tiny.gif.animationFromBytes

1pub fn animationFromBytes(storage: *Storage, bytes: []const u8) Error!Animation {2    const regions = try storage.acquire(bytes);3    errdefer storage.reset();45    var reader = stream.Reader{ .bytes = bytes };6    const header = try stream.readHeader(&reader);7    var control = model.Control{};8    var loop_count: ?u16 = null;9    var frame_index: usize = 0;10    var trailer = false;1112    while (!trailer) {13        switch (try reader.byte()) {14            0x21 => {15                const label = try reader.byte();16                switch (label) {17                    0xf9 => control = try stream.readControl(&reader),18                    0xff => {19                        const size = try reader.byte();20                        const app = try reader.take(size);21                        if (size == 11 and (std.mem.eql(u8, app, "NETSCAPE2.0") or std.mem.eql(u8, app, "ANIMEXTS1.0"))) {22                            loop_count = try readLoopCount(&reader) orelse loop_count;23                        } else {24                            try stream.skipSubBlocks(&reader);25                        }26                    },27                    else => try stream.skipSubBlocks(&reader),28                }29            },30            0x2c => {31                if (frame_index >= regions.frames.len) return error.FrameCapacityExceeded;32                const snapshot = regions.retained_rgba8[frame_index * regions.canvas.len ..][0..regions.canvas.len];33                regions.frames[frame_index] = try decodeFrame(34                    &reader,35                    header,36                    control,37                    regions.canvas,38                    regions.previous_canvas,39                    regions.indices,40                    regions.compressed,41                    snapshot,42                );43                frame_index += 1;44                control = .{};45            },46            0x3b => trailer = true,47            else => return error.InvalidDescriptor,48        }49    }5051    if (frame_index == 0) return error.NoFrames;52    if (frame_index != regions.frames.len) return error.DecodeInputMismatch;53    return .{54        .width = header.width,55        .height = header.height,56        .frames = regions.frames[0..frame_index],57        .loop_count = loop_count,58    };59}

1pub const animationFromBytes = decode.animationFromBytes;