diff --git a/ui/src/terminal.rs b/ui/src/terminal.rs index 10a9f397..9199748b 100644 --- a/ui/src/terminal.rs +++ b/ui/src/terminal.rs @@ -108,3 +108,332 @@ derive_csi_sequence!( pub const BRACKET_PASTE_START: &[u8] = b"\x1B[200~"; pub const BRACKET_PASTE_END: &[u8] = b"\x1B[201~"; + +pub use braille::BraillePixelIter; +mod braille { + mod tests { + const _X_QRCODE: [u16; 3 * 48] = [ + 0xff3f, 0x3cf3, 0xff03, 0xff3f, 0x3cf3, 0xff03, 0x0330, 0x0333, 0x0003, 0x0330, 0x0333, + 0x0003, 0xf333, 0xf030, 0x3f03, 0xf333, 0xf030, 0x3f03, 0xf333, 0xfc33, 0x3f03, 0xf333, + 0xfc33, 0x3f03, 0xf333, 0x0f33, 0x3f03, 0xf333, 0x0f33, 0x3f03, 0x0330, 0x3033, 0x0003, + 0x0330, 0x3033, 0x0003, 0xff3f, 0x33f3, 0xff03, 0xff3f, 0x33f3, 0xff03, 0x0000, 0xc003, + 0x0000, 0x0000, 0xc003, 0x0000, 0x3333, 0xfc00, 0xc300, 0x3333, 0xfc00, 0xc300, 0xc3c0, + 0x3f30, 0x0c00, 0xc3c0, 0x3f30, 0x0c00, 0xcff0, 0x3f03, 0xcf00, 0xcff0, 0x3f03, 0xcf00, + 0x0ccf, 0x0f30, 0xcc00, 0x0ccf, 0x0f30, 0xcc00, 0x0033, 0x3033, 0xf300, 0x0033, 0x3033, + 0xf300, 0x0000, 0xffcc, 0x0c00, 0x0000, 0xffcc, 0x0c00, 0xff3f, 0xccfc, 0x3000, 0xff3f, + 0xccfc, 0x3000, 0x0330, 0xf0cf, 0x0f00, 0x0330, 0xf0cf, 0x0f00, 0xf333, 0xcffc, 0x3003, + 0xf333, 0xcffc, 0x3003, 0xf333, 0x0030, 0xf000, 0xf333, 0x0030, 0xf000, 0xf333, 0x3f03, + 0x0303, 0xf333, 0x3f03, 0x0303, 0x0330, 0x3030, 0xf003, 0x0330, 0x3030, 0xf003, 0xff3f, + 0x0333, 0x3303, 0xff3f, 0x0333, 0x3303, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, + 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, + 0x0000, + ]; + + const _XTTHOMAS: [u16; 3 * 48] = [ + 0xFFFF, 0xFF0F, 0x0000, 0xFFFF, 0xFF0F, 0x0000, 0x1FFC, 0xC10F, 0x0000, 0x0FFC, 0x810F, + 0x0000, 0x07FC, 0x010F, 0x0000, 0x07FC, 0x010F, 0x0000, 0x03FC, 0x010E, 0x0000, 0x03FC, + 0x010E, 0x0000, 0x01FC, 0x010C, 0x0000, 0x00FC, 0x0100, 0x0000, 0x00FC, 0x0100, 0x0000, + 0x00FC, 0x0100, 0x0000, 0x00FC, 0x0100, 0x0000, 0x00FC, 0x0100, 0x0000, 0x00FC, 0x0100, + 0x0000, 0x00FC, 0x0100, 0x0000, 0x00FC, 0x0100, 0x0000, 0x00FC, 0xFDFF, 0xFF7F, 0x00FC, + 0xFDFF, 0xFF7F, 0x00FC, 0xFDE0, 0x0F7E, 0x00FC, 0x7DE0, 0x0F7C, 0x00FC, 0x3DE0, 0x0F78, + 0x00FC, 0x3DE0, 0x0F78, 0x00FC, 0x1DE0, 0x0F70, 0x00FC, 0x1DE0, 0x0F70, 0x00FC, 0x0DE0, + 0x0F60, 0x00FC, 0x01E0, 0x0F00, 0x00FE, 0x07E0, 0x0F00, 0xC0FF, 0x1FE0, 0x0F00, 0xC0FF, + 0x1FE0, 0x0F00, 0x0000, 0x00E0, 0x0F00, 0x0000, 