Initial commit

6 files changed, 950 insertions, 0 deletions

diff --git a/external/construct/formats/graphics/__init__.py b/external/construct/formats/graphics/__init__.py
new file mode 100644
index 0000000..4abda02
--- /dev/null
+++ b/external/construct/formats/graphics/__init__.py
@@ -0,0 +1,4 @@
+"""
+graphic file formats, including imagery (bmp, jpg, gif, png, ...),
+models (3ds, ...), etc.
+"""
diff --git a/external/construct/formats/graphics/bmp.py b/external/construct/formats/graphics/bmp.py
new file mode 100644
index 0000000..abe1ad0
--- /dev/null
+++ b/external/construct/formats/graphics/bmp.py
@@ -0,0 +1,113 @@
+"""
+Windows/OS2 Bitmap (BMP)
+this could have been a perfect show-case file format, but they had to make
+it ugly (all sorts of alignment or
+"""
+from construct import *
+
+
+#===============================================================================
+# pixels: uncompressed
+#===============================================================================
+def UncompressedRows(subcon, align_to_byte = False):
+    """argh! lines must be aligned to a 4-byte boundary, and bit-pixel
+    lines must be aligned to full bytes..."""
+    if align_to_byte:
+        line_pixels = Bitwise(
+            Aligned(Array(lambda ctx: ctx.width, subcon), modulus = 8)
+        )
+    else:
+        line_pixels = Array(lambda ctx: ctx.width, subcon)
+    return Array(lambda ctx: ctx.height,
+        Aligned(line_pixels, modulus = 4)
+    )
+
+uncompressed_pixels = Switch("uncompressed", lambda ctx: ctx.bpp,
+    {
+        1 : UncompressedRows(Bit("index"), align_to_byte = True),
+        4 : UncompressedRows(Nibble("index"), align_to_byte = True),
+        8 : UncompressedRows(Byte("index")),
+        24 : UncompressedRows(
+            Sequence("rgb", Byte("red"), Byte("green"), Byte("blue"))
+        ),
+    }
+)
+
+#===============================================================================
+# pixels: Run Length Encoding (RLE) 8 bit
+#===============================================================================
+class RunLengthAdapter(Adapter):
+    def _encode(self, obj):
+        return len(obj), obj[0]
+    def _decode(self, obj):
+        length, value = obj
+        return [value] * length
+
+rle8pixel = RunLengthAdapter(
+    Sequence("rle8pixel",
+        Byte("length"),
+        Byte("value")
+    )
+)
+
+#===============================================================================
+# file structure
+#===============================================================================
+bitmap_file = Struct("bitmap_file",
+    # header
+    Const(String("signature", 2), "BM"),
+    ULInt32("file_size"),
+    Padding(4),
+    ULInt32("data_offset"),
+    ULInt32("header_size"),
+    Enum(Alias("version", "header_size"),
+        v2 = 12,
+        v3 = 40,
+        v4 = 108,
+    ),
+    ULInt32("width"),
+    ULInt32("height"),
+    Value("number_of_pixels", lambda ctx: ctx.width * ctx.height),
+    ULInt16("planes"),
+    ULInt16("bpp"), # bits per pixel
+    Enum(ULInt32("compression"),
+        Uncompressed = 0,
+        RLE8 = 1,
+        RLE4 = 2,
+        Bitfields = 3,
+        JPEG = 4,
+        PNG = 5,
+    ),
+    ULInt32("image_data_size"), # in bytes
+    ULInt32("horizontal_dpi"),
+    ULInt32("vertical_dpi"),
+    ULInt32("colors_used"),
+    ULInt32("important_colors"),
+
+    # palette (24 bit has no palette)
+    OnDemand(
+        Array(lambda ctx: 2 ** ctx.bpp if ctx.bpp <= 8 else 0,
+            Struct("palette",
+                Byte("blue"),
+                Byte("green"),
+                Byte("red"),
+                Padding(1),
+            )
+        )
+    ),
+
+    # pixels
+    OnDemandPointer(lambda ctx: ctx.data_offset,
+        Switch("pixels", lambda ctx: ctx.compression,
+            {
+                "Uncompressed" : uncompressed_pixels,
+            }
+        ),
+    ),
+)
+
+
