一.帶隱藏文本信息的圖片

通過RGB 分量值的小量變動，不影響對圖片的識別。因此，我們可以在圖片加入文字信息。

最終達到如下效果:

首先，在該組件中加入img用于顯示圖片

<canvas ref='canvas' v-show='0'></canvas><img :src='http://www.cgvv.com.cn/bcjs/imageUrl' v-if='imageUrl'/>

調用方法

encryptionImg({ width = ’’, height = ’’, content = ’’, }){ 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.font = ’16px Microsoft Yahei’; ctx.textAlign = ’left’; ctx.textBaseline = ’top’; ctx.fillText(content, 12, ctxHeight/2, ctxWidth);17 const textData = ctx.getImageData(0, 0, ctxWidth, ctxHeight); this.imageUrl = this.mergeData(textData.data, ’R’,ctxWidth,ctxHeight);19 }

把文字和圖片整合成一張圖

mergeData(newData, color, width, height) { let img = this.img this.ctx.drawImage(img, 0, 0, width, height); this.originalData = this.ctx.getImageData(0, 0, width, height); var oData = this.originalData.data; var bit, offset; switch (color) { case ’R’: bit = 0; offset = 3; break; case ’G’: bit = 1; offset = 2; break; case ’B’: bit = 2; offset = 1; break; } for (var i = 0; i < oData.length; i++) { if (i % 4 == bit) { if (newData[i + offset] === 0 && (oData[i] % 2 === 1)) { if (oData[i] === 255) {oData[i]-- } else {oData[i]++ } } else if (newData[i + offset] !== 0 && (oData[i] % 2 === 0)) { if (oData[i] === 255) {oData[i]-- } else {oData[i]++ } } } } this.ctx.putImageData(this.originalData, 0, 0); return this.canvas.toDataURL(); },

調用下面方法，解開圖片信息

decryptImg(){ var data = this.originalData.data; for(var i = 0; i < data.length; i++){ if(i % 4 == 0){ if(data[i] % 2 == 0){ data[i] = 0; } else { data[i] = 255; } } else if(i % 4 == 3){ continue; } else { data[i] = 0; } } this.ctx.putImageData(this.originalData, 0, 0); this.imageUrl = this.canvas.toDataURL(); },

二.圖片水印

watermark({ content = ’’, container = ’’, width = ’’, height = ’’, position = ’bottom-right’, font = ’16px 微軟雅黑’, 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 }

參考

http://www.alloyteam.com/2016/03/image-steganography/

到此這篇關于vue中使用帶隱藏文本信息的圖片、圖片水印的文章就介紹到這了,更多相關vue 隱藏文本信息圖片水印內容請搜索好吧啦網以前的文章或繼續瀏覽下面的相關文章希望大家以后多多支持好吧啦網！