YAPF v1: fast byte-aligned format, SIMD, tools and plugins

Format (version 1, replaces the earlier experimental versions):
- per-tile YCoCg-R or subtract-green colour transform, 8-bit modular
- 12 row filters per 8-row band (Left, Gradient, Up-right, Up-average,
  Up 1-8 rows), none with more than a one-add serial dependency
- residuals in groups of 8 at the group's width (w bits x 8 = w bytes),
  4-bit control codes with repeat-previous-width runs chosen by DP
- constant and stored tiles, independent 64x64 tiles, mips, GPU hints
- all sizes validated before decoding; corrupt input is rejected

Library:
- SIMD on by default: SSSE3 (runtime CPUID check; GCC, Clang, MSVC,
  MinGW) and NEON on ARM64; -DYAPF_NO_SIMD for plain C
- yapf_load_memory, yapf_load_mt, yapf_load_memory_mt
- 6-10x faster decoding than PNG (stb_image) on one core; -O2 and -O3
  builds perform the same
- fixes for macOS (sysconf) and the Windows import library exports

Tools and integrations:
- `yapf` CLI: convert PNG/JPG/TGA/BMP/PSD/GIF <-> YAPF, info, bench,
  thumbnail, mips
- JavaScript and Python bindings (byte-identical to the C encoder)
- GIMP 3 plugin: exports the flattened image, optional mipmaps
- Blender extension: import (also as plane), export, drag and drop
- VS Code preview, Figma plugin, Photoshop scripts, Linux MIME type and
  thumbnailer
- Makefile, updated build.sh / build.bat, tools/build_release.sh
- tests/test_yapf.c (784 checks) and bindings/js/test.js

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

extensions/photoshop/Open YAPF.jsx

@@ -0,0 +1,28 @@
+// Open YAPF — opens .yapf images in Photoshop.
+// Copyright 2026 Nexoniarz — Apache License 2.0.
+// Install: copy this folder's .jsx / .jsxinc files (and yapf / yapf.exe)
+// into Photoshop's Presets/Scripts folder; then File > Scripts > Open YAPF.
+
+#target photoshop
+#include "yapf_common.jsxinc"
+
+(function () {
+    var filter = YAPF_IS_WINDOWS ? "YAPF images:*.yapf,All files:*.*"
+                                 : function (f) { return f instanceof Folder || /\.yapf$/i.test(f.name); };
+    var files = File.openDialog("Open YAPF image", filter, true);
+    if (!files) return;
+    if (!(files instanceof Array)) files = [files];
+
+    for (var i = 0; i < files.length; i++) {
+        var tmp = yapfTempFile(".png");
+        if (!yapfRun([files[i].fsName, tmp.fsName], tmp)) {
+            alert("Could not open " + files[i].name + ".\n\n" + YAPF_TOOL_HELP);
+            return;
+        }
+        var doc = app.open(tmp);
+        // The temporary PNG is no longer needed once the document is open;
+        // use File > Scripts > Save as YAPF to write a .yapf again.
+        doc.info.caption = files[i].fsName;
+        tmp.remove();
+    }
+})();

extensions/photoshop/README.md

@@ -0,0 +1,33 @@
+# YAPF for Photoshop
+
+Two scripts that appear under **File → Scripts**:
+
+- **Open YAPF** — opens one or more `.yapf` files as documents.
+- **Save as YAPF** — saves the visible image of the active document (a
+  flattened 8-bit copy; your document is not changed), keeping
+  transparency, with an optional mip chain.
+
+They convert through the `yapf` command-line tool, so Photoshop needs no
+native plugin.
+
+## Install
+
+1. Download `yapf-<your platform>.zip` from the
+   [Releases](https://github.com/Nexoniarz/YAPF/releases) (or build the tool:
+   `make` → `build/yapf`).
+2. Copy `Open YAPF.jsx`, `Save as YAPF.jsx`, `yapf_common.jsxinc` **and**
+   `yapf` / `yapf.exe` into Photoshop's scripts folder:
+   - Windows: `C:\Program Files\Adobe\Adobe Photoshop <version>\Presets\Scripts`
+   - macOS: `/Applications/Adobe Photoshop <version>/Presets/Scripts`
+3. Restart Photoshop.  The scripts are under **File → Scripts**; you can give
+   them keyboard shortcuts in **Edit → Keyboard Shortcuts** or record them
+   in Actions.
+
+Instead of copying `yapf` next to the scripts you can put it on your `PATH`.
+
+## Status
+
+The scripts are written for Photoshop CC's ExtendScript and are not yet
+tested inside Photoshop (the converter itself is fully tested).  A native
+format plugin (`.8bi` / `.plugin`, so `.yapf` shows up directly in the Open
+and Save dialogs) needs Adobe's Photoshop SDK and is planned.

