@leafer/image/src/ImageManager.ts

@leafer/image

import { IImageManager, ILeaferImageConfig, ILeaferImage, IExportFileType } from '@leafer/interface'
import { Creator } from '@leafer/platform'
import { FileHelper, Resource } from '@leafer/file'
import { TaskProcessor } from '@leafer/task'


export const ImageManager: IImageManager = {

    maxRecycled: 10,

    recycledList: [],

    patternTasker: new TaskProcessor(),

    get(config: ILeaferImageConfig): ILeaferImage {
        let image: ILeaferImage = Resource.get(config.url)
        if (!image) Resource.set(config.url, image = Creator.image(config))
        image.use++
        return image
    },

    recycle(image: ILeaferImage): void {
        image.use--
        setTimeout(() => { if (!image.use) I.recycledList.push(image) })
    },

    clearRecycled(): void {
        const list = I.recycledList
        if (list.length > I.maxRecycled) {
            list.forEach(image => (!image.use && image.url) && Resource.remove(image.url))
            list.length = 0
        }
    },

    hasAlphaPixel(config: ILeaferImageConfig): boolean {
        return FileHelper.alphaPixelTypes.some(item => I.isFormat(item, config))
    },

    isFormat(format: IExportFileType, config: ILeaferImageConfig): boolean {
        if (config.format === format) return true
        const { url } = config
        if (url.startsWith('data:')) {
            if (url.startsWith('data:' + FileHelper.mineType(format))) return true
        } else {
            if (url.includes('.' + format) || url.includes('.' + FileHelper.upperCaseTypeMap[format])) return true
            else if (format === 'png' && !url.includes('.')) return true // blob: 等无后缀名协议的图片无法分析类型，直接当透明图片处理
        }
        return false
    },

    destroy(): void {
        I.recycledList = []
    }

}

const I = ImageManager