+if __name__ == "__main__":
+    obj = bitmap_file.parse_stream(open("../../../tests/bitmap8.bmp", "rb"))
+    print (obj)
+    print (repr(obj.pixels.value))
diff --git a/external/construct/formats/graphics/emf.py b/external/construct/formats/graphics/emf.py
new file mode 100644
index 0000000..4f00a03
--- /dev/null
+++ b/external/construct/formats/graphics/emf.py
@@ -0,0 +1,198 @@
+"""
+Enhanced Meta File
+"""
+from construct import *
+
+
+record_type = Enum(ULInt32("record_type"),
+    ABORTPATH = 68,
+    ANGLEARC = 41,
+    ARC = 45,
+    ARCTO = 55,
+    BEGINPATH = 59,
+    BITBLT = 76,
+    CHORD = 46,
+    CLOSEFIGURE = 61,
+    CREATEBRUSHINDIRECT = 39,
+    CREATEDIBPATTERNBRUSHPT = 94,
+    CREATEMONOBRUSH = 93,
+    CREATEPALETTE = 49,
+    CREATEPEN = 38,
+    DELETEOBJECT = 40,
+    ELLIPSE = 42,
+    ENDPATH = 60,
+    EOF = 14,
+    EXCLUDECLIPRECT = 29,
+    EXTCREATEFONTINDIRECTW = 82,
+    EXTCREATEPEN = 95,
+    EXTFLOODFILL = 53,
+    EXTSELECTCLIPRGN = 75,
+    EXTTEXTOUTA = 83,
+    EXTTEXTOUTW = 84,
+    FILLPATH = 62,
+    FILLRGN = 71,
+    FLATTENPATH = 65,
+    FRAMERGN = 72,
+    GDICOMMENT = 70,
+    HEADER = 1,
+    INTERSECTCLIPRECT = 30,
+    INVERTRGN = 73,
+    LINETO = 54,
+    MASKBLT = 78,
+    MODIFYWORLDTRANSFORM = 36,
+    MOVETOEX = 27,
+    OFFSETCLIPRGN = 26,
+    PAINTRGN = 74,
+    PIE = 47,
+    PLGBLT = 79,
+    POLYBEZIER = 2,
+    POLYBEZIER16 = 85,
+    POLYBEZIERTO = 5,
+    POLYBEZIERTO16 = 88,
+    POLYDRAW = 56,
+    POLYDRAW16 = 92,
+    POLYGON = 3,
+    POLYGON16 = 86,
+    POLYLINE = 4,
+    POLYLINE16 = 87,
+    POLYLINETO = 6,
+    POLYLINETO16 = 89,
+    POLYPOLYGON = 8,
+    POLYPOLYGON16 = 91,
+    POLYPOLYLINE = 7,
+    POLYPOLYLINE16 = 90,
+    POLYTEXTOUTA = 96,
+    POLYTEXTOUTW = 97,
+    REALIZEPALETTE = 52,
+    RECTANGLE = 43,
+    RESIZEPALETTE = 51,
+    RESTOREDC = 34,
+    ROUNDRECT = 44,
+    SAVEDC = 33,
+    SCALEVIEWPORTEXTEX = 31,
+    SCALEWINDOWEXTEX = 32,
+    SELECTCLIPPATH = 67,
+    SELECTOBJECT = 37,
+    SELECTPALETTE = 48,
+    SETARCDIRECTION = 57,
+    SETBKCOLOR = 25,
+    SETBKMODE = 18,
+    SETBRUSHORGEX = 13,
+    SETCOLORADJUSTMENT = 23,
+    SETDIBITSTODEVICE = 80,
+    SETMAPMODE = 17,
+    SETMAPPERFLAGS = 16,
+    SETMETARGN = 28,
+    SETMITERLIMIT = 58,
+    SETPALETTEENTRIES = 50,
+    SETPIXELV = 15,
+    SETPOLYFILLMODE = 19,
+    SETROP2 = 20,
+    SETSTRETCHBLTMODE = 21,
+    SETTEXTALIGN = 22,
+    SETTEXTCOLOR = 24,
+    SETVIEWPORTEXTEX = 11,
+    SETVIEWPORTORGEX = 12,
+    SETWINDOWEXTEX = 9,
+    SETWINDOWORGEX = 10,
+    SETWORLDTRANSFORM = 35,
+    STRETCHBLT = 77,
+    STRETCHDIBITS = 81,
+    STROKEANDFILLPATH = 63,
+    STROKEPATH = 64,
+    WIDENPATH = 66,
+    _default_ = Pass,
+)
+
+generic_record = Struct("records",
+    record_type,
+    ULInt32("record_size"),      # Size of the record in bytes 
+    Union("params",              # Parameters
+        Field("raw", lambda ctx: ctx._.record_size - 8),
+        Array(lambda ctx: (ctx._.record_size - 8) // 4, ULInt32("params"))
+    ),
+)
+
+header_record = Struct("header_record",
+    Const(record_type, "HEADER"),
+    ULInt32("record_size"),              # Size of the record in bytes 
+    SLInt32("bounds_left"),              # Left inclusive bounds 
+    SLInt32("bounds_right"),             # Right inclusive bounds 
+    SLInt32("bounds_top"),               # Top inclusive bounds 
+    SLInt32("bounds_bottom"),            # Bottom inclusive bounds 
+    SLInt32("frame_left"),               # Left side of inclusive picture frame 
+    SLInt32("frame_right"),              # Right side of inclusive picture frame 
+    SLInt32("frame_top"),                # Top side of inclusive picture frame 
+    SLInt32("frame_bottom"),             # Bottom side of inclusive picture frame 
+    Const(ULInt32("signature"), 0x464D4520),
+    ULInt32("version"),                  # Version of the metafile 
