将影像添加到画布

Question

我正在尝试从svg创建图像。

我到目前为止所做的是捕获使用RaphaelJS创建的内联svg，然后使用svg代码创建一个图像，然后将其添加到画布上，我在这里找到了一篇文章，向我展示了如何缩放图像以适合画布。

但是，我想使图像变大。我对svg和canvas非常陌生，所以我不确定这是否是一种好方法。我的最终目标是生成和图像，我可以添加到PDF。我使用的代码如下。

var svgc = document.getElementById('graph').innerHTML; 
var image = new Image(); 
image.src = "data:image/svg+xml," + encodeURIComponent(svgc); 
var canvas = document.getElementById('viewport'); 

context = canvas.getContext('2d'); 

drawImageScaled(image, context); 

function drawImageScaled(img, ctx) { 
    var canvas = ctx.canvas; 
    var hRatio = canvas.width/img.width; 
    var vRatio = canvas.height/img.height; 
    var ratio = Math.min(hRatio, vRatio); 
    var centerShift_x = (canvas.width - img.width * ratio)/2; 
    var centerShift_y = (canvas.height - img.height * ratio)/2; 
    ctx.clearRect(0, 0, canvas.width, canvas.height); 
    ctx.drawImage(img, 0, 0, img.width, img.height, 
        centerShift_x, centerShift_y, img.width * ratio, img.height * ratio); 
} 

