direct_write.rs

   1use std::{borrow::Cow, sync::Arc};
   2
   3use ::util::ResultExt;
   4use anyhow::{anyhow, Result};
   5use collections::HashMap;
   6use itertools::Itertools;
   7use parking_lot::{RwLock, RwLockUpgradableReadGuard};
   8use smallvec::SmallVec;
   9use windows::{
  10    core::*,
  11    Win32::{
  12        Foundation::*,
  13        Globalization::GetUserDefaultLocaleName,
  14        Graphics::{
  15            Direct2D::{Common::*, *},
  16            DirectWrite::*,
  17            Dxgi::Common::*,
  18            Gdi::LOGFONTW,
  19            Imaging::{D2D::IWICImagingFactory2, *},
  20        },
  21        System::{Com::*, SystemServices::LOCALE_NAME_MAX_LENGTH},
  22        UI::WindowsAndMessaging::*,
  23    },
  24};
  25
  26use crate::*;
  27
  28#[derive(Debug)]
  29struct FontInfo {
  30    font_family: String,
  31    font_face: IDWriteFontFace3,
  32    features: IDWriteTypography,
  33    is_system_font: bool,
  34    is_emoji: bool,
  35}
  36
  37pub(crate) struct DirectWriteTextSystem(RwLock<DirectWriteState>);
  38
  39struct DirectWriteComponent {
  40    locale: String,
  41    factory: IDWriteFactory5,
  42    bitmap_factory: IWICImagingFactory2,
  43    d2d1_factory: ID2D1Factory,
  44    in_memory_loader: IDWriteInMemoryFontFileLoader,
  45    builder: IDWriteFontSetBuilder1,
  46    text_renderer: Arc<TextRendererWrapper>,
  47    render_context: GlyphRenderContext,
  48}
  49
  50struct GlyphRenderContext {
  51    params: IDWriteRenderingParams3,
  52    dc_target: ID2D1DeviceContext4,
  53}
  54
  55// All use of the IUnknown methods should be "thread-safe".
  56unsafe impl Sync for DirectWriteComponent {}
  57unsafe impl Send for DirectWriteComponent {}
  58
  59struct DirectWriteState {
  60    components: DirectWriteComponent,
  61    system_ui_font_name: SharedString,
  62    system_font_collection: IDWriteFontCollection1,
  63    custom_font_collection: IDWriteFontCollection1,
  64    fonts: Vec<FontInfo>,
  65    font_selections: HashMap<Font, FontId>,
  66    font_id_by_identifier: HashMap<FontIdentifier, FontId>,
  67}
  68
  69#[derive(Debug, Clone, Hash, PartialEq, Eq)]
  70struct FontIdentifier {
  71    postscript_name: String,
  72    weight: i32,
  73    style: i32,
  74}
  75
  76impl DirectWriteComponent {
  77    pub fn new() -> Result<Self> {
  78        unsafe {
  79            let factory: IDWriteFactory5 = DWriteCreateFactory(DWRITE_FACTORY_TYPE_SHARED)?;
  80            let bitmap_factory: IWICImagingFactory2 =
  81                CoCreateInstance(&CLSID_WICImagingFactory2, None, CLSCTX_INPROC_SERVER)?;
  82            let d2d1_factory: ID2D1Factory =
  83                D2D1CreateFactory(D2D1_FACTORY_TYPE_MULTI_THREADED, None)?;
  84            // The `IDWriteInMemoryFontFileLoader` here is supported starting from
  85            // Windows 10 Creators Update, which consequently requires the entire
  86            // `DirectWriteTextSystem` to run on `win10 1703`+.
  87            let in_memory_loader = factory.CreateInMemoryFontFileLoader()?;
  88            factory.RegisterFontFileLoader(&in_memory_loader)?;
  89            let builder = factory.CreateFontSetBuilder()?;
  90            let mut locale_vec = vec![0u16; LOCALE_NAME_MAX_LENGTH as usize];
  91            GetUserDefaultLocaleName(&mut locale_vec);
  92            let locale = String::from_utf16_lossy(&locale_vec);
  93            let text_renderer = Arc::new(TextRendererWrapper::new(&locale));
  94            let render_context = GlyphRenderContext::new(&factory, &d2d1_factory)?;
  95
  96            Ok(DirectWriteComponent {
  97                locale,
  98                factory,
  99                bitmap_factory,
 100                d2d1_factory,
 101                in_memory_loader,
 102                builder,
 103                text_renderer,
 104                render_context,
 105            })
 106        }
 107    }
 108}
 109
 110impl GlyphRenderContext {
 111    pub fn new(factory: &IDWriteFactory5, d2d1_factory: &ID2D1Factory) -> Result<Self> {
 112        unsafe {
 113            let default_params: IDWriteRenderingParams3 =
 114                factory.CreateRenderingParams()?.cast()?;
 115            let gamma = default_params.GetGamma();
 116            let enhanced_contrast = default_params.GetEnhancedContrast();
 117            let gray_contrast = default_params.GetGrayscaleEnhancedContrast();
 118            let cleartype_level = default_params.GetClearTypeLevel();
 119            let grid_fit_mode = default_params.GetGridFitMode();
 120
 121            let params = factory.CreateCustomRenderingParams(
 122                gamma,
 123                enhanced_contrast,
 124                gray_contrast,
 125                cleartype_level,
 126                DWRITE_PIXEL_GEOMETRY_RGB,
 127                DWRITE_RENDERING_MODE1_NATURAL_SYMMETRIC,
 128                grid_fit_mode,
 129            )?;
 130            let dc_target = {
 131                let target = d2d1_factory.CreateDCRenderTarget(&get_render_target_property(
 132                    DXGI_FORMAT_B8G8R8A8_UNORM,
 133                    D2D1_ALPHA_MODE_PREMULTIPLIED,
 134                ))?;
 135                let target = target.cast::<ID2D1DeviceContext4>()?;
 136                target.SetTextRenderingParams(&params);
 137                target
 138            };
 139
 140            Ok(Self { params, dc_target })
 141        }
 142    }
 143}
 144
 145impl DirectWriteTextSystem {
 146    pub(crate) fn new() -> Result<Self> {
 147        let components = DirectWriteComponent::new()?;
 148        let system_font_collection = unsafe {
 149            let mut result = std::mem::zeroed();
 150            components
 151                .factory
 152                .GetSystemFontCollection(false, &mut result, true)?;
 153            result.unwrap()
 154        };
 155        let custom_font_set = unsafe { components.builder.CreateFontSet()? };
 156        let custom_font_collection = unsafe {
 157            components
 158                .factory
 159                .CreateFontCollectionFromFontSet(&custom_font_set)?
