Add GIF file format.

README.md

@@ -28,6 +28,7 @@ Format        | Read          | Write         |
 PNG           | ✅           | ✅            |
 JPEG          | ✅           |               |
 BMP           | ✅           | ✅            |
+GIF           | ✅           |               |
 SVG           | ✅           |               |
 
 ### Joins and caps

src/pixie.nim

@@ -1,12 +1,12 @@
 import bumpy, chroma, flatty/binny, os, pixie/blends, pixie/common,
-    pixie/fileformats/bmp, pixie/fileformats/jpg, pixie/fileformats/png,
+    pixie/fileformats/bmp, pixie/fileformats/gif, pixie/fileformats/jpg, pixie/fileformats/png,
     pixie/fileformats/svg, pixie/images, pixie/masks, pixie/paints, pixie/paths, vmath
 
 export blends, bumpy, chroma, common, images, masks, paints, paths, vmath
 
 type
   FileFormat* = enum
-    ffPng, ffBmp, ffJpg
+    ffPng, ffBmp, ffJpg, ffGif
 
 proc decodeImage*(data: string | seq[uint8]): Image =
   ## Loads an image from a memory.
@@ -19,6 +19,8 @@ proc decodeImage*(data: string | seq[uint8]): Image =
   elif data.len > 5 and
     (data.readStr(0, 5) == xmlSignature or data.readStr(0, 4) == svgSignature):
     decodeSvg(data)
+  elif data.len > 6 and data.readStr(0, 6) in gifSignatures:
+    decodeGif(data)
   else:
     raise newException(PixieError, "Unsupported image file format")
 
@@ -35,6 +37,8 @@ proc encodeImage*(image: Image, fileFormat: FileFormat): string =
     image.encodeJpg()
   of ffBmp:
     image.encodeBmp()
+  of ffGif:
+    raise newException(PixieError, "Unsupported image format")
 
 proc writeFile*(image: Image, filePath: string, fileFormat: FileFormat) =
   ## Writes an image to a file.

tests/test_gif.nim

@@ -1,4 +1,4 @@
-import pixie/fileformats/gif, pixie/fileformats/png
+import pixie/fileformats/gif, pixie/fileformats/png, pixie
 
 var img = decodeGIF(readFile("tests/images/gif/3x5.gif"))
 writeFile("tests/images/gif/3x5.png", img.encodePng())
@@ -8,3 +8,6 @@ writeFile("tests/images/gif/audrey.png", img2.encodePng())
 
 var img3 = decodeGIF(readFile("tests/images/gif/sunflower.gif"))
 writeFile("tests/images/gif/sunflower.png", img3.encodePng())
+
+var img4 = readImage("tests/images/gif/sunflower.gif")
+doAssert img3.data == img4.data