animation: Allow multiple input files

Userland/Utilities/animation.cpp

@@ -14,7 +14,7 @@
 #include <LibGfx/ImageFormats/WebPWriter.h>
 
 struct Options {
-    StringView in_path;
+    Vector<StringView> in_paths;
     StringView out_path;
     bool write_full_frames { false };
     Gfx::AnimationWriter::AllowInterFrameCompression allow_inter_frame_compression { Gfx::AnimationWriter::AllowInterFrameCompression::Yes };
@@ -24,7 +24,7 @@ static ErrorOr<Options> parse_options(Main::Arguments arguments)
 {
     Options options;
     Core::ArgsParser args_parser;
-    args_parser.add_positional_argument(options.in_path, "Path to input image file", "FILE");
+    args_parser.add_positional_argument(options.in_paths, "Paths to input image file", "FILE");
     args_parser.add_option(options.out_path, "Path to output image file", "output", 'o', "FILE");
 
     bool inter_frame_compression_full = false;
@@ -55,34 +55,56 @@ ErrorOr<int> serenity_main(Main::Arguments arguments)
 {
     Options options = TRY(parse_options(arguments));
 
-    // FIXME: Allow multiple single frames as input too, and allow manually setting their duration.
+    if (options.in_paths.is_empty())
+        return Error::from_string_literal("Need at least one input file");
 
-    auto file = TRY(Core::MappedFile::map(options.in_path));
-    auto decoder = TRY(Gfx::ImageDecoder::try_create_for_raw_bytes(file->bytes()));
-    if (!decoder)
-        return Error::from_string_literal("Could not find decoder for input file");
+    Vector<NonnullOwnPtr<Core::MappedFile>> files;
+    Vector<NonnullRefPtr<Gfx::ImageDecoder>> decoders;
+    for (auto in_path : options.in_paths) {
+        files.append(TRY(Core::MappedFile::map(in_path)));
+        auto decoder = TRY(Gfx::ImageDecoder::try_create_for_raw_bytes(files.last()->bytes()));
+        if (!decoder)
+            return Error::from_string_literal("Could not find decoder for input file");
+        decoders.append(decoder.release_nonnull());
+    }
+
+    VERIFY(!decoders.is_empty());
+    auto output_size = decoders[0]->size();
+    for (auto const& decoder : decoders) {
+        if (decoder->size() != output_size)
+            return Error::from_string_literal("All input images must have the same dimensions");
+    }
+
+    // FIXME: Make overridable?
+    auto output_loop_count = decoders[0]->loop_count();
 
     auto output_file = TRY(Core::File::open(options.out_path, Core::File::OpenMode::Write));
     auto output_stream = TRY(Core::OutputBufferedFile::create(move(output_file)));
 
     auto animation_writer = TRY([&]() -> ErrorOr<NonnullOwnPtr<Gfx::AnimationWriter>> {
         if (options.out_path.ends_with(".apng"sv))
-            return Gfx::PNGWriter::start_encoding_animation(*output_stream, decoder->size(), decoder->loop_count());
+            return Gfx::PNGWriter::start_encoding_animation(*output_stream, output_size, output_loop_count);
         if (options.out_path.ends_with(".webp"sv))
-            return Gfx::WebPWriter::start_encoding_animation(*output_stream, decoder->size(), decoder->loop_count());
+            return Gfx::WebPWriter::start_encoding_animation(*output_stream, output_size, output_loop_count);
         if (options.out_path.ends_with(".gif"sv))
-            return Gfx::GIFWriter::start_encoding_animation(*output_stream, decoder->size(), decoder->loop_count());
+            return Gfx::GIFWriter::start_encoding_animation(*output_stream, output_size, output_loop_count);
         return Error::from_string_literal("Unable to find a encoder for the requested extension.");
     }());
 
     RefPtr<Gfx::Bitmap> last_frame;
-    for (size_t i = 0; i < decoder->frame_count(); ++i) {
-        auto frame = TRY(decoder->frame(i));
-        if (options.write_full_frames) {
-            TRY(animation_writer->add_frame(*frame.image, frame.duration));
-        } else {
-            TRY(animation_writer->add_frame_relative_to_last_frame(*frame.image, frame.duration, last_frame, options.allow_inter_frame_compression));
-            last_frame = frame.image;
+    for (auto const& decoder : decoders) {
+        for (size_t i = 0; i < decoder->frame_count(); ++i) {
+            auto frame = TRY(decoder->frame(i));
+
+            // FIXME: Make overridable, at least for single-frame inputs?
+            auto frame_duration = frame.duration;
+
+            if (options.write_full_frames) {
+                TRY(animation_writer->add_frame(*frame.image, frame_duration));
+            } else {
+                TRY(animation_writer->add_frame_relative_to_last_frame(*frame.image, frame_duration, last_frame, options.allow_inter_frame_compression));
+                last_frame = frame.image;
+            }
         }
     }