0x00E0, 0x0F00, 0x0000, 0x00E0, 0x0F00, + 0x0000, 0x00E0, 0x0F00, 0x0000, 0x00E0, 0x0F00, 0x0000, 0x00E0, 0x0F00, 0x0000, 0x00E0, + 0x0F00, 0x0000, 0x00E0, 0x0F00, 0x0000, 0x00E0, 0x0F00, 0x0000, 0x00E0, 0x0F00, 0x0000, + 0x00E0, 0x0F00, 0x0000, 0x00E0, 0x0F00, 0x0000, 0x00E0, 0x0F00, 0x0000, 0x00E0, 0x0F00, + 0x0000, 0x00F0, 0x3F00, 0x0000, 0x00FE, 0xFF00, 0x0000, 0x00FE, 0xFF00, 0x0000, 0x0000, + 0x0000, + ]; + + const _FBIRD_SCALED_DOWN: [u16; 3 * 48] = [ + 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, + 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, + 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, + 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, + 0x0000, 0x00e0, 0x0100, 0x0000, 0x0000, 0x0f00, 0x0000, 0x0000, 0x3c00, 0x0000, 0x00e0, + 0x790c, 0x0000, 0x00fc, 0xff3f, 0x0000, 0x0043, 0xffff, 0x0300, 0x0000, 0xfc0f, 0x0000, + 0x0000, 0xf00f, 0x0000, 0x0000, 0xf00f, 0x0000, 0x0000, 0xf00f, 0x0000, 0x0000, 0xfc07, + 0x0000, 0x0000, 0xfc03, 0x0000, 0x0000, 0xfc00, 0x0000, 0x0000, 0x0e00, 0x0000, 0x0000, + 0x0700, 0x0000, 0x0000, 0x0700, 0x0000, 0x0040, 0x0300, 0x0000, 0x0000, 0x0200, 0x0000, + 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, + 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, + 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, + 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, + 0x0000, + ]; + + const _FBIRD: [u16; 3 * 48] = [ + 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, + 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, + 0x0000, 0x0000, 0x007E, 0x0000, 0x0000, 0x00E0, 0x0700, 0x0000, 0x0080, 0x1F00, 0x0000, + 0x0000, 0x7F00, 0x0000, 0x007E, 0xFCE0, 0x0000, 0xC0FF, 0xFFF9, 0x0300, 0xF0FF, 0xFFFF, + 0x0700, 0x0CE8, 0xFFFF, 0xFF00, 0x0080, 0xFFFF, 0x0103, 0x0000, 0xFEFF, 0x0000, 0x0000, + 0xF8FF, 0x0000, 0x0000, 0xF07F, 0x0000, 0x0000, 0xF07F, 0x0000, 0x0000, 0xF87F, 0x0000, + 0x0000, 0xFC3F, 0x0000, 0x0000, 0xFE3F, 0x0000, 0x0000, 0xFE1F, 0x0000, 0x0000, 0xFF07, + 0x0000, 0x0000, 0xFF01, 0x0000, 0x0080, 0x0F00, 0x0000, 0x0080, 0x0700, 0x0000, 0x00C0, + 0x0300, 0x0000, 0x00E0, 0x0300, 0x0000, 0x00F0, 0x0300, 0x0000, 0x00E8, 0x0100, 0x0000, + 0x0080, 0x0100, 0x0000, 0x0000, 0x0100, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, + 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, + 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, + 