reactos/reactos
Jan 2025 – Apr 2026
11 Months active
Languages Used
CC++MarkdownRCTextinfrcCMake
Technical Skills
API DevelopmentAPI ImplementationAPI TestingC ProgrammingC programmingC++
Katayama Hirofumi MZ
PROFILE
Katayama Hirofumi Mz
Hirofumi Katayama contributed to the reactos/reactos repository by engineering core improvements across Windows-like subsystems, focusing on input method integration, font rendering, and shell stability. He modernized IME and MSCTF components using C and C++, refactored build systems with CMake, and enhanced localization for Japanese users. His work included implementing advanced API surfaces, optimizing font and resource management, and improving UI reliability through targeted bug fixes and code refactoring. By addressing system-level challenges such as input reliability, rendering performance, and build efficiency, Katayama delivered maintainable solutions that improved internationalization, user experience, and long-term codebase quality.
Overall Statistics
Feature vs Bugs
70%Features
Repository Contributions
267Total
Bugs
50
Commits
267
Features
119
Lines of code
186,314
Activity Months11
Your Network
89 peopleWork History
April 2026
6 Commits • 2 Features
Apr 1, 2026April 2026 (2026-04) – Monthly summary for reactos/reactos. Highlights include delivery of font rendering enhancements and IME/Win3 compatibility work, improving stability, performance, and internationalization support. Key features delivered and bugs fixed are summarized below, with business impact and technical achievements.
6 Commits • 2 Features
Apr 1, 2026April 2026 (2026-04) – Monthly summary for reactos/reactos. Highlights include delivery of font rendering enhancements and IME/Win3 compatibility work, improving stability, performance, and internationalization support. Key features delivered and bugs fixed are summarized below, with business impact and technical achievements.
April 2026
March 2026
18 Commits • 3 Features
Mar 1, 2026March 2026: Key features delivered and bug fixes for IME and packaging. Improvements to multilingual input reliability across IMM32 include Windows interoperability, enhanced error handling and validation, and updated documentation. ZIP creation performance was boosted by switching to file mapping to support large archives. Targeted codebase maintenance/refactoring of font and resource handling improves readability and maintainability. Together, these changes enhance user experience for multilingual input, enable scalable packaging workflows, and strengthen code quality and testability for future iterations.
March 2026
18 Commits • 3 Features
Mar 1, 2026March 2026: Key features delivered and bug fixes for IME and packaging. Improvements to multilingual input reliability across IMM32 include Windows interoperability, enhanced error handling and validation, and updated documentation. ZIP creation performance was boosted by switching to file mapping to support large archives. Targeted codebase maintenance/refactoring of font and resource handling improves readability and maintainability. Together, these changes enhance user experience for multilingual input, enable scalable packaging workflows, and strengthen code quality and testability for future iterations.
February 2026
16 Commits • 7 Features
Feb 1, 2026February 2026 (2026-02) monthly summary for reactos/reactos: Key features delivered, major bugs fixed, and business-value-focused outcomes. Highlights include IME enhancements across UI and Console for East Asian input reliability; enhanced address bar parsing for relative paths and omitted drive letters; a new font look-up cache that speeds text rendering; improved file deletion workflows in Zip Folders and Fonts folder with proper confirmations and context-menu support; and wallpaper list integrity fixes preventing display of deleted files and addressing a resource leak. These changes improve input reliability, navigation usability, rendering performance, deletion workflows, and overall stability. Technologies/skills demonstrated include Imm32/IME handling, UI and Shell integration, font rendering optimization, caching strategies, localization readiness, and maintainability-focused refactors.
16 Commits • 7 Features
Feb 1, 2026February 2026 (2026-02) monthly summary for reactos/reactos: Key features delivered, major bugs fixed, and business-value-focused outcomes. Highlights include IME enhancements across UI and Console for East Asian input reliability; enhanced address bar parsing for relative paths and omitted drive letters; a new font look-up cache that speeds text rendering; improved file deletion workflows in Zip Folders and Fonts folder with proper confirmations and context-menu support; and wallpaper list integrity fixes preventing display of deleted files and addressing a resource leak. These changes improve input reliability, navigation usability, rendering performance, deletion workflows, and overall stability. Technologies/skills demonstrated include Imm32/IME handling, UI and Shell integration, font rendering optimization, caching strategies, localization readiness, and maintainability-focused refactors.
