107 lines
2.5 KiB
Go
107 lines
2.5 KiB
Go
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package maze
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import (
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"fmt"
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"image"
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"image/color"
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"image/png"
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"os"
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)
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var (
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// DefaultWallColor is used for wall cells.
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DefaultWallColor = color.RGBA{R: 0, G: 0, B: 0, A: 255}
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// DefaultPathColor is used for open maze cells.
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DefaultPathColor = color.RGBA{R: 255, G: 255, B: 255, A: 255}
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// DefaultSolutionColor is used to highlight solution cells.
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DefaultSolutionColor = color.RGBA{R: 0, G: 180, B: 0, A: 255}
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)
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// RenderOptions controls how a maze image is rendered.
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type RenderOptions struct {
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Scale int
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WallColor color.RGBA
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PathColor color.RGBA
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SolutionColor color.RGBA
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HighlightPath bool
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}
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// DefaultRenderOptions returns baseline rendering options.
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func DefaultRenderOptions() RenderOptions {
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return RenderOptions{
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Scale: 5,
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WallColor: DefaultWallColor,
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PathColor: DefaultPathColor,
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SolutionColor: DefaultSolutionColor,
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HighlightPath: false,
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}
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}
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// RenderImage converts a maze grid into an RGBA image.
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//
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// If options.HighlightPath is true, Solve is used and solution cells are painted
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// with options.SolutionColor.
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func RenderImage(grid Grid, options RenderOptions) (*image.RGBA, error) {
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width, height, err := validateGrid(grid)
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if err != nil {
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return nil, err
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}
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if options.Scale <= 0 {
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return nil, fmt.Errorf("scale must be greater than zero")
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}
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img := image.NewRGBA(image.Rect(0, 0, width*options.Scale, height*options.Scale))
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var solutionPath [][]bool
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if options.HighlightPath {
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solutionPath, err = Solve(grid)
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if err != nil {
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return nil, err
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}
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}
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for cellY := 0; cellY < height; cellY++ {
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startY := cellY * options.Scale
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for cellX := 0; cellX < width; cellX++ {
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startX := cellX * options.Scale
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pixel := options.WallColor
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if grid[cellY][cellX] == 1 {
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pixel = options.PathColor
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if options.HighlightPath && solutionPath[cellY][cellX] {
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pixel = options.SolutionColor
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}
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}
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for dy := 0; dy < options.Scale; dy++ {
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row := img.Pix[(startY+dy)*img.Stride:]
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for dx := 0; dx < options.Scale; dx++ {
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offset := (startX + dx) * 4
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row[offset+0] = pixel.R
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row[offset+1] = pixel.G
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row[offset+2] = pixel.B
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row[offset+3] = pixel.A
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}
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}
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}
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}
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return img, nil
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}
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// SavePNG renders a maze image and writes it to a PNG file.
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func SavePNG(grid Grid, outputPath string, options RenderOptions) error {
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img, err := RenderImage(grid, options)
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if err != nil {
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return err
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}
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f, err := os.Create(outputPath)
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if err != nil {
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return err
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}
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defer f.Close()
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return png.Encode(f, img)
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}
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