+    ULInt32("size"),                     # Size of the metafile in bytes 
+    ULInt32("num_of_records"),           # Number of records in the metafile 
+    ULInt16("num_of_handles"),           # Number of handles in the handle table 
+    Padding(2),
+    ULInt32("description_size"),         # Size of description string in WORDs 
+    ULInt32("description_offset"),       # Offset of description string in metafile 
+    ULInt32("num_of_palette_entries"),   # Number of color palette entries 
+    SLInt32("device_width_pixels"),      # Width of reference device in pixels 
+    SLInt32("device_height_pixels"),     # Height of reference device in pixels 
+    SLInt32("device_width_mm"),          # Width of reference device in millimeters
+    SLInt32("device_height_mm"),         # Height of reference device in millimeters
+    
+    # description string
+    Pointer(lambda ctx: ctx.description_offset,
+        StringAdapter(
+            Array(lambda ctx: ctx.description_size,
+                Field("description", 2)
+            )
+        )
+    ),
+    
+    # padding up to end of record
+    Padding(lambda ctx: ctx.record_size - 88),
+)
+
+emf_file = Struct("emf_file",
+    header_record,
+    Array(lambda ctx: ctx.header_record.num_of_records - 1, 
+        generic_record
+    ),
+)
+
+
+if __name__ == "__main__":
+    obj = emf_file.parse_stream(open("../../../tests/emf1.emf", "rb"))
+    print (obj)
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
diff --git a/external/construct/formats/graphics/gif.py b/external/construct/formats/graphics/gif.py
new file mode 100644
index 0000000..fa50150
--- /dev/null
+++ b/external/construct/formats/graphics/gif.py
@@ -0,0 +1,151 @@
+# Contributed by
+# Dany Zatuchna (danzat at gmail)
+""" Implementation of the following grammar for the GIF89a file format
+<GIF Data Stream> ::=     Header <Logical Screen> <Data>* Trailer
+
+<Logical Screen> ::=      Logical Screen Descriptor [Global Color Table]
+
+<Data> ::=                <Graphic Block>  |
+                          <Special-Purpose Block>
+
+<Graphic Block> ::=       [Graphic Control Extension] <Graphic-Rendering Block>
+
+<Graphic-Rendering Block> ::=  <Table-Based Image>  |
+                               Plain Text Extension
+
+<Table-Based Image> ::=   Image Descriptor [Local Color Table] Image Data
+
+<Special-Purpose Block> ::=    Application Extension  |
+                               Comment Extension
+"""
+from construct import *
+import six
+
+
+data_sub_block = Struct("data_sub_block",
+    ULInt8("size"),
+    String("data", lambda ctx: ctx["size"])
+)
+
+gif_logical_screen = Struct("logical_screen",
+    ULInt16("width"),
+    ULInt16("height"),
+    BitStruct("flags",
+        Bit("global_color_table"),
+        BitField("color_resolution", 3),
+        Bit("sort_flag"),
+        BitField("global_color_table_bpp", 3)
+    ),
+    ULInt8("bgcolor_index"),
+    ULInt8("pixel_aspect_ratio"),
+    If(lambda ctx: ctx["flags"]["global_color_table"],
+        Array(lambda ctx: 2**(ctx["flags"]["global_color_table_bpp"] + 1),
+            Struct("palette",
+                ULInt8("R"),
+                ULInt8("G"),
+                ULInt8("B")
+            )
+        )
+    )
+)
+
+gif_header = Struct("gif_header",
+    Const(String("signature", 3), six.b("GIF")),
+    Const(String("version", 3), six.b("89a")),
+)
+
+application_extension = Struct("application_extension",
+    Const(ULInt8("block_size"), 11),
+    String("application_identifier", 8),
+    String("application_auth_code", 3),
+    data_sub_block,
+    ULInt8("block_terminator")
+)
+
+comment_extension = Struct("comment_extension",
+    data_sub_block,
+    ULInt8("block_terminator")
+)
+
+graphic_control_extension = Struct("graphic_control_extension",
+    Const(ULInt8("block_size"), 4),
+    BitStruct("flags",
+        BitField("reserved", 3),
