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/*! This crate allows you to easily write text. Usage: ```no_run # extern crate glium; # extern crate glium_text_rusttype as glium_text; # extern crate cgmath; # use std::fs::File; # fn main() { # let display: glium::Display = unsafe { std::mem::uninitialized() }; // The `TextSystem` contains the shaders and elements used for text display. let system = glium_text::TextSystem::new(&display); // Creating a `FontTexture`, which a regular `Texture` which contains the font. // Note that loading the systems fonts is not covered by this library. let font = glium_text::FontTexture::new( &display, File::open("font.ttf").unwrap(), 32, glium_text::FontTexture::ascii_character_list() ).unwrap(); // Creating a `TextDisplay` which contains the elements required to draw a specific sentence. let text = glium_text::TextDisplay::new(&system, &font, "Hello world!"); // Finally, drawing the text is done like this: let matrix = [[1.0, 0.0, 0.0, 0.0], [0.0, 1.0, 0.0, 0.0], [0.0, 0.0, 1.0, 0.0], [0.0, 0.0, 0.0, 1.0]]; glium_text::draw(&text, &system, &mut display.draw(), matrix, (1.0, 1.0, 0.0, 1.0)); # } ``` `FontTexture` will rasterize exact characters it's told to. It can be passed anything that implements `IntoIterator<char>` trait. It is possible to use chained ranges with it like this: `(0 .. 0x7f+1).chain(0x400 .. 0x4ff+1).filter_map(std::char::from_u32)` This will rasterize font with characters from "Basic Latin" and "Cyrillic" sets. Here is a complete list of ranges with description. *As of now, Rust doesn't provide a way to create inclusive ranges yet so thou shall add +1 to the outer bound.* | Start | End | Description | |-------+-------+-----------------------------------------| | 0000 | 007F | Basic Latin | | 0080 | 00FF | C1 Controls and Latin-1 Supplement | | 0100 | 017F | Latin Extended-A | | 0180 | 024F | Latin Extended-B | | 0250 | 02AF | IPA Extensions | | 02B0 | 02FF | Spacing Modifier Letters | | 0300 | 036F | Combining Diacritical Marks | | 0370 | 03FF | Greek/Coptic | | 0400 | 04FF | Cyrillic | | 0500 | 052F | Cyrillic Supplement | | 0530 | 058F | Armenian | | 0590 | 05FF | Hebrew | | 0600 | 06FF | Arabic | | 0700 | 074F | Syriac | | 0780 | 07BF | Thaana | | 0900 | 097F | Devanagari | | 0980 | 09FF | Bengali/Assamese | | 0A00 | 0A7F | Gurmukhi | | 0A80 | 0AFF | Gujarati | | 0B00 | 0B7F | Oriya | | 0B80 | 0BFF | Tamil | | 0C00 | 0C7F | Telugu | | 0C80 | 0CFF | Kannada | | 0D00 | 0DFF | Malayalam | | 0D80 | 0DFF | Sinhala | | 0E00 | 0E7F | Thai | | 0E80 | 0EFF | Lao | | 0F00 | 0FFF | Tibetan | | 1000 | 109F | Myanmar | | 10A0 | 10FF | Georgian | | 1100 | 11FF | Hangul Jamo | | 1200 | 137F | Ethiopic | | 13A0 | 13FF | Cherokee | | 1400 | 167F | Unified Canadian Aboriginal Syllabics | | 1680 | 169F | Ogham | | 16A0 | 16FF | Runic | | 1700 | 171F | Tagalog | | 1720 | 173F | Hanunoo | | 1740 | 175F | Buhid | | 1760 | 177F | Tagbanwa | | 1780 | 17FF | Khmer | | 1800 | 18AF | Mongolian | | 1900 | 194F | Limbu | | 1950 | 197F | Tai Le | | 19E0 | 19FF | Khmer Symbols | | 1D00 | 1D7F | Phonetic Extensions | | 1E00 | 1EFF | Latin Extended Additional | | 1F00 | 1FFF | Greek Extended | | 2000 | 206F | General Punctuation | | 2070 | 209F | Superscripts and Subscripts | | 20A0 | 20CF | Currency Symbols | | 20D0 | 20FF | Combining Diacritical Marks for Symbols | | 2100 | 214F | Letterlike Symbols | | 2150 | 218F | Number Forms | | 2190 | 21FF | Arrows | | 2200 | 22FF | Mathematical Operators | | 2300 | 23FF | Miscellaneous Technical | | 2400 | 243F | Control Pictures | | 2440 | 245F | Optical Character Recognition | | 2460 | 24FF | Enclosed Alphanumerics | | 2500 | 257F | Box Drawing | | 2580 | 259F | Block Elements | | 25A0 | 25FF | Geometric