Merge pull request #72 from jgoerzen/main

Add new --batch option to read batch commands from stdin

Author: maresb

README.md

@@ -180,6 +180,45 @@ Any picture with JPEG standard may be printed. Beware it will be downsized to ta
 Take care of the trailing "" - you may enter text here which gets printed in
 front of the image
 
+### More control with batch mode
+
+When run with `--batch`, labelle gives you more control over the output.  As the
+UI does, this mode allows multiple blocks of each type.  `--batch` reads from
+stdin.  Each line must begin with a command, a colon, and then details.  The
+commands are:
+
+* `LABELLE-LABEL-SPEC-VERSION:1` must be the first line.
+* `TEXT`: Starts a new text block.  Any previous text lines will be printed
+  first.
+* `NEWLINE`: Adds an additional line to the current block of text or QR. Used to
+  create multiline blocks.
+* `QR`: Creates a QR code block
+
+For instance, this input:
+
+```text
+LABELLE-LABEL-SPEC-VERSION:1
+TEXT:FD12
+NEWLINE:2013
+QR:1234
+TEXT:BIG
+TEXT:LINE1
+NEWLINE:LINE2
+QR:12345
+```
+
+Creates a label with:
+
+* A 2-line text block (first line `FD12`, second line `2013`)
+* Then, a QR code for 1234
+* Then, a line-line text block with the text `BIG`
+* Then, another 2-line text block
+* Finally, a QR code
+
+Which looks like this:
+
+![Batch mode example](doc/batch-example.png)
+
 ## GUI
 
 ### Run Labelle GUI

doc/batch-example.png

@@ -6,6 +6,7 @@
 # this notice are preserved.
 # === END LICENSE STATEMENT ===
 import logging
+import sys
 from pathlib import Path
 from typing import List, NoReturn, Optional
 
@@ -200,6 +201,10 @@ def default(
             "--qr", callback=qr_callback, help="QR code", rich_help_panel="Elements"
         ),
     ] = None,
+    batch: Annotated[
+        bool,
+        typer.Option(help="Read batch commands from stdin", rich_help_panel="Elements"),
+    ] = False,
     barcode_content: Annotated[
         Optional[str],
         typer.Option("--barcode", help="Barcode", rich_help_panel="Elements"),
@@ -482,20 +487,67 @@ def default(
             BarcodeRenderEngine(content=barcode_content, barcode_type=barcode_type)
         )
 
-    if text:
+    def render_text(lines):
         render_engines.append(
             TextRenderEngine(
-                text_lines=text,
+                text_lines=lines,
                 font_file_name=font_path,
                 frame_width_px=frame_width_px,
                 font_size_ratio=int(font_scale) / 100.0,
                 align=align,
             )
         )
 
+    if text:
+        render_text(text)
+
     if picture:
         render_engines.append(PictureRenderEngine(picture))
 
+    if batch:
+        accumulator: List[str] = []
+        accumulator_type: str = "empty"
+
+        def flush_all():
+            nonlocal accumulator
+            nonlocal accumulator_type
+            if accumulator_type == "text":
+                render_text(accumulator)
+            elif accumulator_type == "qr":
+                render_engines.append(
+                    QrRenderEngine(qr_callback("\n".join(accumulator)))
+                )
+
+            accumulator = []
+            accumulator_type = "empty"
+
+        # Verify version
+        line = sys.stdin.readline().strip()
+        parts = line.split(":", 1)
+        if not (parts[0] == "LABELLE-LABEL-SPEC-VERSION" and parts[1] == "1"):
+            err_console = Console(stderr=True)
+            err_console.print(
+                "Error: Batch doesn't begin with LABELLE-LABEL-SPEC-VERSION:1"
+            )
+            raise typer.Exit()
+
+        for line in sys.stdin:
+            line = line.rstrip("\r\n")
+            parts = line.split(":", 1)
+            if parts[0] == "TEXT":
+                flush_all()
+                accumulator_type = "text"
+                accumulator.append(parts[1])
+            elif parts[0] == "QR":
+                flush_all()
+                accumulator_type = "qr"
+                accumulator.append(parts[1])
+            elif parts[0] == "NEWLINE":
+                accumulator.append(parts[1])
+            else:
+                print("WARNING: invalid command", line)
+        flush_all()
+
     if fixed_length is None:
         min_label_mm_len = min_length
         max_label_mm_len = max_length