 160        };
 161        let system_ui_font_name = get_system_ui_font_name();
 162
 163        Ok(Self(RwLock::new(DirectWriteState {
 164            components,
 165            system_ui_font_name,
 166            system_font_collection,
 167            custom_font_collection,
 168            fonts: Vec::new(),
 169            font_selections: HashMap::default(),
 170            font_id_by_identifier: HashMap::default(),
 171        })))
 172    }
 173}
 174
 175impl PlatformTextSystem for DirectWriteTextSystem {
 176    fn add_fonts(&self, fonts: Vec<Cow<'static, [u8]>>) -> Result<()> {
 177        self.0.write().add_fonts(fonts)
 178    }
 179
 180    fn all_font_names(&self) -> Vec<String> {
 181        self.0.read().all_font_names()
 182    }
 183
 184    fn all_font_families(&self) -> Vec<String> {
 185        self.0.read().all_font_families()
 186    }
 187
 188    fn font_id(&self, font: &Font) -> Result<FontId> {
 189        let lock = self.0.upgradable_read();
 190        if let Some(font_id) = lock.font_selections.get(font) {
 191            Ok(*font_id)
 192        } else {
 193            let mut lock = RwLockUpgradableReadGuard::upgrade(lock);
 194            let font_id = lock.select_font(font);
 195            lock.font_selections.insert(font.clone(), font_id);
 196            Ok(font_id)
 197        }
 198    }
 199
 200    fn font_metrics(&self, font_id: FontId) -> FontMetrics {
 201        self.0.read().font_metrics(font_id)
 202    }
 203
 204    fn typographic_bounds(&self, font_id: FontId, glyph_id: GlyphId) -> Result<Bounds<f32>> {
 205        self.0.read().get_typographic_bounds(font_id, glyph_id)
 206    }
 207
 208    fn advance(&self, font_id: FontId, glyph_id: GlyphId) -> anyhow::Result<Size<f32>> {
 209        self.0.read().get_advance(font_id, glyph_id)
 210    }
 211
 212    fn glyph_for_char(&self, font_id: FontId, ch: char) -> Option<GlyphId> {
 213        self.0.read().glyph_for_char(font_id, ch)
 214    }
 215
 216    fn glyph_raster_bounds(
 217        &self,
 218        params: &RenderGlyphParams,
 219    ) -> anyhow::Result<Bounds<DevicePixels>> {
 220        self.0.read().raster_bounds(params)
 221    }
 222
 223    fn rasterize_glyph(
 224        &self,
 225        params: &RenderGlyphParams,
 226        raster_bounds: Bounds<DevicePixels>,
 227    ) -> anyhow::Result<(Size<DevicePixels>, Vec<u8>)> {
 228        self.0.read().rasterize_glyph(params, raster_bounds)
 229    }
 230
 231    fn layout_line(&self, text: &str, font_size: Pixels, runs: &[FontRun]) -> LineLayout {
 232        self.0
 233            .write()
 234            .layout_line(text, font_size, runs)
 235            .log_err()
 236            .unwrap_or(LineLayout {
 237                font_size,
 238                ..Default::default()
 239            })
 240    }
 241}
 242
 243impl DirectWriteState {
 244    fn add_fonts(&mut self, fonts: Vec<Cow<'static, [u8]>>) -> Result<()> {
 245        for font_data in fonts {
 246            match font_data {
 247                Cow::Borrowed(data) => unsafe {
 248                    let font_file = self
 249                        .components
 250                        .in_memory_loader
 251                        .CreateInMemoryFontFileReference(
 252                            &self.components.factory,
 253                            data.as_ptr() as _,
 254                            data.len() as _,
 255                            None,
 256                        )?;
 257                    self.components.builder.AddFontFile(&font_file)?;
 258                },
 259                Cow::Owned(data) => unsafe {
 260                    let font_file = self
 261                        .components
 262                        .in_memory_loader
 263                        .CreateInMemoryFontFileReference(
 264                            &self.components.factory,
 265                            data.as_ptr() as _,
 266                            data.len() as _,
 267                            None,
 268                        )?;
 269                    self.components.builder.AddFontFile(&font_file)?;
 270                },
 271            }
 272        }
 273        let set = unsafe { self.components.builder.CreateFontSet()? };
 274        let collection = unsafe {
 275            self.components
 276                .factory
 277                .CreateFontCollectionFromFontSet(&set)?
 278        };
 279        self.custom_font_collection = collection;
 280
 281        Ok(())
 282    }
 283
 284    unsafe fn generate_font_features(
 285        &self,
 286        font_features: &FontFeatures,
 287    ) -> Result<IDWriteTypography> {
 288        let direct_write_features = self.components.factory.CreateTypography()?;
 289        apply_font_features(&direct_write_features, font_features)?;
 290        Ok(direct_write_features)
 291    }
 292
 293    unsafe fn get_font_id_from_font_collection(
 294        &mut self,
 295        family_name: &str,
 296        font_weight: FontWeight,
 297        font_style: FontStyle,
 298        font_features: &FontFeatures,
 299        is_system_font: bool,
 300    ) -> Option<FontId> {
 301        let collection = if is_system_font {
 302            &self.system_font_collection
 303        } else {
 304            &self.custom_font_collection
 305        };
 306        let fontset = collection.GetFontSet().log_err()?;
 307        let font = fontset
 308            .GetMatchingFonts(
 309                &HSTRING::from(family_name),
 310                font_weight.into(),
 311                DWRITE_FONT_STRETCH_NORMAL,
 312                font_style.into(),
 313            )
 314            .log_err()?;
 315        let total_number = font.GetFontCount();
 316        for index in 0..total_number {
 317            let Some(font_face_ref) = font.GetFontFaceReference(index).log_err() else {
 318                continue;
 319            };
 320            let Some(font_face) = font_face_ref.CreateFontFace().log_err() else {
 321                continue;
 322            };
 323            let Some(identifier) = get_font_identifier(&font_face, &self.components.locale) else {
 324                continue;
 325            };
 326            let is_emoji = font_face.IsColorFont().as_bool();
 327            let Some(direct_write_features) = self.generate_font_features(font_features).log_err()
 328            else {
 329                continue;
 330            };
 331            let font_info = FontInfo {
 332                font_family: family_name.to_owned(),
 333                font_face,
 334                is_system_font,
 335                features: direct_write_features,
 336                is_emoji,
 337            };
 338            let font_id = FontId(self.fonts.len());
 339            self.fonts.push(font_info);
