shiny/example/goban/board.go - exp - Git at Google

 // Copyright 2015 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.

 // +build example
 //
 // This build tag means that "go install golang.org/x/exp/shiny/..." doesn't
 // install this example program. Use "go run main.go board.go xy.go" to run it
 // or "go install -tags=example" to install it.

 package main

 import (
 	"image"
 	"image/color"
 	_ "image/jpeg"
 	_ "image/png"
 	"log"
 	"math/rand"
 	"os"
 	"path/filepath"
 	"strings"

 	"golang.org/x/image/draw"
 )

 const maxBoard = 21 // Maximum board size we can handle.

 var ZP = image.ZP // For brevity.

 type stoneColor uint8

 const (
 	blank stoneColor = iota // Unused
 	black
 	white
 )

 // Piece represents a stone on the board. A nil Piece is "blank".
 // The delta records pixel offset from the central dot.
 type Piece struct {
 	stone *Stone
 	ij    IJ
 	delta image.Point
 	color stoneColor
 }

 type Board struct {
 	Dims
 	pieces         []*Piece // The board. Dimensions are 1-indexed. 1, 1 is the lower left corner.
 	image          *image.RGBA
 	stone          []Stone // All the black stones, followed by all the white stones.
 	numBlackStones int
 	numWhiteStones int
 }

 type Stone struct {
 	originalImage *image.RGBA
 	originalMask  *image.Alpha
 	image         *image.RGBA
 	mask          *image.Alpha
 }

 func NewBoard(dim, percent int) *Board {
 	switch dim {
 	case 9, 13, 19, 21:
 	default:
 		return nil
 	}
 	boardTexture := get("goboard.jpg", 0)
 	b := new(Board)
 	b.Dims.Init(dim, 100)
 	b.pieces = make([]*Piece, maxBoard*maxBoard)
 	b.image = image.NewRGBA(boardTexture.Bounds())
 	draw.Draw(b.image, b.image.Bounds(), boardTexture, ZP, draw.Src)
 	dir, err := os.Open("asset")
 	if err != nil {
 		log.Fatal(err)
 	}
 	defer dir.Close()
 	names, err := dir.Readdirnames(0)
 	if err != nil {
 		log.Fatal(err)
 	}
 	circleMask := makeCircle()
 	// Blackstones go first
 	for _, name := range names {
 		if strings.HasPrefix(name, "blackstone") {
 			s, m := makeStone(name, circleMask)
 			b.stone = append(b.stone, Stone{s, m, nil, nil})
 			b.numBlackStones++
 		}
 	}
 	for _, name := range names {
 		if strings.HasPrefix(name, "whitestone") {
 			s, m := makeStone(name, circleMask)
 			b.stone = append(b.stone, Stone{s, m, nil, nil})
 			b.numWhiteStones++
 		}
 	}
 	b.Resize(percent) // TODO
 	return b
 }

 func (b *Board) Resize(percent int) {
 	b.Dims.Resize(percent)
 	for i := range b.stone {
 		stone := &b.stone[i]
 		stone.image = resizeRGBA(stone.originalImage, b.stoneDiam)
 		stone.mask = resizeAlpha(stone.originalMask, b.stoneDiam)
 	}
 }

 func resizeRGBA(src *image.RGBA, size int) *image.RGBA {
 	dst := image.NewRGBA(image.Rect(0, 0, size, size))
 	draw.ApproxBiLinear.Scale(dst, dst.Bounds(), src, src.Bounds(), draw.Src, nil)
 	return dst
 }

 func resizeAlpha(src *image.Alpha, size int) *image.Alpha {
 	dst := image.NewAlpha(image.Rect(0, 0, size, size))
 	draw.ApproxBiLinear.Scale(dst, dst.Bounds(), src, src.Bounds(), draw.Src, nil)
 	return dst
 }

 func (b *Board) piece(ij IJ) *Piece {
 	return b.pieces[(ij.j-1)*b.Dims.dim+ij.i-1]
 }

 func jitter() int {
 	max := 25 * *scale / 100
 	if max&1 == 0 {
 		max++
 	}
 	return rand.Intn(max) - max/2
 }

