[pull] libpng16 from pnggroup:libpng16

.appveyor.yml

@@ -2,7 +2,8 @@ version: 1.6.x-{build}
 
 branches:
   except:
-    - /libpng[0-1][0-7]/
+    - /master/
+    - /v[0-9]+[.][0-9]+[.][0-9]+/
 
 image:
   - Visual Studio 2022
@@ -47,6 +48,7 @@ install:
   - 'if "%TOOLCHAIN%"=="vstudio" C:\tools\vcpkg\vcpkg.exe integrate install'
   - 'if "%TOOLCHAIN%"=="llvm" C:\tools\vcpkg\vcpkg.exe install zlib:%ARCH%-windows'
   - 'if "%TOOLCHAIN%"=="llvm" C:\tools\vcpkg\vcpkg.exe integrate install'
+  - 'if "%TOOLCHAIN%"=="msys2" if "%AUTOMATION%"=="cmake" C:\msys64\usr\bin\pacman.exe -S --noconfirm mingw-w64-%ARCH%-cmake mingw-w64-%ARCH%-ninja'
 
 before_build:
   - 'if "%TOOLCHAIN%"=="vstudio" set CI_CMAKE_GENERATOR=Visual Studio 17 2022'
@@ -57,11 +59,11 @@ before_build:
   - 'if "%TOOLCHAIN%"=="vstudio" if "%ARCH%"=="arm64" set CI_CMAKE_VARS=-DPNG_TESTS=0'
   - 'if "%TOOLCHAIN%"=="llvm" set CI_CMAKE_GENERATOR=Ninja'
   - 'if "%TOOLCHAIN%"=="llvm" set CI_CMAKE_TOOLCHAIN_FILE=C:\tools\vcpkg\scripts\buildsystems\vcpkg.cmake'
-  - 'if "%TOOLCHAIN%"=="llvm" set CI_CC=clang.exe'
-  - 'if "%TOOLCHAIN%"=="msys2" if "%AUTOMATION%"=="cmake" set CI_CMAKE_GENERATOR=Unix Makefiles'
-  - 'if "%TOOLCHAIN%"=="msys2" if "%ARCH%"=="i686" set PATH=C:\msys64\mingw32\bin;%PATH%'
-  - 'if "%TOOLCHAIN%"=="msys2" if "%ARCH%"=="x86_64" set PATH=C:\msys64\mingw64\bin;%PATH%'
-  - 'if "%TOOLCHAIN%"=="msys2" set CI_CC=%ARCH%-w64-mingw32-gcc.exe'
+  - 'if "%TOOLCHAIN%"=="llvm" set CI_CC=clang'
+  - 'if "%TOOLCHAIN%"=="msys2" set CI_CMAKE_GENERATOR=Ninja'
+  - 'if "%TOOLCHAIN%"=="msys2" set CI_CC=gcc'
+  - 'if "%TOOLCHAIN%"=="msys2" if "%ARCH%"=="i686" set MSYSTEM=MINGW32'
+  - 'if "%TOOLCHAIN%"=="msys2" if "%ARCH%"=="x86_64" set MSYSTEM=MINGW64'
   - 'set CI_CMAKE_BUILD_FLAGS=-j2'
   - 'set CI_CTEST_FLAGS=-j2'
   - 'set CI_MAKE_FLAGS=-j2'
@@ -75,4 +77,5 @@ build_script:
   - 'if "%TOOLCHAIN%"=="msys2" if "%AUTOMATION%"=="makefiles" C:\msys64\usr\bin\bash.exe -l "%APPVEYOR_BUILD_FOLDER%\ci\ci_verify_makefiles.sh"'
 
 cache:
-  - C:\tools\vcpkg\installed
+  - 'C:\tools\vcpkg\installed'
+  - 'C:\msys64\var\cache\pacman'

