Status color of glyphs

[ollimeier]

Fixes #926

Here a screenshot:

[justvanrossum]

Thanks! Looks very good.

Possible refinements:

• reduce the opacity of the color while in edit mode, maybe 50%?
• while I don't think the thickness of the color bar should be fully fixed in screen pixels, I feel it is getting too thin at very small sizes, and too dominant when zooming in. Suggestion: define a minimum and maximum thickness in screen pixels, and clamp the 50 value between them. Something like this:

  const thickness = clamp(50, parameters.minThickness, parameters.maxThickness);

[justvanrossum]

• Ane minor suggestion
• The value of "50" should also be related to the units per em (but see also previous review)

[ollimeier]

Thanks a lot for your feedback, Just.
I added a opacity for the status color. But to make it work I had to create a new function rgbaToFillStyle, because rgbaToCSS does not work with the alpha value for canvas 2d, please see the following documentation:
https://doc.qt.io/qt-5/qml-qtquick-context2d.html#fillStyle-prop
Or do you have a different idea how to solve this?

Also, to make it work with two different colors (with and without transparency) for editing and non-editing mode had to split it into two separate registerVisualizationLayerDefinition or is there a way to make it possible with one, which I am not aware of?

Beside that, I tried to implement const thickness = clamp(50, parameters.minThickness, parameters.maxThickness);, but when I added minThickness and maxThickness to the parameters, the values were scaled (related to the zoom), resulting in weird values/sizes for the status color box in the background.

I hope this all make somehow sense to you.
Here a short demo video of the modifications:

fontra-status-color.mp4

[justvanrossum]

I added a opacity for the status color. But to make it work I had to create a new function rgbaToFillStyle, because rgbaToCSS does not work with the alpha value for canvas 2d, please see the following documentation:
https://doc.qt.io/qt-5/qml-qtquick-context2d.html#fillStyle-prop

It is not that rgbaToCSS() does not work with the alpha value for canvas 2d, it does not work with the alpha value, period. You have discovered a bug :) So instead of adding a new function, you should fix the bug in the existing function.

Also, to make it work with two different colors (with and without transparency) for editing and non-editing mode had to split it into two separate registerVisualizationLayerDefinition or is there a way to make it possible with one, which I am not aware of?

Good point. While it is possible to compare positionedGlyph to model.getSelectedPositionedGlyph(), this is not ideal, and I have created #1345 to make this easier. Rebase to main, and you can use the positionedGlyph.isEditing flag.

Beside that, I tried to implement const thickness = clamp(50, parameters.minThickness, parameters.maxThickness);, but when I added minThickness and maxThickness to the parameters, the values were scaled (related to the zoom), resulting in weird values/sizes for the status color box in the background.

Having them scaled was exactly my intention. I want min and max values that are in pixels ("let the status bar not be thinner than X pixels and not be thicker than Y pixels"). So, calculate a base thickness by doing 0.05 * unitsPerEm (not scaled to pixels, this is in font units), and clamp that value between the scaled min and max values. Suggested minThickness: 3; suggested maxThickness: 15. We can fine tune later. This is exactly what I described earlier, though, but I hope it is clearer now.

[ollimeier]

I am closing this PR, because there are some weird conflicts. I will create a new one in a sec.

[justvanrossum]

Some minor comments. Almost done!