Add noise filter

README.md

@@ -1 +1,23 @@
 # FalsiSignPy
+
+Simulate the look of hand signed and scanned documents. FalsiSignPy is inspired
+by [FalsiSign](https://gitlab.com/edouardklein/falsisign) by Edouard Klein.
+
+## Installation
+
+Use the package manager [pip](https://pip.pypa.io/en/stable/) to install FalsiSignPy.
+
+```bash
+pip install FalsiSignPy
+```
+
+## Usage
+
+Before using FalsiSignPy, a collection of real signature images is needed. This can be
+done by scanning and cropping signatures and saving them into a folder.
+
+Afterwards, FalsiSignPy can be started with `falsisignpy`.
+
+## License
+
+FalsiSignPy is licensed under the [MIT](https://github.com/srwi/FalsiSignPy/blob/master/LICENSE) license.

falsisignpy/falsisignpy.py

@@ -5,8 +5,8 @@
 from enum import Enum
 from typing import Any, Callable, Dict, Optional, Tuple
 
+import filter
 import PySimpleGUI as sg
-import scanner
 import utils
 from pdf import PDF
 from PIL import Image
@@ -36,10 +36,11 @@ def __init__(self) -> None:
         self._mode: Mode = Mode.EDIT
 
         self._filters = [
-            scanner.Grayscale("Grayscale", enabled=True),
-            scanner.Blur("Blur", enabled=False, initial_strength=1, strength_range=(0, 20)),
-            scanner.Rotate("Random rotate", enabled=True, initial_strength=1, strength_range=(0, 10)),
-            scanner.AutoContrast("Autocontrast cutoff", enabled=True, initial_strength=2, strength_range=(0, 45)),
+            filter.Grayscale("Grayscale", enabled=True),
+            filter.Noise("Noise", enabled=False, initial_strength=0.1, strength_range=(0, 1)),
+            filter.Blur("Blur", enabled=False, initial_strength=1, strength_range=(0, 5)),
+            filter.Rotate("Random rotate", enabled=True, initial_strength=1, strength_range=(0, 10)),
+            filter.AutoContrast("Autocontrast cutoff", enabled=True, initial_strength=2, strength_range=(0, 45)),
         ]
 
     def _create_window(self) -> sg.Window:
@@ -54,7 +55,7 @@ def _create_window(self) -> sg.Window:
         signature_options = [
             [
                 sg.Text("Selected signature:"),
-                sg.Combo([], key="-DROPDOWN-", enable_events=True, readonly=True, expand_x=True),
+                sg.Combo([], key="-DROPDOWN-", enable_events=True, readonly=True, expand_x=True, disabled=True),
                 sg.FolderBrowse("Browse", key="-SIGNATURE-BROWSE-", target="-SIGNATURE-BROWSE-", enable_events=True),
             ],
             [
@@ -198,7 +199,7 @@ def _load_signatures(self, values: Dict[str, Any]) -> None:
             return
 
         signature_filenames = list(signatures.keys())
-        self._window["-DROPDOWN-"].update(values=signature_filenames, set_to_index=0)
+        self._window["-DROPDOWN-"].update(values=signature_filenames, set_to_index=0, disabled=False)
         self._select_signature(signatures[signature_filenames[0]])
         self._loaded_signatures = signatures
 
@@ -402,11 +403,11 @@ def _on_window_resized(self, _: Dict[str, Any]) -> None:
             current_page = self._pdf.get_page_image(self._current_page, signed=self._mode == Mode.PREVIEW)
             self._update_page(current_page)
 
-    def _set_filter_enabled(self, filter_: scanner.Filter, value: bool) -> None:
+    def _set_filter_enabled(self, filter_: filter.Filter, value: bool) -> None:
         filter_.set_enabled(value)
         self._update_current_page()
 
-    def _set_filter_strength(self, filter_: scanner.Filter, value: float) -> None:
+    def _set_filter_strength(self, filter_: filter.Filter, value: float) -> None:
         filter_.set_strength(value)
         self._update_current_page()
 
@@ -466,7 +467,7 @@ def start(self) -> None:
 if __name__ == "__main__":
     # Enable DPI awareness on Windows 8 and above
     if os.name == "nt" and int(platform.release()) >= 8:
-        ctypes.windll.shcore.SetProcessDpiAwareness(True)
+        ctypes.windll.shcore.SetProcessDpiAwareness(True)  # type: ignore
 
     app = FalsiSignPy()
     app.start()

falsisignpy/scanner.py → falsisignpy/filter.py

@@ -2,6 +2,7 @@
 import random
 from typing import Optional, Tuple
 
+import numpy as np
 from PIL import Image, ImageFilter, ImageOps
 from PIL.Image import Resampling
 
@@ -81,3 +82,14 @@ def _apply(self, image: Image.Image) -> Image.Image:
 
         random_strength = random.uniform(-float(self.strength), float(self.strength))
         return image.rotate(angle=random_strength, fillcolor="white", resample=Resampling.BILINEAR)
+
+
+class Noise(Filter):
+    def _apply(self, image: Image.Image) -> Image.Image:
+        if self.strength is None:
+            return image
+
+        image_array = np.array(image)
+        salt_mask = np.random.random(image_array.shape[:2]) < (self.strength / 1000)
+        image_array[salt_mask] = np.random.randint(0, 255)
+        return Image.fromarray(image_array)

falsisignpy/pdf.py

@@ -1,8 +1,8 @@
 import pathlib as pl
 from typing import Dict, List
 
+import filter
 import fitz
-import scanner
 from PIL import Image
 from signature import Signature
 
@@ -51,7 +51,7 @@ def clear_page_signatures(self, page_number: int) -> None:
 
         self._signatures[page_number] = {}
 
-    def save(self, path: pl.Path, filters: List[scanner.Filter]) -> None:
+    def save(self, path: pl.Path, filters: List[filter.Filter]) -> None:
         if len(self._pages) == 0:
             raise RuntimeError("Can not save empty document.")