[Question] Why does Images have no backgrounds

[TenEniunlsl]

As you can see (ImageView.cs)
stc.RenderBackground(cr, 0, 0, allocation.Width, allocation.Height);
is currently commented out, why i have tried it and it works?

Also why is ther unreachable Code, is it needed?

`
protected override bool OnDrawn(Context cr)
{
var allocation = Allocation;
var stc = this.StyleContext;
//stc.RenderBackground(cr, 0, 0, allocation.Width, allocation.Height);

		if (Image is not { } image)
			return true;

		// HACK: Gtk sends sometimes a draw event while the widget reallocates.
		//       In that case we would draw in the wrong area, which may lead to artifacts
		//       if no other widget updates it. Alternative: we could clip the
		//       allocation bounds, but this may have other issues.
		if (allocation.Width == 1 && allocation.Height == 1 && allocation.X == -1 && allocation.Y == -1) // the allocation coordinates on reallocation
			return base.OnDrawn(cr);


		var imgSize = Measure(Aspect, new Size(image.Width, image.Height), allocation.Width, allocation.Height);
		var x = (allocation.Width - imgSize.Width) / 2;
		var y = (allocation.Height - imgSize.Height) / 2;

		if (false)

#pragma warning disable CS0162 // Unreachable code detected
{
using var region = Window.VisibleRegion;
using var frame = Window.BeginDrawFrame(region);
using var crr = frame.CairoContext;
crr.DrawPixbuf(image, x, y, allocation.Width, allocation.Height);
Window.EndDrawFrame(frame);
}
#pragma warning restore CS0162 // Unreachable code detected
else
{
cr.DrawPixbuf(image, x, y, imgSize.Width, imgSize.Height);
}

		return false;
	}

`

[TenEniunlsl]

Sorry the Editor breaks it strangely

[lytico]

maui-linux/src/Core/src/Platform/Gtk/ImageView.cs

Lines 119 to 156 in 118de7c

	protected override bool OnDrawn(Context cr)
	{
	var allocation = Allocation;
	var stc = this.StyleContext;
	// stc.RenderBackground(cr, 0, 0, a.Width, a.Height);
	if (Image is not { } image)
	return true;
	// HACK: Gtk sends sometimes a draw event while the widget reallocates.
	// In that case we would draw in the wrong area, which may lead to artifacts
	// if no other widget updates it. Alternative: we could clip the
	// allocation bounds, but this may have other issues.
	if (allocation.Width == 1 && allocation.Height == 1 && allocation.X == -1 && allocation.Y == -1) // the allocation coordinates on reallocation
	return base.OnDrawn(cr);
	var imgSize = Measure(Aspect, new Size(image.Width, image.Height), allocation.Width, allocation.Height);
	var x = (allocation.Width - imgSize.Width) / 2;
	var y = (allocation.Height - imgSize.Height) / 2;
	if (false)
	#pragma warning disable CS0162 // Unreachable code detected
	{
	using var region = Window.VisibleRegion;
	using var frame = Window.BeginDrawFrame(region);
	using var crr = frame.CairoContext;
	crr.DrawPixbuf(image, x, y, allocation.Width, allocation.Height);
	Window.EndDrawFrame(frame);
	}
	#pragma warning restore CS0162 // Unreachable code detected
	else
	{
	cr.DrawPixbuf(image, x, y, imgSize.Width, imgSize.Height);
	}
	return false;
	}

In the unreachable code part, it gets a fresh CairoContext from the Window, and just from the visible region.

In the currently running code part, it takes the CairoContext provided as a parameter.

I don't remember why i had to use the unreachable code, and don't remember if it worked.
It was left here as a sort of comment.

[TenEniunlsl]

ok but why is stc.RenderBackground(cr, 0, 0, allocation.Width, allocation.Height); commented out, it looks like it works?

ChatGPT means it would maybe better to implement background paintinf by my self, cause preventing so repainting calls

[lytico]

maui-linux/src/Core/src/Platform/Gtk/ImageView.cs

Line 123 in 118de7c

// stc.RenderBackground(cr, 0, 0, a.Width, a.Height);

I looked in git-history, and that commented out code doesn't scale the image correctly. The size of the image has to be done with Measure, cause there could be other aspects how big the image should be.

ChatGPT means it would maybe better to implement background paintinf by my self, cause preventing so repainting calls

Style.Background is complete other thing. The commented code "miss-used" background painting to show the image, but this was interim code before i implemented scaling. That could should be removed.