dear-imgui-rs 0.17.0

use crate::fonts::atlas::FontAtlasLoaderError;
use crate::fonts::atlas::loader::{FontLoader, FontLoaderFlags};
use crate::sys;

use super::FontAtlas;

impl FontAtlas {
    /// Sets the font loader for this atlas.
    ///
    /// This allows using custom font backends like FreeType with additional features.
    /// Returns an error if any font source has already been added, before native state changes.
    /// The loader must be static because Dear ImGui stores the raw `ImFontLoader*`.
    pub fn set_font_loader(&self, loader: &'static FontLoader) -> Result<(), FontAtlasLoaderError> {
        self.assert_mutation_allowed("FontAtlas::set_font_loader()");
        let source_count = unsafe { (*self.raw()).Sources.Size };
        assert!(
            source_count >= 0,
            "FontAtlas::set_font_loader() observed a negative native source count"
        );
        if source_count != 0 {
            return Err(FontAtlasLoaderError::SourcesAlreadyAdded {
                source_count: source_count as usize,
            });
        }
        unsafe {
            sys::ImFontAtlas_SetFontLoader(self.raw(), loader.as_ptr());
        }
        Ok(())
    }

    // Note: switching to the FreeType loader at runtime requires access to the
    // C++ symbol ImGuiFreeType_GetFontLoader(), which may not be available in
    // prebuilt dear-imgui-sys distributions. If needed, prefer configuring the
    // loader from the sys layer or ensure the symbol is exported, then add a
    // thin wrapper here.

    /// Sets global font loader flags
    ///
    /// These flags apply to all fonts loaded with this atlas unless overridden
    /// in individual FontConfig instances.
    pub fn set_font_loader_flags(&self, flags: FontLoaderFlags) {
        self.assert_mutation_allowed("FontAtlas::set_font_loader_flags()");
        unsafe {
            (*self.raw()).FontLoaderFlags = flags.0;
        }
    }

    /// Gets the current font loader flags
    pub fn font_loader_flags(&self) -> FontLoaderFlags {
        unsafe { FontLoaderFlags((*self.raw()).FontLoaderFlags) }
    }
}