 340            self.font_id_by_identifier.insert(identifier, font_id);
 341            return Some(font_id);
 342        }
 343        None
 344    }
 345
 346    unsafe fn update_system_font_collection(&mut self) {
 347        let mut collection = std::mem::zeroed();
 348        if self
 349            .components
 350            .factory
 351            .GetSystemFontCollection(false, &mut collection, true)
 352            .log_err()
 353            .is_some()
 354        {
 355            self.system_font_collection = collection.unwrap();
 356        }
 357    }
 358
 359    fn select_font(&mut self, target_font: &Font) -> FontId {
 360        unsafe {
 361            if target_font.family == ".SystemUIFont" {
 362                let family = self.system_ui_font_name.clone();
 363                self.find_font_id(
 364                    family.as_ref(),
 365                    target_font.weight,
 366                    target_font.style,
 367                    &target_font.features,
 368                )
 369                .unwrap()
 370            } else {
 371                self.find_font_id(
 372                    target_font.family.as_ref(),
 373                    target_font.weight,
 374                    target_font.style,
 375                    &target_font.features,
 376                )
 377                .unwrap_or_else(|| {
 378                    let family = self.system_ui_font_name.clone();
 379                    log::error!("{} not found, use {} instead.", target_font.family, family);
 380                    self.get_font_id_from_font_collection(
 381                        family.as_ref(),
 382                        target_font.weight,
 383                        target_font.style,
 384                        &target_font.features,
 385                        true,
 386                    )
 387                    .unwrap()
 388                })
 389            }
 390        }
 391    }
 392
 393    unsafe fn find_font_id(
 394        &mut self,
 395        family_name: &str,
 396        weight: FontWeight,
 397        style: FontStyle,
 398        features: &FontFeatures,
 399    ) -> Option<FontId> {
 400        // try to find target font in custom font collection first
 401        self.get_font_id_from_font_collection(family_name, weight, style, features, false)
 402            .or_else(|| {
 403                self.get_font_id_from_font_collection(family_name, weight, style, features, true)
 404            })
 405            .or_else(|| {
 406                self.update_system_font_collection();
 407                self.get_font_id_from_font_collection(family_name, weight, style, features, true)
 408            })
 409    }
 410
 411    fn layout_line(
 412        &mut self,
 413        text: &str,
 414        font_size: Pixels,
 415        font_runs: &[FontRun],
 416    ) -> Result<LineLayout> {
 417        if font_runs.is_empty() {
 418            return Ok(LineLayout {
 419                font_size,
 420                ..Default::default()
 421            });
 422        }
 423        unsafe {
 424            let text_renderer = self.components.text_renderer.clone();
 425            let text_wide = text.encode_utf16().collect_vec();
 426
 427            let mut utf8_offset = 0usize;
 428            let mut utf16_offset = 0u32;
 429            let text_layout = {
 430                let first_run = &font_runs[0];
 431                let font_info = &self.fonts[first_run.font_id.0];
 432                let collection = if font_info.is_system_font {
 433                    &self.system_font_collection
 434                } else {
 435                    &self.custom_font_collection
 436                };
 437                let format = self.components.factory.CreateTextFormat(
 438                    &HSTRING::from(&font_info.font_family),
 439                    collection,
 440                    font_info.font_face.GetWeight(),
 441                    font_info.font_face.GetStyle(),
 442                    DWRITE_FONT_STRETCH_NORMAL,
 443                    font_size.0,
 444                    &HSTRING::from(&self.components.locale),
 445                )?;
 446
 447                let layout = self.components.factory.CreateTextLayout(
 448                    &text_wide,
 449                    &format,
 450                    f32::INFINITY,
 451                    f32::INFINITY,
 452                )?;
 453                let current_text = &text[utf8_offset..(utf8_offset + first_run.len)];
 454                utf8_offset += first_run.len;
 455                let current_text_utf16_length = current_text.encode_utf16().count() as u32;
 456                let text_range = DWRITE_TEXT_RANGE {
 457                    startPosition: utf16_offset,
 458                    length: current_text_utf16_length,
 459                };
 460                layout.SetTypography(&font_info.features, text_range)?;
 461                utf16_offset += current_text_utf16_length;
 462
 463                layout
 464            };
 465
 466            let mut first_run = true;
 467            let mut ascent = Pixels::default();
 468            let mut descent = Pixels::default();
 469            for run in font_runs {
 470                if first_run {
 471                    first_run = false;
 472                    let mut metrics = vec![DWRITE_LINE_METRICS::default(); 4];
 473                    let mut line_count = 0u32;
 474                    text_layout.GetLineMetrics(Some(&mut metrics), &mut line_count as _)?;
 475                    ascent = px(metrics[0].baseline);
 476                    descent = px(metrics[0].height - metrics[0].baseline);
 477                    continue;
 478                }
 479                let font_info = &self.fonts[run.font_id.0];
 480                let current_text = &text[utf8_offset..(utf8_offset + run.len)];
 481                utf8_offset += run.len;
 482                let current_text_utf16_length = current_text.encode_utf16().count() as u32;
 483
 484                let collection = if font_info.is_system_font {
 485                    &self.system_font_collection
 486                } else {
 487                    &self.custom_font_collection
 488                };
 489                let text_range = DWRITE_TEXT_RANGE {
 490                    startPosition: utf16_offset,
 491                    length: current_text_utf16_length,
 492                };
 493                utf16_offset += current_text_utf16_length;
 494                text_layout.SetFontCollection(collection, text_range)?;
 495                text_layout
 496                    .SetFontFamilyName(&HSTRING::from(&font_info.font_family), text_range)?;
 497                text_layout.SetFontSize(font_size.0, text_range)?;
