go.mod and castling support

.gitignore

@@ -0,0 +1 @@
+.idea

README.md

@@ -22,12 +22,21 @@ Initialize the renderer with a FEN notation.
 board, _ := chessimage.NewRendererFromFEN("rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1")
 ```
 
-Render the chess board to a png `image.Image` interface.
+Render the chess board to a png `image.Image` interface. This will use the internal (embedded) images, that are licensed under the CC license (see ./assets/license.md)
 
 ```go
 f, _ := os.Create("board.png")
 defer f.Close()
-image, _ := board.Render(chessimage.Options{AssetPath: "./assets/")})
+image, _ := board.Render(chessimage.Options{})
+png.Encode(f, image)
+```
+
+If you want to use your own chess piece images, provide a path to an asset folder:
+
+```go
+f, _ := os.Create("board.png")
+defer f.Close()
+image, _ := board.Render(chessimage.Options{AssetPath: "./assets/"})
 png.Encode(f, image)
 ```
 
@@ -46,6 +55,18 @@ board.SetLastMove(chessimage.LastMove{
 
 ![](./docs/board_with_moves.png)
 
+To highlight a castling move, use the MoveType field of the LastMove struct. Note that the From and To fields are not being used when highlighting castling moves.
+
+```go
+board.SetLastMove(chessimage.LastMove{
+	MoveType: chessimage.MoveTypeCastlingWK,
+})
+```
+
+[Example](./blob/master/examples/castling.go)
+
+![](./docs/castling.png)
+
 ## Mark Checked
 
 You can highlight a tile as "checked".
@@ -69,9 +90,9 @@ options := chessimage.Options{
 renderer.Render(options)
 ```
 
-#### AssetPath (**Required**)
+#### AssetPath
 
-Specify the path of the image assets for the individual pieces. Feel free to use the assets packaged in this repo, but be aware they are under CC license.
+Specify the path of the image assets for the individual pieces. Feel free to use the assets embedded in this repo, but be aware they are under CC license.
 
 #### Inverted (`false`)
 

board.go

@@ -5,20 +5,12 @@ import "fmt"
 // Tile represents a specific position of a tile on a chess board
 type Tile int8
 
-func (s Tile) rank() int {
-	return int(int(s) / 8)
+func (t Tile) rankFile() (int, int) {
+	return int(t) / 8, int(t) % 8
 }
 
-func (s Tile) rankInverted() int {
-	return 7 - s.rank()
-}
-
-func (s Tile) file() int {
-	return int(s) % 8
-}
-
-func (s Tile) fileInverted() int {
-	return 7 - s.file()
+func (t Tile) rankFileInv() (int, int) {
+	return 7 - int(t)/8, 7 - int(t)%8
 }
 
 func tileFromRankFile(rank int, file int) Tile {
@@ -32,13 +24,24 @@ type position struct {
 
 type board []position
 
-//LastMove represents two tiles that indicate a piece was moved
+type MoveType int
+
+const (
+	MoveTypeStandard MoveType = iota
+	MoveTypeCastlingWK
+	MoveTypeCastlingWQ
+	MoveTypeCastlingBK
+	MoveTypeCastlingBQ
+)
+
+// LastMove represents two tiles that indicate a piece was moved
 type LastMove struct {
-	From Tile
-	To   Tile
+	From     Tile
+	To       Tile
+	MoveType MoveType
 }
 
-//TileFromAN will attempt to get a tile by its algebraic notation (ie: "e5")
+// TileFromAN will attempt to get a tile by its algebraic notation (ie: "e5")
 func TileFromAN(an string) (Tile, error) {
 	tile, ok := tileMap[an]
 	if !ok {

embed.go

@@ -0,0 +1,41 @@
+package chessimage
+
+import (
+	_ "embed"
+)
+
+//go:embed "assets/pl.png"
+var whitePawn []byte
+
+//go:embed "assets/pd.png"
+var blackPawn []byte
+
+//go:embed "assets/bl.png"
+var whiteBishop []byte
+
+//go:embed "assets/bd.png"
+var blackBishop []byte
+
+//go:embed "assets/nl.png"
+var whiteKnight []byte
+
+//go:embed "assets/nd.png"
+var blackKnight []byte
+
+//go:embed "assets/rl.png"
+var whiteRook []byte
+
+//go:embed "assets/rd.png"
+var blackRook []byte
+
+//go:embed "assets/ql.png"
+var whiteQueen []byte
+
+//go:embed "assets/qd.png"
+var blackQueen []byte
+
+//go:embed "assets/kl.png"
+var whiteKing []byte
+
+//go:embed "assets/kd.png"
+var blackKing []byte

examples/board_with_moves.go

@@ -1,3 +1,4 @@
+//go:build ignore
 // +build ignore
 
 package main
@@ -15,13 +16,13 @@ func main() {
 	if err != nil {
 		log.Fatalln(err)
 	}
-	board.SetLastMove(chessimage.LastMove{
-		From: chessimage.E2,
-		To:   chessimage.E4,
-	})
-	image, err := board.Render(chessimage.Options{
-		AssetPath: "./assets/",
-	})
+	board.SetLastMove(
+		chessimage.LastMove{
+			From: chessimage.E2,
+			To:   chessimage.E4,
+		},
+	)
+	image, err := board.Render(chessimage.Options{})
 	if err != nil {
 		log.Fatalln(err)
 	}

