vue中使用带隐藏文本信息的图片、图片水印的方法

this.imageUrl = this.canvas.toDataURL();
},

二.图片水印

watermark({
    content = '',
    container = '',
    width = '',
    height = '',
    position = 'bottom-right',
    font = '16px 微软雅黑',
    fillStyle = 'rgba(255, 255, 255, 1)',
    zIndex = 11000,
   } = {}) {
    let img = this.img
    const imgRatio = img.naturalWidth / img.naturalHeight;
    const ctxWidth = width || img.naturalWidth;
    const ctxHeight = height || ctxWidth / imgRatio;
    this.canvas.width = ctxWidth;
    this.canvas.height = ctxHeight;
    const ctx = this.ctx;
    ctx.drawImage(img, 0, 0, ctxWidth, ctxHeight);
    ctx.shadowColor = 'rgba(0, 0, 0, 0.2)';
    ctx.shadowOffsetX = 2;
    ctx.shadowOffsetY = 2;
    ctx.shadowBlur = 2;
    ctx.font = font;
    ctx.fillStyle = fillStyle;
    if(position == 'center') {
     ctx.textAlign = 'center';
     ctx.textBaseline = 'middle';
     ctx.fillText(content, ctxWidth / 2, ctxHeight / 2, ctxWidth)
    }else if(position == 'bottom-right') {
     ctx.textAlign = 'right';
     ctx.textBaseline = 'alphabetic';
     ctx.fillText(content, ctxWidth-12, ctxHeight-12, ctxWidth)
    }
    const base64Url = this.canvas.toDataURL();
    if(container) {
     const div = document.createElement('div');
     div.setAttribute('style', ` width: ${ctxWidth}px; height: ${ctxHeight}px; z-index: ${zIndex};
     pointer-events: none; background-repeat: repeat; background-image: url('${base64Url}')`);
     container.insertBefore(div, null);
    }
    this.imageUrl = base64Url
   }

参考

不能说的秘密——前端也能玩的图片隐写术

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