34 lines
882 B
TypeScript
34 lines
882 B
TypeScript
export async function getTextColorOnImage(url) {
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let canvas
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const width = 100
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const height = 50
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try {
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// 1. 创建离屏Canvas
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canvas = wx.createOffscreenCanvas({ type: '2d', width, height })
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const ctx = canvas.getContext('2d')
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// 2. 加载图片
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const img = canvas.createImage()
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await new Promise((resolve) => {
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img.onload = resolve
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img.src = url
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})
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// 3. 绘制并分析图像
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ctx.drawImage(img, 0, 0, width, height)
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// TODO: 增加取样，提高精确性
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const pixelData = ctx.getImageData(10, 10, 1, 1).data
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// 4. 计算文字颜色
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const brightness = (pixelData[0] * 2126 + pixelData[1] * 7152 + pixelData[2] * 722) / 10000
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return { textColor: brightness > 128 ? 'black' : 'white' }
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} finally {
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// 释放资源
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if (canvas) {
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canvas.width = 0;
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canvas.height = 0;
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}
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}
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}
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