Extensions read YAPF 2; Nix package

- KDE thumbnailer: texture loader, decodes only the mip it needs; GPU
  blocks, 16-bit and float via the new yapf_tex_to_rgba8. Tested through
  KDE's plugin loader with KF6 from nixpkgs.
- Photoshop: shows the tool's error message; HDR textures open as 32-bit
  (.hdr), 16-bit stays 16-bit; 16-bit documents save as 16-bit.
- CLI: 16-bit PNG export, readable conversion errors.
- default.nix: yapf tool, library, header, MIME type and thumbnailer
  (absolute store path); runs the test suite.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01DVrVthWN8GsmgHGUhhsCYm

extensions/photoshop/Open YAPF.jsx

@@ -14,9 +14,11 @@
     if (!(files instanceof Array)) files = [files];
 
     for (var i = 0; i < files.length; i++) {
-        var tmp = yapfTempFile(".png");
+        // 8 / 16-bit images come through PNG (16 bits are kept); half,
+        // float and BC6H HDR textures through Radiance .hdr (32-bit).
+        var tmp = yapfTempFile(yapfIsHdr(files[i]) ? ".hdr" : ".png");
         if (!yapfRun([files[i].fsName, tmp.fsName], tmp)) {
-            alert("Could not open " + files[i].name + ".\n\n" + YAPF_TOOL_HELP);
+            alert("Could not open " + files[i].name + ".\n\n" + yapfFailText());
             return;
         }
         var doc = app.open(tmp);

extensions/photoshop/README.md

@@ -25,6 +25,16 @@ native plugin.
 
 Instead of copying `yapf` next to the scripts you can put it on your `PATH`.
 
+## What opens how
+
+Every YAPF file the `yapf` tool reads (version 1 and 2): 8-bit images open
+as 8-bit documents, 16-bit textures as 16-bit documents, half / float and
+BC6H HDR textures as 32-bit documents (through Radiance `.hdr`), other GPU
+blocks (BC1–BC7) decoded to 8-bit.  Cubes, arrays and animations open their
+first image.  When a file cannot be opened, the alert shows the tool's
+reason (for example a damaged file).  Saving keeps 8 or 16 bits per
+channel.
+
 ## Status
 
 The scripts are written for Photoshop CC's ExtendScript and are not yet

extensions/photoshop/Save as YAPF.jsx

@@ -22,8 +22,10 @@
     try {
         if (copy.mode !== DocumentMode.RGB && copy.mode !== DocumentMode.GRAYSCALE)
             copy.changeMode(ChangeMode.RGB);
-        if (copy.bitsPerChannel !== BitsPerChannelType.EIGHT)
-            copy.bitsPerChannel = BitsPerChannelType.EIGHT;
+        // 8 and 16 bits per channel are kept (16-bit becomes a 16-bit
+        // YAPF texture); 32-bit documents are saved as 16-bit.
+        if (copy.bitsPerChannel === BitsPerChannelType.THIRTYTWO)
+            copy.bitsPerChannel = BitsPerChannelType.SIXTEEN;
         var opts = new PNGSaveOptions();
         opts.interlaced = false;
         copy.saveAs(tmp, opts, true, Extension.LOWERCASE);
@@ -35,6 +37,6 @@
     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; }
+    if (!ok) { alert("Could not write " + out.name + ".\n\n" + yapfFailText()); return; }
     alert("Saved " + out.fsName + " (" + Math.round(out.length / 1024) + " KB)");
 })();

extensions/photoshop/yapf_common.jsxinc

@@ -20,16 +20,52 @@ function yapfTool() {
     return names[0];                              // rely on the PATH
 }
 
-// Runs the tool; returns true when `expectOut` was produced.
-function yapfRun(args, expectOut) {
+// Runs the tool with its output (stdout) going to `stdoutFile` when given.
+// Returns the tool's error text ("" when it printed none).
+function yapfExec(args, stdoutFile) {
+    var errFile = yapfTempFile(".txt");
     var cmd = yapfQuote(yapfTool());
     for (var i = 0; i < args.length; i++) cmd += " " + (args[i].charAt(0) === "-" ? args[i] : yapfQuote(args[i]));
+    if (stdoutFile) cmd += " > " + yapfQuote(stdoutFile.fsName);
+    cmd += " 2> " + yapfQuote(errFile.fsName);
     if (YAPF_IS_WINDOWS) cmd = '"' + cmd + '"';    // cmd.exe strips one pair of quotes
-    if (expectOut.exists) expectOut.remove();
     app.system(cmd);
+    var text = yapfReadText(errFile);
+    errFile.remove();
+    return text;
+}
+
+function yapfReadText(f) {
+    if (!f.exists || !f.open("r")) return "";
+    var t = f.read();
+    f.close();
+    return t.replace(/\s+$/, "");
+}
+
+// Runs the tool; returns true when `expectOut` was produced.  The tool's
+// own message (why it failed) is left in yapfLastError.
+var yapfLastError = "";
+function yapfRun(args, expectOut) {
+    if (expectOut.exists) expectOut.remove();
+    yapfLastError = yapfExec(args, null);
     return expectOut.exists;
 }
 
+// The tool's message, or the help text when the tool could not be run.
+function yapfFailText() {
+    return /yapf: /.test(yapfLastError) ? yapfLastError : YAPF_TOOL_HELP;
+}
+
+// True when a .yapf file holds float / HDR data (half, float, BC6H), so it
+// should open as a 32-bit document instead of a clamped 8-bit one.
+function yapfIsHdr(file) {
+    var info = yapfTempFile(".txt");
+    yapfExec(["info", file.fsName], info);
+    var text = yapfReadText(info);
+    info.remove();
+    return /payload\s*:[^\n]*(half float|, float|BC6H)/.test(text);
+}
+
 function yapfTempFile(ext) {
     return new File(Folder.temp.fsName + "/yapf_" + new Date().getTime() + "_" +
                     Math.floor(Math.random() * 1e6) + ext);