Add text fit safety margin

app/app.py

@@ -43,6 +43,7 @@ PRINT_QUEUE_ENABLED = os.environ.get("PRINT_QUEUE_ENABLED", "1").lower() in {"1"
 PRINT_QUEUE_RETRY_SECONDS = int(os.environ.get("PRINT_QUEUE_RETRY_SECONDS", "30"))
 DPI = int(os.environ.get("LABEL_DPI", "180"))
 PTOUCH_SUPPORTS_COPIES: bool | None = None
+TEXT_FIT_EXTRA_MM = 6
 
 TAPE_WIDTHS_MM = [3.5, 6, 9, 12, 18, 24]
 PRINTABLE_TAPE_PX = {
@@ -111,6 +112,43 @@ def text_lines(text: str) -> list[str]:
     return text.split("\n")
 
 
+def text_natural_width_mm(obj: dict[str, Any], scale: float) -> float:
+    font_size = scaled_mm_to_px(float(obj.get("fontSizeMm", 5)), scale)
+    font = get_font(font_size, bool(obj.get("bold", False)))
+    scratch = Image.new("1", (1, 1), 0)
+    scratch_draw = ImageDraw.Draw(scratch)
+    widths = []
+    for line in text_lines(str(obj.get("text", "")) or " "):
+        box = scratch_draw.textbbox((0, 0), line or " ", font=font)
+        widths.append((box[2] - box[0]) / scale)
+    return max(2, max(widths, default=0) + TEXT_FIT_EXTRA_MM)
+
+
+def autofit_text_objects_for_render(design: dict[str, Any], scale: float) -> dict[str, Any]:
+    if not bool(design.get("autoLength", True)):
+        return design
+    fitted = dict(design)
+    objects = []
+    margin = float(fitted.get("marginMm", 2))
+    for obj in fitted.get("objects", []):
+        if not isinstance(obj, dict):
+            objects.append(obj)
+            continue
+        item = dict(obj)
+        if item.get("type") in {"text", "symbol"} and not item.get("manualSize"):
+            item["w"] = text_natural_width_mm(item, scale)
+        objects.append(item)
+    fitted["objects"] = objects
+    length_end = margin
+    orientation = fitted.get("orientation", "landscape")
+    for obj in objects:
+        if not isinstance(obj, dict) or obj.get("hidden"):
+            continue
+        length_end = max(length_end, float(obj.get("y", 0)) + float(obj.get("h", 0)) if orientation == "portrait" else float(obj.get("x", 0)) + float(obj.get("w", 0)))
+    fitted["lengthMm"] = max(float(fitted.get("lengthMm", 70)), min(500, length_end + margin))
+    return fitted
+
+
 def draw_text(image: Image.Image, draw: ImageDraw.ImageDraw, obj: dict[str, Any], scale: float) -> None:
     x, y, w, h = object_box(obj, scale)
     text = str(obj.get("text", "Text"))
@@ -261,6 +299,8 @@ def render_design_image(design: dict[str, Any]) -> Image.Image:
     tape_width = float(design.get("tapeWidthMm", 24))
     if tape_width not in TAPE_WIDTHS_MM:
         raise ValueError("Ungueltige Bandbreite.")
+    scale = render_scale_for_tape(tape_width)
+    design = autofit_text_objects_for_render(design, scale)
     length = clamp(float(design.get("lengthMm", 70)), 10, 500)
     orientation = design.get("orientation", "landscape")
     if orientation == "portrait":
@@ -268,7 +308,6 @@ def render_design_image(design: dict[str, Any]) -> Image.Image:
     else:
         canvas_w_mm, canvas_h_mm = length, tape_width
 
-    scale = render_scale_for_tape(tape_width)
     image = new_label_image(scaled_mm_to_px(canvas_w_mm, scale), scaled_mm_to_px(canvas_h_mm, scale))
     max_height_px = printable_px_for_tape(tape_width)
     if image.height > max_height_px: