add text to hpgl tab

text_to_hpgl.py

@@ -0,0 +1,105 @@
+"""
+Convert text to HPGL using a font file (.otf, .ttf).
+Uses matplotlib TextPath; flattens curves to line segments.
+"""
+from __future__ import division
+import os
+
+# Path codes from matplotlib.path.Path
+MOVETO = 1
+LINETO = 2
+CURVE3 = 3
+CURVE4 = 4
+CLOSEPOLY = 79
+
+
+def _flatten_quadratic(p0, p1, p2, n=10):
+    """Quadratic Bezier: B(t) = (1-t)^2 P0 + 2(1-t)t P1 + t^2 P2."""
+    for i in range(1, n + 1):
+        t = i / n
+        u = 1 - t
+        x = u * u * p0[0] + 2 * u * t * p1[0] + t * t * p2[0]
+        y = u * u * p0[1] + 2 * u * t * p1[1] + t * t * p2[1]
+        yield (x, y)
+
+
+def _flatten_cubic(p0, p1, p2, p3, n=10):
+    """Cubic Bezier: B(t) = (1-t)^3 P0 + 3(1-t)^2 t P1 + 3(1-t)t^2 P2 + t^3 P3."""
+    for i in range(1, n + 1):
+        t = i / n
+        u = 1 - t
+        x = u * u * u * p0[0] + 3 * u * u * t * p1[0] + 3 * u * t * t * p2[0] + t * t * t * p3[0]
+        y = u * u * u * p0[1] + 3 * u * u * t * p1[1] + 3 * u * t * t * p2[1] + t * t * t * p3[1]
+        yield (x, y)
+
+
+def text_to_hpgl(text, font_path, size_pt=72, units_per_pt=14):
+    """
+    Convert text to HPGL string using the given font file.
+    size_pt: font size in points.
+    units_per_pt: HPGL units per point (default ~0.35 mm per pt).
+    Returns HPGL string (IN;SP1;PU x,y;PD;PA x,y;...).
+    """
+    try:
+        from matplotlib.textpath import TextPath
+        from matplotlib.font_manager import FontProperties
+    except ImportError:
+        raise RuntimeError('matplotlib is required for text-to-HPGL. Install with: pip install matplotlib')
+
+    if not text or not font_path or not os.path.isfile(font_path):
+        raise ValueError('Need non-empty text and a valid font file path.')
+
+    prop = FontProperties(fname=font_path)
+    path = TextPath((0, 0), text, size=size_pt, prop=prop)
+    vertices = path.vertices
+    codes = path.codes
+
+    if codes is None:
+        codes = [MOVETO] + [LINETO] * (len(vertices) - 1)
+
+    # Scale to HPGL units (y flip: matplotlib y up, HPGL typically y up too; we keep same)
+    scale = units_per_pt
+    segments = []
+    i = 0
+    contour_start = None
+
+    while i < len(codes):
+        code = codes[i]
+        if code == MOVETO:
+            x, y = vertices[i]
+            segments.append(('PU', int(round(x * scale)), int(round(y * scale))))
+            contour_start = (int(round(x * scale)), int(round(y * scale)))
+            i += 1
+        elif code == LINETO:
+            x, y = vertices[i]
+            segments.append(('PD', int(round(x * scale)), int(round(y * scale))))
+            i += 1
+        elif code == CLOSEPOLY:
+            if contour_start:
+                segments.append(('PD', contour_start[0], contour_start[1]))
+            contour_start = None
+            i += 1
+        elif code == CURVE3 and i + 1 < len(vertices):
+            for (x, y) in _flatten_quadratic(
+                (vertices[i - 1][0], vertices[i - 1][1]),
+                (vertices[i][0], vertices[i][1]),
+                (vertices[i + 1][0], vertices[i + 1][1]),
+            ):
+                segments.append(('PD', int(round(x * scale)), int(round(y * scale))))
+            i += 2
+        elif code == CURVE4 and i + 2 < len(vertices):
+            p0, p1, p2, p3 = vertices[i - 1], vertices[i], vertices[i + 1], vertices[i + 2]
+            for (x, y) in _flatten_cubic(p0, p1, p2, p3):
+                segments.append(('PD', int(round(x * scale)), int(round(y * scale))))
+            i += 3
+        else:
+            i += 1
+
+    out = ['IN', 'SP1']
+    for seg in segments:
+        if seg[0] == 'PU':
+            out.append('PU{},{}'.format(seg[1], seg[2]))
+        else:
+            out.append('PD{},{}'.format(seg[1], seg[2]))
+    out.append('PU')
+    return ';'.join(out) + ';'