1 files changed, 254 insertions, 0 deletions
diff --git a/internal/stylegrid/stylegrid.go b/internal/stylegrid/stylegrid.go
new file mode 100644
index 0000000..5aeb5f0
--- /dev/null
+++ b/internal/stylegrid/stylegrid.go
@@ -0,0 +1,254 @@
+// Package stylegrid builds a single montage image comparing all configured art styles and story themes.
+package stylegrid
+
+import (
+	"context"
+	"fmt"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"sort"
+	"strings"
+
+	"codeberg.org/snonux/comicforge/internal/config"
+	"codeberg.org/snonux/comicforge/internal/image"
+	"codeberg.org/snonux/comicforge/internal/provider"
+)
+
+// DefaultScene is the shared composition so style differences stay comparable.
+const DefaultScene = "A lone traveler with a backpack pauses on a rocky hill at golden sunset, wind moving their coat; a distant ruined stone tower on the horizon; wide scenic shot, clear silhouette, atmospheric sky."
+
+// Job is one cell in the reference grid.
+type Job struct {
+	Kind   string // "style" or "theme"
+	Header string // shown in the header bar above the image
+	Prompt string // full image generation prompt
+}
+
+// BuildJobs expands config style pools and story genres into generation jobs.
+func BuildJobs(cfg *config.Config, scene string) []Job {
+	if cfg == nil {
+		return nil
+	}
+	scene = strings.TrimSpace(scene)
+	if scene == "" {
+		scene = DefaultScene
+	}
+	base := "Single full-frame illustration only. No text, lettering, captions, logos, or watermarks inside the artwork. No borders inside the image. 16:9 composition.\n\nScene (keep this layout consistent for comparison):\n" + scene + "\n\n"
+
+	families := []struct {
+		title string
+		lines []string
+	}{
+		{"Comic", cfg.Styles.Comic},
+		{"Realistic", cfg.Styles.Realistic},
+		{"Cartoon", cfg.Styles.Cartoon},
+		{"Action 90s", cfg.Styles.Action90s},
+		{"Manga", cfg.Styles.Manga},
+		{"Horror", cfg.Styles.Horror},
+		{"Watercolor", cfg.Styles.Watercolor},
+		{"Pulp", cfg.Styles.Pulp},
+		{"Mecha", cfg.Styles.Mecha},
+		{"Pixel Art", cfg.Styles.PixelArt},
+		{"Ink Wash", cfg.Styles.InkWash},
+		{"Clay", cfg.Styles.Clay},
+	}
+
+	var jobs []Job
+	for _, fam := range families {
+		for i, line := range fam.lines {
+			line = strings.TrimSpace(line)
+			if line == "" {
+				continue
+			}
+			header := fmt.Sprintf("Style · %s (%d/%d)", fam.title, i+1, len(fam.lines))
+			prompt := base + "Rendering — apply this visual style precisely:\n" + line
+			jobs = append(jobs, Job{Kind: "style", Header: header, Prompt: prompt})
+		}
+	}
+
+	for i, g := range cfg.Story.Genres {
+		g = strings.TrimSpace(g)
+		if g == "" {
+			continue
+		}
+		header := fmt.Sprintf("Theme / genre (%d/%d): %s", i+1, len(cfg.Story.Genres), truncateRunes(g, 72))
+		prompt := base + "Rendering — interpret the same scene with mood, palette, and staging strongly guided by this story genre (illustrated comic or graphic-novel finish, readable shapes):\n" + g
+		jobs = append(jobs, Job{Kind: "theme", Header: header, Prompt: prompt})
+	}
+	return jobs
+}
+
+func truncateRunes(s string, max int) string {
+	r := []rune(s)
+	if len(r) <= max {
+		return s
+	}
+	return string(r[:max-1]) + "…"
+}
+
+// MontageOptions tunes the output sheet.
+type MontageOptions struct {
+	CellW   int
+	CellH   int
+	HeaderH int
+	TileX   int
+	Gutter  int
+	BG      string
+}
+
+func defaultMontageOptions(nCells int) MontageOptions {
+	// ~5 columns for the default grid (~27 cells).
+	tileX := 5
+	if nCells <= 4 {
+		tileX = 2
+	}
+	return MontageOptions{
+		CellW:   640,
+		CellH:   360,
+		HeaderH: 56,
+		TileX:   tileX,
+		Gutter:  6,
+		BG:      "#1a1a1a",
+	}
+}
+
+// GenerateMontage renders each job with img, labels tiles, and runs ImageMagick montage.
+func GenerateMontage(ctx context.Context, img provider.ImageProvider, aspectRatio string, jobs []Job, outPath string, opts MontageOptions) error {
+	if len(jobs) == 0 {
+		return fmt.Errorf("no style/theme jobs (empty config lists?)")
