uniapp canvas中base64数据图片生成小程序海报

文章索引

一、问题：

base64数据图片在开发工具中显示正常，真机模拟不显示；

二、解决

将base64数据图片转存到本地临时文件

namespace Image {
  /**
   * 获取图片全路径
   * @param name 图片名
   * @returns
   */
  export const getImageUrl = (name: string): string => import.meta.env.VITE_IMG + name

  /**
   * 获取图片信息
   * @param src 图片路径
   * @returns
   */
  export const getImageInfo = (src: string): Promise<string> =>
    new Promise((resolve, reject) => {
      uni.getImageInfo({
        src,
        success: res => resolve(res.path),
        fail: err => reject(err)
      })
    })

  /**
   * 将 base64 图片数据转本地图片
   * @param base64Data base64图片数据
   * @returns
   */
  export const getBase64ImageInfo = (base64Data: string): Promise<string> => {
    const fs = uni.getFileSystemManager()

    return new Promise((resolve, reject) => {
      const [, format, bodyData] = /data:image\/(\w+);base64,(.*)/.exec(base64Data) || []

      if (!format) {
        reject(new Error('ERROR_BASE64SRC_PARSE'))
      }

      const FILE_BASE_NAME = 'tmp_base64src'
      const filePath = `${wx.env.USER_DATA_PATH}/${FILE_BASE_NAME}.${format}`
      const buffer = uni.base64ToArrayBuffer(bodyData)

      fs.writeFile({
        filePath,
        data: buffer,
        encoding: 'binary',
        success: () => resolve(filePath),
        fail: () => reject(new Error('ERROR_BASE64SRC_WRITE'))
      })
    })
  }

  /**
   * 删除本地临时文件
   * @param filePath 临时图片地址
   * @returns
   */
  export const removeTmpImage = (filePath: string): Promise<void> =>
    new Promise(() => {
      const fs = uni.getFileSystemManager()

      fs.unlink({
        filePath,
        success: res => console.log(res),
        fail: e => console.log(e)
      })
    })
}

export default Image

namespace Image {

/**

* 获取图片全路径

* @param name 图片名

* @returns

export const getImageUrl = (name: string): string => import.meta.env.VITE_IMG + name

/**

* 获取图片信息

* @param src 图片路径

* @returns

export const getImageInfo = (src: string): Promise<string> =>

new Promise((resolve, reject) => {

uni.getImageInfo({

src,

success: res => resolve(res.path),

fail: err => reject(err)

})

/**

* 将 base64 图片数据转本地图片

* @param base64Data base64图片数据

* @returns

export const getBase64ImageInfo = (base64Data: string): Promise<string> => {

const fs = uni.getFileSystemManager()

return new Promise((resolve, reject) => {

const [, format, bodyData] = /data:image\/(\w+);base64,(.*)/.exec(base64Data) || []

if (!format) {

reject(new Error('ERROR_BASE64SRC_PARSE'))

}

const FILE_BASE_NAME = 'tmp_base64src'

const filePath = `${wx.env.USER_DATA_PATH}/${FILE_BASE_NAME}.${format}`

const buffer = uni.base64ToArrayBuffer(bodyData)

fs.writeFile({

filePath,

data: buffer,

encoding: 'binary',

success: () => resolve(filePath),

fail: () => reject(new Error('ERROR_BASE64SRC_WRITE'))

})

}

/**

* 删除本地临时文件

* @param filePath 临时图片地址

* @returns

export const removeTmpImage = (filePath: string): Promise<void> =>

new Promise(() => {

const fs = uni.getFileSystemManager()

fs.unlink({

filePath,

success: res => console.log(res),

fail: e => console.log(e)

})

}

export default Image