- API: add new zint_symbol dpmm field for output resolution (BMP/

EMF/PCX/PNG/TIF only, i.e. excluding EPS, GIF & SVG)
- Add support for specifying scale by X-dimension and resolution
  with new option `--scalexdimdp` for CLI/Tcl & new API function
  `ZBarcode_Scale_From_XdimDp()` (+ `ZBarcode_XdimDp_From_Scale()`
  & `ZBarcode_Default_Xdim()`) and new GUI popup; manual: document
- BMP/EMF/PCX/PNG/TIF: use new `dpmm` resolution field (for EMF
  following Inkscape)
- backend_qt: add `dpmm()`, `vectorWidth()`, `vectorHeight()`,
  `noPng()`, `getVersion()`, `takesGS1AIData()`, & `XdimDp` stuff
  incl. new `QZintXdimDp` struct for passing around scale vars &
  use in `getAsCLI()`; add comments
- Raise `scale` limit to 200 (from 100) to allow for large dpmm
- output: create directories & subdirectories as necessary for
  output path using new function `out_fopen()` and use in BMP/EMF/
  EPS/GIF/PCX/PNG/SVG/TIF
- DPLEIT/DPIDENT: format HRT according to (incomplete)
  documentation, and set default height to 72X (from 50X)
- CODE128B renamed to CODE128AB as can use subsets A and/or B
- CODABAR: fix minimum height calc
- EMF: fix indexing of handles (zero-based not 1-based)
- GUI: fix symbology zap (previous technique of clearing and
  re-loading settings without doing a sync no longer works);
  fix UPCEAN guard descent enable
- MAILMARK: better error message if input < 14 characters
- GUI: add "Default" button for DAFT tracker ratio & enable/disable
  various default buttons; use new `takesGS1AIData()` to
  enable/disable GS1-specific checkboxes
- CLI: use new `validate_float()` to parse float options (7
  significant digits allowed only, no scientific notation)
- DATAMATRIX/GRIDMATRIX/PDF417/QR/ULTRA: micro-optimize structapp
  ID parse
- library/CLI: fiddle with static asserts (make CHAR_BIT sensitive,
  supposedly)
- win32/README: update building libpng (assembly removed)
- README.linux: document incompatibility of Qt6 >= 6.3
- manual: expand Barcode Studio waffle
- test suite: change range separator to hyphen and allow multiple
  excludes

backend/dmatrix.c

@@ -1686,7 +1686,7 @@ static int dm_encode_segs(struct zint_symbol *symbol, struct zint_seg segs[], co
         if (symbol->structapp.id[0]) {
             int id, id_len, id1_err, id2_err;
 
-            for (id_len = 0; id_len < 32 && symbol->structapp.id[id_len]; id_len++);
+            for (id_len = 1; id_len < 7 && symbol->structapp.id[id_len]; id_len++);
 
             if (id_len > 6) { /* ID1 * 1000 + ID2 */
                 strcpy(symbol->errtxt, "722: Structured Append ID too long (6 digit maximum)");