wezterm/font/src/ft/ftwrap.rs

//! Higher level freetype bindings
use failure::Error;
pub use freetype::freetype::*;
use std::ffi::CString;
use std::ptr;

/// Translate an error and value into a result
fn ft_result<T>(err: FT_Error, t: T) -> Result<T, Error> {
    if err.succeeded() {
        Ok(t)
    } else {
        Err(format_err!("FreeType error {:?}", err))
    }
}

pub struct Face {
    pub face: FT_Face,
}

impl Drop for Face {
    fn drop(&mut self) {
        unsafe {
            FT_Done_Face(self.face);
        }
    }
}

impl Face {
    pub fn set_char_size(
        &mut self,
        char_width: FT_F26Dot6,
        char_height: FT_F26Dot6,
        horz_resolution: FT_UInt,
        vert_resolution: FT_UInt,
    ) -> Result<(), Error> {
        ft_result(
            unsafe {
                FT_Set_Char_Size(
                    self.face,
                    char_width,
                    char_height,
                    horz_resolution,
                    vert_resolution,
                )
            },
            (),
        )
    }

    pub fn has_codepoint(&self, cp: char) -> bool {
        unsafe {
            FT_Get_Char_Index(self.face, cp as u64) != 0
        }
    }

    pub fn load_and_render_glyph(
        &mut self,
        glyph_index: FT_UInt,
        load_flags: FT_Int32,
        render_mode: FT_Render_Mode,
    ) -> Result<&FT_GlyphSlotRec_, Error> {
        unsafe {
            let res = FT_Load_Glyph(self.face, glyph_index, load_flags);
            if res.succeeded() {
                FT_Render_Glyph((*self.face).glyph, render_mode);
            }
            ft_result(res, &*(*self.face).glyph)
        }
    }
}

pub struct Library {
    lib: FT_Library,
}

impl Drop for Library {
    fn drop(&mut self) {
        unsafe {
            FT_Done_FreeType(self.lib);
        }
    }
}

impl Library {
    pub fn new() -> Result<Library, Error> {
        let mut lib = ptr::null_mut();
        let res = unsafe { FT_Init_FreeType(&mut lib as *mut _) };
        let lib = ft_result(res, lib)?;
        Ok(Library { lib })
    }

    pub fn new_face<P>(
        &self,
        path: P,
        face_index: FT_Long,
    ) -> Result<Face, Error>
    where
        P: Into<Vec<u8>>,
    {
        let mut face = ptr::null_mut();
        let path = CString::new(path.into())?;

        let res = unsafe {
            FT_New_Face(self.lib, path.as_ptr(), face_index, &mut face as *mut _)
        };
        Ok(Face { face: ft_result(res, face)? })
    }

    pub fn set_lcd_filter(
        &mut self,
        filter: FT_LcdFilter,
    ) -> Result<(), Error> {
        unsafe {
            ft_result(FT_Library_SetLcdFilter(self.lib, filter), ())
        }
    }
}