Add support for decoding images from a pointer and a length instead of a string (TODO: qoi, ppm)

added support for open type format 12

examples/text.nim

@@ -5,6 +5,7 @@ image.fill(rgba(255, 255, 255, 255))
 
 var font = readFont("examples/data/Roboto-Regular_1.ttf")
 font.size = 20
+font.paint.color = color(1, 0, 0)
 
 let text = "Typesetting is the arrangement and composition of text in graphic design and publishing in both digital and traditional medias."
 

pixie.nimble

@@ -1,4 +1,4 @@
-version     = "5.0.6"
+version     = "5.0.7"
 author      = "Andre von Houck and Ryan Oldenburg"
 description = "Full-featured 2d graphics library for Nim."
 license     = "MIT"

src/pixie.nim

@@ -49,8 +49,39 @@ proc decodeImageDimensions*(
   ## Decodes an image's dimensions from memory.
   decodeImageDimensions(data.cstring, data.len)
 
+template compare_as(T: typedesc, p,q: pointer): bool =
+  cast[ptr T](p)[] == cast[ptr T](q)[]
+
+proc decodeImage*(data: pointer, len: int): Image {.raises: [PixieError].} =
+  ## Loads an image from memory, from a pointer and a length.
+  if len > 8 and compare_as(uint64, data, pngSignature.addr):
+    decodePng(data, len).convertToImage()
+  elif len > 2 and compare_as(uint16, data, jpegStartOfImage.addr):
+    decodeJpeg(data, len)
+  elif len > 2 and compare_as(array[2,char], data, bmpSignature.cstring):
+    decodeBmp(data, len)
+  elif len > 5 and
+      compare_as(array[5,char], data, xmlSignature.cstring) or 
+      compare_as(array[4,char], data, svgSignature.cstring):
+    # TODO: avoid allocating/initializing string
+    var s = newStringOfCap(len)
+    s.setLen len
+    copyMem(s.cstring, data, len)
+    newImage(parseSvg(s))
+  elif len > 6 and compare_as(array[6,char], data, gifSignatures[0].cstring) or 
+      compare_as(array[6,char], data, gifSignatures[1].cstring):
+    newImage(decodeGif(data, len))
+  # TODO
+  # elif len > (14+8) and compare_as(array[4,char], data, qoiSignature.cstring):
+  #   decodeQoi(data, len).convertToImage()
+  # elif len > 9 and compare_as(array[2,char], data, ppmSignatures[0].cstring) or 
+  #     compare_as(array[2,char], data, ppmSignatures[1].cstring):
+  #   decodePpm(data, len)
+  else:
+    raise newException(PixieError, "Unsupported image file format")
+
 proc decodeImage*(data: string): Image {.raises: [PixieError].} =
-  ## Loads an image from memory.
+  ## Loads an image from memory as a string.
   if data.len > 8 and data.readUint64(0) == cast[uint64](pngSignature):
     decodePng(data).convertToImage()
   elif data.len > 2 and data.readUint16(0) == cast[uint16](jpegStartOfImage):

src/pixie/contexts.nim

@@ -481,8 +481,8 @@ proc fillText*(ctx: Context, text: string, at: Vec2) {.raises: [PixieError].} =
 proc fillText*(
   ctx: Context, text: string, x, y: float32
 ) {.inline, raises: [PixieError].} =
-  ## Draws the outlines of the characters of a text string at the specified
-  ## coordinates.
+  ## Draws a text string at the specified coordinates, filling the string's
+  ## characters with the current fillStyle
   ctx.fillText(text, vec2(x, y))
 
 proc strokeText*(ctx: Context, text: string, at: Vec2) {.raises: [PixieError].} =

src/pixie/fileformats/bmp.nim

@@ -227,6 +227,17 @@ proc decodeBmp*(data: string): Image {.raises: [PixieError].} =
 
   decodeDib(data[14].unsafeAddr, data.len - 14)
 
+proc decodeBmp*(data: pointer, len: int): Image {.raises: [PixieError].} =
+  ## Decodes bitmap data into an image.
+  if len < 14:
+    failInvalid()
+
+  # BMP Header
+  if cast[ptr int16](data)[] != cast[ptr int16]("BM".cstring)[]:
+    failInvalid()
+
+  decodeDib(cast[ptr UncheckedArray[char]](data)[14].addr, len - 14)
+
 proc decodeBmpDimensions*(
   data: pointer, len: int
 ): ImageDimensions {.raises: [PixieError].} =

src/pixie/fileformats/gif.nim

@@ -22,12 +22,18 @@ template failInvalid() =
 when defined(release):
   {.push checks: off.}
 