 498                text_layout.SetFontStyle(font_info.font_face.GetStyle(), text_range)?;
 499                text_layout.SetFontWeight(font_info.font_face.GetWeight(), text_range)?;
 500                text_layout.SetTypography(&font_info.features, text_range)?;
 501            }
 502
 503            let mut runs = Vec::new();
 504            let renderer_context = RendererContext {
 505                text_system: self,
 506                index_converter: StringIndexConverter::new(text),
 507                runs: &mut runs,
 508                utf16_index: 0,
 509                width: 0.0,
 510            };
 511            text_layout.Draw(
 512                Some(&renderer_context as *const _ as _),
 513                &text_renderer.0,
 514                0.0,
 515                0.0,
 516            )?;
 517            let width = px(renderer_context.width);
 518
 519            Ok(LineLayout {
 520                font_size,
 521                width,
 522                ascent,
 523                descent,
 524                runs,
 525                len: text.len(),
 526            })
 527        }
 528    }
 529
 530    fn font_metrics(&self, font_id: FontId) -> FontMetrics {
 531        unsafe {
 532            let font_info = &self.fonts[font_id.0];
 533            let mut metrics = std::mem::zeroed();
 534            font_info.font_face.GetMetrics(&mut metrics);
 535
 536            FontMetrics {
 537                units_per_em: metrics.Base.designUnitsPerEm as _,
 538                ascent: metrics.Base.ascent as _,
 539                descent: -(metrics.Base.descent as f32),
 540                line_gap: metrics.Base.lineGap as _,
 541                underline_position: metrics.Base.underlinePosition as _,
 542                underline_thickness: metrics.Base.underlineThickness as _,
 543                cap_height: metrics.Base.capHeight as _,
 544                x_height: metrics.Base.xHeight as _,
 545                bounding_box: Bounds {
 546                    origin: Point {
 547                        x: metrics.glyphBoxLeft as _,
 548                        y: metrics.glyphBoxBottom as _,
 549                    },
 550                    size: Size {
 551                        width: (metrics.glyphBoxRight - metrics.glyphBoxLeft) as _,
 552                        height: (metrics.glyphBoxTop - metrics.glyphBoxBottom) as _,
 553                    },
 554                },
 555            }
 556        }
 557    }
 558
 559    fn raster_bounds(&self, params: &RenderGlyphParams) -> Result<Bounds<DevicePixels>> {
 560        let render_target = &self.components.render_context.dc_target;
 561        unsafe {
 562            render_target.SetUnitMode(D2D1_UNIT_MODE_DIPS);
 563            render_target.SetDpi(96.0 * params.scale_factor, 96.0 * params.scale_factor);
 564        }
 565        let font = &self.fonts[params.font_id.0];
 566        let glyph_id = [params.glyph_id.0 as u16];
 567        let advance = [0.0f32];
 568        let offset = [DWRITE_GLYPH_OFFSET::default()];
 569        let glyph_run = DWRITE_GLYPH_RUN {
 570            fontFace: unsafe { std::mem::transmute_copy(&font.font_face) },
 571            fontEmSize: params.font_size.0,
 572            glyphCount: 1,
 573            glyphIndices: glyph_id.as_ptr(),
 574            glyphAdvances: advance.as_ptr(),
 575            glyphOffsets: offset.as_ptr(),
 576            isSideways: BOOL(0),
 577            bidiLevel: 0,
 578        };
 579        let bounds = unsafe {
 580            render_target.GetGlyphRunWorldBounds(
 581                D2D_POINT_2F { x: 0.0, y: 0.0 },
 582                &glyph_run,
 583                DWRITE_MEASURING_MODE_NATURAL,
 584            )?
 585        };
 586        // todo(windows)
 587        // This is a walkaround, deleted when figured out.
 588        let y_offset;
 589        let extra_height;
 590        if params.is_emoji {
 591            y_offset = 0;
 592            extra_height = 0;
 593        } else {
 594            // make some room for scaler.
 595            y_offset = -1;
 596            extra_height = 2;
 597        }
 598
 599        if bounds.right < bounds.left {
 600            Ok(Bounds {
 601                origin: point(0.into(), 0.into()),
 602                size: size(0.into(), 0.into()),
 603            })
 604        } else {
 605            Ok(Bounds {
 606                origin: point(
 607                    ((bounds.left * params.scale_factor).ceil() as i32).into(),
 608                    ((bounds.top * params.scale_factor).ceil() as i32 + y_offset).into(),
 609                ),
 610                size: size(
 611                    (((bounds.right - bounds.left) * params.scale_factor).ceil() as i32).into(),
 612                    (((bounds.bottom - bounds.top) * params.scale_factor).ceil() as i32
 613                        + extra_height)
 614                        .into(),
 615                ),
 616            })
 617        }
 618    }
 619
 620    fn glyph_for_char(&self, font_id: FontId, ch: char) -> Option<GlyphId> {
 621        let font_info = &self.fonts[font_id.0];
 622        let codepoints = [ch as u32];
 623        let mut glyph_indices = vec![0u16; 1];
 624        unsafe {
 625            font_info
 626                .font_face
 627                .GetGlyphIndices(codepoints.as_ptr(), 1, glyph_indices.as_mut_ptr())
 628                .log_err()
 629        }
 630        .map(|_| GlyphId(glyph_indices[0] as u32))
 631    }
 632
 633    fn rasterize_glyph(
 634        &self,
 635        params: &RenderGlyphParams,
 636        glyph_bounds: Bounds<DevicePixels>,
 637    ) -> Result<(Size<DevicePixels>, Vec<u8>)> {
 638        if glyph_bounds.size.width.0 == 0 || glyph_bounds.size.height.0 == 0 {
 639            return Err(anyhow!("glyph bounds are empty"));
 640        }
 641
 642        let font_info = &self.fonts[params.font_id.0];
 643        let glyph_id = [params.glyph_id.0 as u16];
 644        let advance = [glyph_bounds.size.width.0 as f32];
 645        let offset = [DWRITE_GLYPH_OFFSET {
 646            advanceOffset: -glyph_bounds.origin.x.0 as f32 / params.scale_factor,
 647            ascenderOffset: glyph_bounds.origin.y.0 as f32 / params.scale_factor,
 648        }];
 649        let glyph_run = DWRITE_GLYPH_RUN {
 650            fontFace: unsafe { std::mem::transmute_copy(&font_info.font_face) },
 651            fontEmSize: params.font_size.0,
 652            glyphCount: 1,
 653            glyphIndices: glyph_id.as_ptr(),
 654            glyphAdvances: advance.as_ptr(),
 655            glyphOffsets: offset.as_ptr(),
 656            isSideways: BOOL(0),
 657            bidiLevel: 0,
 658        };
 659
 660        // Add an extra pixel when the subpixel variant isn't zero to make room for anti-aliasing.
