Italic-style look for upright font

[pv4]

Is it possible to add an option/setting to get an italic-style look for upright font?

On the picture attached you can see how cyrillic would look like if such an option existed and was enabled. E.g. look at de having de.italic style applied as well as many other glyphs.

The variant attached was got by building with

[buildPlans.iosevka-some.slopes]
upright='italic'

and applying the sed before building:

sed -i "s/\.upright/.italic/g" font-src/glyphs/common/derivatives.*

[be5invis]

Merge into #599. This is about slope angle customization.

[pv4]

This is about slope angle customization.

Not really. I don't want "Italic with a zero slope angle". I want "Regular with italic look AND zero slope angle".

I think I've found a better way than in the original post.

First, allow changing isItalic in private-build-plans.toml:

diff -Napur Iosevka-dev.orig/font-src/support/parameters.js Iosevka-dev/font-src/support/parameters.js
--- Iosevka-dev.orig/font-src/support/parameters.js     2021-07-17 08:50:52.000000000 +0300
+++ Iosevka-dev/font-src/support/parameters.js  2021-07-23 16:32:41.084191868 +0300
@@ -135,6 +135,9 @@ function createMetricDataSet(sink, mo) {
 function numericFieldHandler(sink, key, x) {
        if (x != null && isFinite(x)) sink[key] = x;
 }
+function booleanFieldHandler(sink, key, x) {
+       sink[key] = x;
+}
 function subObjectHandler(sink, key, obj) {
        sink[key] = {};
        createMetricDataSet(sink[key], obj);
@@ -154,5 +157,6 @@ const metricOverrideHandlers = {
        powerlineShiftX: numericFieldHandler,
        onumZeroHeightRatio: numericFieldHandler,
        multiplies: subObjectHandler,
-       adds: subObjectHandler
+       adds: subObjectHandler,
+       isItalic: booleanFieldHandler
 };

Then, use the following settings for build plan:

[buildPlans.iosevka-some.slopes]
upright='normal'

[buildPlans.iosevka-some.metric-override]
isItalic=true

Now iosevka-some-regular.ttf has the look I want.

Could you consider please making such a possibility supported? In #599 you wrote:

I think slope angles less than 10° should work, but not tested.

I guess zero is less than 10 so it "should work". But font-src/meta/naming.ptl has the following code that makes me think that using isItalic for Regular family is wrong and would behave badly in some environments.

set font.os2.fsSelection : accumulate : list
[...]
    list  Ot.Os2.FsSelection.ITALIC            (isItalic || isOblique)
    list  Ot.Os2.FsSelection.REGULAR           (!isBold && !isItalic && !isOblique)
[...]
set font.head.macStyle : accumulate : list
[...]
    list  Ot.Head.MacStyle.Italic     (isItalic || isOblique)

What do you think?

[be5invis]

With the new slope customization, you can do that. The result is like

[buildPlans.iosevka-custom.slopes.upright]
angle = 0
shape = "italic"
menu  = "upright"
css   = "normal"

[pv4]

Thank you!