如何根据背景图片规格添加水印对角限制高度和宽度而不损失标志质量？

Question

问题摘要：我的预期结果是能够对角地框住水印，无论背景图像的宽度和高度如何，它始终符合限制和尺寸，以保持徽标的质量。

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为了不失去用作水印的图像的质量，我必须根据要粘贴的图像的宽度重新调整其大小，但正如您在我将在下面发布的图像中看到的那样代码中，当图像高度太小时，水印超出了图像的限制。

如果我需要根据其他图像的宽度调整水印以保持质量，我应该如何调整高度和宽度，以便水印完美地适合其他图像，无论其高度或宽度如何？

from PIL import Image

def watermark_with_transparency(input_image_path,
                                output_image_path,
                                watermark_image_path):
    
    TRANSPARENCY = 20
    angle = 30

    base_image = Image.open(input_image_path)
    w_img, h_img = base_image.size
    
    basewidth = w_img
    watermark = Image.open(watermark_image_path)
    wpercent = (basewidth/float(watermark.size[0]))
    hsize = int((float(watermark.size[1])*float(wpercent)))
    watermark = watermark.resize((basewidth,hsize), Image.ANTIALIAS)
    watermark = watermark.rotate( angle, expand=1 )
    w_logo, h_logo = watermark.size

    center_y = int(h_img / 2)
    center_x = int(w_img / 2)
    top_y = center_y - int(h_logo / 2)
    left_x = center_x - int(w_logo / 2)

    if watermark.mode!='RGBA':
        alpha = Image.new('L', (w_img, h_img), 255)
        watermark.putalpha(alpha)

    paste_mask = watermark.split()[3].point(lambda i: i * TRANSPARENCY / 100.)
    base_image.paste(watermark, (left_x,top_y), mask=paste_mask)
    base_image.show()
    base_image.save(output_image_path)

if __name__ == '__main__':
    watermark_with_transparency(
        'jogos_de_hoje_na_tv.png',
        'watermark_create.png',
        'logo_com_transparencia.png'
        )

当前结果：

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我尝试添加这样的宽度：

    basehight = h_img
    hpercent = (basehight/float(watermark.size[0]))
    wsize = int((float(watermark.size[0])*float(hpercent)))

    watermark = watermark.resize((wsize,hsize), Image.ANTIALIAS)

但结果是水印具有很大的高度，并且在尺寸调整方面没有任何质量。

Answer 1

我这样更改您的代码：

def watermark_with_transparency(input_image_path,
                                output_image_path,
                                watermark_image_path):
    TRANSPARENCY = 20
    angle = 30
    base_image = Image.open(input_image_path)
    base_image.show()
    w_img, h_img = base_image.size
    basewidth = w_img
    watermark = Image.open(watermark_image_path)
    watermark = watermark.rotate(angle, expand=True)
    wpercent = (basewidth / float(watermark.size[0]))
    hpercent = h_img / float(watermark.size[1])
    if wpercent < hpercent:
        hsize = int((float(watermark.size[1]) * float(wpercent)))
        watermark = watermark.resize((basewidth, hsize), Image.ANTIALIAS)
    else:
        wsize = int((float(watermark.size[0]) * float(hpercent)))
        watermark = watermark.resize((wsize, h_img), Image.ANTIALIAS)
    w_logo, h_logo = watermark.size
    center_y = int(h_img / 2)
    center_x = int(w_img / 2)
    top_y = center_y - int(h_logo / 2)
    left_x = center_x - int(w_logo / 2)
    if watermark.mode != 'RGBA':
        alpha = Image.new('L', (w_img, h_img), 255)
        watermark.putalpha(alpha)
    paste_mask = watermark.split()[3].point(lambda i: i * TRANSPARENCY / 100.)
    base_image.paste(watermark, (left_x, top_y), mask=paste_mask)
    base_image.show()
    base_image.save(output_image_path)

想法是，当您调整水印大小时，您必须检查哪个因素（高度或宽度）是最小的并且您想要采用它。否则，在代码的第一个版本中，调整大小没有考虑到新高度可能大于输入图像高度。

Answer 2

from PIL import Image
import math

def add_watermark(source, source_output_path, watermark):
    source_image = Image.open( source )
    watermark_image = Image.open(watermark)

    source_image_width, source_image_height = source_image.size
    watermark_image_width = math.ceil( (source_image_width * 70 ) / 100 ) 
    # float(watermark_image.size[0]))
    watermark_image_height = math.ceil( ( source_image_height * 70 ) / 100 ) # float(watermark_image.size[1])

    watermark_x_axis = math.ceil( (source_image_width * 15 ) / 100 )
    watermark_y_axis = math.ceil( ( source_image_height * 15 ) / 100 )

    watermark_image = watermark_image.resize((watermark_image_width, watermark_image_height), Image.Resampling.LANCZOS )

    # Calculate the position to place the watermark (bottom-right corner)
    watermark_position = (watermark_x_axis, watermark_y_axis)

    # Create a copy of the input image
    source_with_watermark = source_image.copy()

    # Paste the watermark image onto the input image
    watermark_image_paste_mask = watermark_image.split()[3].point(lambda i: i * 50 / 100 )
    source_with_watermark.paste(watermark_image, watermark_position, mask=watermark_image_paste_mask)

    # Save the image with the watermark
    source_with_watermark.save( source_output_path )

add_watermark("source-image-path/m.png", "source-output-image-path/m.png", "watermark-image-path/m.png")

试试这个#m