.cmake-format.yaml

@@ -0,0 +1,94 @@
+# https://pypi.org/project/cmakelang
+# https://github.com/cheshirekow/cmake_format
+
+# ----------------------
+# Options for formatting
+# ----------------------
+
+# How wide to allow formatted cmake files
+# TODO: Reflow the CMake files to allow setting the maximum line width to 100.
+line_width: 255
+
+# How many spaces to tab for indent
+tab_size: 2
+
+# If true, lines are indented using tab characters (utf-8 0x09) instead of
+# <tab_size> space characters (utf-8 0x20). In cases where the layout would
+# require a fractional tab character, the behavior of the fractional
+# indentation is governed by <fractional_tab_policy>
+use_tabchars: false
+
+# If <use_tabchars> is True, then the value of this variable indicates how
+# fractional indentions are handled during whitespace replacement. If set to
+# 'use-space', fractional indentation is left as spaces (utf-8 0x20). If set
+# to `round-up` fractional indentation is replaced with a single tab character
+# (utf-8 0x09) effectively shifting the column to the next tabstop
+fractional_tab_policy: "use-space"
+
+# Enable comment markup parsing and reflow
+enable_markup: false
+
+# -------------------
+# Options for linting
+# -------------------
+
+# Lint codes to disable
+disabled_codes: [
+  # TODO:
+  # Reconcile the CMake variable names with the patterns below, then
+  # re-enable the "invalid variable name XXX" messages.
+  "C0103",
+
+  # TODO:
+  # Add brief COMMENT arguments to the `add_custom_target` commands.
+  "C0113",
+]
+
+# Regular expression pattern describing valid function names
+function_pattern: "[0-9a-z_]+"
+
+# Regular expression pattern describing valid macro names
+macro_pattern: "[0-9A-Z_]+"
+
+# Regular expression pattern describing valid names for variables with global
+# (cache) scope
+global_var_pattern: "[A-Z][0-9A-Z_]+"
+
+# Regular expression pattern describing valid names for variables with global
+# scope (but internal semantic)
+internal_var_pattern: "_[A-Z][0-9A-Z_]+"
+
+# Regular expression pattern describing valid names for variables with local
+# scope
+local_var_pattern: "[a-z][a-z0-9_]+"
+
+# Regular expression pattern describing valid names for privatedirectory
+# variables
+private_var_pattern: "_[0-9a-z_]+"
+
+# Regular expression pattern describing valid names for public directory
+# variables
+public_var_pattern: "[A-Z][0-9A-Z_]+"
+
+# Regular expression pattern describing valid names for function/macro
+# arguments and loop variables.
+argument_var_pattern: "[a-z][a-z0-9_]+"
+
+# Regular expression pattern describing valid names for keywords used in
+# functions or macros
+keyword_pattern: "[A-Z][0-9A-Z_]+"
+
+# In the heuristic for C0201, how many conditionals to match within a loop in
+# before considering the loop a parser
+max_conditionals_custom_parser: 2
+
+# Require at least this many newlines between statements;
+# require no more than this many newlines between statements;
+# etc.
+min_statement_spacing: 1
+max_statement_spacing: 2
+max_returns: 6
+max_branches: 12
+max_arguments: 5
+max_localvars: 15
+max_statements: 50

.editorconfig

@@ -7,32 +7,49 @@ charset = utf-8
 insert_final_newline = true
 trim_trailing_whitespace = true
 
-# Traditionally, the end-of-line character has been platform-specific.
-end_of_line = unset
+[*.txt]
+indent_size = unset
+indent_style = space
 
 [*.[chS]]
+indent_size = 3
+indent_style = space
+max_doc_length = 80
+max_line_length = 80
+
+[*.dfa]
+indent_size = 3
 indent_style = space
-max_line_length = 81
+max_doc_length = 80
+max_line_length = 80
 
-[*.{awk,cmake,dfa,in,sh}]
+[*.awk]
+indent_size = 3
 indent_style = space
+max_doc_length = 80
 max_line_length = 100
 
-[*.txt]
+[*.cmake]
+indent_size = 2
 indent_style = space
-max_line_length = unset
+max_doc_length = 80
+max_line_length = 100
 
-[{Makefile.in,ltmain.sh}]
-indent_style = unset
-insert_final_newline = unset
-max_line_length = unset
-trim_trailing_whitespace = unset
+[*.sh]
+indent_size = 4
+indent_style = space
+max_doc_length = 100
+max_line_length = 100
 
-[*~]
+[{Makefile.in,aclocal.m4,ltmain.sh}]
+indent_size = unset
 indent_style = unset
 insert_final_newline = unset
+max_doc_length = unset
 max_line_length = unset
 trim_trailing_whitespace = unset
 
 [COMMIT_EDITMSG]
+indent_style = space
+max_doc_length = unset
 max_line_length = 72

.editorconfig-checker.json

@@ -0,0 +1,10 @@
+{
+  "Disable": {
+    "Charset": true,
+    "IndentSize": true
+  },
+  "Exclude": [
+    ".git/",
+    "out/"
+  ]
+}