-proc decodeGif*(data: string): Gif {.raises: [PixieError].} =
+template compare_as(T: typedesc, p,q: pointer): bool =
+  cast[ptr T](p)[] == cast[ptr T](q)[]
+
+proc decodeGif*(data: pointer, len: int): Gif {.raises: [PixieError].} =
+  let data = cast[ptr UncheckedArray[uint8]](data)
   ## Decodes GIF data.
-  if data.len < 13:
+  if len < 13:
     failInvalid()
 
-  if data[0 .. 5] notin gifSignatures:
+  if not (len > 6 and 
+      compare_as(array[6,char], data, gifSignatures[0].cstring) or 
+      compare_as(array[6,char], data, gifSignatures[1].cstring)):
     raise newException(PixieError, "Invalid GIF file signature")
 
   result = Gif()
@@ -49,7 +55,7 @@ proc decodeGif*(data: string): Gif {.raises: [PixieError].} =
 
   var pos = 13
 
-  if pos + globalColorTableSize * 3 > data.len:
+  if pos + globalColorTableSize * 3 > len:
     failInvalid()
 
   var
@@ -69,7 +75,7 @@ proc decodeGif*(data: string): Gif {.raises: [PixieError].} =
 
   proc skipSubBlocks() =
     while true: # Skip data sub-blocks
-      if pos + 1 > data.len:
+      if pos + 1 > len:
         failInvalid()
 
       let subBlockSize = data.readUint8(pos).int
@@ -82,7 +88,7 @@ proc decodeGif*(data: string): Gif {.raises: [PixieError].} =
 
   var controlExtension: ControlExtension
   while true:
-    if pos + 1 > data.len:
+    if pos + 1 > len:
       failInvalid()
 
     let blockType = data.readUint8(pos)
@@ -90,7 +96,7 @@ proc decodeGif*(data: string): Gif {.raises: [PixieError].} =
 
     case blockType:
     of 0x2c: # Image
-      if pos + 9 > data.len:
+      if pos + 9 > len:
         failInvalid()
 
       let
@@ -108,7 +114,7 @@ proc decodeGif*(data: string): Gif {.raises: [PixieError].} =
       if imageWidth > screenWidth or imageHeight > screenHeight:
         raise newException(PixieError, "Invalid GIF frame dimensions")
 
-      if pos + localColorTableSize * 3 > data.len:
+      if pos + localColorTableSize * 3 > len:
         failInvalid()
 
       var localColorTable: seq[ColorRGBX]
@@ -123,7 +129,7 @@ proc decodeGif*(data: string): Gif {.raises: [PixieError].} =
           )
           pos += 3
 
-      if pos + 1 > data.len:
+      if pos + 1 > len:
         failInvalid()
 
       let minCodeSize = data.readUint8(pos).int
@@ -135,7 +141,7 @@ proc decodeGif*(data: string): Gif {.raises: [PixieError].} =
       # The image data is contained in a sequence of sub-blocks
       var lzwDataBlocks: seq[(int, int)] # (offset, len)
       while true:
-        if pos + 1 > data.len:
+        if pos + 1 > len:
           failInvalid()
 
         let subBlockSize = data.readUint8(pos).int
@@ -144,7 +150,7 @@ proc decodeGif*(data: string): Gif {.raises: [PixieError].} =
         if subBlockSize == 0:
           break
 
-        if pos + subBlockSize > data.len:
+        if pos + subBlockSize > len:
           failInvalid()
 
         lzwDataBlocks.add((pos, subBlockSize))
@@ -307,7 +313,7 @@ proc decodeGif*(data: string): Gif {.raises: [PixieError].} =
       controlExtension = ControlExtension()
 
     of 0x21: # Extension
-      if pos + 1 > data.len:
+      if pos + 1 > len:
         failInvalid()
 
       let extensionType = data.readUint8(pos + 0)
@@ -316,7 +322,7 @@ proc decodeGif*(data: string): Gif {.raises: [PixieError].} =
       case extensionType:
       of 0xf9:
         # Graphic Control Extension
-        if pos + 1 > data.len:
+        if pos + 1 > len:
           failInvalid()
 
         let blockSize = data.readUint8(pos).int
@@ -325,7 +331,7 @@ proc decodeGif*(data: string): Gif {.raises: [PixieError].} =
         if blockSize != 4:
           failInvalid()
 
-        if pos + blockSize > data.len:
+        if pos + blockSize > len:
           failInvalid()
 
         controlExtension.fields = data.readUint8(pos + 0)
@@ -344,7 +350,7 @@ proc decodeGif*(data: string): Gif {.raises: [PixieError].} =
 
       of 0xff:
         # Application Specific
-        if pos + 1 > data.len:
+        if pos + 1 > len:
           failInvalid()
 
         let blockSize = data.readUint8(pos).int
@@ -353,7 +359,7 @@ proc decodeGif*(data: string): Gif {.raises: [PixieError].} =
         if blockSize != 11:
           failInvalid()
 