Shapes | | 2600 | 26FF | Miscellaneous Symbols | | 2700 | 27BF | Dingbats | | 27C0 | 27EF | Miscellaneous Mathematical Symbols-A | | 27F0 | 27FF | Supplemental Arrows-A | | 2800 | 28FF | Braille Patterns | | 2900 | 297F | Supplemental Arrows-B | | 2980 | 29FF | Miscellaneous Mathematical Symbols-B | | 2A00 | 2AFF | Supplemental Mathematical Operators | | 2B00 | 2BFF | Miscellaneous Symbols and Arrows | | 2E80 | 2EFF | CJK Radicals Supplement | | 2F00 | 2FDF | Kangxi Radicals | | 2FF0 | 2FFF | Ideographic Description Characters | | 3000 | 303F | CJK Symbols and Punctuation | | 3040 | 309F | Hiragana | | 30A0 | 30FF | Katakana | | 3100 | 312F | Bopomofo | | 3130 | 318F | Hangul Compatibility Jamo | | 3190 | 319F | Kanbun (Kunten) | | 31A0 | 31BF | Bopomofo Extended | | 31F0 | 31FF | Katakana Phonetic Extensions | | 3200 | 32FF | Enclosed CJK Letters and Months | | 3300 | 33FF | CJK Compatibility | | 3400 | 4DBF | CJK Unified Ideographs Extension A | | 4DC0 | 4DFF | Yijing Hexagram Symbols | | 4E00 | 9FAF | CJK Unified Ideographs | | A000 | A48F | Yi Syllables | | A490 | A4CF | Yi Radicals | | AC00 | D7AF | Hangul Syllables | | D800 | DBFF | High Surrogate Area | | DC00 | DFFF | Low Surrogate Area | | E000 | F8FF | Private Use Area | | F900 | FAFF | CJK Compatibility Ideographs | | FB00 | FB4F | Alphabetic Presentation Forms | | FB50 | FDFF | Arabic Presentation Forms-A | | FE00 | FE0F | Variation Selectors | | FE20 | FE2F | Combining Half Marks | | FE30 | FE4F | CJK Compatibility Forms | | FE50 | FE6F | Small Form Variants | | FE70 | FEFF | Arabic Presentation Forms-B | | FF00 | FFEF | Halfwidth and Fullwidth Forms | | FFF0 | FFFF | Specials | | 10000 | 1007F | Linear B Syllabary | | 10080 | 100FF | Linear B Ideograms | | 10100 | 1013F | Aegean Numbers | | 10300 | 1032F | Old Italic | | 10330 | 1034F | Gothic | | 10380 | 1039F | Ugaritic | | 10400 | 1044F | Deseret | | 10450 | 1047F | Shavian | | 10480 | 104AF | Osmanya | | 10800 | 1083F | Cypriot Syllabary | | 1D000 | 1D0FF | Byzantine Musical Symbols | | 1D100 | 1D1FF | Musical Symbols | | 1D300 | 1D35F | Tai Xuan Jing Symbols | | 1D400 | 1D7FF | Mathematical Alphanumeric Symbols | | 20000 | 2A6DF | CJK Unified Ideographs Extension B | | 2F800 | 2FA1F | CJK Compatibility Ideographs Supplement | | E0000 | E007F | Tags | | E0100 | E01EF | Variation Selectors Supplement | */ #![warn(missing_docs)] extern crate rusttype; #[macro_use] extern crate glium; use std::borrow::Cow; use std::collections::HashMap; use std::default::Default; use std::io::Read; use std::ops::Deref; use std::rc::Rc; use rusttype::{Rect, Point}; use glium::DrawParameters; use glium::backend::Context; use glium::backend::Facade; /// Texture which contains the characters of the font. pub struct FontTexture { texture: glium::texture::Texture2d, character_infos: HashMap<char, CharacterInfos>, } /// #[derive(Debug)] pub enum Error { /// A glyph for this character is not present in font. NoGlyph(char), /// An Error that comes directly from Rusttype. RusttypeError(rusttype::Error), } impl From<rusttype::Error> for Error { fn from(error: rusttype::Error) -> Self { Error::RusttypeError(error) } } /// Object that contains the elements shared by all `TextDisplay` objects. /// /// Required to create a `TextDisplay`. pub struct TextSystem { context: Rc<Context>, program: glium::Program, } /// Object that will allow you to draw a text. pub struct TextDisplay<F> where F: Deref<Target=FontTexture> { context: Rc<Context>, texture: F, vertex_buffer: Option<glium::VertexBuffer<VertexFormat>>, index_buffer: Option<glium::IndexBuffer<u16>>, total_text_width: f32, text_height: f32, is_empty: bool, } // structure containing informations about a character of a font #[derive(Copy, Clone, Debug)] struct