func (im *ImageMap) Neighbors(node astar.Node, edges []astar.Edge) ([]astar.Edge, error) {
x := int(node) % im.Width
y := int(node) / im.Width
off := y*im.YStride + x*im.XStride
c := im.Pix[off]
if x > 0 {
edges = append(edges, astar.Edge{Node: node - 1, Cost: 1 + colorCost(c, im.Pix[off-im.XStride])})
if y > 0 {
edges = append(edges, astar.Edge{Node: node - 1 - astar.Node(im.Width), Cost: math.Sqrt2 + colorCost(c, im.Pix[off-im.XStride-im.YStride])})
}
if y < im.Height-1 {
edges = append(edges, astar.Edge{Node: node - 1 + astar.Node(im.Width), Cost: math.Sqrt2 + colorCost(c, im.Pix[off-im.XStride+im.YStride])})
}
}
if x < im.Width-1 {
edges = append(edges, astar.Edge{Node: node + 1, Cost: 1 + colorCost(c, im.Pix[off+im.XStride])})
if y > 0 {
edges = append(edges, astar.Edge{Node: node + 1 - astar.Node(im.Width), Cost: math.Sqrt2 + colorCost(c, im.Pix[off+im.XStride-im.YStride])})
}
if y < im.Height-1 {
edges = append(edges, astar.Edge{Node: node + 1 + astar.Node(im.Width), Cost: math.Sqrt2 + colorCost(c, im.Pix[off+im.XStride+im.YStride])})
}
}
if y > 0 {
edges = append(edges, astar.Edge{Node: node - astar.Node(im.Width), Cost: 1 + colorCost(c, im.Pix[off-im.YStride])})
}
if y < im.Height-1 {
edges = append(edges, astar.Edge{Node: node + astar.Node(im.Width), Cost: 1 + colorCost(c, im.Pix[off+im.YStride])})
}
return edges, nil
}
func main() {
if len(os.Args) < 2 {
log.Fatal("syntax: imagepath [path]")
}
rd, err := os.Open(os.Args[1])
if err != nil {
log.Fatal(err)
}
defer rd.Close()
img, _, err := image.Decode(rd)
if err != nil {
log.Fatal(err)
}
log.Println("Processing image")
im, err := NewImageMap(img)
if err != nil {
log.Fatal(err)
}
if len(os.Args) > 2 {
wr, err := os.Create("cpu.prof")
if err != nil {
log.Fatal(err)
}
defer wr.Close()
if err := pprof.StartCPUProfile(wr); err != nil {
log.Fatal(err)
}
}
log.Println("Finding path")
var memStats runtime.MemStats
runtime.ReadMemStats(&memStats)
totalAlloc := memStats.TotalAlloc
t := time.Now()
path, err := astar.FindPath(im, 0, astar.Node(img.Bounds().Dx()-1+img.Bounds().Dx()*(img.Bounds().Dy()-1)))
pprof.StopCPUProfile()
if err != nil {
log.Fatal(err)
}
log.Printf("\t%d ms", time.Since(t).Nanoseconds()/1e6)
runtime.ReadMemStats(&memStats)
log.Printf("\t%d MB allocated", (memStats.TotalAlloc-totalAlloc)/(1024*1024))
log.Printf("Nodes in path: %d", len(path))
log.Println("Rendering path")
for _, node := range path {
x := int(node) % img.Bounds().Dx()
y := int(node) / img.Bounds().Dx()
im.Set(x, y, color.RGBA{0, 255, 0, 255})
}
log.Println("Encoding/writing output image")
wr, err := os.Create("out.jpg")
if err != nil {
log.Fatal(err)
}
if err := jpeg.Encode(wr, img, nil); err != nil {
log.Fatal(err)
}
wr.Close()
}