+	}
+	if _, err := exec.LookPath("convert"); err != nil {
+		return fmt.Errorf("ImageMagick convert not found: %w", err)
+	}
+	if _, err := exec.LookPath("montage"); err != nil {
+		return fmt.Errorf("ImageMagick montage not found: %w", err)
+	}
+	arImg, ok := img.(provider.AspectRatioImageProvider)
+	if !ok {
+		return fmt.Errorf("image provider %q does not support aspect ratio", img.Name())
+	}
+	if err := img.IsAvailable(); err != nil {
+		return err
+	}
+
+	tmpDir, err := os.MkdirTemp("", "comicforge-stylegrid-*")
+	if err != nil {
+		return err
+	}
+	defer func() { _ = os.RemoveAll(tmpDir) }()
+
+	for i := range jobs {
+		raw := filepath.Join(tmpDir, fmt.Sprintf("raw_%03d.png", i))
+		if err := arImg.GenerateImageWithAspectRatio(ctx, jobs[i].Prompt, raw, aspectRatio); err != nil {
+			return fmt.Errorf("job %d (%s): %w", i, jobs[i].Header, err)
+		}
+		norm := filepath.Join(tmpDir, fmt.Sprintf("norm_%03d.png", i))
+		if err := normalizeCell(raw, norm, opts.CellW, opts.CellH); err != nil {
+			return fmt.Errorf("normalize %d: %w", i, err)
+		}
+		lblPath := filepath.Join(tmpDir, fmt.Sprintf("caption_%03d.txt", i))
+		if err := os.WriteFile(lblPath, []byte(jobs[i].Header), 0o644); err != nil {
+			return err
+		}
+		labeled := filepath.Join(tmpDir, fmt.Sprintf("labeled_%03d.png", i))
+		if err := addCaptionHeader(norm, labeled, lblPath, opts.CellW, opts.HeaderH); err != nil {
+			return fmt.Errorf("header %d: %w", i, err)
+		}
+	}
+
+	labeledPaths, err := filepath.Glob(filepath.Join(tmpDir, "labeled_*.png"))
+	if err != nil {
+		return err
+	}
+	sort.Strings(labeledPaths)
+
+	args := []string{}
+	for _, p := range labeledPaths {
+		args = append(args, p)
+	}
+	args = append(args,
+		"-tile", fmt.Sprintf("%dx", opts.TileX),
+		"-geometry", fmt.Sprintf("+%d+%d", opts.Gutter, opts.Gutter),
+		"-background", opts.BG,
+		outPath,
+	)
+	cmd := exec.CommandContext(ctx, "montage", args...)
+	out, err := cmd.CombinedOutput()
+	if err != nil {
+		return fmt.Errorf("montage: %w\n%s", err, strings.TrimSpace(string(out)))
+	}
+	return nil
+}
+
+func normalizeCell(src, dst string, w, h int) error {
+	// Cover crop to exact WxH.
+	args := []string{
+		src,
+		"-resize", fmt.Sprintf("%dx%d^", w, h),
+		"-gravity", "center",
+		"-extent", fmt.Sprintf("%dx%d", w, h),
+		dst,
+	}
+	cmd := exec.Command("convert", args...)
+	out, err := cmd.CombinedOutput()
+	if err != nil {
+		return fmt.Errorf("convert resize: %w\n%s", err, strings.TrimSpace(string(out)))
+	}
+	return nil
+}
+
+func addCaptionHeader(imagePath, outPath, captionFile string, cellW, headerH int) error {
+	// caption:@file wraps text; header bar above the art.
+	args := []string{
+		"(",
+		"-background", "#252525",
+		"-fill", "#f2f2f2",
+		"-size", fmt.Sprintf("%dx%d", cellW-20, headerH-8),
+		"caption:@" + captionFile,
+		")",
+		imagePath,
+		"-append",
+		outPath,
+	}
+	cmd := exec.Command("convert", args...)
+	out, err := cmd.CombinedOutput()
+	if err != nil {
+		return fmt.Errorf("convert caption: %w\n%s", err, strings.TrimSpace(string(out)))
+	}
+	return nil
+}
+
+// Run loads config from path, builds jobs, and writes outPath.
+func Run(ctx context.Context, configPath, outPath, scene, aspectRatio string) error {
+	cfg, err := config.Load(configPath)
+	if err != nil {
+		return err
+	}
+	jobs := BuildJobs(cfg, scene)
+	opts := defaultMontageOptions(len(jobs))
+
+	img, err := buildImageProvider(cfg)
+	if err != nil {
+		return err
+	}
+	if strings.TrimSpace(aspectRatio) == "" {
+		aspectRatio = cfg.Comic.AspectRatio
+	}
+	if strings.TrimSpace(aspectRatio) == "" {
+		aspectRatio = "16:9"
+	}
+	return GenerateMontage(ctx, img, aspectRatio, jobs, outPath, opts)
+}
+
+func buildImageProvider(cfg *config.Config) (provider.ImageProvider, error) {
+	p, err := image.DefaultRegistry().NewFromConfig(cfg)
+	if err != nil {
+		return nil, err
+	}
+	ip, ok := p.(provider.ImageProvider)
+	if !ok {
+		return nil, fmt.Errorf("image provider %q does not satisfy ImageProvider", cfg.Provider.Image)
+	}
+	return ip, nil
+}