Ben Wagner

This commit provides a **maintenance fix** for the **Fontations font scanner**, addressing two distinct issues related to font metadata retrieval. It **corrects the retrieval of font instance names**, ensuring the requested instance's name is used instead of a default. Additionally, it resolves a bug where **font variation positions** were not correctly populated if a style was not explicitly defined. The changes in `src/ports/SkFontScanner_fontations.cpp` involve **refactoring common logic** within the `scanInstance` function to ensure accurate instance indexing and efficient position extraction, thereby improving the reliability of **font metadata handling**.

This commit **improves font shaping behavior** within the **SkShaper HarfBuzz integration** by **removing a custom `hb_font_funcs_set_variation_glyph_func` implementation** in `modules/skshaper/src/SkShaper_harfbuzz.cpp`. Previously, this custom function incorrectly returned the base glyph, which was less effective than HarfBuzz's default handling for variation glyphs. This **bug fix** allows HarfBuzz to utilize its internal TrueType implementation or default behavior, leading to a better user experience for font rendering. Additionally, the `skhb_nominal_glyph` function is refactored to directly use `unicharToGlyph` for nominal glyph retrieval.

This commit **improves the robustness** of the **PDF rendering engine** by preventing assertion failures when encountering invalid font data. Specifically, the `SkPDFStrike::Make` function in `src/pdf/SkPDFFont.cpp` is modified to return `nullptr` if a typeface has no size (`unitsPerEm <= 0`) or no glyphs (`glyphCount <= 0`). This **bug fix** ensures the **PDF backend** gracefully handles malformed or empty typefaces, such as `SkEmptyTypeface`, preventing potential crashes during PDF generation. The change is safely integrated as the sole caller, `SkPDFDevice::internalDrawGlyphRun`, already anticipates and handles a `nullptr` return.

This commit **fixes** an outdated and inefficient method for retrieving the units per em (UPEM) within the **Skia typeface port for macOS**. It **corrects** the `SkTypeface_Mac::onGetUPEM` implementation by directly calling `CTFontGetUnitsPerEm` on the internal `CTFontRef`. This **refactoring** in `src/ports/SkTypeface_mac_ct.cpp` eliminates a legacy approach that unnecessarily created a `CGFont`, which was a leftover from an older CoreGraphics-based architecture. The change improves the **accuracy and performance of font metric calculations** for Mac typefaces.

This commit performs a **dependency roll of the Expat XML parsing library**, updating it from version 2.7.1 to 2.7.4 by incorporating 322 upstream commits. This **maintenance update** affects the project's build system, including `DEPS` and `bazel/deps.json`, and the generated dependency files. It also adjusts the `expat_config.h` configuration, undefining specific feature macros to align with the updated **`expat` library**. The change ensures the project utilizes the latest improvements and fixes from the upstream `libexpat` repository.

This commit performs a **maintenance update** by **rolling the HarfBuzz dependency** from version `31695252` to `9cb1fee5`. This significant update incorporates **727 upstream commits** from the **HarfBuzz text shaping library**, potentially bringing in numerous bug fixes, performance enhancements, or new capabilities. The change affects the project's **dependency management** via `DEPS` and `bazel/deps.json`, and updates the **build configurations** for both **Bazel** (`bazel/external/harfbuzz/BUILD.bazel`) and **GN** (`third_party/harfbuzz/BUILD.gn`) to include any new source files. This ensures the project utilizes a more current and robust version of the critical text shaping component.

This commit performs a **dependency roll** for the **FreeType font rendering library**, updating it from version `b91f75bd` to `264b5fbf`. This **maintenance** update incorporates 43 upstream FreeType commits, potentially bringing **bug fixes, performance enhancements, or new features** to the project's font rendering capabilities. The change affects the **build system (DEPS, bazel/deps.json)** and **infrastructure dependency generation**, alongside minor copyright year updates in FreeType configuration files like `ftoption.h` for Android and no-type1 builds. The primary impact is an updated and potentially more robust font rendering subsystem.

This commit introduces a new build argument, `skia_enable_fontmgr_fontations_empty`, to enhance control over the **Skia build system**. This **build system enhancement** allows for the **conditional compilation** of the `fontmgr_fontations_empty` target, which is associated with the **fontations font manager** subsystem. Previously, this target was always built when `fontations` was available, but now developers can explicitly exclude it. The change primarily affects `BUILD.gn` and `gn/skia.gni` by defining and utilizing this new flag, providing greater flexibility and potential build time optimizations.

This commit **refactors** the **GN build dependencies** for **Skia's core and main library targets**, aiming to simplify typeface-related dependencies. It clarifies that the `//:core` target directly requires **typeface factories**, rather than the broader font manager, and adjusts these to be private dependencies. Concurrently, this **build system maintenance** ensures that both **typeface factory** and **font manager** targets are correctly exposed as **public dependencies** for the main `//:skia` library. This change improves the precision and clarity of the build graph by explicitly defining necessary dependencies for `//:core` and `//:skia`.

This commit introduces **new font metrics** to the **CanvasKit module**, specifically exposing the thickness and position of underline and strikeout properties. It **enhances the `canvaskit_bindings.cpp`** to provide these detailed metrics, allowing for more precise text rendering and layout. A corresponding **test case** in `font_test.js` was added to verify the correct retrieval and accuracy of these new properties. This **new capability** empowers web developers to achieve more accurate and sophisticated text styling within CanvasKit applications.