examples/castling.go

@@ -0,0 +1,22 @@
+package main
+
+import (
+	"image/png"
+	"log"
+	"os"
+
+	"github.com/cjsaylor/chessimage"
+)
+
+func main() {
+	board, err := chessimage.NewRendererFromFEN("r1bqkbnr/ppp2ppp/2np4/4p3/4P3/3B1N2/PPPP1PPP/RNBQ1RK1 b kq - 3 4")
+	if err != nil {
+		log.Fatalln(err)
+	}
+	board.SetLastMove(chessimage.LastMove{MoveType: chessimage.MoveTypeCastlingWK})
+	image, err := board.Render(chessimage.Options{})
+	if err != nil {
+		log.Fatalln(err)
+	}
+	png.Encode(os.Stdout, image)
+}

examples/king_checked.go

@@ -15,12 +15,14 @@ func main() {
 	if err != nil {
 		log.Fatalln(err)
 	}
-	board.SetLastMove(chessimage.LastMove{
-		From: chessimage.D7,
-		To:   chessimage.G4,
-	})
+	board.SetLastMove(
+		chessimage.LastMove{
+			From: chessimage.D7,
+			To:   chessimage.G4,
+		},
+	)
 	board.SetCheckTile(chessimage.G1)
-	image, err := board.Render(chessimage.Options{AssetPath: "./assets/"})
+	image, err := board.Render(chessimage.Options{})
 	if err != nil {
 		log.Fatalln(err)
 	}

examples/king_checked_inverted.go

@@ -15,12 +15,14 @@ func main() {
 	if err != nil {
 		log.Fatalln(err)
 	}
-	board.SetLastMove(chessimage.LastMove{
-		From: chessimage.D7,
-		To:   chessimage.G4,
-	})
+	board.SetLastMove(
+		chessimage.LastMove{
+			From: chessimage.D7,
+			To:   chessimage.G4,
+		},
+	)
 	board.SetCheckTile(chessimage.G1)
-	image, err := board.Render(chessimage.Options{AssetPath: "./assets/", Inverted: true})
+	image, err := board.Render(chessimage.Options{Inverted: true})
 	if err != nil {
 		log.Fatalln(err)
 	}

examples/starting_board.go

@@ -1,3 +1,4 @@
+//go:build ignore
 // +build ignore
 
 package main
@@ -15,9 +16,7 @@ func main() {
 	if err != nil {
 		log.Fatalln(err)
 	}
-	image, err := board.Render(chessimage.Options{
-		AssetPath: "./assets/",
-	})
+	image, err := board.Render(chessimage.Options{})
 	if err != nil {
 		log.Fatalln(err)
 	}

go.mod

@@ -0,0 +1,11 @@
+module github.com/hultan/chessimage
+
+go 1.19
+
+require (
+	github.com/flopp/go-findfont v0.0.0-20180308170802-e788239e52bc
+	github.com/fogleman/gg v1.1.0
+	golang.org/x/image v0.0.0-20180708004352-c73c2afc3b81
+)
+
+require github.com/golang/freetype v0.0.0-20170609003504-e2365dfdc4a0 // indirect

go.sum

@@ -0,0 +1,8 @@
+github.com/flopp/go-findfont v0.0.0-20180308170802-e788239e52bc h1:cqzZoaYMsDUGa4J2OP6UiJqRxXHarhT8tKkO/WpFL5Y=
+github.com/flopp/go-findfont v0.0.0-20180308170802-e788239e52bc/go.mod h1:IOE5a/919uJLUrsF48h4y96LcOEjPWbZkMEAMPQDEnQ=
+github.com/fogleman/gg v1.1.0 h1:wVTfU9tB/LDr2eI5HILatkzBQLD3yl0KtPFt8KlcSIY=
+github.com/fogleman/gg v1.1.0/go.mod h1:R/bRT+9gY/C5z7JzPU0zXsXHKM4/ayA+zqcVNZzPa1k=
+github.com/golang/freetype v0.0.0-20170609003504-e2365dfdc4a0 h1:DACJavvAHhabrF08vX0COfcOBJRhZ8lUbR+ZWIs0Y5g=
+github.com/golang/freetype v0.0.0-20170609003504-e2365dfdc4a0/go.mod h1:E/TSTwGwJL78qG/PmXZO1EjYhfJinVAhrmmHX6Z8B9k=
+golang.org/x/image v0.0.0-20180708004352-c73c2afc3b81 h1:00VmoueYNlNz/aHIilyyQz/MHSqGoWJzpFv/HW8xpzI=
+golang.org/x/image v0.0.0-20180708004352-c73c2afc3b81/go.mod h1:ux5Hcp/YLpHSI86hEcLt0YII63i6oz57MZXIpbrjZUs=