Fix up merged PRs: GIF export goes through main's export path

The Export dialog's GIF choice runs through SlideApp::export_as (desktop and web download),
.gif is a writable output extension for convert/run, and the CLI help pages describe GIF output
and --export-params. A file.export `slides` range string ("1-3,5") works for GIF as for PDF.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

apps/deckcraft-cli/src/help.rs

@@ -50,19 +50,22 @@ OUT-t0.250.png and so on. Prints each image's path, size, transition and time.
         usage: "convert IN OUT",
         summary: "save a presentation in the format OUT's extension names",
         details: "Opens IN (.deckcraft or .pptx) and writes it to OUT, in the format OUT's extension names:
-.deckcraft, .pptx, .pdf, .txt or .md for the outline, .png or .jpg for the first slide. Any other
-extension is written as .deckcraft. Prints OUT.
+.deckcraft, .pptx, .pdf, .txt or .md for the outline, .png or .jpg for the first slide, .gif for an
+animated GIF with one frame per slide. Other extensions are refused. Prints OUT.
 
   deckcraft-cli convert deck.deckcraft deck.pptx",
     },
     Subcommand {
         name: "run",
-        usage: "run [--in FILE | --sample] [--cmd COMMAND[=PARAMS]]... [--save OUT] [--export OUT] [--print]",
+        usage: "run [--in FILE | --sample] [--cmd COMMAND[=PARAMS]]... [--save OUT] [--export OUT [--export-params JSON]] [--print]",
         summary: "run commands on a presentation, then save or export it",
         details: "Runs commands, in order, on one presentation: FILE with --in, the sample presentation with --sample,
 else a new one with an empty title slide. Then --save writes the presentation: .deckcraft keeps
 everything; .pptx, .pdf and .md (the outline) are written as convert writes them. --export writes the
-current slide as .png or .jpg, or the presentation as .pdf or .pptx.
+current slide as .png or .jpg, or the presentation as .pdf, .pptx or an animated .gif (one frame per
+slide). --export-params passes file.export options as one JSON object, such as
+'{\"width\": \"large\", \"secondsPerSlide\": 3, \"loop\": false, \"slides\": [0, 1, 2]}' for a GIF
+(`deckcraft-cli describe file.export` lists them).
 
 Each --cmd is one command: COMMAND is a command id, then `=`, then the command's parameters as one
 JSON object. Quote it for the shell. A command that needs no parameters is just its id.

apps/deckcraft-cli/tests/convert.rs

@@ -21,7 +21,7 @@ fn convert_rejects_output_formats_it_cannot_write() {
     let out = Command::new(env!("CARGO_BIN_EXE_deckcraft-cli")).args(["run", "--sample", "--export"]).arg(&input).output().unwrap();
     assert!(out.status.success(), "{}", String::from_utf8_lossy(&out.stderr));
 
-    for name in ["out.odp", "out.gif", "out.svg", "out.outline", "out"] {
+    for name in ["out.odp", "out.bmp", "out.svg", "out.outline", "out"] {
         let target = dir.join(name);
         let out = cli(&[Path::new("convert"), &input, &target]);
         assert!(!out.status.success(), "{name}: convert should fail");

crates/engine/src/tests.rs

@@ -237,7 +237,8 @@ fn writable_format_for_path_rejects_formats_deckcraft_does_not_write() {
     assert_eq!(f("a.pdf"), Some("pdf"));
     assert_eq!(f("a.jpg"), Some("jpeg"));
     assert_eq!(f("a.txt"), Some("outline"));
-    for path in ["a.odp", "a.gif", "a.svg", "a.outline", "a", "dir.v2/a"] {
+    assert_eq!(f("a.gif"), Some("gif"));
+    for path in ["a.odp", "a.bmp", "a.svg", "a.outline", "a", "dir.v2/a"] {
         assert_eq!(f(path), None, "{path}");
     }
 }

crates/ui-egui/src/lib.rs

@@ -506,6 +506,7 @@ impl SlideApp {
             "pptx" => ("pptx", "pptx", false),
             "outline" | "txt" => ("txt", "outline", false),
             "deckcraft" => ("deckcraft", "deckcraft", false),
+            "gif" => ("gif", "gif", false),
             other => {
                 self.set_status(format!("DeckCraft can't export “{other}”"));
                 return false;
@@ -535,6 +536,7 @@ impl SlideApp {
                 Ok(if format == "png" { img.to_png_at(dpi) } else { img.to_jpeg_at(92, Some(dpi)) })
             }
             "pdf" => deckcraft_engine::cmd::file::pdf_bytes(&doc, &extra),
+            "gif" => deckcraft_engine::cmd::file::gif_bytes(&doc, &extra),
             other => deckcraft_engine::cmd::file::save_bytes(&doc, other),
         };
         self.download(&suggested, bytes)