From 9fc5a5f4ce6f276aa823adf293ad00801823e3b6 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=BAlio=20C=C3=A9sar=20Batista?= <julio@terrastruct.com>
Date: Thu, 13 Apr 2023 18:50:39 -0300
Subject: [PATCH] wip gif export

---
 d2cli/export.go      | 22 +++++++++++++++-------
 d2cli/export_test.go |  2 +-
 d2cli/main.go        | 27 +++++++++++++++++++--------
 3 files changed, 35 insertions(+), 16 deletions(-)

diff --git a/d2cli/export.go b/d2cli/export.go
index 8cd2f1601..a1e84db6f 100644
--- a/d2cli/export.go
+++ b/d2cli/export.go
@@ -1,10 +1,18 @@
 package d2cli
 
-import "path/filepath"
+import (
+	"path/filepath"
+)
 
 type exportExtension string
 
-var KNOWN_EXTENSIONS = []string{".svg", ".png", ".pptx", ".pdf"}
+const GIF = ".gif"
+const PNG = ".png"
+const PPTX = ".pptx"
+const PDF = ".pdf"
+const SVG = ".svg"
+
+var KNOWN_EXTENSIONS = []string{SVG, PNG, PDF, PPTX, GIF}
 
 func getExportExtension(outputPath string) exportExtension {
 	ext := filepath.Ext(outputPath)
@@ -14,17 +22,17 @@ func getExportExtension(outputPath string) exportExtension {
 		}
 	}
 	// default is svg
-	return exportExtension(".svg")
+	return exportExtension(SVG)
 }
 
 func (ex exportExtension) supportsAnimation() bool {
-	return ex == ".svg"
+	return ex == SVG || ex == GIF
 }
 
-func (ex exportExtension) requiresPngRenderer() bool {
-	return ex == ".png" || ex == ".pdf" || ex == ".pptx"
+func (ex exportExtension) requiresPNGRenderer() bool {
+	return ex == PNG || ex == PDF || ex == PPTX || ex == GIF
 }
 
 func (ex exportExtension) supportsDarkTheme() bool {
-	return ex == ".svg"
+	return ex == SVG
 }
diff --git a/d2cli/export_test.go b/d2cli/export_test.go
index 8518b1850..c3c6e0434 100644
--- a/d2cli/export_test.go
+++ b/d2cli/export_test.go
@@ -67,7 +67,7 @@ func TestOutputFormat(t *testing.T) {
 			assert.Equal(t, tc.extension, extension)
 			assert.Equal(t, tc.supportsAnimation, extension.supportsAnimation())
 			assert.Equal(t, tc.supportsDarkTheme, extension.supportsDarkTheme())
-			assert.Equal(t, tc.requiresPngRender, extension.requiresPngRenderer())
+			assert.Equal(t, tc.requiresPngRender, extension.requiresPNGRenderer())
 		})
 	}
 }
diff --git a/d2cli/main.go b/d2cli/main.go
index 1ceaf7371..f0c5e7ea0 100644
--- a/d2cli/main.go
+++ b/d2cli/main.go
@@ -38,6 +38,7 @@ import (
 	"oss.terrastruct.com/d2/lib/pptx"
 	"oss.terrastruct.com/d2/lib/textmeasure"
 	"oss.terrastruct.com/d2/lib/version"
+	"oss.terrastruct.com/d2/lib/xgif"
 
 	"cdr.dev/slog"
 	"cdr.dev/slog/sloggers/sloghuman"
@@ -190,9 +191,10 @@ func Run(ctx context.Context, ms *xmain.State) (err error) {
 	if outputPath != "-" {
 		outputPath = ms.AbsPath(outputPath)
 		if *animateIntervalFlag > 0 && !outputFormat.supportsAnimation() {
-			return xmain.UsageErrorf("-animate-interval can only be used when exporting to SVG.\nYou provided: %s", filepath.Ext(outputPath))
+			return xmain.UsageErrorf("-animate-interval can only be used when exporting to SVG or GIF.\nYou provided: %s", filepath.Ext(outputPath))
+		} else if *animateIntervalFlag <= 0 && outputFormat == GIF {
+			return xmain.UsageErrorf("-animate-interval must be greater than 0 for GIF outputs.\nYou provided: %d", *animateIntervalFlag)
 		}
-
 	}
 
 	match := d2themescatalog.Find(*themeFlag)
@@ -242,7 +244,7 @@ func Run(ctx context.Context, ms *xmain.State) (err error) {
 		}
 	}
 	var pw png.Playwright
-	if outputFormat.requiresPngRenderer() {
+	if outputFormat.requiresPNGRenderer() {
 		pw, err = png.InitPlaywright()
 		if err != nil {
 			return err
@@ -351,8 +353,9 @@ func compile(ctx context.Context, ms *xmain.State, plugin d2plugin.Plugin, rende
 		return nil, false, err
 	}
 
-	switch filepath.Ext(outputPath) {
-	case ".pdf":
+	ext := getExportExtension(outputPath)
+	switch ext {
+	case PDF:
 		pageMap := buildBoardIDToIndex(diagram, nil, nil)
 		pdf, err := renderPDF(ctx, ms, plugin, renderOpts, outputPath, page, ruler, diagram, nil, nil, pageMap)
 		if err != nil {
@@ -361,7 +364,7 @@ func compile(ctx context.Context, ms *xmain.State, plugin d2plugin.Plugin, rende
 		dur := time.Since(start)
 		ms.Log.Success.Printf("successfully compiled %s to %s in %s", ms.HumanPath(inputPath), ms.HumanPath(outputPath), dur)
 		return pdf, true, nil
-	case ".pptx":
+	case PPTX:
 		var username string
 		if user, err := user.Current(); err == nil {
 			username = user.Username
@@ -398,11 +401,19 @@ func compile(ctx context.Context, ms *xmain.State, plugin d2plugin.Plugin, rende
 		if err != nil {
 			return nil, false, err
 		}
+		// TODO: test GIF with 1 frame
 		var out []byte
 		if len(boards) > 0 {
 			out = boards[0]
 			if animateInterval > 0 {
-				out, err = d2animate.Wrap(diagram, boards, renderOpts, int(animateInterval))
+				if ext == GIF {
+					tl, br := diagram.NestedBoundingBox()
+					width := png.SCALE*(br.X-tl.X) + renderOpts.Pad*2
+					height := png.SCALE*(br.Y-tl.Y) + renderOpts.Pad*2
+					out, err = xgif.AnimatePNGs(boards, width, height, int(animateInterval))
+				} else {
+					out, err = d2animate.Wrap(diagram, boards, renderOpts, int(animateInterval))
+				}
 				if err != nil {
 					return nil, false, err
 				}
@@ -599,7 +610,7 @@ func render(ctx context.Context, ms *xmain.State, compileDur time.Duration, plug
 }
 
 func _render(ctx context.Context, ms *xmain.State, plugin d2plugin.Plugin, opts d2svg.RenderOpts, outputPath string, bundle, forceAppendix bool, page playwright.Page, ruler *textmeasure.Ruler, diagram *d2target.Diagram) ([]byte, error) {
-	toPNG := filepath.Ext(outputPath) == ".png"
+	toPNG := getExportExtension(outputPath).requiresPNGRenderer()
 	svg, err := d2svg.Render(diagram, &d2svg.RenderOpts{
 		Pad:           opts.Pad,
 		Sketch:        opts.Sketch,