+        BitField("disposal_method", 3),
+        Bit("user_input_flag"),
+        Bit("transparent_color_flag"),
+    ),
+    ULInt16("delay"),
+    ULInt8("transparent_color_index"),
+    ULInt8("block_terminator")
+)
+
+plain_text_extension = Struct("plain_text_extension",
+    Const(ULInt8("block_size"), 12),
+    ULInt16("text_left"),
+    ULInt16("text_top"),
+    ULInt16("text_width"),
+    ULInt16("text_height"),
+    ULInt8("cell_width"),
+    ULInt8("cell_height"),
+    ULInt8("foreground_index"),
+    ULInt8("background_index"),
+    data_sub_block,
+    ULInt8("block_terminator")
+)
+
+extension = Struct("extension",
+    ULInt8("label"),
+    Switch("ext", lambda ctx: ctx["label"], {
+        0xFF: application_extension,
+        0xFE: comment_extension,
+        0xF9: graphic_control_extension,
+        0x01: plain_text_extension
+    })
+)
+
+image_descriptor = Struct("image_descriptor",
+    ULInt16("left"),
+    ULInt16("top"),
+    ULInt16("width"),
+    ULInt16("height"),
+    BitStruct("flags",
+        Bit("local_color_table"),
+        Bit("interlace"),
+        Bit("sort"),
+        BitField("reserved", 2),
+        BitField("local_color_table_bpp", 3)
+    ),
+    If(lambda ctx: ctx["flags"]["local_color_table"],
+        Array(lambda ctx: 2**(ctx["flags"]["local_color_table_bpp"] + 1),
+            Struct("palette",
+                ULInt8("R"),
+                ULInt8("G"),
+                ULInt8("B")
+            )
+        )
+    ),
+    ULInt8("LZW_minimum_code_size"),
+    RepeatUntil(lambda obj, ctx: obj.size == 0, data_sub_block)
+)
+
+gif_data = Struct("gif_data",
+    ULInt8("introducer"),
+    Switch("dat", lambda ctx: ctx["introducer"], {
+        0x21: extension,
+        0x2C: image_descriptor
+    })
+)
+
+gif_file = Struct("gif_file",
+    gif_header,
+    gif_logical_screen,
+    OptionalGreedyRange(gif_data),
+    #Const(ULInt8("trailer"), 0x3B)
+)
+
+if __name__ == "__main__":
+    f = open("../../../tests/sample.gif", "rb")
+    s = f.read()
+    f.close()
+    print(gif_file.parse(s))
diff --git a/external/construct/formats/graphics/png.py b/external/construct/formats/graphics/png.py
new file mode 100644
index 0000000..39edf3a
--- /dev/null
+++ b/external/construct/formats/graphics/png.py
@@ -0,0 +1,355 @@
+"""
+Portable Network Graphics (PNG) file format
+Official spec: http://www.w3.org/TR/PNG
+
+Original code contributed by Robin Munn (rmunn at pobox dot com)
+(although the code has been extensively reorganized to meet Construct's
+coding conventions)
+"""
+from construct import *
+import six
+
+
+#===============================================================================
+# utils
+#===============================================================================
+def Coord(name, field=UBInt8):
+    return Struct(name,
+        field("x"),
+        field("y"),
+    )
+
+compression_method = Enum(UBInt8("compression_method"),
+    deflate = 0,
+    _default_ = Pass
+)
+
+
+#===============================================================================
+# 11.2.3: PLTE - Palette
+#===============================================================================
+plte_info = Struct("plte_info",
+    Value("num_entries", lambda ctx: ctx._.length / 3),
+    Array(lambda ctx: ctx.num_entries,
+        Struct("palette_entries",
+            UBInt8("red"),
+            UBInt8("green"),
+            UBInt8("blue"),
+        ),
+    ),
+)
+
+#===============================================================================
+# 11.2.4: IDAT - Image data
+#===============================================================================
+idat_info = OnDemand(
+    Field("idat_info", lambda ctx: ctx.length),
+)
+
+#===============================================================================
+# 11.3.2.1: tRNS - Transparency
+#===============================================================================
