Written the ImageWriter

io/writer/image.go

@@ -1,11 +1,110 @@
 package writer
 
 import (
+	"errors"
+	"image"
+	"image/color"
+	"image/draw"
+	"image/png"
 	"maze-solver/maze"
+	"os"
+
+	"github.com/mazznoer/colorgrad"
 )
 
-type ImageWriter struct{}
+type ImageWriter struct {
+	Filename              string
+	Maze                  *maze.SolvedMaze
+	CellWidth, CellHeight int
+	WallColor, PathColor  color.Color
+	SolutionGradient      colorgrad.Gradient
+	img                   *image.RGBA
+}
 
-func (w *ImageWriter) Write(filename string, maze *maze.SolvedMaze) error {
+func (w *ImageWriter) Write() error {
+	if w.Filename[len(w.Filename)-4:] != ".png" {
+		return errors.New("Filename of ImageWriter doesn't have .png extension. The only suppported image type is png")
+	}
+
+	w.img = image.NewRGBA(image.Rect(0, 0, w.Maze.Width*w.CellWidth, w.Maze.Height*w.CellHeight))
+
+	// Fill the image with walls
+	draw.Draw(w.img, w.img.Bounds(), &image.Uniform{w.WallColor}, image.Pt(0, 0), draw.Src)
+
+	// Fill in the paths
+	var x0, y0, width, height int
+	for _, node := range w.Maze.Nodes {
+		x0 = node.Coords.X * w.CellWidth
+		y0 = node.Coords.Y * w.CellHeight
+		if node.Right != nil {
+			width = (node.Right.Coords.X - node.Coords.X + 1) * w.CellWidth
+			height = w.CellHeight
+			w.draw(x0, y0, width, height, w.PathColor)
+		}
+
+		if node.Down != nil {
+			width = w.CellWidth
+			height = (node.Down.Coords.Y - node.Coords.Y + 1) * w.CellHeight
+			w.draw(x0, y0, width, height, w.PathColor)
+		}
+	}
+
+	// Fill in the solution
+	total_len := w.getSolutionLength()
+	colors := w.SolutionGradient.Colors(uint(total_len + 1))
+	c := 0
+	width, height = w.CellWidth, w.CellHeight
+	for i, from := range w.Maze.Solution[:len(w.Maze.Solution)-1] {
+		to := w.Maze.Solution[i+1]
+		if from.Coords.X == to.Coords.X {
+			x0 = from.Coords.X * w.CellWidth
+
+			for y := from.Coords.Y; y < to.Coords.Y; y++ {
+				y0 = y * w.CellHeight
+				w.draw(x0, y0, width, height, colors[c])
+				c++
+			}
+			y0 = to.Coords.Y * w.CellHeight
+			w.draw(x0, y0, width, height, colors[c])
+		} else {
+			y0 = from.Coords.Y * w.CellHeight
+
+			if from.Coords.X < to.Coords.X {
+				for x := from.Coords.X; x < to.Coords.X; x++ {
+					x0 = x * w.CellWidth
+					w.draw(x0, y0, width, height, colors[c])
+					c++
+				}
+			} else {
+				for x := from.Coords.X; x > to.Coords.X; x-- {
+					x0 = x * w.CellWidth
+					w.draw(x0, y0, width, height, colors[c])
+					c++
+				}
+			}
+			x0 = to.Coords.X * w.CellWidth
+			w.draw(x0, y0, width, height, colors[c])
+		}
+	}
+
+	f, err := os.Create(w.Filename)
+	if err != nil {
+		return err
+	}
+	png.Encode(f, w.img)
+	f.Close()
 	return nil
 }
+
+func (w *ImageWriter) getSolutionLength() int {
+	ret := 0
+	for i, node := range w.Maze.Solution[:len(w.Maze.Solution)-1] {
+		next := w.Maze.Solution[i+1]
+		ret += int(node.Coords.Distance(next.Coords))
+	}
+	return ret
+}
+
+func (w *ImageWriter) draw(x0, y0, width, height int, color color.Color) {
+	draw.Draw(w.img, image.Rect(x0, y0, x0+width, y0+height), &image.Uniform{color}, image.Pt(0, 0), draw.Src)
+}