 func (b *Board) putPiece(ij IJ, piece *Piece) {
 	b.pieces[(ij.j-1)*b.Dims.dim+ij.i-1] = piece
 	if piece != nil {
 		piece.ij = ij
 		piece.delta = image.Point{jitter(), jitter()}
 	}
 }

 func (b *Board) selectBlackPiece() *Piece {
 	return &Piece{
 		stone: &b.stone[rand.Intn(b.numBlackStones)],
 		color: black,
 	}
 }

 func (b *Board) selectWhitePiece() *Piece {
 	return &Piece{
 		stone: &b.stone[b.numBlackStones+rand.Intn(b.numWhiteStones)],
 		color: white,
 	}
 }

 func makeStone(name string, circleMask *image.Alpha) (*image.RGBA, *image.Alpha) {
 	stone := get(name, stoneSize0)
 	dst := image.NewRGBA(stone.Bounds())
 	// Make the whole area black, for the shadow.
 	draw.Draw(dst, dst.Bounds(), image.Black, ZP, draw.Src)
 	// Lay in the stone within the circle so it shows up inside the shadow.
 	draw.DrawMask(dst, dst.Bounds(), stone, ZP, circleMask, ZP, draw.Over)
 	return dst, makeShadowMask(stone)
 }

 func get(name string, size int) image.Image {
 	f, err := os.Open(filepath.Join("asset", name))
 	if err != nil {
 		log.Fatal(err)
 	}
 	i, _, err := image.Decode(f)
 	if err != nil {
 		log.Fatal(err)
 	}
 	f.Close()
 	if size != 0 {
 		r := i.Bounds()
 		if r.Dx() != size || r.Dy() != size {
 			log.Fatalf("bad stone size %s for %s; must be %d[2]×%d[2]", r, name, size)
 		}
 	}
 	return i
 }

 func makeCircle() *image.Alpha {
 	mask := image.NewAlpha(image.Rect(0, 0, stoneSize0, stoneSize0))
 	// Make alpha work on stone.
 	// Shade gives shape, to be applied with black.
 	for y := 0; y < stoneSize0; y++ {
 		y2 := stoneSize0/2 - y
 		y2 *= y2
 		for x := 0; x < stoneSize0; x++ {
 			x2 := stoneSize0/2 - x
 			x2 *= x2
 			if x2+y2 <= stoneRad2 {
 				mask.SetAlpha(x, y, color.Alpha{255})
 			}
 		}
 	}
 	return mask
 }

 func makeShadowMask(stone image.Image) *image.Alpha {
 	mask := image.NewAlpha(stone.Bounds())
 	// Make alpha work on stone.
 	// Shade gives shape, to be applied with black.
 	const size = 256
 	const diam = 225
 	for y := 0; y < size; y++ {
 		y2 := size/2 - y
 		y2 *= y2
 		for x := 0; x < size; x++ {
 			x2 := size/2 - x
 			x2 *= x2
 			if x2+y2 > stoneRad2 {
 				red, _, _, _ := stone.At(x, y).RGBA()
 				mask.SetAlpha(x, y, color.Alpha{255 - uint8(red>>8)})
 			} else {
 				mask.SetAlpha(x, y, color.Alpha{255})
 			}
 		}
 	}
 	return mask
 }