February 2026
January 2026
32 Commits • 15 Features
Jan 1, 2026In January 2026, delivered cross-cutting improvements across IME support, shell stability, localization, and build efficiency. Implemented new headers for advanced IME support, enhanced IME reliability with LoadIMM, expanded localization (ja-JP) across multiple modules, improved shell notification and parsing reliability through PIDL translation and NULL/flag fixes, and boosted file handling with ZIPFLDR UTF-8 path and dropped-files support. Built performance improvements were achieved by removing PSdk dependencies in favor of XDK, accelerating integration cycles and release readiness.
January 2026
32 Commits • 15 Features
Jan 1, 2026In January 2026, delivered cross-cutting improvements across IME support, shell stability, localization, and build efficiency. Implemented new headers for advanced IME support, enhanced IME reliability with LoadIMM, expanded localization (ja-JP) across multiple modules, improved shell notification and parsing reliability through PIDL translation and NULL/flag fixes, and boosted file handling with ZIPFLDR UTF-8 path and dropped-files support. Built performance improvements were achieved by removing PSdk dependencies in favor of XDK, accelerating integration cycles and release readiness.
July 2025
13 Commits • 3 Features
Jul 1, 2025July 2025 highlights for reactos/reactos: Delivered major modernization and reliability improvements across input subsystem and window management, with a focus on business value and user experience. The work spans MSCTF modernization (C++ port, Wine fork, and TF feature additions), build system hygiene for localization, IME UI stability fixes, and enhanced window management for ghost windows and fullscreen app handling. These efforts improve stability, cross-locale usability, and overall responsiveness for Windows-like environments built on ReactOS.
13 Commits • 3 Features
Jul 1, 2025July 2025 highlights for reactos/reactos: Delivered major modernization and reliability improvements across input subsystem and window management, with a focus on business value and user experience. The work spans MSCTF modernization (C++ port, Wine fork, and TF feature additions), build system hygiene for localization, IME UI stability fixes, and enhanced window management for ghost windows and fullscreen app handling. These efforts improve stability, cross-locale usability, and overall responsiveness for Windows-like environments built on ReactOS.
July 2025
June 2025
56 Commits • 33 Features
Jun 1, 2025June 2025 (2025-06) monthly summary for reactos/reactos. The team delivered strong localization expansion, core text-input framework modernization, and user-experience/UI enhancements, accompanied by code quality improvements and test infrastructure updates. Key work spans across localization, UI surfaces, and stability improvements for shell and input subsystems, enabling better business value through broader reach and more reliable user experiences. Key features delivered: - Expanded Japanese (ja-JP) localization across 11 modules (BUTTERFLIES, CIRCLES, CYLFRAC, MATRIX, MAZESCR, SSSTARS, STARFIELD, SYSTEMINFO, VCDCONTROLTOOL, VGAFONTEDIT, BLANKSCR) with a build fix for CYLFRAC to ensure consistent ja-JP translations. - MSCTF modernization: Refactored ITfLangBarMgr to C++ and translated ITfDocumentMgr into C++, enabling easier maintenance and more robust text input integration. - Explorer UI enhancements: AppBar Part 3 and fullscreen handling to improve UX consistency and usability in the Explorer surface. - IMM32/SDK modernization: Refactor IMM32 and fix code annotations; added SAL2 annotations and tracing (NTUSER/ime.c) to improve code quality, diagnostics, and future maintainability. - UX correctness improvements: Alt+Tab no longer switches to IME-related windows, reducing user confusion and improving focus behavior. Major bugs fixed: - Alt+Tab: Don’t switch to IME-related window (#8061). - EXPLORER: Fix MINMAXINFO handling to reflect min/max sizes correctly (#8100). - NTUSER/IME: IntTrackPopupMenuEx: Check TPMPARAMS.cbSize (#8092). - INDICDLL: Don’t use WH_KEYBOARD_LL; use WH_KEYBOARD (#8142). - SHLWAPI_APITEST: Fix IsQSForward testcase and related API test stability (#8124/8137). Overall impact and accomplishments: - Localization coverage expanded to a broad set of modules, enabling better global reach and user experience for Japanese-speaking users. - Core OS components related to text input and shell/UI were modernized, increasing maintainability, testability, and future-proofing the codebase. - UI and UX improvements reduce user friction and improve reliability across common workflows (Explorer, Alt+Tab, and input-related surfaces). - Strengthened code quality through annotation improvements (SAL2), C++ refactors, and enhanced test dependencies, benefiting long-term stability and reduce regression risk. Technologies/skills demonstrated: - C++ modernization of system components (ITfLangBarMgr, ITfDocumentMgr, IMM32). - IDL/COM integration implications and CICERO MSCTF changes. - Localization processes and multi-module translation management. - Windows UI/UX patterns (Explorer AppBar, fullscreen handling, Alt+Tab behavior). - Code quality disciplines: SAL2 annotations, tracing, test scaffolding, and build fixes.