+trns_info = Switch("trns_info", lambda ctx: ctx._.image_header.color_type, 
+    {
+        "greyscale": Struct("data",
+            UBInt16("grey_sample")
+        ),
+        "truecolor": Struct("data",
+            UBInt16("red_sample"),
+            UBInt16("blue_sample"),
+            UBInt16("green_sample"),
+        ),
+        "indexed": Array(lambda ctx: ctx.length,
+            UBInt8("alpha"),
+        ),
+    }
+)
+
+#===============================================================================
+# 11.3.3.1: cHRM - Primary chromacities and white point
+#===============================================================================
+chrm_info = Struct("chrm_info",
+    Coord("white_point", UBInt32),
+    Coord("red", UBInt32),
+    Coord("green", UBInt32),
+    Coord("blue", UBInt32),
+)
+
+#===============================================================================
+# 11.3.3.2: gAMA - Image gamma
+#===============================================================================
+gama_info = Struct("gama_info",
+    UBInt32("gamma"),
+)
+
+#===============================================================================
+# 11.3.3.3: iCCP - Embedded ICC profile
+#===============================================================================
+iccp_info = Struct("iccp_info",
+    CString("name"),
+    compression_method,
+    Field("compressed_profile", 
+        lambda ctx: ctx._.length - (len(ctx.name) + 2)
+    ),
+)
+
+#===============================================================================
+# 11.3.3.4: sBIT - Significant bits
+#===============================================================================
+sbit_info = Switch("sbit_info", lambda ctx: ctx._.image_header.color_type, 
+    {
+        "greyscale": Struct("data",
+            UBInt8("significant_grey_bits"),
+        ),
+        "truecolor": Struct("data",
+            UBInt8("significant_red_bits"),
+            UBInt8("significant_green_bits"),
+            UBInt8("significant_blue_bits"),
+        ),
+        "indexed": Struct("data",
+            UBInt8("significant_red_bits"),
+            UBInt8("significant_green_bits"),
+            UBInt8("significant_blue_bits"),
+        ),
+        "greywithalpha": Struct("data",
+            UBInt8("significant_grey_bits"),
+            UBInt8("significant_alpha_bits"),
+        ),
+        "truewithalpha": Struct("data",
+            UBInt8("significant_red_bits"),
+            UBInt8("significant_green_bits"),
+            UBInt8("significant_blue_bits"),
+            UBInt8("significant_alpha_bits"),
+        ),
+    }
+)
+
+#===============================================================================
+# 11.3.3.5: sRGB - Standard RPG color space
+#===============================================================================
+srgb_info = Struct("srgb_info",
+    Enum(UBInt8("rendering_intent"),
+        perceptual = 0,
+        relative_colorimetric = 1,
+        saturation = 2,
+        absolute_colorimetric = 3,
+        _default_ = Pass,
+    ),
+)
+
+#===============================================================================
+# 11.3.4.3: tEXt - Textual data
+#===============================================================================
+text_info = Struct("text_info",
+    CString("keyword"),
+    Field("text", lambda ctx: ctx._.length - (len(ctx.keyword) + 1)),
+)
+
+#===============================================================================
+# 11.3.4.4: zTXt - Compressed textual data
+#===============================================================================
+ztxt_info = Struct("ztxt_info",
+    CString("keyword"),
+    compression_method,
+    OnDemand(
+        Field("compressed_text",
+            # As with iCCP, length is chunk length, minus length of
+            # keyword, minus two: one byte for the null terminator,
+            # and one byte for the compression method.