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, + 0x0000, + ]; + + const _XFISH: [u16; 3 * 48] = [ + 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, + 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, + 0x0000, 0x0000, 0x007E, 0x0000, 0x0000, 0x00E0, 0x0700, 0x0000, 0x0080, 0x1F00, 0x0000, + 0x0000, 0x7F00, 0x0000, 0x007E, 0xFCE0, 0x0000, 0xC0FF, 0xFFF9, 0x0300, 0xF0FF, 0xFFFF, + 0x0700, 0x0CE8, 0xFFFF, 0xFF00, 0x0080, 0xFFFF, 0x0103, 0x0000, 0xFEFF, 0x0000, 0x0000, + 0xF8FF, 0x0000, 0x0000, 0xF07F, 0x0000, 0x0000, 0xF07F, 0x0000, 0x0000, 0xF87F, 0x0000, + 0x0000, 0xFC3F, 0x0000, 0x0000, 0xFE3F, 0x0000, 0x0000, 0xFE1F, 0x0000, 0x0000, 0xFF07, + 0x0000, 0x0000, 0xFF01, 0x0000, 0x0080, 0x0F00, 0x0000, 0x0080, 0x0700, 0x0000, 0x00C0, + 0x0300, 0x0000, 0x00E0, 0x0300, 0x0000, 0x00F0, 0x0300, 0x0000, 0x00E8, 0x0100, 0x0000, + 0x0080, 0x0100, 0x0000, 0x0000, 0x0100, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, + 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, + 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, + 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, + 0x0000, + ]; + + const _XFACE: [u16; 3 * 48] = [ + 0xAAAA, 0xAAAA, 0xAAAA, 0x0000, 0x0000, 0x0000, 0xAAAA, 0xAAAA, 0xAAA8, 0x0000, 0x0000, + 0x0000, 0xA222, 0x2222, 0x222A, 0x0000, 0x0000, 0x0000, 0xAAAA, 0xAAAA, 0xAAA2, 0x0000, + 0x0000, 0x0000, 0xA222, 0x2222, 0x2228, 0x0000, 0x0000, 0x0000, 0xAAAA, 0xAAAA, 0xAAAA, + 0x0000, 0x0000, 0x0000, 0xA222, 0x2222, 0x2222, 0x0000, 0x0000, 0x0000, 0xAAAA, 0xAAAA, + 0xAAA8, 0x0000, 0x0000, 0x0000, 0xA222, 0x2222, 0x222A, 0x0000, 0x0000, 0x0000, 0xAAAA, + 0xAAAA, 0xAAA2, 0x0000, 0x0000, 0x0000, 0xA222, 0x2222, 0x2228, 0x0000, 0x0000, 0x0000, + 0xAAAA, 0xAAAA, 0xAAAA, 0x0000, 0x0000, 0x0000, 0xA222, 0x2222, 0x2222, 0x0000, 0x0000, + 0x0000, 0xAAAA, 0xAAAA, 0xAAA8, 0x0000, 0x0000, 0x0000, 0xA222, 0x2222, 0x222A, 0x0000, + 0x0000, 0x0000, 0xAAAA, 0xAAAA, 0xAAA2, 0x0000, 0x0000, 0x0000, 0xA222, 0x2222, 0x2228, + 0x0000, 0x0000, 0x0000, 0xAAAA, 0xAAAA, 0xAAAA, 0x0000, 0x0000, 0x0000, 0xA222, 0x2222, + 0x2222, 0x0000, 0x0000, 0x0000, 0xAAAA, 0xAAAA, 0xAAA8, 0x0000, 0x0000, 0x0000, 0xA222, + 0x2222, 0x222A, 0x0000, 0x0000, 0x0000, 0xAAAA, 0xAAAA, 0xAAA2, 0x0000, 0x0000, 0x0000, + 0xA222, 0x2222, 0x2228, 0x0000, 0x0000, 0x0000, 0xAAAA, 0xAAAA, 0xAAAA, 0x0000, 0x0000, + 0x0000, + ]; + + #[test] + fn test_braille() { + /* lines has 12 bitmaps, with 3 bitmap making each line that is 4 lines. + * lines = [ + * a_0, a_1, a_2, + * b_0, b_1, b_2, + * c_0, c_1, c_2, + * d_0, d_1, d_2, + * ]; + */ + println!