 661        let mut bitmap_size = glyph_bounds.size;
 662        if params.subpixel_variant.x > 0 {
 663            bitmap_size.width += DevicePixels(1);
 664        }
 665        if params.subpixel_variant.y > 0 {
 666            bitmap_size.height += DevicePixels(1);
 667        }
 668        let bitmap_size = bitmap_size;
 669
 670        let total_bytes;
 671        let bitmap_format;
 672        let render_target_property;
 673        let bitmap_width;
 674        let bitmap_height;
 675        let bitmap_stride;
 676        let bitmap_dpi;
 677        if params.is_emoji {
 678            total_bytes = bitmap_size.height.0 as usize * bitmap_size.width.0 as usize * 4;
 679            bitmap_format = &GUID_WICPixelFormat32bppPBGRA;
 680            render_target_property = get_render_target_property(
 681                DXGI_FORMAT_B8G8R8A8_UNORM,
 682                D2D1_ALPHA_MODE_PREMULTIPLIED,
 683            );
 684            bitmap_width = bitmap_size.width.0 as u32;
 685            bitmap_height = bitmap_size.height.0 as u32;
 686            bitmap_stride = bitmap_size.width.0 as u32 * 4;
 687            bitmap_dpi = 96.0;
 688        } else {
 689            total_bytes = bitmap_size.height.0 as usize * bitmap_size.width.0 as usize;
 690            bitmap_format = &GUID_WICPixelFormat8bppAlpha;
 691            render_target_property =
 692                get_render_target_property(DXGI_FORMAT_A8_UNORM, D2D1_ALPHA_MODE_STRAIGHT);
 693            bitmap_width = bitmap_size.width.0 as u32 * 2;
 694            bitmap_height = bitmap_size.height.0 as u32 * 2;
 695            bitmap_stride = bitmap_size.width.0 as u32;
 696            bitmap_dpi = 192.0;
 697        }
 698
 699        unsafe {
 700            let bitmap = self.components.bitmap_factory.CreateBitmap(
 701                bitmap_width,
 702                bitmap_height,
 703                bitmap_format,
 704                WICBitmapCacheOnLoad,
 705            )?;
 706            let render_target = self
 707                .components
 708                .d2d1_factory
 709                .CreateWicBitmapRenderTarget(&bitmap, &render_target_property)?;
 710            let brush = render_target.CreateSolidColorBrush(&BRUSH_COLOR, None)?;
 711            let subpixel_shift = params
 712                .subpixel_variant
 713                .map(|v| v as f32 / SUBPIXEL_VARIANTS as f32);
 714            let baseline_origin = D2D_POINT_2F {
 715                x: subpixel_shift.x / params.scale_factor,
 716                y: subpixel_shift.y / params.scale_factor,
 717            };
 718
 719            // This `cast()` action here should never fail since we are running on Win10+, and
 720            // ID2D1DeviceContext4 requires Win8+
 721            let render_target = render_target.cast::<ID2D1DeviceContext4>().unwrap();
 722            render_target.SetUnitMode(D2D1_UNIT_MODE_DIPS);
 723            render_target.SetDpi(
 724                bitmap_dpi * params.scale_factor,
 725                bitmap_dpi * params.scale_factor,
 726            );
 727            render_target.SetTextRenderingParams(&self.components.render_context.params);
 728            render_target.BeginDraw();
 729
 730            if params.is_emoji {
 731                // WARN: only DWRITE_GLYPH_IMAGE_FORMATS_COLR has been tested
 732                let enumerator = self.components.factory.TranslateColorGlyphRun(
 733                    baseline_origin,
 734                    &glyph_run as _,
 735                    None,
 736                    DWRITE_GLYPH_IMAGE_FORMATS_COLR
 737                        | DWRITE_GLYPH_IMAGE_FORMATS_SVG
 738                        | DWRITE_GLYPH_IMAGE_FORMATS_PNG
 739                        | DWRITE_GLYPH_IMAGE_FORMATS_JPEG
 740                        | DWRITE_GLYPH_IMAGE_FORMATS_PREMULTIPLIED_B8G8R8A8,
 741                    DWRITE_MEASURING_MODE_NATURAL,
 742                    None,
 743                    0,
 744                )?;
 745                while enumerator.MoveNext().is_ok() {
 746                    let Ok(color_glyph) = enumerator.GetCurrentRun() else {
 747                        break;
 748                    };
 749                    let color_glyph = &*color_glyph;
 750                    let brush_color = translate_color(&color_glyph.Base.runColor);
 751                    brush.SetColor(&brush_color);
 752                    match color_glyph.glyphImageFormat {
 753                        DWRITE_GLYPH_IMAGE_FORMATS_PNG
 754                        | DWRITE_GLYPH_IMAGE_FORMATS_JPEG
 755                        | DWRITE_GLYPH_IMAGE_FORMATS_PREMULTIPLIED_B8G8R8A8 => render_target
 756                            .DrawColorBitmapGlyphRun(
 757                                color_glyph.glyphImageFormat,
 758                                baseline_origin,
 759                                &color_glyph.Base.glyphRun,
 760                                color_glyph.measuringMode,
 761                                D2D1_COLOR_BITMAP_GLYPH_SNAP_OPTION_DEFAULT,
 762                            ),
 763                        DWRITE_GLYPH_IMAGE_FORMATS_SVG => render_target.DrawSvgGlyphRun(
 764                            baseline_origin,
 765                            &color_glyph.Base.glyphRun,
 766                            &brush,
 767                            None,
 768                            color_glyph.Base.paletteIndex as u32,
 769                            color_glyph.measuringMode,
 770                        ),
 771                        _ => render_target.DrawGlyphRun(
 772                            baseline_origin,
 773                            &color_glyph.Base.glyphRun,
 774                            Some(color_glyph.Base.glyphRunDescription as *const _),
 775                            &brush,
 776                            color_glyph.measuringMode,
 777                        ),
 778                    }
 779                }
 780            } else {
 781                render_target.DrawGlyphRun(
 782                    baseline_origin,
 783                    &glyph_run,
 784                    None,
 785                    &brush,
 786                    DWRITE_MEASURING_MODE_NATURAL,
 787                );
 788            }
 789            render_target.EndDraw(None, None)?;
 790
 791            let mut raw_data = vec![0u8; total_bytes];
 792            if params.is_emoji {
 793                bitmap.CopyPixels(std::ptr::null() as _, bitmap_stride, &mut raw_data)?;
 794                // Convert from BGRA with premultiplied alpha to BGRA with straight alpha.