.github/workflows/lint.yml

@@ -0,0 +1,34 @@
+# Copyright (C) 2024 Cosmin Truta
+# SPDX-License-Identifier: MIT-0
+
+name: Linting libpng
+
+on:
+  push:
+    branches:
+      - libpng16
+      - libpng18
+  pull_request:
+    branches:
+      - libpng16
+      - libpng18
+
+jobs:
+  lint:
+    runs-on: ubuntu-latest
+    timeout-minutes: 5
+    steps:
+      - name: Set up the cache
+        uses: actions/cache@v4
+        with:
+          path: ~/.cache/pip
+          key: ${{ runner.os }}-pip-${{ hashFiles('**/pip.txt') }}
+          restore-keys: ${{ runner.os }}-pip-
+      - name: Install yamllint
+        run: pip install yamllint
+      - name: Install editorconfig-checker
+        uses: editorconfig-checker/action-editorconfig-checker@main
+      - name: Check out the code
+        uses: actions/checkout@v4
+      - name: Run the linting script
+        run: bash ./ci/ci_lint.sh

.github/workflows/verify-linux.yml

@@ -0,0 +1,35 @@
+# Copyright (C) 2025 Cosmin Truta
+# SPDX-License-Identifier: MIT-0
+
+name: Verifying libpng on Linux
+
+on:
+  push:
+    branches:
+      - libpng16
+      - libpng18
+  pull_request:
+    branches:
+      - libpng16
+      - libpng18
+
+jobs:
+  verify-linux:
+    runs-on: ubuntu-latest
+    timeout-minutes: 10
+    steps:
+      - name: Install dependencies
+        run: |
+          sudo apt-get update -qq
+          sudo apt-get install -y --no-install-recommends build-essential zlib1g-dev
+          if [[ "${{ github.ref }}" != refs/*/libpng16 && "${{ github.base_ref }}" != libpng16 ]]
+          then
+            sudo apt-get install -y --no-install-recommends autoconf automake libtool m4
+          fi
+      - name: Check out the code
+        uses: actions/checkout@v4
+      - name: Run the configure verification script
+        run: bash ./ci/ci_verify_configure.sh
+        env:
+          CI_MAKE_FLAGS: -j2
+          CI_SANITIZERS: address,undefined

.github/workflows/verify-macos.yml

@@ -0,0 +1,28 @@
+# Copyright (C) 2025 Cosmin Truta
+# SPDX-License-Identifier: MIT-0
+
+name: Verifying libpng on macOS
+
+on:
+  push:
+    branches:
+      - libpng16
+      - libpng18
+  pull_request:
+    branches:
+      - libpng16
+      - libpng18
+
+jobs:
+  verify-macos:
+    runs-on: macos-latest
+    timeout-minutes: 10
+    steps:
+      - name: Check out the code
+        uses: actions/checkout@v4
+      - name: Run the CMake verification script
+        run: bash ./ci/ci_verify_cmake.sh
+        env:
+          CI_CMAKE_GENERATOR: Xcode
+          CI_CMAKE_BUILD_FLAGS: -j2
+          CI_CTEST_FLAGS: -j2

.github/workflows/verify-windows.yml

@@ -0,0 +1,51 @@
+# Copyright (C) 2025 Cosmin Truta
+# SPDX-License-Identifier: MIT-0
+
+name: Verifying libpng on Windows
+
+on:
+  push:
+    branches:
+      - libpng16
+      - libpng18
+  pull_request:
+    branches:
+      - libpng16
+      - libpng18
+
+jobs:
+  verify-windows:
+    strategy:
+      matrix:
+        include:
+          - os: windows-2025
+            vcpkg_triplet: x64-windows
+            cmake_generator: Visual Studio 18 2026
+            cmake_generator_platform: x64
+          - os: windows-11-arm
+            vcpkg_triplet: arm64-windows
+            cmake_generator: Visual Studio 17 2022
+            cmake_generator_platform: ARM64
+    runs-on: ${{ matrix.os }}
+    timeout-minutes: 10
+    steps:
+      - name: Set up vcpkg cache
+        uses: actions/cache@v4
+        with:
+          path: C:/vcpkg/installed
+          key: ${{ runner.os }}-vcpkg-${{ matrix.vcpkg_triplet }}-${{ hashFiles('vcpkg.json', '**/vcpkg.json') }}
+          restore-keys: ${{ runner.os }}-vcpkg-${{ matrix.vcpkg_triplet }}-
+      - name: Install dependencies
+        run: |
+          vcpkg install zlib:${{ matrix.vcpkg_triplet }}
+          vcpkg integrate install
+      - name: Check out the code
+        uses: actions/checkout@v4
+      - name: Run the CMake verification script
+        run: bash ./ci/ci_verify_cmake.sh
+        env:
+          CI_CMAKE_GENERATOR: ${{ matrix.cmake_generator }}
+          CI_CMAKE_GENERATOR_PLATFORM: ${{ matrix.cmake_generator_platform }}
+          CI_CMAKE_TOOLCHAIN_FILE: C:/vcpkg/scripts/buildsystems/vcpkg.cmake
+          CI_CMAKE_BUILD_FLAGS: -j2
+          CI_CTEST_FLAGS: -j2