add -d:useStb

src/pixie/fileformats/jpg.nim

@@ -1,17 +1,23 @@
-import pixie/images, pixie/common, pixie/fileformats/stb_image/stb_image
+import pixie/images, pixie/common
+
+when defined(useStb):
+  import pixie/fileformats/stb_image/stb_image
 
 const
   jpgStartOfImage* = [0xFF.uint8, 0xD8]
 
 proc decodeJpg*(data: seq[uint8]): Image =
   ## Decodes the JPEG into an Image.
-  var
+  when not defined(useStb):
-    width: int
+    raise newException(PixieError, "Decoding JPG requires -d:useStb")
-    height: int
+  else:
-  let pixels = loadFromMemory(data, width, height)
+    var
+      width: int
+      height: int
+    let pixels = loadFromMemory(data, width, height)
 
-  result = newImage(width, height)
+    result = newImage(width, height)
-  copyMem(result.data[0].addr, pixels[0].unsafeAddr, pixels.len)
+    copyMem(result.data[0].addr, pixels[0].unsafeAddr, pixels.len)
 
 proc decodeJpg*(data: string): Image {.inline.} =
   decodeJpg(cast[seq[uint8]](data))

tests/test_jpg.nim

@@ -1,5 +1,6 @@
-import pixie/fileformats/jpg
+when defined(useStb):
+  import pixie/fileformats/jpg
 
-let
+  let
-  original = readFile("tests/images/jpg/jpeg420exif.jpg")
+    original = readFile("tests/images/jpg/jpeg420exif.jpg")
-  stbDecoded = decodeJpg(original)
+    stbDecoded = decodeJpg(original)