CharacterInfos { // coordinates of the character top-left hand corner on the font's texture tex_coords: (f32, f32), // width and height of character in texture units tex_size: (f32, f32), // size of the character in EMs size: (f32, f32), // number of EMs between the bottom of the character and the base line of text height_over_line: f32, // number of EMs at the left of the character left_padding: f32, // number of EMs at the right of the character right_padding: f32, } struct TextureData { data: Vec<f32>, width: u32, height: u32, } impl<'a> glium::texture::Texture2dDataSource<'a> for &'a TextureData { type Data = f32; fn into_raw(self) -> glium::texture::RawImage2d<'a, f32> { glium::texture::RawImage2d { data: Cow::Borrowed(&self.data), width: self.width, height: self.height, format: glium::texture::ClientFormat::F32, } } } #[derive(Copy, Clone)] struct VertexFormat { position: [f32; 2], tex_coords: [f32; 2], } implement_vertex!(VertexFormat, position, tex_coords); impl FontTexture { /// Vec<char> of complete ASCII range (from 0 to 255 bytes) pub fn ascii_character_list() -> Vec<char> { (0 .. 255).filter_map(::std::char::from_u32).collect() } /// Creates a new texture representing a font stored in a `FontTexture`. /// This function is very expensive as it needs to rasterize font into a /// texture. Complexity grows as `font_size**2 * characters_list.len()`. /// **Avoid rasterizing everything at once as it will be slow and end up in /// out of memory abort.** pub fn new<R, F, I>(facade: &F, font: R, font_size: u32, characters_list: I) -> Result<FontTexture, Error> where R: Read, F: Facade, I: IntoIterator<Item=char> { // building the freetype face object let font: Vec<u8> = font.bytes().map(|c| c.unwrap()).collect(); let collection = ::rusttype::FontCollection::from_bytes(&font[..])?; let font = collection.into_font().unwrap(); // building the infos let (texture_data, chr_infos) = build_font_image(&font, characters_list.into_iter(), font_size)?; // we load the texture in the display let texture = glium::texture::Texture2d::new(facade, &texture_data).unwrap(); Ok(FontTexture { texture, character_infos: chr_infos, }) } } /*impl glium::uniforms::AsUniformValue for FontTexture { fn as_uniform_value(&self) -> glium::uniforms::UniformValue { glium::uniforms::AsUniformValue::as_uniform_value(&self.texture) } }*/ impl TextSystem { /// Builds a new text system that must be used to build `TextDisplay` objects. pub fn new<F>(facade: &F) -> TextSystem where F: Facade { TextSystem { context: facade.get_context().clone(), program: program!(facade, 140 => { vertex: " #version 140 uniform mat4 matrix; in vec2 position; in vec2 tex_coords; out vec2 v_tex_coords; void main() { gl_Position = matrix * vec4(position, 0.0, 1.0); v_tex_coords = tex_coords; } ", fragment: " #version 140 in vec2 v_tex_coords; out vec4 f_color; uniform vec4 color; uniform sampler2D tex; void main() { vec4 c = vec4(color.rgb, color.a * texture(tex, v_tex_coords)); if (c.a <= 0.01) { discard; } else { f_color = c; } } " }, 110 => { vertex: " #version 110 attribute vec2 position; attribute vec2 tex_coords; varying vec2 v_tex_coords; uniform mat4 matrix; void main() { gl_Position = matrix * vec4(position.x, position.y, 0.0, 1.0); v_tex_coords = tex_coords; } ", fragment: " #version 110 varying vec2 v_tex_coords; uniform vec4 color; uniform sampler2D tex; void main() { gl_FragColor = vec4(color.rgb, color.a * texture2D(tex, v_tex_coords)); if (gl_FragColor.a <= 0.01) { discard; } } " }, ).unwrap() } } } impl<F> TextDisplay<F> where F: Deref<Target=FontTexture> { /// Builds a new text display that allows you to draw text. pub fn new(system: &TextSystem, texture: F, text: &str) -> TextDisplay<F> { let mut text_display = TextDisplay { context: system.context.clone(), texture, vertex_buffer: None, index_buffer: None, total_text_width: 0.0, text_height: 0.0, is_empty: true, }; text_display.set_text(text); text_display } /// Returns the width in GL units of the text. pub fn get_width(&self) -> f32 { self.total_text_width } /// Returns the height in GL units of the text. pub fn get_height(&self) -> f32 { self.text_height } /// Modifies the text on this display. pub fn set_text(&mut self, text: &str) { self.is_empty = true; self.total_text_width = 0.0; self.vertex_buffer = None; self.index_buffer = None; // returning if no text if text.is_empty() { return; } // these arrays will contain the vertex buffer and index buffer data let mut vertex_buffer_data = Vec::with_capacity(text.len() * 4 * 4); let mut index_buffer_data = Vec::with_capacity(text.len() * 6); // iterating over the characters of the string for character in text.chars() { let infos = match self.texture.character_infos.get(&character) { Some(infos) => infos, None => continue, }; self.is_empty = false; // adding the quad in the index buffer { let first_vertex_offset = vertex_buffer_data.len() as u16; index_buffer_data.push(first_vertex_offset); index_buffer_data.push(first_vertex_offset + 1); index_buffer_data.push(first_vertex_offset + 2); index_buffer_data.push(first_vertex_offset + 2); index_buffer_data.push(first_vertex_offset + 1); index_buffer_data.push(first_vertex_offset + 3); } // self.total_text_width += infos.left_padding; // calculating coords let left_coord = self.total_text_width; let right_coord = left_coord + infos.size.0; let top_coord = infos.height_over_line; let bottom_coord = infos.height_over_line - infos.size.1; // top-left vertex vertex_buffer_data.push(VertexFormat { position: [left_coord, top_coord], tex_coords: [infos.tex_coords.0, infos.tex_coords.1], }); // top-right vertex vertex_buffer_data.push(VertexFormat { position: [right_coord, top_coord], tex_coords: [infos.tex_coords.0 + infos.tex_size.0, infos.tex_coords.1], }); // bottom-left vertex vertex_buffer_data.push(VertexFormat { position: [left_coord, bottom_coord], tex_coords: [infos.tex_coords.0, infos.tex_coords.1 + infos.tex_size.1], }); // bottom-right vertex vertex_buffer_data.push(VertexFormat { position: [right_coord, bottom_coord], tex_coords: [ infos.tex_coords.0 + infos.tex_size.0, infos.tex_coords.1 + infos.tex_size.1 ], }); // going to next char self.total_text_width = right_coord + infos.right_padding; if top_coord > self.text_height { self.text_height = top_coord; } } if !vertex_buffer_data.len() != 0 { // building the vertex buffer self.vertex_buffer = Some(glium::VertexBuffer::new(&self.context, &vertex_buffer_data).unwrap()); // building the index buffer self.index_buffer = Some(glium::IndexBuffer::new(&self.context, glium::index::PrimitiveType::TrianglesList, &index_buffer_data).unwrap()); } } } /// Draws linear-filtered text. /// /// ## About the matrix /// /// The matrix must be column-major post-muliplying (which is the usual way to do in OpenGL). /// /// One unit in height corresponds to a line of text, but the text can go above or under. /// The bottom of the line is at `0.0`, the top is at `1.0`. /// You need to adapt your matrix by taking these into consideration. pub fn draw<F, S: ?Sized, M>( text: &TextDisplay<F>, system: &TextSystem, target: &mut S, matrix: M, color: (f32, f32, f32, f32) ) -> Result<(), glium::DrawError> where S: glium::Surface, M: Into<[[f32; 4]; 4]>, F: Deref<Target=FontTexture> { let behavior = glium::uniforms::SamplerBehavior { magnify_filter: glium::uniforms::MagnifySamplerFilter::Linear, minify_filter: glium::uniforms::MinifySamplerFilter::Linear, .. Default::default() }; let params = { use