feat: Add sixel support

wallhaven/cli.go

@@ -5,6 +5,7 @@ import (
 	"os"
 	"os/exec"
 	"path/filepath"
+	"strconv"
 	"strings"
 
 	"github.com/spf13/cobra"
@@ -209,21 +210,22 @@ func Preview(cmd *cobra.Command, args []string) error {
 
 	text := args[0]
 
+	if strings.Contains(text, "-->") || strings.Contains(text, "<--") {
+		return nil
+	}
+
 	fzf_preview_lines := os.Getenv("FZF_PREVIEW_LINES")
 	fzf_preview_columns := os.Getenv("FZF_PREVIEW_COLUMNS")
-	_, exists := os.LookupEnv("KITTY_WINDOW_ID")
-
-	path, _ := exec.LookPath("chafa")
 
-	if strings.Contains(text, "-->") {
-		return nil
-	} else if strings.Contains(text, "<--") {
-		return nil
-	}
+	// Check for terminal capabilities
+	kittySupport := os.Getenv("KITTY_WINDOW_ID") != ""
+	sixelSupport := checkSixelSupport()
 
 	url := re.FindStringSubmatch(text)[1]
 
-	if exists {
+	// Priority: Kitty > Sixel > Chafa
+	switch {
+	case kittySupport:
 		command = exec.Command(
 			"kitty",
 			"icat",
@@ -235,15 +237,71 @@ func Preview(cmd *cobra.Command, args []string) error {
 			"--scale-up",
 			url,
 		)
-	} else if path != "" {
+
+	case sixelSupport:
+		// Download image for sixel conversion
 		err := DLSave(url, &config.TempFolder)
 		if err != nil {
 			return err
 		}
 
+		// Get terminal dimensions
+		width, height, err := getPreviewPaneDimensions()
+		if err != nil {
+			// Fallback to FZF environment variables if available
+			if fzfLines := os.Getenv("FZF_PREVIEW_LINES"); fzfLines != "" {
+				if fzfCols := os.Getenv("FZF_PREVIEW_COLUMNS"); fzfCols != "" {
+					width = fzfCols
+					height = fzfLines
+				}
+			} else {
+				// Last resort fallback
+				width = "80"
+				height = "24"
+			}
+		}
+
 		SplitUrl := strings.Split(url, "/")
 		FileName := SplitUrl[len(SplitUrl)-1]
+		file = filepath.Join(config.TempFolder, FileName)
+
+		// Convert terminal cells to pixels for sixel
+		pixelWidth, pixelHeight := cellsToPixels(width, height)
+
+		// Try img2sixel first (better quality)
+		if path, err := exec.LookPath("img2sixel"); err == nil {
+			command = exec.Command(
+				path,
+				"-w", pixelWidth,
+				file,
+			)
+		} else if path, err := exec.LookPath("magick"); err == nil {
+			// Fallback to ImageMagick convert
+			command = exec.Command(
+				path,
+				file,
+				"-resize", fmt.Sprintf("%sx%s>", pixelWidth, pixelHeight),
+				"-quality", "100",
+				"sixel:-",
+			)
+		} else {
+			return fmt.Errorf("sixel support detected but no converter found (install libsixel or imagemagick)")
+		}
+
+	default:
+		// Fallback to chafa
+		path, err := exec.LookPath("chafa")
+		if err != nil {
+			return fmt.Errorf("no supported image preview method found")
+		}
 
+		err = DLSave(url, &config.TempFolder)
+		if err != nil {
+			return err
+		}
+
+		SplitUrl := strings.Split(url, "/")
+		FileName := SplitUrl[len(SplitUrl)-1]
 		file = filepath.Join(config.TempFolder, FileName)
 
 		command = exec.Command(
@@ -252,20 +310,106 @@ func Preview(cmd *cobra.Command, args []string) error {
 			fmt.Sprintf("--size=%sx%s", fzf_preview_columns, fzf_preview_lines),
 			"--clear",
 		)
-	} else {
-		return fmt.Errorf("You either need chafa or the kitty terminal.")
 	}
 
 	command.Stdout = os.Stdout
 	command.Stderr = os.Stderr
 
 	if err := command.Run(); err != nil {
-		return fmt.Errorf("failed to execute command: %s", err)
+		return fmt.Errorf("failed to execute preview command: %s", err)
 	}
 