+            lambda ctx: ctx._.length - (len(ctx.keyword) + 2),
+        ),
+    ),
+)
+
+#===============================================================================
+# 11.3.4.5: iTXt - International textual data
+#===============================================================================
+itxt_info = Struct("itxt_info",
+    CString("keyword"),
+    UBInt8("compression_flag"),
+    compression_method,
+    CString("language_tag"),
+    CString("translated_keyword"),
+    OnDemand(
+        Field("text",
+            lambda ctx: ctx._.length - (len(ctx.keyword) + 
+            len(ctx.language_tag) + len(ctx.translated_keyword) + 5),
+        ),
+    ),
+)
+
+#===============================================================================
+# 11.3.5.1: bKGD - Background color
+#===============================================================================
+bkgd_info = Switch("bkgd_info", lambda ctx: ctx._.image_header.color_type, 
+    {
+        "greyscale": Struct("data",
+            UBInt16("background_greyscale_value"),
+            Alias("grey", "background_greyscale_value"),
+        ),
+        "greywithalpha": Struct("data",
+            UBInt16("background_greyscale_value"),
+            Alias("grey", "background_greyscale_value"),
+        ),
+        "truecolor": Struct("data",
+            UBInt16("background_red_value"),
+            UBInt16("background_green_value"),
+            UBInt16("background_blue_value"),
+            Alias("red", "background_red_value"),
+            Alias("green", "background_green_value"),
+            Alias("blue", "background_blue_value"),
+        ),
+        "truewithalpha": Struct("data",
+            UBInt16("background_red_value"),
+            UBInt16("background_green_value"),
+            UBInt16("background_blue_value"),
+            Alias("red", "background_red_value"),
+            Alias("green", "background_green_value"),
+            Alias("blue", "background_blue_value"),
+        ),
+        "indexed": Struct("data",
+            UBInt16("background_palette_index"),
+            Alias("index", "background_palette_index"),
+        ),
+    }
+)
+
+#===============================================================================
+# 11.3.5.2: hIST - Image histogram
+#===============================================================================
+hist_info = Array(lambda ctx: ctx._.length / 2,
+    UBInt16("frequency"),
+)
+
+#===============================================================================
+# 11.3.5.3: pHYs - Physical pixel dimensions
+#===============================================================================
+phys_info = Struct("phys_info",
+    UBInt32("pixels_per_unit_x"),
+    UBInt32("pixels_per_unit_y"),
+    Enum(UBInt8("unit"),
+        unknown = 0,
+        meter = 1,
+        _default_ = Pass
+    ),
+)
+
+#===============================================================================
+# 11.3.5.4: sPLT - Suggested palette
+#===============================================================================
+def splt_info_data_length(ctx):
+    if ctx.sample_depth == 8:
+        entry_size = 6
+    else:
+        entry_size = 10
+    return (ctx._.length - len(ctx.name) - 2) / entry_size
+
+splt_info = Struct("data",
+    CString("name"),
+    UBInt8("sample_depth"),
+    Array(lambda ctx: splt_info_data_length,
+        IfThenElse("table", lambda ctx: ctx.sample_depth == 8,