-        if pos + blockSize > data.len:
+        if pos + blockSize > len:
           failInvalid()
 
         pos += blockSize
@@ -378,6 +384,9 @@ proc decodeGif*(data: string): Gif {.raises: [PixieError].} =
   for interval in result.intervals:
     result.duration += interval
 
+proc decodeGif*(data: string): Gif {.raises: [PixieError].} =
+  return decodeGif(data.cstring, data.len)
+
 proc decodeGifDimensions*(
   data: pointer, len: int
 ): ImageDimensions {.raises: [PixieError].} =

src/pixie/fileformats/jpeg.nim

@@ -1,5 +1,5 @@
 import chroma, flatty/binny, ../common, ../images, ../internal,
-    ../simd, std/decls, std/sequtils, std/strutils
+    ../simd, std/sequtils, std/strutils
 
 # This JPEG decoder is loosely based on stb_image which is public domain.
 
@@ -547,7 +547,7 @@ proc fillBitBuffer(state: var DecoderState) =
 
 proc huffmanDecode(state: var DecoderState, tableCurrent, table: int): uint8 =
   ## Decode a uint8 from the huffman table.
-  var huffman {.byaddr.} = state.huffmanTables[tableCurrent][table]
+  var huffman = state.huffmanTables[tableCurrent][table].addr
 
   state.fillBitBuffer()
 
@@ -884,14 +884,15 @@ proc idctBlock(component: var Component, offset: int, data: array[64, int16]) =
 
 proc decodeBlock(state: var DecoderState, comp, row, column: int) =
   ## Decodes a block.
-  var data {.byaddr.} = state.components[comp].blocks[row][column]
+  var data = state.components[comp].blocks[row][column].addr
+
   if state.progressive:
     if state.spectralStart == 0:
-      state.decodeProgressiveBlock(comp, data)
+      state.decodeProgressiveBlock(comp, data[])
     else:
-      state.decodeProgressiveContinuationBlock(comp, data)
+      state.decodeProgressiveContinuationBlock(comp, data[])
   else:
-    state.decodeRegularBlock(comp, data)
+    state.decodeRegularBlock(comp, data[])
 
 proc checkRestart(state: var DecoderState) =
   ## Check if we might have run into a restart marker, then deal with it.
@@ -941,7 +942,7 @@ proc quantizationAndIDCTPass(state: var DecoderState) =
       failInvalid()
     for column in 0 ..< h:
       for row in 0 ..< w:
-        var data {.byaddr.} = state.components[comp].blocks[row][column]
+        var data = state.components[comp].blocks[row][column].addr
 
         when defined(amd64) and allowSimd:
           for i in 0 ..< 8: # 8 per pass
@@ -957,7 +958,7 @@ proc quantizationAndIDCTPass(state: var DecoderState) =
 
         state.components[comp].idctBlock(
           state.components[comp].widthStride * column * 8 + row * 8,
-          data
+          data[]
         )
 
 proc magnifyXBy2(mask: Mask): Mask =
@@ -1091,12 +1092,12 @@ proc buildImage(state: var DecoderState): Image =
     else:
       failInvalid("invalid orientation")
 
-proc decodeJpeg*(data: string): Image {.raises: [PixieError].} =
+proc decodeJpeg*(data: pointer, len: int): Image {.raises: [PixieError].} =
   ## Decodes the JPEG into an Image.
 
   var state = DecoderState()
-  state.buffer = cast[ptr UncheckedArray[uint8]](data.cstring)
-  state.len = data.len
+  state.buffer = cast[ptr UncheckedArray[uint8]](data)
+  state.len = len
 
   while true:
     if state.readUint8() != 0xFF:
@@ -1156,6 +1157,10 @@ proc decodeJpeg*(data: string): Image {.raises: [PixieError].} =
 
   state.buildImage()
 
+proc decodeJpeg*(data: string): Image {.raises: [PixieError].} =
+  ## Decodes the JPEG into an Image.
+  decodeJpeg(data.cstring, data.len)
+
 proc decodeJpegDimensions*(
   data: pointer, len: int
 ): ImageDimensions {.raises: [PixieError].} =