June 2025
56 Commits • 33 Features
Jun 1, 2025June 2025 (2025-06) monthly summary for reactos/reactos. The team delivered strong localization expansion, core text-input framework modernization, and user-experience/UI enhancements, accompanied by code quality improvements and test infrastructure updates. Key work spans across localization, UI surfaces, and stability improvements for shell and input subsystems, enabling better business value through broader reach and more reliable user experiences. Key features delivered: - Expanded Japanese (ja-JP) localization across 11 modules (BUTTERFLIES, CIRCLES, CYLFRAC, MATRIX, MAZESCR, SSSTARS, STARFIELD, SYSTEMINFO, VCDCONTROLTOOL, VGAFONTEDIT, BLANKSCR) with a build fix for CYLFRAC to ensure consistent ja-JP translations. - MSCTF modernization: Refactored ITfLangBarMgr to C++ and translated ITfDocumentMgr into C++, enabling easier maintenance and more robust text input integration. - Explorer UI enhancements: AppBar Part 3 and fullscreen handling to improve UX consistency and usability in the Explorer surface. - IMM32/SDK modernization: Refactor IMM32 and fix code annotations; added SAL2 annotations and tracing (NTUSER/ime.c) to improve code quality, diagnostics, and future maintainability. - UX correctness improvements: Alt+Tab no longer switches to IME-related windows, reducing user confusion and improving focus behavior. Major bugs fixed: - Alt+Tab: Don’t switch to IME-related window (#8061). - EXPLORER: Fix MINMAXINFO handling to reflect min/max sizes correctly (#8100). - NTUSER/IME: IntTrackPopupMenuEx: Check TPMPARAMS.cbSize (#8092). - INDICDLL: Don’t use WH_KEYBOARD_LL; use WH_KEYBOARD (#8142). - SHLWAPI_APITEST: Fix IsQSForward testcase and related API test stability (#8124/8137). Overall impact and accomplishments: - Localization coverage expanded to a broad set of modules, enabling better global reach and user experience for Japanese-speaking users. - Core OS components related to text input and shell/UI were modernized, increasing maintainability, testability, and future-proofing the codebase. - UI and UX improvements reduce user friction and improve reliability across common workflows (Explorer, Alt+Tab, and input-related surfaces). - Strengthened code quality through annotation improvements (SAL2), C++ refactors, and enhanced test dependencies, benefiting long-term stability and reduce regression risk. Technologies/skills demonstrated: - C++ modernization of system components (ITfLangBarMgr, ITfDocumentMgr, IMM32). - IDL/COM integration implications and CICERO MSCTF changes. - Localization processes and multi-module translation management. - Windows UI/UX patterns (Explorer AppBar, fullscreen handling, Alt+Tab behavior). - Code quality disciplines: SAL2 annotations, tracing, test scaffolding, and build fixes.
May 2025
54 Commits • 24 Features
May 1, 2025May 2025 (2025-05) focused on strengthening the Windows-like subsystem in ReactOS by delivering core IME input integration, UI refinements, and IMM32/SDK improvements, while expanding localization coverage and reducing external dependencies. These efforts improved input reliability, UI consistency, and developer productivity, delivering tangible business value across end-user workflows and maintainability.
54 Commits • 24 Features
May 1, 2025May 2025 (2025-05) focused on strengthening the Windows-like subsystem in ReactOS by delivering core IME input integration, UI refinements, and IMM32/SDK improvements, while expanding localization coverage and reducing external dependencies. These efforts improved input reliability, UI consistency, and developer productivity, delivering tangible business value across end-user workflows and maintainability.
May 2025
April 2025
11 Commits • 4 Features
Apr 1, 2025April 2025 highlights for reactos/reactos: delivered foundational build-system modernization, substantial font/UI improvements, and stability enhancements that collectively improve maintainability, build reliability, and end-user experience across Windows-like environments. Key work included refactoring the CMake build with set_wine_module and removal of __WINESRC__ macro to simplify configuration and reduce build breakage; upgrading FreeType to 2.10.0 and adding multi-font support in AddFontResource to improve font rendering; introducing AppBar support for Explorer shell and refining pager and edit-control handling for stability; plus targeted code-quality improvements to IntExtTextOutW and readability.