This commit **fixes a bug** in the **XPS backend** by **correcting the viewport bounds calculation for clamped bitmaps**. Previously, the `SkXPSDevice.cpp` implementation incorrectly accounted only for the clamping region, omitting space for the image itself. This **bug fix** ensures that the **entire drawing, encompassing both the image and its clamping region, is properly contained within the viewport**, resolving rendering issues for clamped bitmaps in XPS.

This commit performs **maintenance refactoring** within the **XPS backend** by centralizing configuration handling during object construction. It modifies the `SkXPSDocument` constructor to **pass initialization options (`opts`) directly to the `SkXPSDevice` constructor**. Consequently, the PNG encoder validation logic is now exclusively handled within the `SkXPSDevice` constructor, eliminating redundant checks that were previously present in `SkXPSDocument`. This change improves the internal consistency and modularity of the XPS device initialization process.

This commit delivers a crucial **bug fix** and **enhancement** to the **Skia PDF backend**, specifically addressing the incorrect association of **marked content** within **Form XObjects** (non-page content streams) with the main page content stream. It introduces a robust mechanism to correctly map marked content in Form XObjects to their respective structure elements, utilizing `StructParents` and `ParentTree` entries, and ensuring structure elements properly reference the content stream via a `/Stm` entry. This change significantly improves the accuracy of **structured PDF output** and **accessibility features** for documents generated by Skia, ensuring that all content, regardless of its stream origin, is correctly represented in the PDF's logical structure. The **SkPDFDevice**, **SkPDFDocument**, and **SkPDFTag** modules are primarily affected, along with Form XObject creation logic.

This commit provides a **bug fix** for the **`modules/bentleyottmann`** module, specifically within the `myers::Event::operator[]` method. It addresses **undefined behavior** that occurred when attempting to obtain a pointer for `SkSpan` construction when the index was one past the end of an internal `std::vector`. The previous approach of `&vector[index]` was problematic in this edge case, as `std::vector` considers such an access a dereference that must be in range. The fix ensures correct pointer acquisition, preventing potential crashes or incorrect behavior, particularly when compiled with newer debugging standard libraries.

This commit **fixes a bug** in the **Android font manager** (`SkFontMgr_android.cpp`) by **adjusting the font fallback order** for character matching. It introduces a new "generic fallback" step for empty fallback family names and refines an existing step, ensuring more robust font resolution. This **refactoring of the font matching logic** within `find_family_style_character` and `matchFamilyStyleCharacter` improves the reliability of font rendering on Android devices. The change addresses an issue where the previous fallback order could lead to incorrect font selections, enhancing the consistency of text display.

This commit **corrects the debugger's rendering behavior** by removing the forced application of an identity matrix. Previously, the **debugger** would inadvertently clear all existing **clipping** from the `canvas` it was drawing to, leading to an inaccurate visual representation. This **maintenance change** ensures the debugger now respects the `canvas`'s current transformation state and clipping, which is crucial for accurately displaying debug information. Furthermore, this modification **enables future development** of features like zoom and pan within the debugger, as it no longer interferes with the `canvas`'s transform.

This commit performs a **refactoring and maintenance** task within the **`MSKPPlayer` tool**, specifically targeting the `CmdRecordCanvas` component. It modifies `CmdRecordCanvas` to **inherit from `SkNWayCanvas`**, which allows for sharing common forwarding implementations and significantly reduces code duplication. This change eliminates many redundant and error-prone methods, such as those related to drawing operations like `onDrawImageRect2`, simplifying the class's constructor and improving overall code robustness and maintainability.

This commit **implements new clip recording capabilities** within the `MSKPPlayer` in `tools/MSKPPlayer.cpp`. It addresses a **critical limitation** where `mskp` files replayed in the viewer application would previously draw without any clips, leading to incorrect rendering. By adding support for recording various clip operations, including `onClipRect`, `onClipRRect`, `onClipPath`, `onClipShader`, `onClipRegion`, and `onResetClip`, the `MSKPPlayer` can now accurately capture and replay these drawing commands. This **feature implementation** ensures that **`mskp` file playback** in the viewer application now correctly reflects all clip geometry, significantly **improving rendering fidelity**.

This commit **enhances the `MSKPPlayer`** by implementing the recording of **canvas layer and matrix operations**, such as saves, restores, and various matrix transformations. Specifically, methods like `willSave`, `didConcat44`, and `didScale` are now captured within `CmdRecordCanvas` in `tools/MSKPPlayer.cpp`. This **new capability** addresses a significant **bug** where `mskp` files previously replayed incorrectly in the viewer application, ensuring accurate drawing and visual representation of recorded content.

This commit introduces a **new capability** to the **CanvasKit debugger** by implementing **explicit FreeType deserialization** for fonts. It adds a **custom font manager and typeface deserialization** mechanism within the `loadSkp` function in `modules/canvaskit/debugger_bindings.cpp`. This **enhancement** resolves an issue where **MSKPs created with Fontations** would render without text due to FreeType ID mismatches. Consequently, the debugger can now **correctly display text** in these previously problematic MSKPs, significantly improving the fidelity and debugging experience for such assets.