Create app.py

app.py

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+# app_colab.py
+import cv2
+import numpy as np
+import matplotlib.pyplot as plt
+from IPython.display import clear_output
+import imageio
+
+def load_image(image_path, scale_percent=50):
+    """Load and resize image"""
+    img = cv2.imread(image_path)
+    if img is None:
+        raise FileNotFoundError(f"Image not found: {image_path}")
+    
+    width = int(img.shape[1] * scale_percent / 100)
+    height = int(img.shape[0] * scale_percent / 100)
+    img = cv2.resize(img, (width, height))
+    return img
+
+def pencil_sketch(img, blur_ksize=21):
+    """Convert image to pencil sketch"""
+    gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
+    inv_gray = 255 - gray
+    blur = cv2.GaussianBlur(inv_gray, (blur_ksize, blur_ksize), 0)
+    sketch = cv2.divide(gray, 255 - blur, scale=256)
+    return sketch
+
+def add_texture(sketch, intensity=15):
+    """Add pencil texture to sketch"""
+    noise = np.random.normal(0, intensity, sketch.shape).astype(np.uint8)
+    sketch_textured = cv2.add(sketch, noise)
+    return sketch_textured
+
+def animate_sketch(sketch, save_gif=False, gif_name="pencil_sketch_animation.gif", show_animation=True):
+    """Animate sketch line by line"""
+    canvas = np.ones_like(sketch) * 255
+    y_indices, x_indices = np.where(sketch < 255)
+    coords = list(zip(x_indices, y_indices))
+    coords.sort(key=lambda pt: sketch[pt[1], pt[0]])  # draw dark pixels first
+    
+    frames = []
+    for i, (x, y) in enumerate(coords):
+        canvas[y, x] = sketch[y, x]
+        if i % 200 == 0:
+            if show_animation:
+                clear_output(wait=True)
+                plt.imshow(canvas, cmap='gray')
+                plt.axis('off')
+                plt.show()
+            if save_gif:
+                frames.append(canvas.copy())
+    
+    # Final frame
+    if show_animation:
+        clear_output(wait=True)
+        plt.imshow(canvas, cmap='gray')
+        plt.axis('off')
+        plt.show()
+    
+    if save_gif:
+        imageio.mimsave(gif_name, frames, duration=0.05)
+        print(f"[INFO] GIF saved as {gif_name}")
+
+    return canvas
+
+# -----------------------------
+# Colab Usage Example
+# -----------------------------
+
+# 1️⃣ Upload your image in Colab:
+from google.colab import files
+uploaded = files.upload()
+image_path = list(uploaded.keys())[0]  # take the first uploaded file
+
+# 2️⃣ Load the image
+img = load_image(image_path, scale_percent=50)
+plt.imshow(cv2.cvtColor(img, cv2.COLOR_BGR2RGB))
+plt.axis('off')
+plt.title("Original Image")
+plt.show()
+
+# 3️⃣ Convert to pencil sketch
+sketch = pencil_sketch(img, blur_ksize=21)
+
+# 4️⃣ Add pencil texture
+sketch_textured = add_texture(sketch, intensity=15)
+
+# 5️⃣ Animate and save as GIF
+final_canvas = animate_sketch(sketch_textured, save_gif=True)
+cv2.imwrite("final_sketch.png", final_canvas)
+print("[INFO] Final sketch saved as final_sketch.png")