completed save rect to RLE file feature

README.md

@@ -31,6 +31,7 @@ Based on: https://youtu.be/FWSR_7kZuYg?si=ix1dmo76D8AmF25F
 * you can paint your own patterns in the game
 * the game can also be started with an empty grid, which is easier to paint patterns
 * wrap around grid mode can be enabled
+* you can also save rectangles of the grid to RLE files
 
 # Install
 
@@ -78,6 +79,8 @@ While it runs, there are a couple of commands you can use:
 * move mouse while middle mouse button pressed: move canvas
 * escape: reset to 1:1 zoom
 * s: save game state to file (can be loaded with -l)
+* c: enter copy mode. Mark a rectangle with the mouse, when you
+  release the mous button it is being saved to an RLE file
 * q: quit
 
 # Report bugs

grid.go

@@ -69,6 +69,11 @@ func GetFilename(generations int64) string {
 	return fmt.Sprintf("dump-%s-%d.gol", now.Format("20060102150405"), generations)
 }
 
+func GetFilenameRLE(generations int64) string {
+	now := time.Now()
+	return fmt.Sprintf("rect-%s-%d.rle", now.Format("20060102150405"), generations)
+}
+
 func (grid *Grid) SaveState(filename string) error {
 	file, err := os.Create(filename)
 	if err != nil {

main.go

@@ -16,6 +16,19 @@ func main() {
 		os.Exit(0)
 	}
 
+	// grid := [][]int64{
+	// 	{0, 1, 1},
+	// 	{0, 1, 0},
+	// 	{1, 1, 0},
+	// }
+
+	// err := rle.StoreGridToRLE(grid, "test.rle", "B3/S23", 3, 3)
+	// if err != nil {
+	// 	panic(err)
+	// }
+
+	// os.Exit(0)
+
 	game := NewGame(config, Play)
 
 	// main loop

rle/rle.go

@@ -1,8 +1,9 @@
-// source: https://github.com/nhoffmann/life by N.Hoffmann 2020.
+// original source: https://github.com/nhoffmann/life by N.Hoffmann 2020.
 package rle
 
 import (
 	"fmt"
+	"os"
 	"regexp"
 	"strconv"
 	"strings"
@@ -52,7 +53,7 @@ func (rle *RLE) partitionFile() error {
 		}
 	}
 
-	return fmt.Errorf("Invlaid input: Header is missing")
+	return fmt.Errorf("invalid input: Header is missing")
 }
 
 func (rle *RLE) parseComments() error {
@@ -98,3 +99,78 @@ func removeWhitespace(input string) string {
 	re := regexp.MustCompile(` *\t*\r*\n*`)
 	return re.ReplaceAllString(input, "")
 }
+
+// Store a grid to an RLE file
+func StoreGridToRLE(grid [][]int64, filename, rule string, width, height int) error {
+	fd, err := os.Create(filename)
+	if err != nil {
+		return err
+	}
+
+	var pattern string
+
+	for y := 0; y < height; y++ {
+		line := ""
+		for x := 0; x < width; x++ {
+			switch grid[y][x] {
+			case 0:
+				line += "b"
+			case 1:
+				line += "o"
+			}
+		}
+
+		// if first row is: 001011110, then line is now:
+		//                  bboboooob
+
+		encoded := RunLengthEncode(line)
+
+		// and now its:     2bob4ob
+		pattern += encoded
+
+		if y != height-1 {
+			pattern += "$"
+		}
+	}
+
+	pattern += "!"
+
+	wrapped := ""
+	for idx, char := range pattern {
+		if idx%70 == 0 && idx != 0 {
+			wrapped += "\n"
+		}
+		wrapped += string(char)
+	}
+
+	_, err = fmt.Fprintf(fd, "#N %s\nx = %d, y = %d, rule = %s\n%s\n",
+		filename, width, height, rule, wrapped)
+
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+// by peterSO on
+// https://codereview.stackexchange.com/questions/238893/run-length-encoding-in-golang
+func RunLengthEncode(s string) string {
+	e := make([]byte, 0, len(s))
+	for i := 0; i < len(s); i++ {
+		c := s[i]
+		j := i + 1
+		for ; j <= len(s); j++ {
+			if j < len(s) && s[j] == c {
+				continue
+			}
+			if j-i > 1 {
+				e = strconv.AppendInt(e, int64(j-i), 10)
+			}
+			e = append(e, c)
+			break
+		}
+		i = j - 1
+	}
+	return string(e)
+}

rule.go

@@ -8,6 +8,7 @@ import (
 
 // a GOL rule
 type Rule struct {
+	Definition string
 	Birth      []int64
 	Death      []int64
 }
@@ -37,7 +38,7 @@ func ParseGameRule(rule string) *Rule {
 		log.Fatalf("Invalid game rule <%s>", rule)
 	}
 
-	golrule := &Rule{}
+	golrule := &Rule{Definition: rule}
 
 	for _, part := range parts {
 		if part[0] == 'B' {

sample-rles/glider.rle

@@ -0,0 +1,2 @@
+x = 3, y = 3, rule = B3/S23
+3o$2bo$bo!

scene-play.go

@@ -12,6 +12,7 @@ import (
 	"github.com/hajimehoshi/ebiten/v2/ebitenutil"
 	"github.com/hajimehoshi/ebiten/v2/inpututil"
 	"github.com/hajimehoshi/ebiten/v2/vector"
+	"github.com/tlinden/golsky/rle"
 	"golang.org/x/image/math/f64"
 )
 
@@ -310,6 +311,8 @@ func (scene *ScenePlay) CheckMarkInput() {
 		scene.Markmode = false
 		scene.MarkTaken = false
 		scene.MarkDone = true
+
+		scene.SaveRectRLE()
 	}
 }
 
@@ -322,6 +325,58 @@ func (scene *ScenePlay) SaveState() {
 	log.Printf("saved game state to %s at generation %d\n", filename, scene.Generations)
 }
 
+func (scene *ScenePlay) SaveRectRLE() {
+	filename := GetFilenameRLE(scene.Generations)
+
+	if scene.Mark.X == scene.Point.X || scene.Mark.Y == scene.Point.Y {
+		log.Printf("can't save non-rectangle\n")
+		return
+	}
+
+	var width int
+	var height int
+	var startx int
+	var starty int
+
+	if scene.Mark.X < scene.Point.X {
+		// mark left point
+		startx = scene.Mark.X
+		width = scene.Point.X - scene.Mark.X
+	} else {
+		// mark right point
+		startx = scene.Point.X
+		width = scene.Mark.X - scene.Point.X
+	}
+
+	if scene.Mark.Y < scene.Point.Y {
+		// mark above point
+		starty = scene.Mark.Y
+		height = scene.Point.Y - scene.Mark.Y
+	} else {
+		// mark below point
+		starty = scene.Point.Y
+		height = scene.Mark.Y - scene.Point.Y
+	}
+
+	grid := make([][]int64, height)
+
+	for y := 0; y < height; y++ {
+		grid[y] = make([]int64, width)
+
+		for x := 0; x < width; x++ {
+			grid[y][x] = scene.Grids[scene.Index].Data[y+starty][x+startx]
+		}
+	}
+
+	err := rle.StoreGridToRLE(grid, filename, scene.Config.Rule.Definition, width, height)
+	if err != nil {
+		log.Printf("failed to save rect to %s: %s\n", filename, err)
+	} else {
+		log.Printf("saved selected rect to %s at generation %d\n", filename, scene.Generations)
+	}
+
+}
+
 func (scene *ScenePlay) Update() error {
 	scene.CheckInput()
 	scene.CheckDraggingInput()