 func (b *Board) Draw(m *image.RGBA) {
 	r := b.image.Bounds()
 	draw.Draw(m, r, b.image, ZP, draw.Src)
 	// Vertical lines.
 	x := b.xInset + b.squareWidth/2
 	y := b.yInset + b.squareHeight/2
 	wid := b.lineWidth
 	for i := 0; i < b.dim; i++ {
 		r := image.Rect(x, y, x+wid, y+(b.dim-1)*b.squareHeight)
 		draw.Draw(m, r, image.Black, ZP, draw.Src)
 		x += b.squareWidth
 	}
 	// Horizontal lines.
 	x = b.xInset + b.squareWidth/2
 	for i := 0; i < b.dim; i++ {
 		r := image.Rect(x, y, x+(b.dim-1)*b.squareWidth+wid, y+wid)
 		draw.Draw(m, r, image.Black, ZP, draw.Src)
 		y += b.squareHeight
 	}
 	// Points.
 	spot := 4
 	if b.dim < 13 {
 		spot = 3
 	}
 	points := []IJ{
 		{spot, spot},
 		{spot, (b.dim + 1) / 2},
 		{spot, b.dim + 1 - spot},
 		{(b.dim + 1) / 2, spot},
 		{(b.dim + 1) / 2, (b.dim + 1) / 2},
 		{(b.dim + 1) / 2, b.dim + 1 - spot},
 		{b.dim + 1 - spot, spot},
 		{b.dim + 1 - spot, (b.dim + 1) / 2},
 		{b.dim + 1 - spot, b.dim + 1 - spot},
 	}
 	for _, ij := range points {
 		b.drawPoint(m, ij)
 	}
 	// Pieces.
 	for i := 1; i <= b.dim; i++ {
 		for j := 1; j <= b.dim; j++ {
 			ij := IJ{i, j}
 			if p := b.piece(ij); p != nil {
 				b.drawPiece(m, ij, p)
 			}
 		}
 	}
 }

 func (b *Board) drawPoint(m *image.RGBA, ij IJ) {
 	pt := ij.XYCenter(&b.Dims)
 	wid := b.lineWidth
 	sz := wid * 3 / 2
 	r := image.Rect(pt.x-sz, pt.y-sz, pt.x+wid+sz, pt.y+wid+sz)
 	draw.Draw(m, r, image.Black, ZP, draw.Src)
 }

 func (b *Board) drawPiece(m *image.RGBA, ij IJ, piece *Piece) {
 	xy := ij.XYStone(&b.Dims)
 	xy = xy.Add(piece.delta)
 	draw.DrawMask(m, xy, piece.stone.image, ZP, piece.stone.mask, ZP, draw.Over)
 }

 func (b *Board) click(m *image.RGBA, x, y, button int) bool {
 	ij, ok := XY{x, y}.IJ(&b.Dims)
 	if !ok {
 		return false
 	}
 	switch button {
 	default:
 		return false
 	case 1:
 		b.putPiece(ij, b.selectBlackPiece())
 	case 2:
 		b.putPiece(ij, b.selectWhitePiece())
 	case 3:
 		b.putPiece(ij, nil)
 	}
 	render(m, b) // TODO: Connect this to paint events.
 	return true
 }
	// Copyright 2015 The Go Authors. All rights reserved.
	// Use of this source code is governed by a BSD-style
	// license that can be found in the LICENSE file.

	// +build example
	//
	// This build tag means that "go install golang.org/x/exp/shiny/..." doesn't
	// install this example program. Use "go run main.go board.go xy.go" to run it
	// or "go install -tags=example" to install it.

	package main

	import (
	"image"
	"image/color"
	_ "image/jpeg"
	_ "image/png"
	"log"
	"math/rand"
	"os"
	"path/filepath"
	"strings"

	"golang.org/x/image/draw"
	)

	const maxBoard = 21 // Maximum board size we can handle.

	var ZP = image.ZP // For brevity.

	type stoneColor uint8

	const (
	blank stoneColor = iota // Unused
	black
	white
	)

	// Piece represents a stone on the board. A nil Piece is "blank".
	// The delta records pixel offset from the central dot.
	type Piece struct {
	stone *Stone
	ij IJ
	delta image.Point
	color stoneColor
	}

	type Board struct {
	Dims
	pieces []*Piece // The board. Dimensions are 1-indexed. 1, 1 is the lower left corner.
	image *image.RGBA
	stone []Stone // All the black stones, followed by all the white stones.
	numBlackStones int
	numWhiteStones int
	}

	type Stone struct {
	originalImage *image.RGBA
	originalMask *image.Alpha
	image *image.RGBA
	mask *image.Alpha
	}

