使用PIL实现图像四象限镜像时遇ValueError: Images do not match问题求助

Let's walk through the issues in your code and fix them one by one — that error is almost always tied to mismatched image sizes or incorrect paste() parameters.

Key Problems in Your Current Code #

• Reversed paste targets/sources: You’re trying to paste the empty temp image into the original image, while passing your mirrored quadrants as masks. That’s backwards — you should be pasting the mirrored quadrants into temp.
• Invalid box coordinates: PIL’s paste() expects the box to follow (left, top, right, bottom) where right > left and bottom > top. Your code has boxes like (int(x/2),0,0,int(y/2)) where right is smaller than left, which triggers size mismatch errors.
• Floating-point division: Using x/2 gives a float in Python 3, but image coordinates need to be integers. Use integer division x//2 instead to avoid this.

Corrected Code #

First, let’s assume your mirror_left (horizontal flip) and mirror_verticle (vertical flip) functions work correctly. Here’s the fixed version of your mirror_four function:

from PIL import Image

def mirror_left(img):
    # Example horizontal flip function (adjust if your implementation differs)
    return img.transpose(Image.FLIP_LEFT_RIGHT)

def mirror_verticle(img):
    # Example vertical flip function (adjust if your implementation differs)
    return img.transpose(Image.FLIP_TOP_BOTTOM)

def mirror_four(image):
    x, y = image.size
    temp = Image.new("RGB", (x, y), "black")
    
    # Option 1: Mirror only the top-left quadrant across all four sections
    tl = image.crop((0, 0, x//2, y//2))
    # Option 2: Mirror the full original image for each quadrant (uncomment below)
    # tl = image
    
    tr = mirror_left(tl)
    bl = mirror_verticle(tl)
    br = mirror_verticle(tr)
    
    # Paste each quadrant into the correct position in temp
    temp.paste(tl, (0, 0, x//2, y//2))          # Top-left
    temp.paste(tr, (x//2, 0, x, y//2))          # Top-right
    temp.paste(bl, (0, y//2, x//2, y))          # Bottom-left
    temp.paste(br, (x//2, y//2, x, y))          # Bottom-right
    
    return temp

What Changed? #

1. Fixed paste direction: Now we’re pasting each mirrored quadrant into the temp image, which is the correct target for your final combined image.
2. Valid box coordinates: Each box now uses valid ranges (e.g., the top-right quadrant starts at x//2 left, 0 top, and extends to x right, y//2 bottom).
3. Integer division: Switched to x//2 and y//2 to ensure we’re passing integer coordinates, which PIL requires for image positioning.
4. Optional quadrant crop: Added a note for two common use cases — mirroring just the top-left quadrant, or mirroring the full original image for each section.

If you still run into errors, double-check your mirror_left and mirror_verticle functions to make sure they return images with the correct size (matching the quadrant size if you’re cropping, or full size if not).

内容的提问来源于stack exchange，提问作者Godly God