+            # Sample depth 8
+            Struct("table",
+                UBInt8("red"),
+                UBInt8("green"),
+                UBInt8("blue"),
+                UBInt8("alpha"),
+                UBInt16("frequency"),
+            ),
+            # Sample depth 16
+            Struct("table",
+                UBInt16("red"),
+                UBInt16("green"),
+                UBInt16("blue"),
+                UBInt16("alpha"),
+                UBInt16("frequency"),
+            ),
+        ),
+    ),
+)
+
+#===============================================================================
+# 11.3.6.1: tIME - Image last-modification time
+#===============================================================================
+time_info = Struct("data",
+    UBInt16("year"),
+    UBInt8("month"),
+    UBInt8("day"),
+    UBInt8("hour"),
+    UBInt8("minute"),
+    UBInt8("second"),
+)
+
+#===============================================================================
+# chunks
+#===============================================================================
+default_chunk_info = OnDemand(
+    HexDumpAdapter(Field(None, lambda ctx: ctx.length))
+)
+
+chunk = Struct("chunk",
+    UBInt32("length"),
+    String("type", 4),
+    Switch("data", lambda ctx: ctx.type, 
+        {
+            "PLTE" : plte_info,
+            "IEND" : Pass,
+            "IDAT" : idat_info,
+            "tRNS" : trns_info,
+            "cHRM" : chrm_info,
+            "gAMA" : gama_info,
+            "iCCP" : iccp_info,
+            "sBIT" : sbit_info,
+            "sRGB" : srgb_info,
+            "tEXt" : text_info,
+            "zTXt" : ztxt_info,
+            "iTXt" : itxt_info,
+            "bKGD" : bkgd_info,
+            "hIST" : hist_info,
+            "pHYs" : phys_info,
+            "sPLT" : splt_info,
+            "tIME" : time_info,
+        },
+        default = default_chunk_info,
+    ),
+    UBInt32("crc"),
+)
+
+image_header_chunk = Struct("image_header",
+    UBInt32("length"),
+    Const(String("type", 4), "IHDR"),
+    UBInt32("width"),
+    UBInt32("height"),
+    UBInt8("bit_depth"),
+    Enum(UBInt8("color_type"),
+        greyscale = 0,
+        truecolor = 2,
+        indexed = 3,
+        greywithalpha = 4,
+        truewithalpha = 6,
+        _default_ = Pass,
+    ),
+    compression_method,
+    Enum(UBInt8("filter_method"),
+        # "adaptive filtering with five basic filter types"
+        adaptive5 = 0,
+        _default_ = Pass,
+    ),
+    Enum(UBInt8("interlace_method"),
+        none = 0,
+        adam7 = 1,
+        _default_ = Pass,
+    ),
+    UBInt32("crc"),
+)
+
+
+#===============================================================================
+# the complete PNG file
+#===============================================================================
+png_file = Struct("png",
+    Magic(six.b("\x89PNG\r\n\x1a\n")),
+    image_header_chunk,
+    Rename("chunks", GreedyRange(chunk)),
+)
diff --git a/external/construct/formats/graphics/wmf.py b/external/construct/formats/graphics/wmf.py
new file mode 100644
index 0000000..55e79dd
--- /dev/null
+++ b/external/construct/formats/graphics/wmf.py
@@ -0,0 +1,129 @@
+"""
+Windows Meta File
+"""
+from construct import *
+
+
+wmf_record = Struct("records",
+    ULInt32("size"), # size in words, including the size, function and params
+    Enum(ULInt16("function"),
+        AbortDoc = 0x0052,