 795                for pixel in raw_data.chunks_exact_mut(4) {
 796                    let a = pixel[3] as f32 / 255.;
 797                    pixel[0] = (pixel[0] as f32 / a) as u8;
 798                    pixel[1] = (pixel[1] as f32 / a) as u8;
 799                    pixel[2] = (pixel[2] as f32 / a) as u8;
 800                }
 801            } else {
 802                let scaler = self.components.bitmap_factory.CreateBitmapScaler()?;
 803                scaler.Initialize(
 804                    &bitmap,
 805                    bitmap_size.width.0 as u32,
 806                    bitmap_size.height.0 as u32,
 807                    WICBitmapInterpolationModeHighQualityCubic,
 808                )?;
 809                scaler.CopyPixels(std::ptr::null() as _, bitmap_stride, &mut raw_data)?;
 810            }
 811            Ok((bitmap_size, raw_data))
 812        }
 813    }
 814
 815    fn get_typographic_bounds(&self, font_id: FontId, glyph_id: GlyphId) -> Result<Bounds<f32>> {
 816        unsafe {
 817            let font = &self.fonts[font_id.0].font_face;
 818            let glyph_indices = [glyph_id.0 as u16];
 819            let mut metrics = [DWRITE_GLYPH_METRICS::default()];
 820            font.GetDesignGlyphMetrics(glyph_indices.as_ptr(), 1, metrics.as_mut_ptr(), false)?;
 821
 822            let metrics = &metrics[0];
 823            let advance_width = metrics.advanceWidth as i32;
 824            let advance_height = metrics.advanceHeight as i32;
 825            let left_side_bearing = metrics.leftSideBearing;
 826            let right_side_bearing = metrics.rightSideBearing;
 827            let top_side_bearing = metrics.topSideBearing;
 828            let bottom_side_bearing = metrics.bottomSideBearing;
 829            let vertical_origin_y = metrics.verticalOriginY;
 830
 831            let y_offset = vertical_origin_y + bottom_side_bearing - advance_height;
 832            let width = advance_width - (left_side_bearing + right_side_bearing);
 833            let height = advance_height - (top_side_bearing + bottom_side_bearing);
 834
 835            Ok(Bounds {
 836                origin: Point {
 837                    x: left_side_bearing as f32,
 838                    y: y_offset as f32,
 839                },
 840                size: Size {
 841                    width: width as f32,
 842                    height: height as f32,
 843                },
 844            })
 845        }
 846    }
 847
 848    fn get_advance(&self, font_id: FontId, glyph_id: GlyphId) -> Result<Size<f32>> {
 849        unsafe {
 850            let font = &self.fonts[font_id.0].font_face;
 851            let glyph_indices = [glyph_id.0 as u16];
 852            let mut metrics = [DWRITE_GLYPH_METRICS::default()];
 853            font.GetDesignGlyphMetrics(glyph_indices.as_ptr(), 1, metrics.as_mut_ptr(), false)?;
 854
 855            let metrics = &metrics[0];
 856
 857            Ok(Size {
 858                width: metrics.advanceWidth as f32,
 859                height: 0.0,
 860            })
 861        }
 862    }
 863
 864    fn all_font_names(&self) -> Vec<String> {
 865        let mut result =
 866            get_font_names_from_collection(&self.system_font_collection, &self.components.locale);
 867        result.extend(get_font_names_from_collection(
 868            &self.custom_font_collection,
 869            &self.components.locale,
 870        ));
 871        result
 872    }
 873
 874    fn all_font_families(&self) -> Vec<String> {
 875        get_font_names_from_collection(&self.system_font_collection, &self.components.locale)
 876    }
 877}
 878
 879impl Drop for DirectWriteState {
 880    fn drop(&mut self) {
 881        unsafe {
 882            let _ = self
 883                .components
 884                .factory
 885                .UnregisterFontFileLoader(&self.components.in_memory_loader);
 886        }
 887    }
 888}
 889
 890struct TextRendererWrapper(pub IDWriteTextRenderer);
 891
 892impl TextRendererWrapper {
 893    pub fn new(locale_str: &str) -> Self {
 894        let inner = TextRenderer::new(locale_str);
 895        TextRendererWrapper(inner.into())
 896    }
 897}
 898
 899#[implement(IDWriteTextRenderer)]
 900struct TextRenderer {
 901    locale: String,
 902}
 903
 904impl TextRenderer {
 905    pub fn new(locale_str: &str) -> Self {
 906        TextRenderer {
 907            locale: locale_str.to_owned(),
 908        }
 909    }
 910}
 911
 912struct RendererContext<'t, 'a, 'b> {
 913    text_system: &'t mut DirectWriteState,
 914    index_converter: StringIndexConverter<'a>,
 915    runs: &'b mut Vec<ShapedRun>,
 916    utf16_index: usize,
 917    width: f32,
 918}
 919
 920#[allow(non_snake_case)]
 921impl IDWritePixelSnapping_Impl for TextRenderer {
 922    fn IsPixelSnappingDisabled(
 923        &self,
 924        _clientdrawingcontext: *const ::core::ffi::c_void,
 925    ) -> windows::core::Result<BOOL> {
 926        Ok(BOOL(0))
 927    }
 928
 929    fn GetCurrentTransform(
 930        &self,
 931        _clientdrawingcontext: *const ::core::ffi::c_void,
 932        transform: *mut DWRITE_MATRIX,
 933    ) -> windows::core::Result<()> {
 934        unsafe {
 935            *transform = DWRITE_MATRIX {
 936                m11: 1.0,
 937                m12: 0.0,
 938                m21: 0.0,
 939                m22: 1.0,
 940                dx: 0.0,
 941                dy: 0.0,
 942            };
 943        }
 944        Ok(())
 945    }
 946
 947    fn GetPixelsPerDip(
 948        &self,
 949        _clientdrawingcontext: *const ::core::ffi::c_void,
 950    ) -> windows::core::Result<f32> {
 951        Ok(1.0)
 952    }
 953}
 954
 955#[allow(non_snake_case)]
 956impl IDWriteTextRenderer_Impl for TextRenderer {
 957    fn DrawGlyphRun(
 958        &self,
 959        clientdrawingcontext: *const ::core::ffi::c_void,
 960        _baselineoriginx: f32,
 961        _baselineoriginy: f32,
 962        _measuringmode: DWRITE_MEASURING_MODE,
 963        glyphrun: *const DWRITE_GLYPH_RUN,
 964        glyphrundescription: *const DWRITE_GLYPH_RUN_DESCRIPTION,
 965        _clientdrawingeffect: Option<&windows::core::IUnknown>,
 966    ) -> windows::core::Result<()> {
 967        unsafe {
 968            let glyphrun = &*glyphrun;
 969            let glyph_count = glyphrun.glyphCount as usize;
 970            if glyph_count == 0 {
 971                return Ok(());
 972            }
 973            let desc = &*glyphrundescription;
 974            let utf16_length_per_glyph = desc.stringLength as usize / glyph_count;
 975            let context =
 976                &mut *(clientdrawingcontext as *const RendererContext as *mut RendererContext);
 977
 978            if glyphrun.fontFace.is_none() {
 979                return Ok(());
 980            }
 981
 982            let font_face = glyphrun.fontFace.as_ref().unwrap();
 983            // This `cast()` action here should never fail since we are running on Win10+, and
 984            // `IDWriteFontFace3` requires Win10
 985            let font_face = &font_face.cast::<IDWriteFontFace3>().unwrap();
 986            let Some((font_identifier, font_struct, is_emoji)) =
 987                get_font_identifier_and_font_struct(font_face, &self.locale)
 988            else {
 989                return Ok(());
 990            };
 991
 992            let font_id = if let Some(id) = context
