Truecolor and ansi 216+16 colors support (#31)

* Support truecolor terminals

* Support ansi 216+16 colors

* update sshot

* Fixed Apple terminal 256 bug/issue

* comment about issue with mac's terminal

ansipixels/ansipixels.go

@@ -30,6 +30,9 @@ type AnsiPixels struct {
 	W, H  int // Width and Height
 	x, y  int // Cursor position
 	C     chan os.Signal
+	// Should image be monochrome, 256 or true color
+	TrueColor bool
+	Color     bool // 256 (216) color mode
 }
 
 func NewAnsiPixels() *AnsiPixels {

ansipixels/fps/fps.go

@@ -83,8 +83,23 @@ func animate(ap *ansipixels.AnsiPixels, frame uint) {
 //go:embed fps.jpg
 var fpsJpg []byte
 
-func Main() int {
+//go:embed fps_colors.jpg
+var fpsColorsJpg []byte
+
+func Main() int { //nolint:funlen // color if/else are a bit long.
+	defaultTrueColor := false
+	if os.Getenv("COLORTERM") != "" {
+		defaultTrueColor = true
+	}
+	defaultColor := false
+	if os.Getenv("TERM") == "xterm-256color" {
+		defaultColor = true
+	}
 	imgFlag := flag.String("image", "", "Image file to display in monochrome in the background instead of the default one")
+	colorFlag := flag.Bool("color", defaultColor,
+		"If your terminal supports color, this will load image in (216) colors instead of monochrome")
+	trueColorFlag := flag.Bool("truecolor", defaultTrueColor,
+		"If your terminal supports truecolor, this will load image in truecolor (24bits) instead of monochrome")
 	cli.MinArgs = 0
 	cli.MaxArgs = 1
 	cli.ArgsHelp = "[maxfps]"
@@ -109,6 +124,8 @@ func Main() int {
 	if err := ap.Open(); err != nil {
 		log.Fatalf("Not a terminal: %v", err)
 	}
+	ap.TrueColor = *trueColorFlag
+	ap.Color = *colorFlag
 	defer func() {
 		ap.ShowCursor()
 		ap.MoveCursor(0, ap.H-2)
@@ -122,7 +139,11 @@ func Main() int {
 	var background *image.RGBA
 	var err error
 	if *imgFlag == "" {
-		background, err = ap.DecodeImage(bytes.NewReader(fpsJpg))
+		if *trueColorFlag || *colorFlag {
+			background, err = ap.DecodeImage(bytes.NewReader(fpsColorsJpg))
+		} else {
+			background, err = ap.DecodeImage(bytes.NewReader(fpsJpg))
+		}
 	} else {
 		background, err = ap.ReadImage(*imgFlag)
 	}

ansipixels/image.go

@@ -1,6 +1,7 @@
 package ansipixels
 
 import (
+	"fmt"
 	"image"
 	"image/color"
 	_ "image/gif"  // Import GIF decoder
@@ -10,6 +11,7 @@ import (
 	"os"
 
 	"fortio.org/log"
+	"fortio.org/safecast"
 	"golang.org/x/image/draw"
 )
 
@@ -25,13 +27,113 @@ const (
 	BottomHalfPixel = '▄'
 )
 
