chessbot/chess/piece.go

74 lines
1.4 KiB
Go

package chess
import (
"fmt"
"image"
"image/color"
"image/png"
"os"
"golang.org/x/image/draw"
)
type Piece struct {
Name PieceName
Color color.Color
Image image.Image
}
type PieceName string
const (
Pawn PieceName = "p"
Knight PieceName = "n"
Bishop PieceName = "b"
Rook PieceName = "r"
Queen PieceName = "q"
King PieceName = "k"
)
type Color color.Color
var (
Light Color = color.RGBA{240, 217, 181, 255}
Dark Color = color.RGBA{181, 136, 99, 255}
)
func NewPiece(name PieceName, color Color) (*Piece, error) {
var (
colorSuffix string
path string
file *os.File
img image.Image
dst *image.RGBA
err error
)
colorSuffix = "l"
if color == Light {
colorSuffix = "l"
} else if color == Dark {
colorSuffix = "d"
} else {
return nil, fmt.Errorf("invalid color: %v", color)
}
path = fmt.Sprintf("assets/1024px-Chess_%s%st45.svg.png", name, colorSuffix)
if file, err = os.Open(path); err != nil {
return nil, err
}
defer file.Close()
if img, err = png.Decode(file); err != nil {
return nil, err
}
// source image for each piece is 1024x1024 and board is 8x8
// so we need to scale each piece down to 128x128 (1024/8)
dst = image.NewRGBA(image.Rect(0, 0, 128, 128))
draw.CatmullRom.Scale(dst, dst.Rect, img, img.Bounds(), draw.Over, nil)
return &Piece{Name: name, Color: color, Image: dst}, nil
}