Add missing Blend Modes and expose BlendMode on Image Control

[leocb]

What does the pull request do?

This PR adds a few missing Blend Modes to the Avalonia blend modes Enum, which enables them to be used in the context render options directly.
This PR also exposes the Blend Mode render option in the Image Control as a StyledProperty RenderMode

What is the current behavior?

Currently the only way to access some blend modes is to use Skia API directly on a custom control, this PR greatly simplifies this.

What is the updated/expected behavior with this PR?

Now simply setting the BlendMode property on the Image control draws the image as expected

How was the solution implemented (if it's not obvious)?

I Added a PushRenderOptions in the Render method of the Image Control

Checklist

• Added unit tests (if possible)? - I don't know if this is test-able, please advise
• Added XML documentation to any related classes?
• Consider submitting a PR to https://github.com/AvaloniaUI/avalonia-docs with user documentation - avalonia/avalonia-docs#599

Fixed issues

Possibly Closes #17901 (if closing discussions from a PR is a thing)

[Gillibald]

Can you add a render test?

https://github.com/AvaloniaUI/Avalonia/blob/master/tests/Avalonia.RenderTests/Controls/ImageTests.cs

[cla-avalonia]

• All contributors have signed the CLA.

[leocb]

@cla-avalonia agree

[robloo]

Isn't this overconstrained to the Skia backend now? We really shouldn't design for Skia by itself. That's caused problems other places already.

IMO this should be abstracted rather than passed through.

[Gillibald]

Direct2D version for reference: https://learn.microsoft.com/en-us/windows/win32/direct2d/blend#blend-modes

[leocb]

I'll see what I can do about D2D, since I used avalonia's Enum for setting the image blend mode, should be straight forward to enable it in D2D too, maybe.

On another note, I see some tests failing, Is the way I did the options push correct? I tried other methods and none worked, I also don't see what I did anywhere else in the code, which worries me I'm doing something not the intended way.

Please advise

[avaloniaui-bot]

You can test this PR using the following package version. 11.3.999-cibuild0054137-alpha. (feed url: https://nuget-feed-all.avaloniaui.net/v3/index.json) [PRBUILDID]

[leocb]

Avalonia/src/Windows/Avalonia.Direct2D1/Media/DrawingContextImpl.cs

Line 152 in 0dd628f

// TODO: How to implement CompositeMode here?

Composite mode is required to use Blend Modes in D2D, implementing this would fall out of what I'm capable of, I think. I'll try tomorrow but no promises. Any pointers would be helpful.

[Gillibald]

Just make sure Avalonia's blend modes are covering options that are supported by major drawing libraries. Don't just map Skia 1:1

You do not have to implement the D2D part

[leocb]

Well, I believe that what I added to the Avalonia Enum are the blend modes basically everybody supports, a few modifications I'd want to do:

• Remove:
  • Modulate: same as Multiply, but the only one that also affects alpha channel.
  • Destination: which, by definition, does nothing, so why have it in the first place.
• Add:
  • Subtract: Dest color - Source color
  • Division: Dest color / Source color

I'd also consider separating them into 2 enums, composition (alpha operations) and blend (pre alpha-mult color operations) - Skia bundles them all together, but D2D has them separate

However, separating them would be a breaking change, your call.

Here's how the current enums map to each other:
Question: would the modes that are not supported simply render as the default?

Composite modes:

Avalonia:	Skia	D2D	Photoshop
Unspecified	kSrcOver	D2D1_COMPOSITE_MODE_SOURCE_OVER	Normal
SourceOver	kSrcOver	D2D1_COMPOSITE_MODE_SOURCE_OVER	Normal
Source	kSrc	D2D1_COMPOSITE_MODE_SOURCE_COPY	❔
Destination ❌	kDst	❔	❔
DestinationOver	kDstOver	D2D1_COMPOSITE_MODE_DESTINATION_OVER	❔
SourceIn	kSrcIn	D2D1_COMPOSITE_MODE_SOURCE_IN	❔
DestinationIn	kDstIn	D2D1_COMPOSITE_MODE_DESTINATION_IN	❔
SourceOut	kSrcOut	D2D1_COMPOSITE_MODE_SOURCE_OUT	❔
DestinationOut	kDstOut	D2D1_COMPOSITE_MODE_DESTINATION_OUT	❔
SourceAtop	kSrcATop	D2D1_COMPOSITE_MODE_SOURCE_ATOP	❔
DestinationAtop	kDstATop	D2D1_COMPOSITE_MODE_DESTINATION_ATOP	❔
Xor	kXor	D2D1_COMPOSITE_MODE_XOR	❔
❔	kClear	❔	Clear
❔	❔	D2D1_COMPOSITE_MODE_BOUNDED_SOURCE_COPY	❔
❔	❔	D2D1_COMPOSITE_MODE_MASK_INVERT	❔

Blend Modes

Avalonia:	Skia	D2D	Photoshop
Screen	kScreen	D2D1_BLEND_MODE_SCREEN	Screen
Overlay	kOverlay	D2D1_BLEND_MODE_OVERLAY	Overlay
Plus	kPlus	D2D1_BLEND_MODE_LINEAR_DODGE	Linear Dodge (Add)
Subtract ➕	❔	D2D1_BLEND_MODE_SUBTRACT	Subtract
Darken	kDarken	D2D1_BLEND_MODE_DARKEN	Darken
Lighten	kLighten	D2D1_BLEND_MODE_LIGHTEN	Lighten
ColorDodge	kColorDodge	D2D1_BLEND_MODE_COLOR_DODGE	Color Dodge
ColorBurn	kColorBurn	D2D1_BLEND_MODE_COLOR_BURN	Color Burn
HardLight	kHardLight	D2D1_BLEND_MODE_HARD_LIGHT	Hard Light
SoftLight	kSoftLight	D2D1_BLEND_MODE_SOFT_LIGHT	Soft Light
Difference	kDifference	D2D1_BLEND_MODE_DIFFERENCE	Difference
Exclusion	kExclusion	D2D1_BLEND_MODE_EXCLUSION	Exclusion
Division ➕	❔	D2D1_BLEND_MODE_DIVISION	Divide
Multiply	kMultiply	D2D1_BLEND_MODE_MULTIPLY	Multiply
Modulate ❌	kModulate	❔	❔
Hue	kHue	D2D1_BLEND_MODE_HUE	Hue
Saturation	kSaturation	D2D1_BLEND_MODE_SATURATION	Saturation
Color	kColor	D2D1_BLEND_MODE_COLOR	Color
Luminosity	kLuminosity	D2D1_BLEND_MODE_LUMINOSITY	Luminosity
❔	❔	D2D1_BLEND_MODE_LINEAR_BURN	Linear Burn
❔	❔	D2D1_BLEND_MODE_DARKER_COLOR	Darker Color
❔	❔	D2D1_BLEND_MODE_LIGHTER_COLOR	Lighter Color
❔	❔	D2D1_BLEND_MODE_VIVID_LIGHT	Vivid Light
❔	❔	D2D1_BLEND_MODE_LINEAR_LIGHT	Linear Light
❔	❔	D2D1_BLEND_MODE_PIN_LIGHT	Pin Light
❔	❔	D2D1_BLEND_MODE_HARD_MIX	Hard Mix
❔	❔	D2D1_BLEND_MODE_DISSOLVE	Dissolve

These last blend modes are variations of other blend modes, mostly never used

[avaloniaui-bot]

You can test this PR using the following package version. 11.3.999-cibuild0054157-alpha. (feed url: https://nuget-feed-all.avaloniaui.net/v3/index.json) [PRBUILDID]