KivyMD中如何设置导入图片的位置并保持其原始朝向？

修复方案 #

前置依赖 #

先安装图片处理库Pillow：

pip install pillow

核心修改点 #

1. 新增EXIF朝向处理逻辑：读取图片的EXIF元数据，自动将图片旋转到正确朝向
2. 调整Image组件配置：开启比例保持，避免图片拉伸变形，同时通过pos_hint自定义图片位置
3. 图片加载逻辑修改：将处理后的图片转为Kivy纹理直接赋值，避免临时文件读写

完整可运行代码 #

from kivy.lang import Builder
from kivymd.app import MDApp
from kivy.core.window import Window
from kivy.graphics.texture import Texture
from plyer import filechooser
from PIL import Image as PILImage, ExifTags
import io

Window.size = (300, 530)

KV = """
MDBoxLayout:
    orientation: 'vertical'

    MDToolbar:
        id: progress_toolbar
        title: 'Progress'

    ScrollView:
        MDGridLayout:
            cols: 2
            adaptive_height: True
            spacing: (10, 15)
            padding: [25, 25]

            MDLabel:
                halign: 'center'
                text: 'Before'

            MDLabel:
                halign: 'center'
                text: 'Now'

            MDCard:
                ripple_behavior: True
                orientation: 'vertical'
                size_hint_y: None
                size: 120, 220
                elevation: 15
                radius: 8
                MDIconButton:
                    icon: "camera-outline"
                    user_font_size: "24sp"
                    pos_hint: {"center_x": .5, "center_y": .5}
                    on_release: app.file_chooser1()
                Image:
                    id: img1
                    allow_stretch: True
                    keep_ratio: True
                    size_hint: 0.9, 0.9
                    # 调整以下参数自定义图片位置
                    pos_hint: {"center_x": 0.5, "center_y": 0.4}

            MDCard:
                ripple_behavior: True
                orientation: 'vertical'
                size_hint_y: None
                size: 120, 220
                elevation: 15
                radius: 8
                MDIconButton:
                    icon: "camera-outline"
                    user_font_size: "24sp"
                    pos_hint: {"center_x": .5, "center_y": .5}
                    on_release: app.file_chooser2()
                Image:
                    id: img2
                    allow_stretch: True
                    keep_ratio: True
                    size_hint: 0.9, 0.9
                    # 调整以下参数自定义图片位置
                    pos_hint: {"center_x": 0.5, "center_y": 0.4}


            MDTextField:
                hint_text: 'Date'
                width: 100

            MDTextField:
                hint_text: 'Date'
                width: 100

"""

class Example(MDApp):
    def build(self):
        return Builder.load_string(KV)
    
    # 辅助函数：处理图片EXIF朝向
    def fix_image_orientation(self, img):
        try:
            for orientation in ExifTags.TAGS.keys():
                if ExifTags.TAGS[orientation]=='Orientation':
                    break
            exif = img._getexif()
            if exif is not None:
                orientation = exif[orientation]
                if orientation == 3:
                    img = img.rotate(180, expand=True)
                elif orientation == 6:
                    img = img.rotate(270, expand=True)
                elif orientation == 8:
                    img = img.rotate(90, expand=True)
        except (AttributeError, KeyError, IndexError):
            # 图片没有EXIF信息的情况直接返回原图
            pass
        return img
    
    # 辅助函数：将PIL图片转为Kivy纹理
    def pil_to_texture(self, pil_img):
        pil_img = pil_img.convert('RGBA')
        data = pil_img.tobytes()
        texture = Texture.create(size=pil_img.size, colorfmt='rgba')
        texture.blit_buffer(data, colorfmt='rgba', bufferfmt='ubyte')
        texture.flip_vertical()
        return texture

    def file_chooser1(self):
        filechooser.open_file(on_selection=self.selected1)

    def file_chooser2(self):
        filechooser.open_file(on_selection=self.selected2)

    def selected1(self, selection1):
        if not selection1:
            return
        # 读取并处理图片
        pil_img = PILImage.open(selection1[0])
        pil_img = self.fix_image_orientation(pil_img)
        self.root.ids.img1.texture = self.pil_to_texture(pil_img)

    def selected2(self, selection2):
        if not selection2:
            return
        # 读取并处理图片
        pil_img = PILImage.open(selection2[0])
        pil_img = self.fix_image_orientation(pil_img)
        self.root.ids.img2.texture = self.pil_to_texture(pil_img)

Example().run()

自定义位置说明 #

你可以直接修改每个Image组件的pos_hint参数调整位置：

• center_x取值范围0~1，0为最左侧，1为最右侧，0.5为水平居中
• center_y取值范围0~1，0为最底部，1为最顶部，0.5为垂直居中
  如果需要固定偏移量，也可以直接设置x和y属性指定绝对坐标。

内容的提问来源于stack exchange，提问作者Edwin