src/pixie/fontformats/opentype.nim

@@ -455,6 +455,7 @@ proc parseCmapTable(buf: string, offset: int): CmapTable =
 
       let format = buf.readUint16(i + 0).swap()
       if format == 4:
+        # https://learn.microsoft.com/en-us/typography/opentype/spec/cmap#format-4-segment-mapping-to-delta-values
         type Format4 = object
           format: uint16
           length: uint16
@@ -518,8 +519,46 @@ proc parseCmapTable(buf: string, offset: int): CmapTable =
             if c != 65535:
               result.runeToGlyphId[Rune(c)] = glyphId.uint16
               result.glyphIdToRune[glyphId.uint16] = Rune(c)
+
+      elif format == 12:
+        # https://learn.microsoft.com/en-us/typography/opentype/spec/cmap#format-12-segmented-coverage
+        type Format12 = object
+          format: uint16
+          reserved: uint16
+          length: uint32
+          language: uint32
+          numGroups: uint32
+
+        buf.eofCheck(i + 16)
+
+        var subTable: Format12
+        subTable.format = format
+        subTable.reserved = buf.readUint16(i + 2).swap()
+        subTable.length = buf.readUint32(i + 4).swap()
+        subTable.language = buf.readUint32(i + 8).swap()
+        subTable.numGroups = buf.readUint32(i + 12).swap()
+        i += 16
+
+        buf.eofCheck(i + subTable.numGroups.int * 12)
+
+        for k in 0 ..< subTable.numGroups:
+          let startCharCode = buf.readUint32(i + 0).swap()
+          let endCharCode = buf.readUint32(i + 4).swap()
+          let startGlyphId = buf.readUint32(i + 8).swap()
+
+          for c in startCharCode .. endCharCode:
+            let glyphId = startGlyphId + (c - startCharCode)
+            if glyphId > uint16.high:
+              # TODO: currently only 16 bit glyph ids are supported
+              raise newException(PixieError, "Found glyph outside of uint16 range: " & $glyphId)
+
+            result.runeToGlyphId[Rune(c)] = uint16(glyphId)
+            result.glyphIdToRune[uint16(glyphId)] = Rune(c)
+
+          i += 12
+
       else:
-        # TODO implement other Windows encodingIDs
+        # TODO implement other windows formats
         discard
     else:
       # TODO implement other cmap platformIDs

src/pixie/images.nim

@@ -497,7 +497,6 @@ proc blendRect(a, b: Image, pos: Ivec2, blendMode: BlendMode) =
         xEnd - xStart
       )
   of MaskBlend:
-    {.linearScanEnd.}
     if yStart + py > 0:
       zeroMem(a.data[0].addr, (yStart + py) * a.width * 4)
     for y in yStart ..< yEnd:
@@ -607,7 +606,6 @@ proc drawSmooth(a, b: Image, transform: Mat3, blendMode: BlendMode) =
       )
 
     of MaskBlend:
-      {.linearScanEnd.}
       if blendMode == MaskBlend and xStart > 0:
         zeroMem(a.data[a.dataIndex(0, y)].addr, xStart * 4)
 

src/pixie/paths.nim

@@ -1505,7 +1505,6 @@ proc fillCoverage(
     )
 
   of MaskBlend:
-    {.linearScanEnd.}
     blendLineCoverageMask(
       image.getUncheckedArray(startX, y),
       cast[ptr UncheckedArray[uint8]](coverages[0].unsafeAddr),
@@ -1560,7 +1559,6 @@ proc fillHits(
         blendLineNormal(image.getUncheckedArray(start, y), rgbx, len)
 
   of MaskBlend:
-    {.linearScanEnd.}
     var filledTo = startX
     for (start, len) in hits.walkInteger(numHits, windingRule, y, image.width):
       if maskClears: # Clear any gap between this fill and the previous fill

tests/test_fonts.nim

@@ -4,6 +4,21 @@ proc wh(image: Image): Vec2 =
   ## Return with and height as a size vector.
   vec2(image.width.float32, image.height.float32)
 
+block:
+  var font = readFont("tests/fonts/NotoEmoji.otf")
+  font.size = 26
+  let image = newImage(800, 300)
+  image.fill(rgba(255, 255, 255, 255))
+  image.fillText(font, """
+🚑🐑👭🔉🚷🦣💆🔁💺🚵🕦🔦🗓🦟😶🦄⌛🍙😄🇽
+🐠💓🦗🎭🏛🔴🫕🧶🍖🦁🏋🌗🛬🕐💡👉🎯🕔🚏🚲
+🐵🎍💳🥬🟦🪘📠📊🎧🎦🎁🌌🪲🦩🤢☎🚺🚾👺🚃
+🐨🌆🥉💭🗳🦵🟪📆🥮⏯🩴💷🦲➗🌶🧜🖖⏰🛗🔻
+📁🧞😃🌴🚶󾠫🦙🔎⏲🔵🖐☦😪🌯🙆🇺😂🍅🇿🚟🤜
+📼👰🍁📽☪🔄🤝🔧🦸🏰🏳🔜🎥🚋🇫🦨🏜🆖🏤🪖⏏""")
+
+  image.xray("tests/fonts/masters/emoji.png")
+
 block:
   var font = readFont("tests/fonts/Roboto-Regular_1.ttf")
   font.size = 24