extensions/photoshop/Save as YAPF.jsx

@@ -0,0 +1,40 @@
+// Save as YAPF — writes the active document as a .yapf image.
+// Copyright 2026 Nexoniarz — Apache License 2.0.
+// The visible result is saved: a flattened 8-bit RGB (or grayscale) copy,
+// transparency kept.  Your document is not modified.
+
+#target photoshop
+#include "yapf_common.jsxinc"
+
+(function () {
+    if (!app.documents.length) { alert("Open a document first."); return; }
+    var doc = app.activeDocument;
+
+    var base = doc.name.replace(/\.[^.]+$/, "");
+    var start = new File((doc.saved && doc.path ? doc.path.fsName : Folder.desktop.fsName) + "/" + base + ".yapf");
+    var out = start.saveDlg("Save as YAPF", YAPF_IS_WINDOWS ? "YAPF images:*.yapf" : undefined);
+    if (!out) return;
+    if (!/\.yapf$/i.test(out.name)) out = new File(out.fsName + ".yapf");
+    var mips = confirm("Also store mipmaps (for game engines / GPUs)?", true, "YAPF");
+
+    var tmp = yapfTempFile(".png");
+    var copy = doc.duplicate(base + " (YAPF export)", true);     // merged copy
+    try {
+        if (copy.mode !== DocumentMode.RGB && copy.mode !== DocumentMode.GRAYSCALE)
+            copy.changeMode(ChangeMode.RGB);
+        if (copy.bitsPerChannel !== BitsPerChannelType.EIGHT)
+            copy.bitsPerChannel = BitsPerChannelType.EIGHT;
+        var opts = new PNGSaveOptions();
+        opts.interlaced = false;
+        copy.saveAs(tmp, opts, true, Extension.LOWERCASE);
+    } finally {
+        copy.close(SaveOptions.DONOTSAVECHANGES);
+    }
+
+    var args = [tmp.fsName, out.fsName];
+    if (mips) args.push("--mips");
+    var ok = yapfRun(args, out);
+    tmp.remove();
+    if (!ok) { alert("Could not write " + out.name + ".\n\n" + YAPF_TOOL_HELP); return; }
+    alert("Saved " + out.fsName + " (" + Math.round(out.length / 1024) + " KB)");
+})();

extensions/photoshop/yapf_common.jsxinc

@@ -0,0 +1,41 @@
+// Shared helpers for the YAPF Photoshop scripts.
+// Copyright 2026 Nexoniarz — Apache License 2.0.
+//
+// The scripts convert through the `yapf` command-line tool.  It is looked
+// up next to these scripts first (yapf.exe / yapf), then on the PATH.
+
+var YAPF_IS_WINDOWS = $.os.indexOf("Windows") !== -1;
+
+function yapfQuote(s) {
+    return '"' + String(s).replace(/"/g, '\\"') + '"';
+}
+
+function yapfTool() {
+    var here = new File($.fileName).parent;
+    var names = YAPF_IS_WINDOWS ? ["yapf.exe"] : ["yapf"];
+    for (var i = 0; i < names.length; i++) {
+        var f = new File(here.fsName + "/" + names[i]);
+        if (f.exists) return f.fsName;
+    }
+    return names[0];                              // rely on the PATH
+}
+
+// Runs the tool; returns true when `expectOut` was produced.
+function yapfRun(args, expectOut) {
+    var cmd = yapfQuote(yapfTool());
+    for (var i = 0; i < args.length; i++) cmd += " " + (args[i].charAt(0) === "-" ? args[i] : yapfQuote(args[i]));
+    if (YAPF_IS_WINDOWS) cmd = '"' + cmd + '"';    // cmd.exe strips one pair of quotes
+    if (expectOut.exists) expectOut.remove();
+    app.system(cmd);
+    return expectOut.exists;
+}
+
+function yapfTempFile(ext) {
+    return new File(Folder.temp.fsName + "/yapf_" + new Date().getTime() + "_" +
+                    Math.floor(Math.random() * 1e6) + ext);
+}
+
+var YAPF_TOOL_HELP =
+    "The 'yapf' command-line tool was not found or failed.\n\n" +
+    "Put yapf" + (YAPF_IS_WINDOWS ? ".exe" : "") + " in the same folder as this script, " +
+    "or add it to your PATH.\nDownload or build it: https://github.com/Nexoniarz/YAPF";