+	// Clean up temporary file if created
 	if file != "" {
 		return os.Remove(file)
 	}
 
 	return nil
 }
+
+// getPreviewPaneDimensions attempts to get the actual preview pane size
+func getPreviewPaneDimensions() (string, string, error) {
+	// Method 1: Try to get terminal size using stty
+	cmd := exec.Command("stty", "size")
+	cmd.Stdin = os.Stdin
+	output, err := cmd.Output()
+	if err == nil {
+		parts := strings.Fields(string(output))
+		if len(parts) == 2 {
+			// fzf preview typically uses ~40% of terminal width
+			// Adjust these percentages based on your fzf configuration
+			totalHeight, _ := strconv.Atoi(parts[0])
+			totalWidth, _ := strconv.Atoi(parts[1])
+
+			// Assuming default fzf preview layout
+			previewHeight := totalHeight - 3               // Account for fzf interface
+			previewWidth := int(float64(totalWidth) * 0.5) // Half screen by default
+
+			return strconv.Itoa(previewWidth), strconv.Itoa(previewHeight), nil
+		}
+	}
+
+	// Method 2: Use tput
+	widthCmd := exec.Command("tput", "cols")
+	heightCmd := exec.Command("tput", "lines")
+
+	widthOut, errW := widthCmd.Output()
+	heightOut, errH := heightCmd.Output()
+
+	if errW == nil && errH == nil {
+		width, _ := strconv.Atoi(strings.TrimSpace(string(widthOut)))
+		height, _ := strconv.Atoi(strings.TrimSpace(string(heightOut)))
+
+		// Adjust for fzf preview pane (customize based on your layout)
+		previewWidth := int(float64(width) * 0.5)
+		previewHeight := height - 3
+
+		return strconv.Itoa(previewWidth), strconv.Itoa(previewHeight), nil
+	}
+
+	return "", "", fmt.Errorf("could not determine terminal dimensions")
+}
+
+// cellsToPixels converts terminal cell dimensions to pixel dimensions
+func cellsToPixels(cellWidth, cellHeight string) (string, string) {
+	// Default cell dimensions (can be made configurable)
+	cellPixelWidth := 9   // Typical terminal cell width in pixels
+	cellPixelHeight := 18 // Typical terminal cell height in pixels
+
+	// Check for common terminal environment variables
+	if os.Getenv("TERM_PROGRAM") == "iTerm.app" {
+		cellPixelWidth = 8
+		cellPixelHeight = 16
+	}
+
+	width, _ := strconv.Atoi(cellWidth)
+	height, _ := strconv.Atoi(cellHeight)
+
+	pixelWidth := width * cellPixelWidth
+	pixelHeight := height * cellPixelHeight
+
+	// Apply some padding to ensure image fits well
+	pixelWidth = int(float64(pixelWidth) * 0.95)
+	pixelHeight = int(float64(pixelHeight) * 0.95)
+
+	return strconv.Itoa(pixelWidth), strconv.Itoa(pixelHeight)
+}
+
+// checkSixelSupport detects if the terminal supports sixel graphics
+func checkSixelSupport() bool {
+	// Check TERM environment variable for known sixel-capable terminals
+	term := os.Getenv("TERM")
+	sixelTerms := []string{"xterm-256color", "mlterm", "yaft-256color", "foot", "contour", "tmux-256color"}
+
+	for _, st := range sixelTerms {
+		if strings.Contains(term, st) {
+			return true
+		}
+	}
+
+	// Check for explicit sixel support environment variable
+	if os.Getenv("SIXEL_SUPPORT") == "1" {
+		return true
+	}
+	return false
+}