glium::BlendingFunction::Addition; use glium::LinearBlendingFactor::*; let blending_function = Addition { source: SourceAlpha, destination: OneMinusSourceAlpha }; let blend = glium::Blend { color: blending_function, alpha: blending_function, constant_value: (1.0, 1.0, 1.0, 1.0), }; DrawParameters { blend, .. Default::default() } }; draw_with_params(text, system, target, matrix, color, behavior, ¶ms) } /// More advanced variant of `draw` which also takes sampler behavior and draw /// parameters. pub fn draw_with_params<F, S: ?Sized, M>( text: &TextDisplay<F>, system: &TextSystem, target: &mut S, matrix: M, color: (f32, f32, f32, f32), sampler_behavior: glium::uniforms::SamplerBehavior, parameters: &DrawParameters ) -> Result<(), glium::DrawError> where S: glium::Surface, M: Into<[[f32; 4]; 4]>, F: Deref<Target=FontTexture> { let matrix = matrix.into(); let &TextDisplay { ref vertex_buffer, ref index_buffer, ref texture, is_empty, .. } = text; let color = [color.0, color.1, color.2, color.3]; // returning if nothing to draw if is_empty || vertex_buffer.is_none() || index_buffer.is_none() { return Ok(()); } let vertex_buffer = vertex_buffer.as_ref().unwrap(); let index_buffer = index_buffer.as_ref().unwrap(); let uniforms = uniform! { matrix: matrix, color: color, tex: glium::uniforms::Sampler(&texture.texture, sampler_behavior) }; target.draw(vertex_buffer, index_buffer, &system.program, &uniforms, ¶meters) } fn build_font_image<I>(font: &rusttype::Font, characters_list: I, font_size: u32) -> Result<(TextureData, HashMap<char, CharacterInfos>), Error> where I: Iterator<Item=char> { use std::iter; // a margin around each character to prevent artifacts const MARGIN: u32 = 2; // glyph size for characters not presented in font. let invalid_character_width = font_size / 2; let size_estimation = characters_list.size_hint().1.unwrap_or(0); // this variable will store the texture data // we set an arbitrary capacity that we think will match what we will need let mut texture_data: Vec<f32> = Vec::with_capacity( size_estimation * font_size as usize * font_size as usize ); // the width is chosen more or less arbitrarily, because we can store // everything as long as the texture is at least as wide as the widest // character we just try to estimate a width so that width ~= height let texture_width = get_nearest_po2(std::cmp::max(font_size * 2 as u32, ((((size_estimation as u32) * font_size * font_size) as f32).sqrt()) as u32)); // we store the position of the "cursor" in the destination texture // this cursor points to the top-left pixel of the next character to write on the texture let mut cursor_offset = (0u32, 0u32); // number of rows to skip at next carriage return let mut rows_to_skip = 0u32; // now looping through the list of characters, filling the texture and returning the informations let em_pixels = font_size as f32; let characters_infos = characters_list.map(|character| { struct Bitmap { rows : i32, width : i32, buffer : Vec<u8> } // loading wanted glyph in the font face // hope scale will set the right pixel size let scaled_glyph = font.glyph(character) .scaled(::rusttype::Scale {x : font_size as f32, y : font_size as f32 }); let h_metrics = scaled_glyph.h_metrics(); let glyph = scaled_glyph .positioned(::rusttype::Point {x : 0.0, y : 0.0 }); let bb = glyph.pixel_bounding_box(); // if no bounding box - we suppose that its invalid character but want it to be draw as empty quad let bb = if let Some(bb) = bb { bb } else { Rect { min: Point {x: 0, y: 0}, max: Point {x: invalid_character_width as i32, y: 0} } }; let mut buffer = vec![0; (bb.height() * bb.width()) as usize]; glyph.draw(|x, y, v| { let x = x; let y = y; buffer[(y * bb.width() as u32 + x) as usize] = (v * 255.0) as u8; }); let bitmap : Bitmap = Bitmap { rows : bb.height(), width : bb.width(), buffer }; // adding a left margin before our character to prevent artifacts cursor_offset.0 += MARGIN; // carriage return our cursor if we don't have enough room to write the next caracter // we add a margin to prevent artifacts if cursor_offset.0 + (bitmap.width as u32) + MARGIN >= texture_width { assert!