Fix: font style setting follows the font intrinsic style

[nborodikhin]

Description

The issue:

• NextUI setting "Font Style" is wrong on either bold or non-bold fonts.

TTF font bears a property what style it is - regular, bold, italic, bold italic. NextUI has a setting to choose the font style (Normal/Bold) which is applied to the system font.

The issue is that due to the the SDL_ttf implementation, there are several possibilities, two if which are wrong. Check the following table which demonstrates the issue on Rounded Mplus 1c font (default NextUI font):

Font Face	Font style: Normal	Font style: Bold
Regular	font drawn Regular Correct	font drawn Bold (synthetic) Inconsistent stroke width, digit metrics
Bold	font drawn Bold Incorrect - normal expected	font drawn Bold Correct

From the table it is clear that:

• Normal style setting yields the Bold look for a Bold face font
• Bold style setting produces an unbalanced look for a Regular face font.
• The only correct visual representation of the font is when the style setting matches the intrinsic font face.

Matching font style setting to the font is important even when system font is bold - third-party apps may use their own fonts but rely on the font style to match NextUI's look-and-fell.

#749 which added the font style setting made it sticky. As a result, when user selected a font with a different font face weight, they get either a non-optimal "synthetic bold" look or a wrong bold look on a normal setting.

This change implements a better approach: on font selection, font style resets to match the selected font face. This way on a font change it always produces the correct combination.

Brief history of the default NextUI font

• 2025-02-01 - v0.01-beta - BPreplay Bold
• 2025-02-28 - v1.7.1-release - Rounded Mplus 1c Bold
• 2025-02-28 - v1.7.2-release - ChillRoundM Regular
• 2025-03-01 - v1.8.0-release - Rounded Mplus 1c Bold
• 2025-04-09 - v3.0.0-release - Rounded Mplus 1c Bold

There was no option to control the style of the font, it was dictated by the font file (same as Normal today).

• 2026-07-09 - v6.12.0 (PR feat: font style is now configurable (fixes #748) #749) introduced a setting to control font style.

Change

• add GFX_getSystemFontFaceStyle() to detect the intrinsic font style before NextUI applies the configured style
• reset the Font Style setting after each font selection and each Appearance reset
• map values in CFG_setFontStyle() to Normal or Bold from the SDL_ttf Bold bit

Testing

• check on tg5040, desktop
• confirm that when I select a Regular face font, Font Style setting drops to Normal