April 2025
11 Commits • 4 Features
Apr 1, 2025April 2025 highlights for reactos/reactos: delivered foundational build-system modernization, substantial font/UI improvements, and stability enhancements that collectively improve maintainability, build reliability, and end-user experience across Windows-like environments. Key work included refactoring the CMake build with set_wine_module and removal of __WINESRC__ macro to simplify configuration and reduce build breakage; upgrading FreeType to 2.10.0 and adding multi-font support in AddFontResource to improve font rendering; introducing AppBar support for Explorer shell and refining pager and edit-control handling for stability; plus targeted code-quality improvements to IntExtTextOutW and readability.
March 2025
28 Commits • 14 Features
Mar 1, 2025March 2025 monthly summary for reactos/reactos. Delivered localization-driven features, UI stabilizations, and foundational tooling enhancements that collectively improve international usability, maintainability, and developer onboarding. The work emphasizes business value through clearer localization, more robust UI components, and scalable coding conventions that support faster future iterations.
28 Commits • 14 Features
Mar 1, 2025March 2025 monthly summary for reactos/reactos. Delivered localization-driven features, UI stabilizations, and foundational tooling enhancements that collectively improve international usability, maintainability, and developer onboarding. The work emphasizes business value through clearer localization, more robust UI components, and scalable coding conventions that support faster future iterations.
March 2025
February 2025
3 Commits • 2 Features
Feb 1, 2025February 2025 monthly summary for reactos/reactos: Delivered targeted enhancements to UI-related Windows APIs and improved test infrastructure, driving stability and maintainability. Key features/bugs delivered include WinList API tests (new WinList.cpp and test suite for CLSID_ShellWindows and shdocvw!WinList_*; updates to CMakeLists.txt and testlist.c), GetWindow GW_ENABLEDPOPUP support (NtUserCallHwnd flow, DWP_GetEnabledPopup helper, and improved error handling/return types), and wallpaper image assets rename for more descriptive filenames. Impact: expands test coverage for SHDOCVW APIs, stabilizes GetWindow behavior, and improves repo hygiene; reduces regressions and accelerates CI validation. Technologies/skills demonstrated: Windows API testing, CMake build/test integration, NtUserCallHwnd modification, error handling, test suite maintenance, asset management.
February 2025
3 Commits • 2 Features
Feb 1, 2025February 2025 monthly summary for reactos/reactos: Delivered targeted enhancements to UI-related Windows APIs and improved test infrastructure, driving stability and maintainability. Key features/bugs delivered include WinList API tests (new WinList.cpp and test suite for CLSID_ShellWindows and shdocvw!WinList_*; updates to CMakeLists.txt and testlist.c), GetWindow GW_ENABLEDPOPUP support (NtUserCallHwnd flow, DWP_GetEnabledPopup helper, and improved error handling/return types), and wallpaper image assets rename for more descriptive filenames. Impact: expands test coverage for SHDOCVW APIs, stabilizes GetWindow behavior, and improves repo hygiene; reduces regressions and accelerates CI validation. Technologies/skills demonstrated: Windows API testing, CMake build/test integration, NtUserCallHwnd modification, error handling, test suite maintenance, asset management.