+        Aldus_Header = 0x0001,
+        AnimatePalette = 0x0436,
+        Arc = 0x0817,
+        BitBlt = 0x0922,
+        Chord = 0x0830,
+        CLP_Header16 = 0x0002,
+        CLP_Header32 = 0x0003,
+        CreateBitmap = 0x06FE,
+        CreateBitmapIndirect = 0x02FD,
+        CreateBrush = 0x00F8,
+        CreateBrushIndirect = 0x02FC,
+        CreateFontIndirect = 0x02FB,
+        CreatePalette = 0x00F7,
+        CreatePatternBrush = 0x01F9,
+        CreatePenIndirect = 0x02FA,
+        CreateRegion = 0x06FF,
+        DeleteObject = 0x01F0,
+        DibBitblt = 0x0940,
+        DibCreatePatternBrush = 0x0142,
+        DibStretchBlt = 0x0B41,
+        DrawText = 0x062F,
+        Ellipse = 0x0418,
+        EndDoc = 0x005E,
+        EndPage = 0x0050,
+        EOF = 0x0000,
+        Escape = 0x0626,
+        ExcludeClipRect = 0x0415,
+        ExtFloodFill = 0x0548,
+        ExtTextOut = 0x0A32,
+        FillRegion = 0x0228,
+        FloodFill = 0x0419,
+        FrameRegion = 0x0429,
+        Header = 0x0004,
+        IntersectClipRect = 0x0416,
+        InvertRegion = 0x012A,
+        LineTo = 0x0213,
+        MoveTo = 0x0214,
+        OffsetClipRgn = 0x0220,
+        OffsetViewportOrg = 0x0211,
+        OffsetWindowOrg = 0x020F,
+        PaintRegion = 0x012B,
+        PatBlt = 0x061D,
+        Pie = 0x081A,
+        Polygon = 0x0324,
+        Polyline = 0x0325,
+        PolyPolygon = 0x0538,
+        RealizePalette = 0x0035,
+        Rectangle = 0x041B,
+        ResetDC = 0x014C,
+        ResizePalette = 0x0139,
+        RestoreDC = 0x0127,
+        RoundRect = 0x061C,
+        SaveDC = 0x001E,
+        ScaleViewportExt = 0x0412,
+        ScaleWindowExt = 0x0410,
+        SelectClipRegion = 0x012C,
+        SelectObject = 0x012D,
+        SelectPalette = 0x0234,
+        SetBKColor = 0x0201,
+        SetBKMode = 0x0102,
+        SetDibToDev = 0x0D33,
+        SelLayout = 0x0149,
+        SetMapMode = 0x0103,
+        SetMapperFlags = 0x0231,
+        SetPalEntries = 0x0037,
+        SetPixel = 0x041F,
+        SetPolyFillMode = 0x0106,
+        SetReLabs = 0x0105,
+        SetROP2 = 0x0104,
+        SetStretchBltMode = 0x0107,
+        SetTextAlign = 0x012E,
+        SetTextCharExtra = 0x0108,
+        SetTextColor = 0x0209,
+        SetTextJustification = 0x020A,
+        SetViewportExt = 0x020E,
+        SetViewportOrg = 0x020D,
+        SetWindowExt = 0x020C,
+        SetWindowOrg = 0x020B,
+        StartDoc = 0x014D,
+        StartPage = 0x004F,
+        StretchBlt = 0x0B23,
+        StretchDIB = 0x0F43,
+        TextOut = 0x0521,
+        _default_ = Pass,
+    ),
+    Array(lambda ctx: ctx.size - 3, ULInt16("params")),
+)
+
+wmf_placeable_header = Struct("placeable_header",
+  Const(ULInt32("key"), 0x9AC6CDD7),
+  ULInt16("handle"),
+  SLInt16("left"),
+  SLInt16("top"),
+  SLInt16("right"),
+  SLInt16("bottom"),
+  ULInt16("units_per_inch"),
+  Padding(4),
+  ULInt16("checksum")
+)
+
+wmf_file = Struct("wmf_file",
+    # --- optional placeable header ---
+    Optional(wmf_placeable_header),
+
+    # --- header ---
+    Enum(ULInt16("type"),
+        InMemory = 0,
+        File = 1,
+    ),
+    Const(ULInt16("header_size"), 9),
+    ULInt16("version"),
+    ULInt32("size"), # file size is in words
+    ULInt16("number_of_objects"),
+    ULInt32("size_of_largest_record"),
+    ULInt16("number_of_params"),
+
+    # --- records ---
+    GreedyRange(wmf_record)
+)