(bitmap.width as u32 <= texture_width); // if this fails, we should increase texture_width cursor_offset.0 = 0; cursor_offset.1 += rows_to_skip; rows_to_skip = 0; } // if the texture data buffer has not enough lines, adding some if rows_to_skip < MARGIN + bitmap.rows as u32 { let diff = MARGIN + (bitmap.rows as u32) - rows_to_skip; rows_to_skip = MARGIN + bitmap.rows as u32; texture_data.extend(iter::repeat(0.0).take((diff * texture_width) as usize)); } // copying the data to the texture let offset_x_before_copy = cursor_offset.0; if bitmap.rows >= 1 { let destination = &mut texture_data[(cursor_offset.0 + cursor_offset.1 * texture_width) as usize ..]; let source = &bitmap.buffer; //ylet source = std::slice::from_raw_parts(source, destination.len()); for y in 0 .. bitmap.rows as u32 { let source = &source[(y * bitmap.width as u32) as usize ..]; let destination = &mut destination[(y * texture_width) as usize ..]; for x in 0 .. bitmap.width { // the values in source are bytes between 0 and 255, but we want floats between 0 and 1 let val: u8 = source[x as usize]; let val = f32::from(val) / f32::from(std::u8::MAX); let dest = &mut destination[x as usize]; *dest = val; } } cursor_offset.0 += bitmap.width as u32; debug_assert!(cursor_offset.0 <= texture_width); } // filling infos about that character // tex_size and tex_coords are in pixels for the moment ; they will be divided // by the texture dimensions later Ok((character, CharacterInfos { tex_size: (bitmap.width as f32, bitmap.rows as f32), tex_coords: (offset_x_before_copy as f32, cursor_offset.1 as f32), size: (bitmap.width as f32, bitmap.rows as f32), left_padding: h_metrics.left_side_bearing as f32, right_padding: (h_metrics.advance_width - bitmap.width as f32 - h_metrics.left_side_bearing as f32) as f32 / 64.0, height_over_line: -bb.min.y as f32, })) }).collect::<Result<Vec<_>, Error>>()?; // adding blank lines at the end until the height of the texture is a power of two { let current_height = texture_data.len() as u32 / texture_width; let requested_height = get_nearest_po2(current_height); texture_data.extend(iter::repeat(0.0).take((texture_width * (requested_height - current_height)) as usize)); } // now our texture is finished // we know its final dimensions, so we can divide all the pixels values into (0,1) range assert!((texture_data.len() as u32 % texture_width) == 0); let texture_height = (texture_data.len() as u32 / texture_width) as f32; let float_texture_width = texture_width as f32; let mut characters_infos = characters_infos.into_iter().map(|mut chr| { chr.1.tex_size.0 /= float_texture_width; chr.1.tex_size.1 /= texture_height; chr.1.tex_coords.0 /= float_texture_width; chr.1.tex_coords.1 /= texture_height; chr.1.size.0 /= em_pixels; chr.1.size.1 /= em_pixels; chr.1.left_padding /= em_pixels; chr.1.right_padding /= em_pixels; chr.1.height_over_line /= em_pixels; chr }).collect::<HashMap<_, _>>(); // this HashMap will not be used mutably any more and it makes sense to // compact it characters_infos.shrink_to_fit(); // returning Ok((TextureData { data: texture_data, width: texture_width, height: texture_height as u32, }, characters_infos)) } /// Function that will calculate the nearest power of two. fn get_nearest_po2(mut x: u32) -> u32 { assert!(x > 0); x -= 1; x = x | (x >> 1); x = x | (x >> 2); x = x | (x >> 4); x = x | (x >> 8); x = x | (x >> 16); x + 1 }