        point1 := imagick.PointInfo{
            X: math.Sin(theeta)*center[0]*2 + center[0],
            Y: math.Cos(theeta)*center[1]*2 + center[1],
        }
        point2 := imagick.PointInfo{
            X: math.Sin(theeta+step*bold*boldNoise)*center[0]*2 + center[0],
            Y: math.Cos(theeta+step*bold*boldNoise)*center[1]*2 + center[1],
        }

        dw.Polygon([]imagick.PointInfo{point0, point1, point2})
    }

    if err := aw.DrawImage(dw); err != nil {
        return err
    }

    return nil
}

func main() {
    flag.Parse()

    imagick.Initialize()
    defer imagick.Terminate()

    mw := imagick.NewMagickWand()
    defer mw.Destroy()
    aw := imagick.NewMagickWand()
    defer aw.Destroy()

    if err := mw.ReadImage(flag.Arg(0)); err != nil {
        panic(err)
    }

    if int(mw.GetNumberImages()) == 1 {
        mw.SetIteratorIndex(0)
        first := mw.GetImage()
        mw.ResetIterator()
        for i := 0; i < 3; i++ {
            mw.AddImage(first.Clone())
        }
    }

    for i := 0; i < int(mw.GetNumberImages()); i++ {
        mw.SetIteratorIndex(i)
        tw := mw.GetImage()
        aw.AddImage(tw)
        if err := speedLine(tw, aw); err != nil {
            fmt.Println(err)
            return
        }
        tw.Destroy()
    }
    mw.ResetIterator()

    aw.SetOption("loop", "0")
    if err := aw.WriteImages(*output, true); err != nil {
        panic(err)
    }
}