	func NewBoard(dim, percent int) *Board {
	switch dim {
	case 9, 13, 19, 21:
	default:
	return nil
	}
	boardTexture := get("goboard.jpg", 0)
	b := new(Board)
	b.Dims.Init(dim, 100)
	b.pieces = make([]Piece, maxBoardmaxBoard)
	b.image = image.NewRGBA(boardTexture.Bounds())
	draw.Draw(b.image, b.image.Bounds(), boardTexture, ZP, draw.Src)
	dir, err := os.Open("asset")
	if err != nil {
	log.Fatal(err)
	}
	defer dir.Close()
	names, err := dir.Readdirnames(0)
	if err != nil {
	log.Fatal(err)
	}
	circleMask := makeCircle()
	// Blackstones go first
	for _, name := range names {
	if strings.HasPrefix(name, "blackstone") {
	s, m := makeStone(name, circleMask)
	b.stone = append(b.stone, Stone{s, m, nil, nil})
	b.numBlackStones++
	}
	}
	for _, name := range names {
	if strings.HasPrefix(name, "whitestone") {
	s, m := makeStone(name, circleMask)
	b.stone = append(b.stone, Stone{s, m, nil, nil})
	b.numWhiteStones++
	}
	}
	b.Resize(percent) // TODO
	return b
	}

	func (b *Board) Resize(percent int) {
	b.Dims.Resize(percent)
	for i := range b.stone {
	stone := &b.stone[i]
	stone.image = resizeRGBA(stone.originalImage, b.stoneDiam)
	stone.mask = resizeAlpha(stone.originalMask, b.stoneDiam)
	}
	}

	func resizeRGBA(src image.RGBA, size int) image.RGBA {
	dst := image.NewRGBA(image.Rect(0, 0, size, size))
	draw.ApproxBiLinear.Scale(dst, dst.Bounds(), src, src.Bounds(), draw.Src, nil)
	return dst
	}

	func resizeAlpha(src image.Alpha, size int) image.Alpha {
	dst := image.NewAlpha(image.Rect(0, 0, size, size))
	draw.ApproxBiLinear.Scale(dst, dst.Bounds(), src, src.Bounds(), draw.Src, nil)
	return dst
	}

	func (b Board) piece(ij IJ) Piece {
	return b.pieces[(ij.j-1)*b.Dims.dim+ij.i-1]
	}

	func jitter() int {
	max := 25 * *scale / 100
	if max&1 == 0 {
	max++
	}
	return rand.Intn(max) - max/2
	}

	func (b Board) putPiece(ij IJ, piece Piece) {
	b.pieces[(ij.j-1)*b.Dims.dim+ij.i-1] = piece
	if piece != nil {
	piece.ij = ij
	piece.delta = image.Point{jitter(), jitter()}
	}
	}

	func (b Board) selectBlackPiece() Piece {
	return &Piece{
	stone: &b.stone[rand.Intn(b.numBlackStones)],
	color: black,
	}
	}

	func (b Board) selectWhitePiece() Piece {
	return &Piece{
	stone: &b.stone[b.numBlackStones+rand.Intn(b.numWhiteStones)],
	color: white,
	}
	}

	func makeStone(name string, circleMask image.Alpha) (image.RGBA, *image.Alpha) {
	stone := get(name, stoneSize0)
	dst := image.NewRGBA(stone.Bounds())
	// Make the whole area black, for the shadow.
	draw.Draw(dst, dst.Bounds(), image.Black, ZP, draw.Src)
	// Lay in the stone within the circle so it shows up inside the shadow.
	draw.DrawMask(dst, dst.Bounds(), stone, ZP, circleMask, ZP, draw.Over)
	return dst, makeShadowMask(stone)
	}

	func get(name string, size int) image.Image {
	f, err := os.Open(filepath.Join("asset", name))
	if err != nil {
	log.Fatal(err)
	}
	i, _, err := image.Decode(f)
	if err != nil {
	log.Fatal(err)
	}
	f.Close()
	if size != 0 {
	r := i.Bounds()
	if r.Dx() != size \|\| r.Dy() != size {
	log.Fatalf("bad stone size %s for %s; must be %d[2]×%d[2]", r, name, size)
	}
	}
	return i
	}

	func makeCircle() *image.Alpha {
	mask := image.NewAlpha(image.Rect(0, 0, stoneSize0, stoneSize0))
	// Make alpha work on stone.
	// Shade gives shape, to be applied with black.
	for y := 0; y < stoneSize0; y++ {
	y2 := stoneSize0/2 - y
	y2 *= y2
	for x := 0; x < stoneSize0; x++ {
	x2 := stoneSize0/2 - x
	x2 *= x2
	if x2+y2 <= stoneRad2 {
	mask.SetAlpha(x, y, color.Alpha{255})
	}
	}
	}
	return mask
	}

	func makeShadowMask(stone image.Image) *image.Alpha {
	mask := image.NewAlpha(stone.Bounds())
	// Make alpha work on stone.
	// Shade gives shape, to be applied with black.
	const size = 256
	const diam = 225
	for y := 0; y < size; y++ {
	y2 := size/2 - y
	y2 *= y2
	for x := 0; x < size; x++ {
	x2 := size/2 - x
	x2 *= x2
	if x2+y2 > stoneRad2 {
	red, _, _, _ := stone.At(x, y).RGBA()
	mask.SetAlpha(x, y, color.Alpha{255 - uint8(red>>8)})
	} else {
	mask.SetAlpha(x, y, color.Alpha{255})
	}
	}
	}
	return mask
	}

	func (b Board) Draw(m image.RGBA) {
	r := b.image.Bounds()
	draw.Draw(m, r, b.image, ZP, draw.Src)
	// Vertical lines.
	x := b.xInset + b.squareWidth/2
	y := b.yInset + b.squareHeight/2
	wid := b.lineWidth
	for i := 0; i < b.dim; i++ {
	r := image.Rect(x, y, x+wid, y+(b.dim-1)*b.squareHeight)
	draw.Draw(m, r, image.Black, ZP, draw.Src)
	x += b.squareWidth
	}
	// Horizontal lines.
	x = b.xInset + b.squareWidth/2
	for i := 0; i < b.dim; i++ {
	r := image.Rect(x, y, x+(b.dim-1)*b.squareWidth+wid, y+wid)
	draw.Draw(m, r, image.Black, ZP, draw.Src)
	y += b.squareHeight
	}
	// Points.
	spot := 4
	if b.dim < 13 {
	spot = 3
	}
	points := []IJ{
	{spot, spot},
	{spot, (b.dim + 1) / 2},
	{spot, b.dim + 1 - spot},
	{(b.dim + 1) / 2, spot},
	{(b.dim + 1) / 2, (b.dim + 1) / 2},
	{(b.dim + 1) / 2, b.dim + 1 - spot},
	{b.dim + 1 - spot, spot},
	{b.dim + 1 - spot, (b.dim + 1) / 2},
	{b.dim + 1 - spot, b.dim + 1 - spot},
	}
	for _, ij := range points {
	b.drawPoint(m, ij)
	}
	// Pieces.
	for i := 1; i <= b.dim; i++ {
	for j := 1; j <= b.dim; j++ {
	ij := IJ{i, j}
	if p := b.piece(ij); p != nil {
	b.drawPiece(m, ij, p)
	}
	}
	}
	}

	func (b Board) drawPoint(m image.RGBA, ij IJ) {
	pt := ij.XYCenter(&b.Dims)
	wid := b.lineWidth
	sz := wid * 3 / 2
	r := image.Rect(pt.x-sz, pt.y-sz, pt.x+wid+sz, pt.y+wid+sz)
	draw.Draw(m, r, image.Black, ZP, draw.Src)
	}

	func (b Board) drawPiece(m image.RGBA, ij IJ, piece *Piece) {
	xy := ij.XYStone(&b.Dims)
	xy = xy.Add(piece.delta)
	draw.DrawMask(m, xy, piece.stone.image, ZP, piece.stone.mask, ZP, draw.Over)
	}

	func (b Board) click(m image.RGBA, x, y, button int) bool {
	ij, ok := XY{x, y}.IJ(&b.Dims)
	if !ok {
	return false
	}
	switch button {
	default:
	return false
	case 1:
	b.putPiece(ij, b.selectBlackPiece())
	case 2:
	b.putPiece(ij, b.selectWhitePiece())
	case 3:
	b.putPiece(ij, nil)
	}
	render(m, b) // TODO: Connect this to paint events.
	return true
	}