January 2025
30 Commits • 12 Features
Jan 1, 2025Month: 2025-01 — ReactOS work across reactos/reactos focused on Shell32 surface testing, UI/UX refinements, font rendering accuracy, and test infrastructure. Delivered API surface expansions for testing, code maintainability improvements, and stability fixes that collectively raise testing coverage, developer velocity, and user-experience reliability. Key features delivered: - Implemented extensive Shell32 APITEST API surface and utilities, including SHGetUserDisplayName, SHShouldShowWizards, ShellExec_RunDLL, unread mail APIs, and StrRStrA/W wrappers, enabling stronger test coverage andSDK parity. - Core Shell32 refactor: moved SHOpenPropSheetA to propsheet.cpp and simplified string handling for maintainability and reduced future regressions. - REGEDIT: Added ES_AUTOHSCROLL style to the address bar for improved usability and accessibility. - Unicode and API surface expansions: added SHGetComputerDisplayNameW API surface and enabled Unicode support for Start Button InvokeCommand. - Font rendering improvements: fixed ftGdiGetTextMetricsW for raster fonts, used Face->num_faces, and addressed glyph alignment for MS Sans Serif to ensure consistent rendering. Major bugs fixed: - BROWSEUI_APITEST: Avoid hardcoded C:\\Windows path to improve test portability. - FREETYPE/NTGDI: Fix ftGdiGetTextMetricsW return behavior for raster fonts and switch to Face->num_faces (#7635,#7646). - EXPLORER: COM interface declarations updated (STDMETHODIMP/override) to ensure ABI compatibility (#7645). - NTUSER: Revert enabling of SM_CXICON settings to align with intended UI scaling behavior (#7682). - SHELL32: SHIsBadInterfacePtr fix (#7664). Overall impact and accomplishments: - Significantly improved test coverage and reliability for Shell32/APITEST and SDK surfaces, enabling more robust QA and faster iteration. - Improved maintainability through targeted refactors and string handling improvements, reducing future risk and onboarding effort. - Enhanced user experience through UI/UX and rendering fixes, supporting more predictable behavior across tests and real-world usage. Technologies/skills demonstrated: - Windows API and Shell32/REGEDIT/NTUSER/SHLWAPI domains, Unicode handling, and API surface design. - C/C++ programming, refactoring, API testing (APITEST), and font rendering/metrics debugging. - Cross-component collaboration, change traceability, and impact-focused delivery.
30 Commits • 12 Features
Jan 1, 2025Month: 2025-01 — ReactOS work across reactos/reactos focused on Shell32 surface testing, UI/UX refinements, font rendering accuracy, and test infrastructure. Delivered API surface expansions for testing, code maintainability improvements, and stability fixes that collectively raise testing coverage, developer velocity, and user-experience reliability. Key features delivered: - Implemented extensive Shell32 APITEST API surface and utilities, including SHGetUserDisplayName, SHShouldShowWizards, ShellExec_RunDLL, unread mail APIs, and StrRStrA/W wrappers, enabling stronger test coverage andSDK parity. - Core Shell32 refactor: moved SHOpenPropSheetA to propsheet.cpp and simplified string handling for maintainability and reduced future regressions. - REGEDIT: Added ES_AUTOHSCROLL style to the address bar for improved usability and accessibility. - Unicode and API surface expansions: added SHGetComputerDisplayNameW API surface and enabled Unicode support for Start Button InvokeCommand. - Font rendering improvements: fixed ftGdiGetTextMetricsW for raster fonts, used Face->num_faces, and addressed glyph alignment for MS Sans Serif to ensure consistent rendering. Major bugs fixed: - BROWSEUI_APITEST: Avoid hardcoded C:\\Windows path to improve test portability. - FREETYPE/NTGDI: Fix ftGdiGetTextMetricsW return behavior for raster fonts and switch to Face->num_faces (#7635,#7646). - EXPLORER: COM interface declarations updated (STDMETHODIMP/override) to ensure ABI compatibility (#7645). - NTUSER: Revert enabling of SM_CXICON settings to align with intended UI scaling behavior (#7682). - SHELL32: SHIsBadInterfacePtr fix (#7664). Overall impact and accomplishments: - Significantly improved test coverage and reliability for Shell32/APITEST and SDK surfaces, enabling more robust QA and faster iteration. - Improved maintainability through targeted refactors and string handling improvements, reducing future risk and onboarding effort. - Enhanced user experience through UI/UX and rendering fixes, supporting more predictable behavior across tests and real-world usage. Technologies/skills demonstrated: - Windows API and Shell32/REGEDIT/NTUSER/SHLWAPI domains, Unicode handling, and API surface design. - C/C++ programming, refactoring, API testing (APITEST), and font rendering/metrics debugging. - Cross-component collaboration, change traceability, and impact-focused delivery.
January 2025
Activity
Loading activity data...
Quality Metrics
Correctness91.2%
Maintainability88.8%
Architecture87.8%
Performance83.6%
AI Usage20.8%
Skills & Technologies
Programming Languages
CC++CMakeIDLImageMarkdownRCTextUnknowninf
Technical Skills
AI IntegrationAPI DevelopmentAPI ImplementationAPI IntegrationAPI TestingAPI developmentAPI testingAccessibility ImprovementBug FixBug FixingBuild OptimizationBuild SystemBuild System ConfigurationBuild System ManagementBuild Systems
Repositories Contributed To
Overview of all repositories you've contributed to across your timeline