Merge pull request #450 from chinapandaman/PPF-449

PPF-449: implement create widget method

.pylintrc

@@ -1,2 +1,2 @@
 [MESSAGES CONTROL]
-disable=C0103, R0913, R0902, R0914, C0209
+disable=C0103, R0913, R0902, R0903, R0914, C0209

PyPDFForm/core/font.py

@@ -6,6 +6,7 @@
 from re import findall
 from typing import Dict, Tuple, Union
 
+from reportlab.pdfbase.acroform import AcroForm
 from reportlab.pdfbase.pdfmetrics import registerFont, standardFonts
 from reportlab.pdfbase.ttfonts import TTFError, TTFont
 
@@ -40,6 +41,7 @@ def register_font(font_name: str, ttf_stream: bytes) -> bool:
 def auto_detect_font(widget: dict) -> str:
     """Returns the font of the text field if it is one of the standard fonts."""
 
+    # pylint: disable=R0912
     result = DEFAULT_FONT
 
     text_appearance = None
@@ -58,6 +60,11 @@ def auto_detect_font(widget: dict) -> str:
         if each.startswith("/"):
             text_segments = findall("[A-Z][^A-Z]*", each.replace("/", ""))
 
+            if len(text_segments) == 1:
+                for k, v in AcroForm.formFontNames.items():
+                    if v == text_segments[0]:
+                        return k
+
             for font in standardFonts:
                 font_segments = findall("[A-Z][^A-Z]*", font.replace("-", ""))
                 if len(font_segments) != len(text_segments):

PyPDFForm/widgets/base.py

@@ -0,0 +1,78 @@
+# -*- coding: utf-8 -*-
+"""Contains base class for all widgets to create."""
+
+from io import BytesIO
+from typing import List
+
+from pypdf import PdfReader
+from reportlab.lib.colors import Color
+from reportlab.pdfgen.canvas import Canvas
+
+from ..core.utils import stream_to_io
+
+
+class Widget:
+    """Base class for all widgets to create."""
+
+    USER_PARAMS = []
+    COLOR_PARAMS = []
+    NONE_DEFAULTS = []
+    ACRO_FORM_FUNC = ""
+
+    def __init__(
+        self,
+        name: str,
+        page_number: int,
+        x: float,
+        y: float,
+        **kwargs,
+    ) -> None:
+        """Sets acro form parameters."""
+
+        self.page_number = page_number
+        self.acro_form_params = {
+            "name": name,
+            "x": x,
+            "y": y,
+        }
+
+        for each in self.USER_PARAMS:
+            user_input, param = each
+            if user_input in kwargs:
+                value = kwargs[user_input]
+                if user_input in self.COLOR_PARAMS:
+                    value = Color(
+                        value[0],
+                        value[1],
+                        value[2],
+                    )
+                self.acro_form_params[param] = value
+            elif user_input in self.NONE_DEFAULTS:
+                self.acro_form_params[param] = None
+
+    def watermarks(self, stream: bytes) -> List[bytes]:
+        """Returns a list of watermarks after creating the widget."""
+
+        pdf = PdfReader(stream_to_io(stream))
+        page_count = len(pdf.pages)
+        watermark = BytesIO()
+
+        canvas = Canvas(
+            watermark,
+            pagesize=(
+                float(pdf.pages[self.page_number - 1].mediabox[2]),
+                float(pdf.pages[self.page_number - 1].mediabox[3]),
+            ),
+        )
+
+        getattr(canvas.acroForm, self.ACRO_FORM_FUNC)(**self.acro_form_params)
+
+        canvas.showPage()
+        canvas.save()
+        watermark.seek(0)
+
+        result = []
+        for i in range(page_count):
+            result.append(watermark.read() if i == self.page_number - 1 else b"")
+
+        return result

PyPDFForm/widgets/checkbox.py

@@ -0,0 +1,11 @@
+# -*- coding: utf-8 -*-
+"""Contains checkbox widget to create."""
+
+from .base import Widget
+
+
+class CheckBoxWidget(Widget):
+    """Checkbox widget to create."""
+
+    USER_PARAMS = [("size", "size")]
+    ACRO_FORM_FUNC = "checkbox"

PyPDFForm/widgets/text.py

@@ -0,0 +1,15 @@
+# -*- coding: utf-8 -*-
+"""Contains text field widget to create."""
+
+from .base import Widget
+
+
+class TextWidget(Widget):
+    """Text field widget to create."""
+
+    USER_PARAMS = [("width", "width"), ("height", "height"),
+                   ("max_length", "maxlen"), ("font", "fontName"),
+                   ("font_size", "fontSize"), ("font_color", "textColor")]
+    COLOR_PARAMS = ["font_color"]
+    NONE_DEFAULTS = ["max_length"]
+    ACRO_FORM_FUNC = "textfield"

PyPDFForm/wrapper.py

@@ -22,6 +22,8 @@
 from .middleware.template import (build_widgets, dropdown_to_text,
                                   set_character_x_paddings)
 from .middleware.text import Text
+from .widgets.text import TextWidget
+from .widgets.checkbox import CheckBoxWidget
 
 
 class PdfWrapper:
@@ -37,11 +39,15 @@ def __init__(
         self.stream = fp_or_f_obj_or_stream_to_stream(template)
         self.widgets = build_widgets(self.stream) if self.stream else {}
 
+        self.global_font = kwargs.get("global_font")
+        self.global_font_size = kwargs.get("global_font_size")
+        self.global_font_color = kwargs.get("global_font_color")
+
         for each in self.widgets.values():
             if isinstance(each, Text):
-                each.font = kwargs.get("global_font")
-                each.font_size = kwargs.get("global_font_size")
-                each.font_color = kwargs.get("global_font_color")
+                each.font = self.global_font
+                each.font_size = self.global_font_size
+                each.font_color = self.global_font_color
 
     def read(self) -> bytes:
         """Reads the file stream of a PDF form."""
@@ -146,6 +152,42 @@ def fill(
 
         return self
 
+    def create_widget(
+        self,
+        widget_type: str,
+        name: str,
+        page_number: int,
+        x: float,
+        y: float,
+        **kwargs,
+    ) -> PdfWrapper:
+        """Creates a new widget on a PDF form."""
+
+        _class = None
+        if widget_type == "text":
+            _class = TextWidget
+        if widget_type == "checkbox":
+            _class = CheckBoxWidget
+        if _class is None:
+            return self
+
+        watermarks = _class(
+            name=name,
+            page_number=page_number,
+            x=x,
+            y=y,
+            **kwargs
+        ).watermarks(self.read())
+
+        self.stream = merge_watermarks_with_pdf(self.read(), watermarks)
+        self.widgets[name] = build_widgets(self.read())[name]
+        if widget_type == "text":
+            self.widgets[name].font = self.global_font
+            self.widgets[name].font_size = self.global_font_size
+            self.widgets[name].font_color = self.global_font_color
+
+        return self
+
     def draw_text(
         self,
         text: str,