-func (ap *AnsiPixels) DrawImage(sx, sy int, img *image.Gray, color string) error {
+func (ap *AnsiPixels) DrawTrueColorImage(sx, sy int, img *image.RGBA) error {
+	ap.MoveCursor(sx, sy)
+	var err error
+	for y := img.Bounds().Min.Y; y < img.Bounds().Max.Y; y += 2 {
+		prev1 := color.RGBA{}
+		prev2 := color.RGBA{}
+		ap.WriteAt(sx, sy, "\033[38;5;%dm\033[48;5;%dm", 0, 0)
+		for x := img.Bounds().Min.X; x < img.Bounds().Max.X; x++ {
+			pixel1 := img.RGBAAt(x, y)
+			pixel2 := img.RGBAAt(x, y+1)
+			switch {
+			case pixel1 == pixel2:
+				if pixel1 == prev1 {
+					_, _ = ap.Out.WriteRune('█')
+					continue // we haven't changed color
+				}
+				if pixel2 == prev2 {
+					_, _ = ap.Out.WriteRune(' ')
+					continue // we haven't changed color
+				}
+				_, _ = ap.Out.WriteString(fmt.Sprintf("\033[38;2;%d;%d;%dm█", pixel1.R, pixel1.G, pixel1.B))
+				prev1 = pixel1
+				continue
+			case pixel1 == prev1 && pixel2 == prev2:
+				_, _ = ap.Out.WriteRune('▀')
+			default:
+				_, _ = ap.Out.WriteString(fmt.Sprintf("\033[38;2;%d;%d;%dm\033[48;2;%d;%d;%dm▀",
+					pixel1.R, pixel1.G, pixel1.B,
+					pixel2.R, pixel2.G, pixel2.B))
+			}
+			prev1 = pixel1
+			prev2 = pixel2
+		}
+		sy++
+		ap.MoveCursor(sx, sy)
+	}
+	_, err = ap.Out.WriteString("\033[0m") // reset color
+	return err
+}
+
+func convertColorTo216(pixel color.RGBA) uint8 {
+	// Check if grayscale
+	shift := 2
+	if (pixel.R>>shift) == (pixel.G>>shift) && (pixel.G>>shift) == (pixel.B>>shift) {
+		// Bugged:
+		// lum := safecast.MustConvert[uint8](max(255, math.Round(0.299*float64(pixel.R)+
+		// 0.587*float64(pixel.G)+0.114*float64(pixel.B))))
+		lum := (uint16(pixel.R) + uint16(pixel.G) + uint16(pixel.B)) / 3
+		return 232 + safecast.MustConvert[uint8](lum*23/255)
+	}
+	// 6x6x6 color cube
+	col := 16 + 36*(pixel.R/51) + 6*(pixel.G/51) + pixel.B/51
+	return col
+}
+
+func (ap *AnsiPixels) Draw216ColorImage(sx, sy int, img *image.RGBA) error {
+	var err error
+	for y := img.Bounds().Min.Y; y < img.Bounds().Max.Y; y += 2 {
+		prevFg := uint8(0)
+		prevBg := uint8(0)
+		ap.WriteAt(sx, sy, "\033[38;5;%dm\033[48;5;%dm", 0, 0)
+		for x := img.Bounds().Min.X; x < img.Bounds().Max.X; x++ {
+			pixel1 := img.RGBAAt(x, y)
+			pixel2 := img.RGBAAt(x, y+1)
+			fgColor := convertColorTo216(pixel1)
+			bgColor := convertColorTo216(pixel2)
+			switch {
+			case fgColor == prevFg && bgColor == prevBg:
+				_, _ = ap.Out.WriteRune('▄')
+				/*
+					case fgColor == bgColor:
+						if fgColor == prevFg {
+							_, _ = ap.Out.WriteRune('█')
+							continue // we haven't changed bg color
+						}
+						if bgColor == prevBg {
+							_, _ = ap.Out.WriteRune(' ')
+							continue // we haven't changed fg color
+						}
+						_, _ = ap.Out.WriteString(fmt.Sprintf("\033[38;5;%dm█", fgColor))
+						prevFg = fgColor
+						continue
+							case fgColor == prevFg:
+								_, _ = ap.Out.WriteString(fmt.Sprintf("\033[48;5;%dm▄", bgColor))
+							case bgColor == prevBg:
+								_, _ = ap.Out.WriteString(fmt.Sprintf("\033[38;5;%dm▄", fgColor))
+				*/
+			default:
+				// Apple's macOS terminal needs lower half pixel or there are gaps where the background shows.
+				_, _ = ap.Out.WriteString(fmt.Sprintf("\033[38;5;%dm\033[48;5;%dm▄", bgColor, fgColor))
+			}
+			prevFg = fgColor
+			prevBg = bgColor
+		}
+		sy++
+	}
+	_, err = ap.Out.WriteString("\033[0m") // reset color
+	return err
+}
+
+func (ap *AnsiPixels) DrawMonoImage(sx, sy int, img *image.Gray, color string) error {
 	ap.WriteAtStr(sx, sy, color)
 	var err error
 	for y := img.Bounds().Min.Y; y < img.Bounds().Max.Y; y += 2 {
 		for x := img.Bounds().Min.X; x < img.Bounds().Max.X; x++ {
-			pixel1 := img.GrayAt(x, y).Y > 127
-			pixel2 := img.GrayAt(x, y+1).Y > 127
+			pixel1 := img.GrayAt(x, y).Y > 90
+			pixel2 := img.GrayAt(x, y+1).Y > 90
 			switch {
 			case pixel1 && pixel2:
 				_, _ = ap.Out.WriteRune(FullPixel)
@@ -67,7 +169,7 @@ func grayScaleImage(rgbaImg *image.RGBA) *image.Gray {
 	return grayImg
 }
 
-func resizeAndCenter(img *image.Gray, maxW, maxH int) *image.Gray {
+func resizeAndCenter(img *image.RGBA, maxW, maxH int) *image.RGBA {
 	// Get original image dimensions
 	origBounds := img.Bounds()
 	origW := origBounds.Dx()
@@ -82,14 +184,14 @@ func resizeAndCenter(img *image.Gray, maxW, maxH int) *image.Gray {
 	newW := int(float64(origW) * scale)
 	newH := int(float64(origH) * scale)
 
-	canvas := image.NewGray(image.Rect(0, 0, maxW, maxH)) // transparent background (aka black for ANSI)
+	canvas := image.NewRGBA(image.Rect(0, 0, maxW, maxH))
 
 	// Calculate the offset to center the image
 	offsetX := (maxW - newW) / 2
 	offsetY := (maxH - newH) / 2
 
 	// Resize the image
-	resized := image.NewGray(image.Rect(0, 0, newW, newH))
+	resized := image.NewRGBA(image.Rect(0, 0, newW, newH))
 	draw.CatmullRom.Scale(resized, resized.Bounds(), img, origBounds, draw.Over, nil)
 	draw.Draw(canvas, image.Rect(offsetX, offsetY, offsetX+newW, offsetY+newH), resized, image.Point{}, draw.Over)
 	return canvas
@@ -124,10 +226,18 @@ func (ap *AnsiPixels) DecodeImage(data io.Reader) (*image.RGBA, error) {
 	return convertToRGBA(img), nil
 }
 
+// Color string is the fallback mono color to use when AnsiPixels.TrueColor is false.
 func (ap *AnsiPixels) ShowImage(imgRGBA *image.RGBA, colorString string) error {
 	err := ap.GetSize()
 	if err != nil {
 		return err
 	}
-	return ap.DrawImage(1, 1, resizeAndCenter(grayScaleImage(imgRGBA), ap.W-2, 2*ap.H-2), colorString)
+	switch {
+	case ap.TrueColor:
+		return ap.DrawTrueColorImage(1, 1, resizeAndCenter(imgRGBA, ap.W-2, 2*ap.H-2))
+	case ap.Color:
+		return ap.Draw216ColorImage(1, 1, resizeAndCenter(imgRGBA, ap.W-2, 2*ap.H-2))
+	default:
+		return ap.DrawMonoImage(1, 1, grayScaleImage(resizeAndCenter(imgRGBA, ap.W-2, 2*ap.H-2)), colorString)
+	}
 }