 993                .text_system
 994                .font_id_by_identifier
 995                .get(&font_identifier)
 996            {
 997                *id
 998            } else {
 999                context.text_system.select_font(&font_struct)
1000            };
1001            let mut glyphs = SmallVec::new();
1002            for index in 0..glyph_count {
1003                let id = GlyphId(*glyphrun.glyphIndices.add(index) as u32);
1004                context
1005                    .index_converter
1006                    .advance_to_utf16_ix(context.utf16_index);
1007                glyphs.push(ShapedGlyph {
1008                    id,
1009                    position: point(px(context.width), px(0.0)),
1010                    index: context.index_converter.utf8_ix,
1011                    is_emoji,
1012                });
1013                context.utf16_index += utf16_length_per_glyph;
1014                context.width += *glyphrun.glyphAdvances.add(index);
1015            }
1016            context.runs.push(ShapedRun { font_id, glyphs });
1017        }
1018        Ok(())
1019    }
1020
1021    fn DrawUnderline(
1022        &self,
1023        _clientdrawingcontext: *const ::core::ffi::c_void,
1024        _baselineoriginx: f32,
1025        _baselineoriginy: f32,
1026        _underline: *const DWRITE_UNDERLINE,
1027        _clientdrawingeffect: Option<&windows::core::IUnknown>,
1028    ) -> windows::core::Result<()> {
1029        Err(windows::core::Error::new(
1030            E_NOTIMPL,
1031            "DrawUnderline unimplemented",
1032        ))
1033    }
1034
1035    fn DrawStrikethrough(
1036        &self,
1037        _clientdrawingcontext: *const ::core::ffi::c_void,
1038        _baselineoriginx: f32,
1039        _baselineoriginy: f32,
1040        _strikethrough: *const DWRITE_STRIKETHROUGH,
1041        _clientdrawingeffect: Option<&windows::core::IUnknown>,
1042    ) -> windows::core::Result<()> {
1043        Err(windows::core::Error::new(
1044            E_NOTIMPL,
1045            "DrawStrikethrough unimplemented",
1046        ))
1047    }
1048
1049    fn DrawInlineObject(
1050        &self,
1051        _clientdrawingcontext: *const ::core::ffi::c_void,
1052        _originx: f32,
1053        _originy: f32,
1054        _inlineobject: Option<&IDWriteInlineObject>,
1055        _issideways: BOOL,
1056        _isrighttoleft: BOOL,
1057        _clientdrawingeffect: Option<&windows::core::IUnknown>,
1058    ) -> windows::core::Result<()> {
1059        Err(windows::core::Error::new(
1060            E_NOTIMPL,
1061            "DrawInlineObject unimplemented",
1062        ))
1063    }
1064}
1065
1066struct StringIndexConverter<'a> {
1067    text: &'a str,
1068    utf8_ix: usize,
1069    utf16_ix: usize,
1070}
1071
1072impl<'a> StringIndexConverter<'a> {
1073    fn new(text: &'a str) -> Self {
1074        Self {
1075            text,
1076            utf8_ix: 0,
1077            utf16_ix: 0,
1078        }
1079    }
1080
1081    fn advance_to_utf8_ix(&mut self, utf8_target: usize) {
1082        for (ix, c) in self.text[self.utf8_ix..].char_indices() {
1083            if self.utf8_ix + ix >= utf8_target {
1084                self.utf8_ix += ix;
1085                return;
1086            }
1087            self.utf16_ix += c.len_utf16();
1088        }
1089        self.utf8_ix = self.text.len();
1090    }
1091
1092    fn advance_to_utf16_ix(&mut self, utf16_target: usize) {
1093        for (ix, c) in self.text[self.utf8_ix..].char_indices() {
1094            if self.utf16_ix >= utf16_target {
1095                self.utf8_ix += ix;
1096                return;
1097            }
1098            self.utf16_ix += c.len_utf16();
1099        }
1100        self.utf8_ix = self.text.len();
1101    }
1102}
1103
1104impl Into<DWRITE_FONT_STYLE> for FontStyle {
1105    fn into(self) -> DWRITE_FONT_STYLE {
1106        match self {
1107            FontStyle::Normal => DWRITE_FONT_STYLE_NORMAL,
1108            FontStyle::Italic => DWRITE_FONT_STYLE_ITALIC,
1109            FontStyle::Oblique => DWRITE_FONT_STYLE_OBLIQUE,
1110        }
1111    }
1112}
1113
1114impl From<DWRITE_FONT_STYLE> for FontStyle {
1115    fn from(value: DWRITE_FONT_STYLE) -> Self {
1116        match value.0 {
1117            0 => FontStyle::Normal,
1118            1 => FontStyle::Italic,
1119            2 => FontStyle::Oblique,
1120            _ => unreachable!(),
1121        }
1122    }
1123}
1124
1125impl Into<DWRITE_FONT_WEIGHT> for FontWeight {
1126    fn into(self) -> DWRITE_FONT_WEIGHT {
1127        DWRITE_FONT_WEIGHT(self.0 as i32)
1128    }
1129}
1130
1131impl From<DWRITE_FONT_WEIGHT> for FontWeight {
1132    fn from(value: DWRITE_FONT_WEIGHT) -> Self {
1133        FontWeight(value.0 as f32)
1134    }
1135}
1136
1137fn get_font_names_from_collection(
1138    collection: &IDWriteFontCollection1,
1139    locale: &str,
1140) -> Vec<String> {
1141    unsafe {
1142        let mut result = Vec::new();
1143        let family_count = collection.GetFontFamilyCount();
1144        for index in 0..family_count {
1145            let Some(font_family) = collection.GetFontFamily(index).log_err() else {
1146                continue;
1147            };
1148            let Some(localized_family_name) = font_family.GetFamilyNames().log_err() else {
1149                continue;
1150            };
1151            let Some(family_name) = get_name(localized_family_name, locale).log_err() else {
1152                continue;
1153            };
1154            result.push(family_name);
1155        }
1156
1157        result
1158    }
1159}
1160
1161fn get_font_identifier_and_font_struct(
1162    font_face: &IDWriteFontFace3,
1163    locale: &str,
1164) -> Option<(FontIdentifier, Font, bool)> {
1165    let postscript_name = get_postscript_name(font_face, locale).log_err()?;
1166    let localized_family_name = unsafe { font_face.GetFamilyNames().log_err() }?;
1167    let family_name = get_name(localized_family_name, locale).log_err()?;
1168    let weight = unsafe { font_face.GetWeight() };
1169    let style = unsafe { font_face.GetStyle() };
1170    let identifier = FontIdentifier {
1171        postscript_name,
1172        weight: weight.0,
1173        style: style.0,
1174    };
1175    let font_struct = Font {
1176        family: family_name.into(),
1177        features: FontFeatures::default(),
1178        weight: weight.into(),
1179        style: style.into(),
1180    };
1181    let is_emoji = unsafe { font_face.IsColorFont().as_bool() };
1182    Some((identifier, font_struct, is_emoji))
1183}
1184
1185#[inline]
1186fn get_font_identifier(font_face: &IDWriteFontFace3, locale: &str) -> Option<FontIdentifier> {
1187    let weight = unsafe { font_face.GetWeight().0 };
1188    let style = unsafe { font_face.GetStyle().0 };
1189    get_postscript_name(font_face, locale)
1190        .log_err()
1191        .map(|postscript_name| FontIdentifier {
1192            postscript_name,
1193            weight,
1194            style,
1195        })
1196}
1197
1198#[inline]
1199fn get_postscript_name(font_face: &IDWriteFontFace3, locale: &str) -> Result<String> {
1200    let mut info = None;
1201    let mut exists = BOOL(0);
1202    unsafe {
1203        font_face.GetInformationalStrings(
1204            DWRITE_INFORMATIONAL_STRING_POSTSCRIPT_NAME,
1205            &mut info,
1206            &mut exists,
1207        )?
