feat: breathing animation from mfp

pkg/anim/reform.go

@@ -0,0 +1,183 @@
+package anim
+
+import (
+	"math"
+	"math/rand"
+	"time"
+
+	"github.com/cfoust/cy/pkg/emu"
+	"github.com/cfoust/cy/pkg/geom"
+	"github.com/cfoust/cy/pkg/geom/image"
+)
+
+const (
+	REFORM_CHARS = "—~±§|[].+$^@*()•x%!?#"
+)
+
+type word struct {
+	row    int
+	col0   int
+	col1   int // exclusive
+	buffer []emu.Glyph
+}
+
+func makeBuffer(size int) []emu.Glyph {
+	buffer := make([]emu.Glyph, size)
+	for i := 0; i < size; i++ {
+		buffer[i] = emu.EmptyGlyph()
+	}
+	return buffer
+}
+
+type Reform struct {
+	in       image.Image
+	out      image.Image
+	duration time.Duration
+	words    []word
+}
+
+var _ Animation = (*Reform)(nil)
+
+func (r *Reform) Init(start image.Image) {
+	r.in = start.Clone()
+	r.out = start
+
+	for row := 0; row < start.Size().R; row++ {
+		var col0 int = -1
+		var first emu.Glyph
+
+		for col := 0; col < start.Size().C; col++ {
+			if start[row][col].Char == ' ' || (col0 != -1 && !start[row][col].SameAttrs(first)) {
+				if col0 == -1 {
+					continue
+				}
+
+				r.words = append(r.words, word{
+					row:    row,
+					col0:   col0,
+					col1:   col,
+					buffer: makeBuffer(col - col0),
+				})
+				col0 = -1
+				continue
+			}
+
+			if col0 != -1 {
+				continue
+			}
+
+			col0 = col
+			first = start[row][col]
+		}
+
+		if col0 == -1 {
+			continue
+		}
+
+		r.words = append(r.words, word{
+			row:    row,
+			col0:   col0,
+			col1:   start.Size().C,
+			buffer: makeBuffer(start.Size().C - col0),
+		})
+	}
+}
+
+// getRandomCharacter returns a random character from a predefined set.
+func getRandomCharacter(isXOnly bool) rune {
+	specialChars := "—~±§|[].+$^@*()•x%!?#"
+	if isXOnly {
+		return 'x'
+	}
+	return rune(specialChars[rand.Intn(len(specialChars))])
+}
+
+func (r *Reform) Update(delta time.Duration) image.Image {
+	cycle := (delta / r.duration)
+	reverse := (cycle % 2) == 0
+	randomCharChance := 0.8
+
+	// Pause at the end of each cycle
+	pauseFactor := 0.2
+	pauseLength := time.Duration(float64(r.duration) * pauseFactor)
+	progress := float64(float64(delta-(cycle*r.duration))) / float64(r.duration-pauseLength)
+
+	if progress > 1 {
+		progress = 1
+	}
+
+	// Easing function for smooth animation
+	easedProgress := -(math.Cos(math.Pi*progress) - 1) / 2
+	easedProgress = math.Pow(easedProgress, 2)
+	if reverse {
+		easedProgress = 1 - easedProgress
+	}
+
+	for _, w := range r.words {
+		length := w.col1 - w.col0
+		charsToShow := int(float64(length) * math.Abs(easedProgress))
+		randomReplaceRange := int(2 * (0.5 - math.Abs(easedProgress-0.5)) * float64(length))
+
+		// Update the temporary text with new characters
+		for j := 0; j < 20; j++ {
+			pos := charsToShow + int((1-rand.Float64())*float64(length)*float64(j)/20)
+			if pos < 0 || pos >= len(w.buffer) {
+				continue
+			}
+
+			if rand.Float64() > randomCharChance {
+				w.buffer[pos].Char = r.in[w.row][w.col0+pos].Char
+			} else {
+				w.buffer[pos].Char = getRandomCharacter(reverse)
+			}
+		}
+
+		if reverse {
+			numRandom := geom.Max(0, charsToShow-1-randomReplaceRange)
+			numReal := geom.Max(0, charsToShow-1)
+
+			// In reverse the order goes: empty, random, real
+			for col := 0; col < length; col++ {
+				if col < numRandom {
+					r.out[w.row][w.col0+col].Char = ' '
+					continue
+				}
+
+				if col < numReal {
+					r.out[w.row][w.col0+col].Char = w.buffer[col].Char
+					continue
+				}
+
+				r.out[w.row][w.col0+col].Char = r.in[w.row][w.col0+col].Char
+			}
+			continue
+		}
+
+		numRandom := geom.Min(charsToShow+randomReplaceRange, length-1)
+
+		// Otherwise the order goes: real, random, empty
+		for col := 0; col < length; col++ {
+			if col < charsToShow {
+				r.out[w.row][w.col0+col].Char = r.in[w.row][w.col0+col].Char
+				continue
+			}
+
+			if col < numRandom {
+				r.out[w.row][w.col0+col].Char = w.buffer[col].Char
+				continue
+			}
+
+			r.out[w.row][w.col0+col].Char = ' '
+		}
+	}
+
+	return r.out
+}
+
+func init() {
+	registerAnimation("mfp-reform", func() Animation {
+		return &Reform{
+			duration: time.Second + time.Millisecond*500,
+		}
+	})
+}

pkg/emu/module.go

@@ -3,7 +3,6 @@ package emu
 import (
 	"fmt"
 	"io"
-	"io/ioutil"
 
 	"github.com/cfoust/cy/pkg/geom"
 
@@ -99,6 +98,11 @@ func (g Glyph) Equal(other Glyph) bool {
 	return g.Char == other.Char && g.Mode == other.Mode && g.FG == other.FG && g.BG == other.BG
 }
 
+// SameAttrs reports whether the two glyphs have the same visual attributes.
+func (g Glyph) SameAttrs(other Glyph) bool {
+	return g.Mode == other.Mode && g.FG == other.FG && g.BG == other.BG
+}
+
 func EmptyGlyph() Glyph {
 	return Glyph{
 		Char: ' ',
@@ -355,7 +359,7 @@ var WithoutHistory TerminalOption = func(info *TerminalInfo) {
 // New returns a new virtual terminal emulator.
 func New(opts ...TerminalOption) Terminal {
 	info := TerminalInfo{
-		w:    ioutil.Discard,
+		w:    io.Discard,
 		cols: geom.DEFAULT_SIZE.C,
 		rows: geom.DEFAULT_SIZE.R,
 	}