("Thomas: "); + for lines in _XTTHOMAS.chunks(12) { + let iter = super::BraillePixelIter::from(lines); + for b in iter { + print!("{}", b); + } + println!(""); + } + + println!("fbird: "); + for lines in _FBIRD.chunks(12) { + let iter = super::BraillePixelIter::from(lines); + for b in iter { + print!("{}", b); + } + println!(""); + } + println!("ABC QR code: "); + for lines in _X_QRCODE.chunks(12) { + let iter = super::BraillePixelIter::from(lines); + for b in iter { + print!("{}", b); + } + println!(""); + } + } + } + struct Braille16bitColumn { + // each u16 in the tuple is one line ( first_line, second_line, third_line, fourth line) */ + bitmaps: (u16, u16, u16, u16), + // reverse 1-indexing, so column: 1 means the left-most column in 16bit word */ + bitcolumn: u32, + } + + /* + impl std::fmt::Debug for Braille16bitColumn { + fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result { + write!( + f, + "Braille16bitColumn {{\n bitmaps: \n{:x}\n{:x}\n{:x}\n{:x},\n bitcolumn: {}\n\n{}\n{:016b}\n{:016b}\n{:016b}\n{:016b},\n + }}",self.bitmaps.0, self.bitmaps.1, self.bitmaps.2, self.bitmaps.3, self.bitcolumn, format!("{:016b}", 0x0001_u16.rotate_left(self.bitcolumn)).replace("0"," ").replace("1", "v"), self.bitmaps.0, self.bitmaps.1, self.bitmaps.2, self.bitmaps.3, + ) + } + } + */ + + /// Iterate on 2x4 pixel blocks from a bitmap and return a unicode braille character for each + /// block. The iterator holds four lines of bitmaps encoded as `u16` numbers in swapped bit + /// order, like the `xbm` graphics format. The bitmap is split to `u16` columns. + /// + /// ## Usage + /// ```no_run + /// /* BEE is the contents of a 48x48 xbm file. xbm is a C-like array of 8bit values, and + /// * each pair was manually (macro-ually?) condensed into a single 16bit value. Each 3 items + /// * represent one pixel row. + /// */ + /// const BEE: [u16; 3 * 48] = [ + /// 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, + /// 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, + /// 0x0000, 0x0002, 0x0000, 0x0000, 0xe003, 0x0000, 0x0000, 0xfc00, 0x0000, 0x0000, 0x3f00, + /// 0x0000, 0x00e0, 0x0f00, 