1208    };
1209    if !exists.as_bool() || info.is_none() {
1210        return Err(anyhow!("No postscript name found for font face"));
1211    }
1212
1213    get_name(info.unwrap(), locale)
1214}
1215
1216// https://learn.microsoft.com/en-us/windows/win32/api/dwrite/ne-dwrite-dwrite_font_feature_tag
1217fn apply_font_features(
1218    direct_write_features: &IDWriteTypography,
1219    features: &FontFeatures,
1220) -> Result<()> {
1221    let tag_values = features.tag_value_list();
1222    if tag_values.is_empty() {
1223        return Ok(());
1224    }
1225
1226    // All of these features are enabled by default by DirectWrite.
1227    // If you want to (and can) peek into the source of DirectWrite
1228    let mut feature_liga = make_direct_write_feature("liga", 1);
1229    let mut feature_clig = make_direct_write_feature("clig", 1);
1230    let mut feature_calt = make_direct_write_feature("calt", 1);
1231
1232    for (tag, value) in tag_values {
1233        if tag.as_str() == "liga" && *value == 0 {
1234            feature_liga.parameter = 0;
1235            continue;
1236        }
1237        if tag.as_str() == "clig" && *value == 0 {
1238            feature_clig.parameter = 0;
1239            continue;
1240        }
1241        if tag.as_str() == "calt" && *value == 0 {
1242            feature_calt.parameter = 0;
1243            continue;
1244        }
1245
1246        unsafe {
1247            direct_write_features.AddFontFeature(make_direct_write_feature(&tag, *value))?;
1248        }
1249    }
1250    unsafe {
1251        direct_write_features.AddFontFeature(feature_liga)?;
1252        direct_write_features.AddFontFeature(feature_clig)?;
1253        direct_write_features.AddFontFeature(feature_calt)?;
1254    }
1255
1256    Ok(())
1257}
1258
1259#[inline]
1260fn make_direct_write_feature(feature_name: &str, parameter: u32) -> DWRITE_FONT_FEATURE {
1261    let tag = make_direct_write_tag(feature_name);
1262    DWRITE_FONT_FEATURE {
1263        nameTag: tag,
1264        parameter,
1265    }
1266}
1267
1268#[inline]
1269fn make_open_type_tag(tag_name: &str) -> u32 {
1270    let bytes = tag_name.bytes().collect_vec();
1271    assert_eq!(bytes.len(), 4);
1272    ((bytes[3] as u32) << 24)
1273        | ((bytes[2] as u32) << 16)
1274        | ((bytes[1] as u32) << 8)
1275        | (bytes[0] as u32)
1276}
1277
1278#[inline]
1279fn make_direct_write_tag(tag_name: &str) -> DWRITE_FONT_FEATURE_TAG {
1280    DWRITE_FONT_FEATURE_TAG(make_open_type_tag(tag_name))
1281}
1282
1283#[inline]
1284fn get_name(string: IDWriteLocalizedStrings, locale: &str) -> Result<String> {
1285    let mut locale_name_index = 0u32;
1286    let mut exists = BOOL(0);
1287    unsafe {
1288        string.FindLocaleName(
1289            &HSTRING::from(locale),
1290            &mut locale_name_index,
1291            &mut exists as _,
1292        )?
1293    };
1294    if !exists.as_bool() {
1295        unsafe {
1296            string.FindLocaleName(
1297                DEFAULT_LOCALE_NAME,
1298                &mut locale_name_index as _,
1299                &mut exists as _,
1300            )?
1301        };
1302        if !exists.as_bool() {
1303            return Err(anyhow!("No localised string for {}", locale));
1304        }
1305    }
1306
1307    let name_length = unsafe { string.GetStringLength(locale_name_index) }? as usize;
1308    let mut name_vec = vec![0u16; name_length + 1];
1309    unsafe {
1310        string.GetString(locale_name_index, &mut name_vec)?;
1311    }
1312
1313    Ok(String::from_utf16_lossy(&name_vec[..name_length]))
1314}
1315
1316#[inline]
1317fn translate_color(color: &DWRITE_COLOR_F) -> D2D1_COLOR_F {
1318    D2D1_COLOR_F {
1319        r: color.r,
1320        g: color.g,
1321        b: color.b,
1322        a: color.a,
1323    }
1324}
1325
1326fn get_system_ui_font_name() -> SharedString {
1327    unsafe {
1328        let mut info: LOGFONTW = std::mem::zeroed();
1329        let font_family = if SystemParametersInfoW(
1330            SPI_GETICONTITLELOGFONT,
1331            std::mem::size_of::<LOGFONTW>() as u32,
1332            Some(&mut info as *mut _ as _),
1333            SYSTEM_PARAMETERS_INFO_UPDATE_FLAGS(0),
1334        )
1335        .log_err()
1336        .is_none()
1337        {
1338            // https://learn.microsoft.com/en-us/windows/win32/uxguide/vis-fonts
1339            // Segoe UI is the Windows font intended for user interface text strings.
1340            "Segoe UI".into()
1341        } else {
1342            let font_name = String::from_utf16_lossy(&info.lfFaceName);
1343            font_name.trim_matches(char::from(0)).to_owned().into()
1344        };
1345        log::info!("Use {} as UI font.", font_family);
1346        font_family
1347    }
1348}
1349
1350#[inline]
1351fn get_render_target_property(
1352    pixel_format: DXGI_FORMAT,
1353    alpha_mode: D2D1_ALPHA_MODE,
1354) -> D2D1_RENDER_TARGET_PROPERTIES {
1355    D2D1_RENDER_TARGET_PROPERTIES {
1356        r#type: D2D1_RENDER_TARGET_TYPE_DEFAULT,
1357        pixelFormat: D2D1_PIXEL_FORMAT {
1358            format: pixel_format,
1359            alphaMode: alpha_mode,
1360        },
1361        dpiX: 96.0,
1362        dpiY: 96.0,
1363        usage: D2D1_RENDER_TARGET_USAGE_NONE,
1364        minLevel: D2D1_FEATURE_LEVEL_DEFAULT,
1365    }
1366}
1367
1368const DEFAULT_LOCALE_NAME: PCWSTR = windows::core::w!("en-US");
1369const BRUSH_COLOR: D2D1_COLOR_F = D2D1_COLOR_F {
1370    r: 1.0,
1371    g: 1.0,
1372    b: 1.0,
1373    a: 1.0,
1374};