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[Python][图像处理]为照片加圆角边框和水印的函数

2007年06月24日 21:23

LP开店需要批量处理一些照片，于是写了两个Python脚本，方便将照片改成圆角边框和添加水印。其中的几个基础函数拿出来共享。
其中水印的代码来自http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/362879。
代码运行需要PIL和aggdraw的支持，PIL不用说了，大名鼎鼎的Python图象处理库，豆瓣就用到了它。aggdraw这个库为绘制图形提供了更多的特性，比如支持线宽、透明度的支持，图形生成质量也比PIL自带的ImageDraw模块高了不少，我在做圆角边处理的时候，对比较小的图片做大半径圆角时，用ImageDraw会产生明显的锯齿，aggdraw就不会，而且aggdraw还可以跟PIL配合使用，非常不错，值得推荐。

#coding:utf8



from PIL import Image, ImageDraw, ImageChops, ImageEnhance, ImageFont

import aggdraw



#--------------------------------

#批量处理照片的函数

#--------------------------------



#将照片变成圆角边

def RoundCorner(image, radius):

    """

    Generate the rounded corner image for orgimage.

    """

    image = image.convert('RGBA')



    #generate the mask image

    mask = Image.new('RGBA', image.size, (0,0,0,0))



    draw = aggdraw.Draw(mask)

    brush = aggdraw.Brush('black')

    

    width, height = mask.size

    draw.rectangle((0, 0, mask.size[0], mask.size[1]), aggdraw.Brush('white'))

    #north-west corner

    draw.pieslice((0,0,radius*2,radius*2), 90, 180, None, brush)

    #north-east corner

    draw.pieslice((width-radius*2, 0, width, radius*2), 0, 90, None, brush)

    #south-west corner

    draw.pieslice((0, height-radius*2, radius*2, height), 180, 270, None, brush)

    #south-east corner

    draw.pieslice((width-radius*2, height-radius*2, width, height), 270, 360, None, brush)



    #center rectangle

    draw.rectangle((radius, radius, width-radius, height-radius), brush)

    #four edge rectangle

    draw.rectangle((radius, 0, width-radius, radius), brush)

    draw.rectangle((0, radius, radius, height-radius), brush)

    draw.rectangle((radius, height-radius, width-radius, height), brush)

    draw.rectangle((width-radius, radius, width, height-radius), brush)



    draw.flush()

    del draw

    

    return ImageChops.add(mask, image)



#加圆角线条边框

def RoundCornerFrame(image, radius, line_width, line_color, opacity=1.0):

    width, height = image.size

    

    draw = aggdraw.Draw(image)

    pen = aggdraw.Pen(line_color, line_width, int(255 * opacity))

    

    #注意: aggdraw对角度的解释与PIL有区别！

    #aggdraw画线的位置是线的中线，因此，需要减除半条线宽

    halfwidth = int(line_width / 2)

    #north-west corner 

    draw.arc((halfwidth, halfwidth, radius*2-halfwidth, radius*2-halfwidth), 90, 180, pen)

    #north-east corner

    draw.arc((width-radius*2+halfwidth, halfwidth, width-halfwidth, radius*2-halfwidth), 0, 90, pen)

    #south-west corner

    draw.arc((halfwidth, height-radius*2+halfwidth, radius*2-halfwidth, height-halfwidth), 180, 270, pen)

    #south-east corner

    draw.arc((width-radius*2+halfwidth, height-radius*2+halfwidth, width-halfwidth, height-halfwidth), 270, 360, pen)

    

    #four edge line

    draw.line((halfwidth, radius, halfwidth, height-radius), pen)

    draw.line((radius, halfwidth, width-radius, halfwidth), pen)

    draw.line((width-halfwidth, radius, width-halfwidth, height-radius), pen)

    draw.line((radius, height-halfwidth, width-radius, height-halfwidth), pen)

    

    draw.flush()

    del draw

    

    return image 

    



def reduce_opacity(im, opacity):

    """Returns an image with reduced opacity."""

    assert opacity >= 0 and opacity <= 1

    if im.mode != 'RGBA':

        im = im.convert('RGBA')

    else:

        im = im.copy()

    alpha = im.split()[3]

    alpha = ImageEnhance.Brightness(alpha).enhance(opacity)

    im.putalpha(alpha)

    return im



#为照片加水印

def Watermark(image, markimage, position, opacity=1):

    """Adds a watermark to an image."""

    im = image

    mark = markimage

    if opacity < 1:

        mark = reduce_opacity(mark, opacity)

    if im.mode != 'RGBA':

        im = im.convert('RGBA')

    # create a transparent layer the size of the image and draw the

    # watermark in that layer.

    layer = Image.new('RGBA', im.size, (0,0,0,0))

    if position == 'tile':

        for y in range(0, im.size[1], mark.size[1]):

            for x in range(0, im.size[0], mark.size[0]):

                layer.paste(mark, (x, y))

    elif position == 'scale':

        # scale, but preserve the aspect ratio

        ratio = min(

            float(im.size[0]) / mark.size[0], float(im.size[1]) / mark.size[1])

        w = int(mark.size[0] * ratio)

        h = int(mark.size[1] * ratio)

        mark = mark.resize((w, h))

        layer.paste(mark, ((im.size[0] - w) / 2, (im.size[1] - h) / 2))

    else:

        layer.paste(mark, position)

    # composite the watermark with the layer

    return Image.composite(layer, im, layer)





#为照片增加文字

def Signature(image, text, position, font=None, color=(255, 0, 0)):

    """

    imprints a PIL image with the indicated text in lower-right corner

    """

    if image.mode != "RGBA":

        image = image.convert("RGBA")

    textdraw = ImageDraw.Draw(image)

    textsize = textdraw.textsize(text, font=font)

    textpos = [image.size[i]-textsize[i]-position[i] for i in [0,1]]

    textdraw.text(textpos, text, font=font, fill=color)



    del textdraw



    return image

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