Adding QOI support

[LuisAlfredo92]

Prerequisites

• I have written a descriptive pull-request title
• I have verified that there are no overlapping pull-requests open
• I have verified that I am following the existing coding patterns and practice as demonstrated in the repository. These follow strict Stylecop rules 👮.
• I have provided test coverage for my change (where applicable)

Description

First of all, I'm sorry for being so late to add this, I've been extremely busy :(
Also I took some time to see the code to understand it and do it with the same structure

Then, I've add some files to work with qoi, at this moment it only identifies qoi images and returns the ImageInfo, but I want to make sure that I'm doing this correctly before doing the rest of functions. I've followed the Stylecop rules with Visual Studio Intellisense.

The test images were taken from the official website in the Test images in QOI and PNG format link.

This is about #2403

Could you review it please?

[CLAassistant]

All committers have signed the CLA.

[antonfirsov]

Since you already implemented Identify, your next step is probably to make sure it actually works. Here's an example test, you want an equivalent for Qoi:

ImageSharp/tests/ImageSharp.Tests/Formats/Png/PngDecoderTests.cs

Lines 338 to 355 in 7d0bbbd

	[Theory]
	[InlineData(TestImages.Png.Bpp1,1)]
	[InlineData(TestImages.Png.Gray4Bpp,4)]
	[InlineData(TestImages.Png.Palette8Bpp,8)]
	[InlineData(TestImages.Png.Pd,24)]
	[InlineData(TestImages.Png.Blur,32)]
	[InlineData(TestImages.Png.Rgb48Bpp,48)]
	[InlineData(TestImages.Png.Rgb48BppInterlaced,48)]
	publicvoidIdentify(stringimagePath,intexpectedPixelSize)
	{
	TestFiletestFile=TestFile.Create(imagePath);
	usingMemoryStreamstream=new(testFile.Bytes,false);
	ImageInfoimageInfo=Image.Identify(stream);
	Assert.NotNull(imageInfo);
	Assert.Equal(expectedPixelSize,imageInfo.PixelType.BitsPerPixel);
	}

(I recommend to validate image size and stuff like QoiChannels and QoiColorSpace there.)

To make sure the format is recognized by Image.Identify and Image.Load and triggers your decoder, you also need to implement and register a "configuration module":

ImageSharp/src/ImageSharp/Configuration.cs

Lines 217 to 225 in 7d0bbbd

	internalstaticConfigurationCreateDefaultInstance()=>new(
	newPngConfigurationModule(),
	newJpegConfigurationModule(),
	newGifConfigurationModule(),
	newBmpConfigurationModule(),
	newPbmConfigurationModule(),
	newTgaConfigurationModule(),
	newTiffConfigurationModule(),
	newWebpConfigurationModule());

[antonfirsov]

There are some some StyleCop complaints breaking the build since we use TreatWarningsAsErrors:
https://github.com/SixLabors/ImageSharp/actions/runs/4885169437/jobs/8735504561?pr=2446

When you will move on to the actual Decode implementation, you want to base your decoder tests on this:

ImageSharp/tests/ImageSharp.Tests/Formats/Pbm/PbmDecoderTests.cs

Lines 81 to 99 in 7d0bbbd

	[Theory]
	[WithFile(BlackAndWhitePlain,PixelTypes.L8,"pbm")]
	[WithFile(BlackAndWhiteBinary,PixelTypes.L8,"pbm")]
	[WithFile(GrayscalePlain,PixelTypes.L8,"pgm")]
	[WithFile(GrayscalePlainNormalized,PixelTypes.L8,"pgm")]
	[WithFile(GrayscaleBinary,PixelTypes.L8,"pgm")]
	[WithFile(GrayscaleBinaryWide,PixelTypes.L16,"pgm")]
	[WithFile(RgbPlain,PixelTypes.Rgb24,"ppm")]
	[WithFile(RgbPlainNormalized,PixelTypes.Rgb24,"ppm")]
	[WithFile(RgbBinary,PixelTypes.Rgb24,"ppm")]
	publicvoidDecodeReferenceImage<TPixel>(TestImageProvider<TPixel>provider,stringextension)
	whereTPixel: unmanaged,IPixel<TPixel>
	{
	usingImage<TPixel>image=provider.GetImage();
	image.DebugSave(provider,extension:extension);
	boolisGrayscale=extensionis"pgm" or "pbm";
	image.CompareToReferenceOutput(provider,grayscale:isGrayscale);
	}

First just make sure visually that DebugSave is saving the right thing. CompareToReferenceOutput would need your reference png to be in the right directory with the right name, we can explain that later.

