Merge pull request #46 from jangko/new_api

New API, fixes #36

apidoc.md

@@ -0,0 +1,61 @@
+## Legacy API
+
+```Nim
+proc encodePNG*(input: string, colorType: PNGColorType, bitDepth, w, h: int, settings = PNGEncoder(nil)): PNG
+proc encodePNG32*(input: string, w, h: int): PNG
+proc encodePNG24*(input: string, w, h: int): PNG
+
+when not defined(js):
+  proc savePNG*(fileName, input: string, colorType: PNGColorType, bitDepth, w, h: int): bool
+  proc savePNG32*(fileName, input: string, w, h: int): bool
+  proc savePNG24*(fileName, input: string, w, h: int): bool
+
+proc prepareAPNG*(colorType: PNGColorType, bitDepth, numPlays: int, settings = PNGEncoder(nil)): PNG
+proc prepareAPNG24*(numPlays = 0): PNG
+proc prepareAPNG32*(numPlays = 0): PNG
+proc addDefaultImage*(png: PNG, input: string, width, height: int, ctl = APNGFrameControl(nil)): bool
+proc addFrame*(png: PNG, frame: string, ctl: APNGFrameControl): bool
+proc encodeAPNG*(png: PNG): string
+
+when not defined(js):
+  proc saveAPNG*(png: PNG, fileName: string): bool
+
+proc decodePNG*(s: Stream, colorType: PNGColorType, bitDepth: int, settings = PNGDecoder(nil)): PNGResult
+proc decodePNG*(s: Stream, settings = PNGDecoder(nil)): PNG
+
+when not defined(js):
+  proc loadPNG*(fileName: string, colorType: PNGColorType, bitDepth: int, settings: PNGDecoder = nil): PNGResult
+  proc loadPNG32*(fileName: string, settings = PNGDecoder(nil)): PNGResult
+  proc loadPNG24*(fileName: string, settings = PNGDecoder(nil)): PNGResult
+
+proc decodePNG32*(input: string, settings = PNGDecoder(nil)): PNGResult
+proc decodePNG24*(input: string, settings = PNGDecoder(nil)): PNGResult
+```
+
+
+## New API
+
+
+```Nim
+proc decodePNG*(T: type, s: Stream, colorType: PNGColorType, bitDepth: int, settings = PNGDecoder(nil)): PNGResult[T]
+proc decodePNG*(T: type, s: Stream, settings = PNGDecoder(nil)): PNG
+
+type
+  PNGRes*[T] = Result[PNGResult[T], string]
+
+when not defined(js):
+  proc loadPNG*(T: type, fileName: string, colorType: PNGColorType, bitDepth: int, settings: PNGDecoder = nil): PNGRes[T]
+  proc loadPNG32*(T: type, fileName: string, settings = PNGDecoder(nil)): PNGRes[T]
+  proc loadPNG24*(T: type, fileName: string, settings = PNGDecoder(nil)): PNGRes[T]
+
+proc decodePNG32*(T: type, input: T, settings = PNGDecoder(nil)): PNGRes[T]
+proc decodePNG24*(T: type, input: T, settings = PNGDecoder(nil)): PNGRes[T]
+```
+
+## How to use PNGRes?
+
+```Nim
+  let res = loadPNG32(seq[uint8], fileName, settings)
+  if res.isOk: result = res.get()  # get PNGResult[seq[uint8]]
+  else: debugEcho res.error()      # get error string
+```