example makes a gif

README.md

@@ -1,3 +1,3 @@
 **go-marvel** is a [Go](https://golang.org) client library for the [Marvel REST API](https://developer.marvel.com/)
 
-See [`example/main.go`](https://github.com/ImJasonH/go-marvel/blob/master/example/main.go), which downloads all issue covers of a series, by series ID (default is "Uncanny X-Men"), and begins to construct a GIF image of them. (TODO)
+See [`example/main.go`](https://github.com/ImJasonH/go-marvel/blob/master/example/main.go), which downloads all issue covers of a series, by series ID (default is "Uncanny X-Men"), and constructs a GIF image of them in reverse order.

example/main.go

@@ -1,6 +1,8 @@
 package main
 
 import (
+	"bufio"
+	"bytes"
 	"flag"
 	"fmt"
 	"image"
@@ -37,8 +39,10 @@ func main() {
 				fmt.Printf("error: %v", err)
 				return
 			}
-			imgs = append(imgs, img)
-			fmt.Printf("fetched %v - %s\n", *iss.IssueNumber, iss.Thumbnail.URL(marvel.PortraitIncredible))
+			if img != nil {
+				imgs = append(imgs, img)
+				fmt.Printf("fetched %v - %s\n", *iss.IssueNumber, iss.Thumbnail.URL(marvel.PortraitIncredible))
+			}
 		}
 		if len(r.Data.Results) < limit {
 			break
@@ -61,7 +65,15 @@ func fetchImage(url string) (image.Image, error) {
 	}
 	defer resp.Body.Close()
 
-	img, err := jpeg.Decode(resp.Body)
+	b := bufio.NewReaderSize(resp.Body, 1)
+	if _, err := b.Peek(1); err == bufio.ErrBufferFull {
+		return nil, nil
+	}
+
+	img, err := jpeg.Decode(b)
+	if err != nil {
+		return nil, nil
+	}
 	return img, err
 }
 
@@ -72,8 +84,23 @@ func writeGIF(filename string, imgs []image.Image) error {
 	}
 	defer f.Close()
 
-	pimgs := []*image.Paletted{}
-	// TODO: convert imgs into pimgs
+	g := gif.GIF{
+		Image: make([]*image.Paletted, len(imgs)),
+		Delay: make([]int, len(imgs)),
+	}
+	b := make([]byte, 0, 1024)
+	for i, img := range imgs {
+		buf := bytes.NewBuffer(b)
+		if err = gif.Encode(buf, img, &gif.Options{NumColors: 256}); err != nil {
+			return err
+		}
+		gimg, err := gif.DecodeAll(buf)
+		if err != nil {
+			return err
+		}
+		g.Delay[i] = 0
+		g.Image[i] = gimg.Image[0]
+	}
 
-	return gif.EncodeAll(f, &gif.GIF{Image:pimgs})
+	return gif.EncodeAll(f, &g)
 }