[LuisAlfredo92]

Thanks for the reviewing, I'll correct everything and tell when I start working on the other functions 👍

[LuisAlfredo92]

Hello again, I can finally work in this again 🎉

I've made the changes you told me, however, I didn't find how to run the tests, so I only added the configurations but didn't test them

Soon I'll try to add the Decode and Encode options

[antonfirsov]

I didn't find how to run the tests.

You can use dotnet test from the command line:

 dotnet test -f net6.0 --filter FullyQualifiedName~QoiDecoderTests

Or if you are using Visual Studio, they should appear in the Test Explorer window.

[LuisAlfredo92]

There are some some StyleCop complaints breaking the build since we use TreatWarningsAsErrors: https://github.com/SixLabors/ImageSharp/actions/runs/4885169437/jobs/8735504561?pr=2446

When you will move on to the actual Decode implementation, you want to base your decoder tests on this:

ImageSharp/tests/ImageSharp.Tests/Formats/Pbm/PbmDecoderTests.cs

Lines 81 to 99 in 7d0bbbd

	[Theory]
	[WithFile(BlackAndWhitePlain,PixelTypes.L8,"pbm")]
	[WithFile(BlackAndWhiteBinary,PixelTypes.L8,"pbm")]
	[WithFile(GrayscalePlain,PixelTypes.L8,"pgm")]
	[WithFile(GrayscalePlainNormalized,PixelTypes.L8,"pgm")]
	[WithFile(GrayscaleBinary,PixelTypes.L8,"pgm")]
	[WithFile(GrayscaleBinaryWide,PixelTypes.L16,"pgm")]
	[WithFile(RgbPlain,PixelTypes.Rgb24,"ppm")]
	[WithFile(RgbPlainNormalized,PixelTypes.Rgb24,"ppm")]
	[WithFile(RgbBinary,PixelTypes.Rgb24,"ppm")]
	publicvoidDecodeReferenceImage<TPixel>(TestImageProvider<TPixel>provider,stringextension)
	whereTPixel: unmanaged,IPixel<TPixel>
	{
	usingImage<TPixel>image=provider.GetImage();
	image.DebugSave(provider,extension:extension);
	boolisGrayscale=extensionis"pgm" or "pbm";
	image.CompareToReferenceOutput(provider,grayscale:isGrayscale);
	}

First just make sure visually that DebugSave is saving the right thing. CompareToReferenceOutput would need your reference png to be in the right directory with the right name, we can explain that later.

Hello again, I need some help with the tests

When I try to test the Qoi decoder, when it tries to get the extension, qoi image format never appears:

However, during debugging, it actually is correctly added:

So I don't know if I must add something else on the code or tests

Just in case, my qoi configuration module adds only a decoder and format detector

EDIT
I created the encoder class just to add it to the configuration (although it doesn't do anything yet) but still doesn't work

[LuisAlfredo92]

Nevermind, I found where the configuration is done

[JimBobSquarePants]

Nevermind, I found where the configuration is done

Sorry, didn't see this. Glad you figured it out. Any other questions please let me know!

[LuisAlfredo92]

Hello!
I've finished the decoder and it passes all the tests 🎉 I've also taken into consideration the edge case and now it works perfectly, however, I'm not sure if I followed correctly the standards of the project, could you check it please?

I'll be working on the encoder now

[LuisAlfredo92]

Hello again
I've finished encoder, decoder and extensions, and all of them have passed all the tests, but we should discuss some things about the encoder (if it's correct to allow file to start with a QOI_OP_RUN) and decoder (throw an exception when the end of stream doesn't end with seven zero-bytes and one byte with value 1). I wrote some comments if you want to check

I'd like to ask for a review to see if I'm not doing something wrong

[LuisAlfredo92]

When you publish the 3.1.0 version, could I add ImageSharp it to the phoboslab/qoi repository README? Maybe on tools or implementations

[antonfirsov]

Yeah I also wanted to call out that we need to get into that hall of fame after the release.