50 lines
1.6 KiB
JavaScript
50 lines
1.6 KiB
JavaScript
/**
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* 将 SVG 字符串转为小程序可用的 data URL（base64 在真机上更稳定）
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*/
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function utf8ToBytes(str) {
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const encoded = encodeURIComponent(str)
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const bytes = []
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for (let i = 0; i < encoded.length; i++) {
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if (encoded.charCodeAt(i) === 37) {
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bytes.push(parseInt(encoded.substring(i + 1, i + 3), 16))
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i += 2
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} else {
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bytes.push(encoded.charCodeAt(i))
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}
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}
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return new Uint8Array(bytes)
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}
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function bytesToBase64(bytes) {
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if (typeof uni !== 'undefined' && typeof uni.arrayBufferToBase64 === 'function') {
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return uni.arrayBufferToBase64(bytes.buffer)
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}
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if (typeof btoa !== 'undefined') {
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let binary = ''
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for (let i = 0; i < bytes.length; i++) {
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binary += String.fromCharCode(bytes[i])
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}
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return btoa(binary)
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}
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const chars = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/'
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let result = ''
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for (let i = 0; i < bytes.length; i += 3) {
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const a = bytes[i]
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const b = i + 1 < bytes.length ? bytes[i + 1] : 0
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const c = i + 2 < bytes.length ? bytes[i + 2] : 0
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result += chars[a >> 2]
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result += chars[((a & 3) << 4) | (b >> 4)]
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result += i + 1 < bytes.length ? chars[((b & 15) << 2) | (c >> 6)] : '='
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result += i + 2 < bytes.length ? chars[c & 63] : '='
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}
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return result
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}
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export function svgToDataUrl(svg) {
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const normalized = String(svg || '').trim()
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if (!normalized) return ''
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const base64 = bytesToBase64(utf8ToBytes(normalized))
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return `data:image/svg+xml;base64,${base64}`
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}
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