How to save the high-definition picture of div by canvas in html
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1. Select the html2canvas version (this version can be magnified to ensure a clear picture)
The default generated canvas image is blurred on the retina device. Processing it into a 2x image can solve this problem:
Varw=$ ("# code") .width ()
Varh=$ ("# code") .height ()
/ / set the width and height of the canvas to 2 times the width and height of the container
Varcanvas=document.createElement ("canvas")
Canvas.width=w*2
Canvas.height=h*2
Canvas.style.width=w+ "px"
Canvas.style.height=h+ "px"
Varcontext=canvas.getContext ("2d")
/ / then zoom the canvas and draw the image twice as large on the canvas
Context.scale (2Jing 2)
Html2canvas (document.querySelector ("# code"), {
Canvas:canvas
Onrendered:function (canvas) {
...
}
})
Download method:
.on ('click','.download',function () {)
('# mycanvas'). Remove ()
Var_height=$ ('.skinReport') .height ()
/ / roll to the top
('html,body') .animate ({scrollTop:0})
If (confirm ('download skin test report?')
{
SetTimeout (function () {
Varcanvas=document.createElement ("canvas")
Wicked $('# skinReport') .width ()
Hobby $('# skinReport') .height ()
Canvas.width=w*2
Canvas.height=h*2
Canvas.style.width=w+ "px"
Canvas.style.height=h+ "px"
Varcontext=canvas.getContext ("2d")
/ / then zoom the canvas and draw the image twice as large on the canvas
Context.scale (2Jing 2)
Html2canvas (document.getElementById ('skinReport'), {
AllowTaint:false
TaintTest:true
Canvas:canvas
Onrendered:function (canvas) {
Canvas.id= "mycanvas"
Canvas.style.display='none'
Document.body.appendChild (canvas)
/ / generate base64 image data
ImgData=canvas.toDataURL (type)
/ / varnewImg=document.createElement ("img")
/ / newImg.src=dataUrl
/ / document.body.appendChild (newImg)
/ / console.log (imgData)
Var_fixType=function (type) {
Type=type.toLowerCase () replace (/ jpg/i,'jpeg')
Varr=type.match (/ png | jpeg | bmp | gif/) [0]
Return'image/'+r
}
/ / process imagedata and replace mimetype
ImgData=imgData.replace (_ fixType (type), 'image/octet-stream')
/ * *
* save files locally
* @ param {String} data the picture data to be saved locally
* @ param {String} filename filename
* /
VarsaveFile=function (data,filename) {
Varsave_link=document.createElementNS ('http://www.w3.org/1999/xhtml','a');
Save_link.href=data
Save_link.download=filename
Varevent=document.createEvent ('MouseEvents')
Event.initMouseEvent ('click',true,false,window,0,0,0,0,0,false,false,false,false,0,null)
Save_link.dispatchEvent (event)
}
/ / the name of the downloaded question
Varfilename=aname+' skin test report'+ (newDate ()). GetTime () +'. + type
/ / download
SaveFile (imgData,filename)
}
Width:1512
Height:15000
})
}, 2500)
}
Else
{
Return
}
})
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