0x0000, 0x00f8, 0x0300, 0x0000, 0x00fe, 0x0000, 0x0080, 0x8f0d, + /// 0x0000, 0x00e0, 0xff7f, 0x0000, 0x00f8, 0xffff, 0x0300, 0x00fc, 0xffff, 0x0f00, 0x00fe, + /// 0xffff, 0x3f00, 0x00ff, 0xffff, 0xff00, 0xc0ff, 0xffff, 0xff01, 0xc0ff, 0xff77, 0xff07, + /// 0xf0f9, 0xffff, 0xff07, 0xf0f0, 0xffef, 0xfd0f, 0xf0e0, 0xffff, 0xfb1f, 0xf0e1, 0xffc1, + /// 0xfb0f, 0xe0f3, 0xffc3, 0xf307, 0xc0f7, 0xffc0, 0xe100, 0xc0ff, 0xd9e0, 0x3f00, 0x803e, + /// 0xc1f8, 0x5f00, 0x8076, 0x43f4, 0xbf18, 0x806c, 0x43fc, 0xf325, 0x0009, 0xc3df, 0x4326, + /// 0x001a, 0xcf3f, 0x622d, 0x0034, 0xff01, 0x2224, 0x00f0, 0xff00, 0x8312, 0x00a0, 0x5700, + /// 0x0309, 0x00f8, 0x1b00, 0x8f06, 0x0048, 0x6000, 0xcd03, 0x0018, 0x6624, 0xdf00, 0x0030, + /// 0x820f, 0x3f00, 0x00c0, 0xf0ff, 0x3f00, 0x0080, 0x03fe, 0x7f00, 0x0000, 0x7ce0, 0x0f00, + /// 0x0000, 0x809f, 0x1c00, 0x0000, 0x0000, 0x3800, 0x0000, 0x0000, 0x7000, 0x0000, 0x0000, + /// 0xe000, + /// ]; + /// + /// for lines in BEE.chunks(12) { + /// let iter = ui::BraillePixelIter::from(lines); + /// for b in iter { + /// print!("{}", b); + /// } + /// println!(""); + /// } + /// ``` + /// + /// Output: + /// + /// ```text + /// ⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⢀⠀⠀⠀ + /// ⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⢀⣀⣤⣶⠾⠛⠉⠀⠀⠀ + /// ⠀⠀⠀⠀⠀⠀⢀⣠⣤⣤⣀⣠⣔⣾⣛⡛⠉⠀⠀⠀⠀⠀⠀⠀ + /// ⠀⠀⠀⠀⣠⣾⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣶⣤⣀⠀⠀⠀⠀ + /// ⠀⠀⣤⣿⠟⠻⣿⣿⣿⣿⣿⣿⣿⣯⢿⣯⡿⣿⣿⣿⣷⣆⠀⠀ + /// ⠀⠀⠻⣿⣦⡀⣼⣿⣿⣿⣿⣿⠯⠉⠉⣿⡿⠘⢿⣿⠿⠟⠁⠀ + /// ⠀⠀⠀⢹⠹⣟⢿⡍⣧⠈⠁⡟⠀⣔⣾⣿⣿⠿⣯⣢⡀⡠⢄⠀ + /// ⠀⠀⠀⠀⠑⠜⣦⣀⣿⣶⣤⣿⠟⠛⠓⠉⣹⠀⠰⢃⢊⠗⡸⠀ + /// ⠀⠀⠀⠀⠀⢰⡚⠞⢛⡑⢣⡅⠀⡀⢀⠀⣟⣶⡀⣴⠵⠊⠀⠀ + /// ⠀⠀⠀⠀⠀⠀⠉⠲⠬⣀⣒⡚⠻⠿⢶⣶⣿⣿⠿⠄⠀⠀⠀⠀ + /// ⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠈⠉⠉⠁⠈⠀⠙⢷⣄⠀⠀⠀ + /// ``` + /// + /// + /// ## Explanation: + /// For the following bitmap: + /// ```text + /// ◻◼◻◻◼◻◻◼◻◻◻◼◼◼◼◼ + /// ◼◼◼◼◼◼◻◻◼◻◼◻◻◼◼◼ + /// ◻◼◼◼◼◼◼◼◻◻◻◻◼◼◻◻ + /// ◼◻◼◼◻◼◼◻◼◼◼◻◻◻◻◻ + /// ``` + /// + /// Iteration on each step examines two columns: + /// ```text + /// ⇩⇩ + /// ◻◼┆◻◻┆◼◻┆◻◼┆◻◻┆◻◼┆◼◼┆◼◼ + /// ◼◼┆◼◼┆◼◼┆◻◻┆◼◻┆◼◻┆◻◼┆◼◼ + /// ◻◼┆◼◼┆◼◼┆◼◼┆◻◻┆◻◻┆◼◼┆◻◻ + /// ◼◻┆◼◼┆◻◼┆◼◻┆◼◼┆◼◻┆◻◻┆◻◻ + /// ``` + /// + /// The first two columns are encoded as: + /// + /// ```text + /// ┏━━━━━━┳━━━━┓ + /// ┃pixels┃bits┃ + /// ┡━━━━━━╇━━━━┩ + /// │ ◻◼ │ 14 │ + /// │ ◼◼ │ 25 │ + /// │ ◻◻ │ 36 │ + /// │ ◼◻ │ 78 │ + /// └──────┴────┘ + /// = + /// braille bitmap is + /// ◻◼◻◼◼◻◼◻ = 0b01011010 = 0x5A + /// 12345678 + /// ``` + /// and braille character is bitmap + 0x2800 (Braille block's position in Unicode) + /// ```text + /// 0x5A + 0x2800 = 0x285A = '⡚' + /// ``` + /// + /// Why three columns? I originally wrote this for X-Face bitmaps, which are 48x48 pixels. + pub struct BraillePixelIter { + columns: [Braille16bitColumn; 3], + column_ptr: usize, + } + + impl From<&[u16]> for BraillePixelIter { + fn from(from: &[u16]) -> Self { + BraillePixelIter { + columns: [ + Braille16bitColumn { + bitmaps: ( + from[0].swap_bytes().reverse_bits(), + from[3].swap_bytes().reverse_bits(), + from[6].swap_bytes().reverse_bits(), + from[9].swap_bytes().reverse_bits(), + ), + bitcolumn: 1, + }, + Braille16bitColumn { + bitmaps: ( + from[1].swap_bytes().reverse_bits(), + from[4].swap_bytes().reverse_bits(), + from[7].swap_bytes().reverse_bits(), + from[10].swap_bytes().reverse_bits(), + ), + bitcolumn: 1, + }, + Braille16bitColumn { + bitmaps: ( + from[2].swap_bytes().reverse_bits(), + from[5].swap_bytes().reverse_bits(), + from[8].swap_bytes().reverse_bits(), + from[11].swap_bytes().reverse_bits(), + ), + bitcolumn: 1, + }, + ], + column_ptr: 0, + } + } + } + + impl Iterator for BraillePixelIter { + type Item = char; + fn next(&mut self) -> Option { + if self.columns[self.column_ptr].bitcolumn == 17 { + if self.column_ptr == 2 { + return None; + } + self.column_ptr += 1; + } + let Braille16bitColumn { + ref bitmaps, + ref mut bitcolumn, + } = &mut self.columns[self.column_ptr]; + /* First bitcolumn out of two (braille is 2x4) */ + let mut bits: u16 = 0x1 & (bitmaps.0.rotate_left(*bitcolumn)); // * 0x1; + bits += (0x1 & (bitmaps.1.rotate_left(*bitcolumn))) * 0x2; + bits += (0x1 & (bitmaps.2.rotate_left(*bitcolumn))) * 0x4; + bits += (0x1 & (bitmaps.3.rotate_left(*bitcolumn))) * 0x40; + /* Second bitcolumn */ + *bitcolumn += 1; + bits += (0x1 & (bitmaps.0.rotate_left(*bitcolumn))) * 0x8; + bits += (0x1 & (bitmaps.1.rotate_left(*bitcolumn))) * 0x10; + bits += (0x1 & (bitmaps.2.rotate_left(*bitcolumn))) * 0x20; + bits += (0x1 & (bitmaps.3.rotate_left(*bitcolumn))) * 0x80; + *bitcolumn += 1; + + /* The Braille Patterns block spans the entire [U+2800, U+28FF] range and bits is a + * 16bit integer ∈ [0x00, 0xFF] so this is guaranteed to be a Unicode char */ + Some(unsafe { std::char::from_u32_unchecked(bits as u32 + 0x2800) }) + } + } +}