Update from SixLabors/ImageSharp - #1

Use bounds checks in Huffman ctr. Fix #798

* Use Matrix5x4 and fix Hue Filter

* Update test references. Fix #802

* Increase tolerance to handle xplat variance.

* Rename to ColorMatrix

* decoding bitmaps with Bitfields masks

* added testcases for Bitfields bitmaps

* added parsing of the complete bitmap V4 header to get the color masks infos for the BITFIELDS compression

* writing now explicitly a Bitamp v3 header (40 bytes)

* added test image for issue #735

* fixed rescaling 5-bit / 6-bit to 0 - 255 range

* BitmapEncoder now writes BMP v4 header

* using MemoryMarshal.Cast to simplify parsing v4 header

* added testcases for bitmap v3, v4, v5

* Bitmap encoder writes again V3 header instead of V4. Additional fields for V4 are zero anyway.

* added parsing of special case for 56 bytes headers

* using the alpha mask in ReadRgb32BitFields() when its present

* added support for bitmasks greater then 8 bits per channel

* using MagickReferenceDecoder reference decoder for the test with 10 bits pixel masks

* changed bitmap constants to hex

* added enum for the bitmap info header type

* added support for 52 bytes header (same as 56 bytes without the alpha mask)

* clarified comment with difference between imagesharp and magick decoder for Rgba321010102

* BmpEncoder now writes a V4 info header and uses BITFIELDS compression

* workaround for issue that the decoder does not decode the alpha channel correctly: For V3 bitmaps, the alpha channel will be ignored during encoding

* Fix #732

* Added support for OS/2 version 2 bitmaps

* throw NotSupportedException, if the file header type is not BM

* renamed Os2v2 to Os2v2Size

* Added BmpThrowHelper similar to the JpegThrowHelper

* Adds support for BI_ALPHABITFIELDS

* Fix for decoding bitmaps with a less than full sized palette

…table, this should hopefully prevent "a generic error occurred in GDI+". Hopefully I didn't miss one... (#835)

* Nomalize jpeg exceptions. Fix #821

* Fix #822

* Fix #823

* Check for correct QT index. Touch #824

* Check DHT props. Touch #824

* Limit sampling factors to 1 & 2. Touch #824

* Add already fixed image 4. Touch #824

* Check for excessive code lengths. Touch #824

* Add already fixed image 6. Touch #824

* Lint progressive scan details. Touch #824

* Add already fixed image 8. Fix #824

* Remove duplicate per-block checks

* Add already fixed image 1. Touch #825

* Don't throw on bad JFIF density units.

* Add already fixed image 3. Touch #825

* Add already fixed image 4. Fix #825

* Check SOFn marker length. Touch #826

* Add already fixed image 2. Touch #826

* Add already fixed image 3. Fix #826

* Add fixed already fixed image. Fix #827

* Revert unneeded bounds check introduced in #804

* Lazily derive the huffman tables. Fix #839

* Lazy invoke fast table

* Add performance tweaks to scan decoder.

* Remove unneccessary classes.

…submodules

#852 Adding instructions to add submodules when cloning the repository

…ge of compiler functionality. (#855)

… with net472 and netcore

Pixel-agnostic Drawing processors and extensions

…antizeOnGray8

# Conflicts:
#	tests/ImageSharp.Tests/Drawing/DrawImageTests.cs

Not using quantization for Grey8 images when encoding 8Bit Bitmaps

* temporarily disable target frameworks

* drop DelegateProcessor

* drop IImageProcessingContext<TPixel>

* drop NamedColors<T>

* drop ColorBuilder<T>

* drop the *Base postfix for clean class hierarchies

* re-enable target frameworks

* use MathF in gradient brushes

* Move PngFilterMethod to the correct namespace.

Added funding file with a link to open collective.

* Remove linq usage from jpeg + formatting

* png

* ICC + formattiing

* Resize

* Fix base class comparison.

* Updating the repo to use Directory.Build.props/targets files

* Adding an InternalsVisibleTo for DynamicProxyGenAssembly2, PublicKeyToken=null

* Removing duplicate includes from the ImageSharp.csproj

* Updating the .gitattributes file to explicitly list the line endings

* Removing the ImageSharp.ruleset file, as the one from standards should be used instead

* Updating the package version management to use `PackageReference Update`

Prevent zigzag overflow. Fix #922

* Fix missing PixelFormats line in first API example

"<Rgba32>" does not appear to be defined without the "using SixLabors.ImageSharp.PixelFormats;" line and causes a "The type or namespace name 'Rgba32' could not be found (are you missing a using directive or an assembly reference?) (CS0246)" error to occur.

* Remove stray newline

* Add bitmap decoder option, how to treat skipped pixels for RLE

* Refactored bitmap tests into smaller tests, instead of just one test which goes through all bitmap files

* Add another adobe v3 header bitmap testcase

* Using the constant from BmpConstants to Identify bitmaps

* Bitmap decoder now can handle oversized palette's

* Add test for invalid palette size

* Renamed RleUndefinedPixelHandling to RleSkippedPixelHandling

* Explicitly using SystemDrawingReferenceDecoder in some BitmapDecoder tests

* Add test cases for unsupported bitmaps

* Comparing RLE test images to reference decoder only on windows

* Add test case for decoding winv4 fast path

* Add another 8 Bit RLE test with magick reference decoder

* Optimize RLE skipped pixel handling

* Refactor RLE decoding to eliminate code duplication

* Using MagickReferenceDecoder for the 8-Bit RLE test

* Prevent overflow

* Cleanup huffman table

* Search for RST markers.

* Fix Benchmarks project

* Bitmap Decoder can now decode BitmapArray

* Add tests for bitmap metadata decoing. Fix an issue that a bitmap with a v5 header would be set in the metadata as an v4 header.

* Fixed issue with decoding bitmap arrays: color map size was not determined correctly. Added more test images.

* Refactor colormap size duplicate declaration.

* Fixed an issue, that when an unsupported bitmap is loaded the typ marker was not correctly shown in the error message

* Throw ImageFormatException on load

* Unseal class and make constructor internal
- This is so that no one can new it up / inherit it outside of the assembly

* Add new exception for distinguish between different exception
- This will be used on image.load operations with invalid image streams

* ImageFormatException -> UnkownImageFormatException

* Add Image.Load throws exception tests

* Add support for decoding RLE24

* Simplified determining colorMapSize, OS/2 always has 3 bytes for each palette entry

* Enum value for RLE24 is remapped to a different value, to be clearly separate from valid windows values.

* temporarily disable target frameworks

* drop DelegateProcessor

* drop IImageProcessingContext<TPixel>

* drop NamedColors<T>

* drop ColorBuilder<T>

* drop the *Base postfix for clean class hierarchies

* adding basic skeletons

* non-generic ImageFrameCollection API definition

* non-generic ImageFrameCollection tests

* cleanup + docs + more tests

* implement ImageFrameCollection methods

* tests for generic PixelOperations.To<TDest>()

* experimental implementation

* fix .ttinclude

* generate generic From<TSourcePixel>(...)

* fix RgbaVector <--> BT709 Gray pixel conversion

* Gray8 and Gray16 using ConvertFromRgbaScaledVector4() by default

* fixed all conversion tests

* ConstructGif_FromDifferentPixelTypes

* fix xmldoc and other StyelCop findings

* re-enable all target frameworks

* fix NonGenericAddFrame() and NonGenericInsertFrame()

* fix remaining bugs