我需要调整画布大小，因为生成的图像太小了。

我想我需要调整图像的大小，但我不知道如何。感谢您的任何帮助。

我已经包括由下面的raphaeljs创建的svg。

<svg height="500" version="1.1" width="1000" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" style="overflow: hidden; position: relative; left: -0.5px;"> 
    <desc style="-webkit-tap-highlight-color: rgba(0, 0, 0, 0);">Created with Raphaël 2.1.2</desc> 
    <defs style="-webkit-tap-highlight-color: rgba(0, 0, 0, 0);"></defs> 
    <rect x="200" y="20" width="50" height="460" rx="0" ry="0" fill="none" stroke="#000" style="-webkit-tap-highlight-color: rgba(0, 0, 0, 0);"></rect> 
    <rect x="200" y="20" width="50" height="50" rx="0" ry="0" fill="#ffff00" stroke="#000000" style="-webkit-tap-highlight-color: rgba(0, 0, 0, 0); opacity: 0.5;" opacity="0.5" stroke-width="2"></rect> 
    <path fill="none" stroke="#000000" d="M300,20L700,20" style="-webkit-tap-highlight-color: rgba(0, 0, 0, 0);"></path> 
    <text x="350" y="30" text-anchor="middle" font-family="&quot;Arial&quot;" font-size="10px" stroke="none" fill="#000000" style="-webkit-tap-highlight-color: rgba(0, 0, 0, 0); text-anchor: middle; font-family: Arial; font-size: 10px;"><tspan dy="3.5" style="-webkit-tap-highlight-color: rgba(0, 0, 0, 0);">Sample Info</tspan></text> 
    <rect x="200" y="20" width="20" height="50" rx="0" ry="0" fill="#00cc00" stroke="#000000" opacity="0.5" stroke-width="2" style="-webkit-tap-highlight-color: rgba(0, 0, 0, 0); opacity: 0.5;"></rect> 
    <rect x="200" y="70" width="50" height="100" rx="0" ry="0" fill="#ff0000" stroke="#000000" opacity="0.5" stroke-width="2" style="-webkit-tap-highlight-color: rgba(0, 0, 0, 0); opacity: 0.5;"></rect> 
    <path fill="none" stroke="#000000" d="M300,70L700,70" style="-webkit-tap-highlight-color: rgba(0, 0, 0, 0);"></path> 
    <text x="350" y="80" text-anchor="middle" font-family="&quot;Arial&quot;" font-size="10px" stroke="none" fill="#000000" style="-webkit-tap-highlight-color: rgba(0, 0, 0, 0); text-anchor: middle; font-family: Arial; font-size: 10px;"><tspan dy="3.5" style="-webkit-tap-highlight-color: rgba(0, 0, 0, 0);">Sample Info</tspan></text> 
    <rect x="200" y="170" width="50" height="300" rx="0" ry="0" fill="#0033cc" stroke="#000000" opacity="0.5" stroke-width="2" style="-webkit-tap-highlight-color: rgba(0, 0, 0, 0); opacity: 0.5;"></rect> 
    <path fill="none" stroke="#000000" d="M300,170L700,170" style="-webkit-tap-highlight-color: rgba(0, 0, 0, 0);"></path> 
    <text x="350" y="180" text-anchor="middle" font-family="&quot;Arial&quot;" font-size="10px" stroke="none" fill="#000000" style="-webkit-tap-highlight-color: rgba(0, 0, 0, 0); text-anchor: middle; font-family: Arial; font-size: 10px;"><tspan dy="3.5" style="-webkit-tap-highlight-color: rgba(0, 0, 0, 0);">Sample Info</tspan></text> 
    <text x="195" y="480" text-anchor="end" font-family="&quot;Arial&quot;" font-size="10px" stroke="none" fill="#000000" style="-webkit-tap-highlight-color: rgba(0, 0, 0, 0); text-anchor: end; font-family: 'Fontin Sans', Fontin-Sans, sans-serif; font-size: 11px; font-style: normal; font-variant: normal; font-weight: normal; font-stretch: normal; line-height: normal;" font="11px 'Fontin Sans', Fontin-Sans, sans-serif"><tspan dy="4" style="-webkit-tap-highlight-color: rgba(0, 0, 0, 0);">0</tspan></text> 
    <text x="195" y="434" text-anchor="end" font-family="&quot;Arial&quot;" font-size="10px" stroke="none" fill="#000000" style="-webkit-tap-highlight-color: rgba(0, 0, 0, 0); text-anchor: end; font-family: 'Fontin Sans', Fontin-Sans, sans-serif; font-size: 11px; font-style: normal; font-variant: normal; font-weight: normal; font-stretch: normal; line-height: normal;" font="11px 'Fontin Sans', Fontin-Sans, sans-serif"><tspan dy="4" style="-webkit-tap-highlight-color: rgba(0, 0, 0, 0);">50</tspan></text> 
    <text x="195" y="388" text-anchor="end" font-family="&quot;Arial&quot;" font-size="10px" stroke="none" fill="#000000" style="-webkit-tap-highlight-color: rgba(0, 0, 0, 0); text-anchor: end; font-family: 'Fontin Sans', Fontin-Sans, sans-serif; font-size: 11px; font-style: normal; font-variant: normal; font-weight: normal; font-stretch: normal; line-height: normal;" font="11px 'Fontin Sans', Fontin-Sans, sans-serif"><tspan dy="4" style="-webkit-tap-highlight-color: rgba(0, 0, 0, 0);">100</tspan></text> 
    <text x="195" y="342" text-anchor="end" font-family="&quot;Arial&quot;" font-size="10px" stroke="none" fill="#000000" style="-webkit-tap-highlight-color: rgba(0, 0, 0, 0); text-anchor: end; font-family: 'Fontin Sans', Fontin-Sans, sans-serif; font-size: 11px; font-style: normal; font-variant: normal; font-weight: normal; font-stretch: normal; line-height: normal;" font="11px 'Fontin Sans', Fontin-Sans, sans-serif"><tspan dy="4" style="-webkit-tap-highlight-color: rgba(0, 0, 0, 0);">150</tspan></text> 
    <text x="195" y="296" text-anchor="end" font-family="&quot;Arial&quot;" font-size="10px" stroke="none" fill="#000000" style="-webkit-tap-highlight-color: rgba(0, 0, 0, 0); text-anchor: end; font-family: 'Fontin Sans', Fontin-Sans, sans-serif; font-size: 11px; font-style: normal; font-variant: normal; font-weight: normal; font-stretch: normal; line-height: normal;" font="11px 'Fontin Sans', Fontin-Sans, sans-serif"><tspan dy="4" style="-webkit-tap-highlight-color: rgba(0, 0, 0, 0);">200</tspan></text> 
    <text x="195" y="250" text-anchor="end" font-family="&quot;Arial&quot;" font-size="10px" stroke="none" fill="#000000" style="-webkit-tap-highlight-color: rgba(0, 0, 0, 0); text-anchor: end; font-family: 'Fontin Sans', Fontin-Sans, sans-serif; font-size: 11px; font-style: normal; font-variant: normal; font-weight: normal; font-stretch: normal; line-height: normal;" font="11px 'Fontin Sans', Fontin-Sans, sans-serif"><tspan dy="4" style="-webkit-tap-highlight-color: rgba(0, 0, 0, 0);">250</tspan></text> 
    <text x="195" y="204" text-anchor="end" font-family="&quot;Arial&quot;" font-size="10px" stroke="none" fill="#000000" style="-webkit-tap-highlight-color: rgba(0, 0, 0, 0); text-anchor: end; font-family: 'Fontin Sans', Fontin-Sans, sans-serif; font-size: 11px; font-style: normal; font-variant: normal; font-weight: normal; font-stretch: normal; line-height: normal;" font="11px 'Fontin Sans', Fontin-Sans, sans-serif"><tspan dy="4" style="-webkit-tap-highlight-color: rgba(0, 0, 0, 0);">300</tspan></text> 
    <text x="195" y="158" text-anchor="end" font-family="&quot;Arial&quot;" font-size="10px" stroke="none" fill="#000000" style="-webkit-tap-highlight-color: rgba(0, 0, 0, 0); text-anchor: end; font-family: 'Fontin Sans', Fontin-Sans, sans-serif; font-size: 11px; font-style: normal; font-variant: normal; font-weight: normal; font-stretch: normal; line-height: normal;" font="11px 'Fontin Sans', Fontin-Sans, sans-serif"><tspan dy="4" style="-webkit-tap-highlight-color: rgba(0, 0, 0, 0);">350</tspan></text> 
    <text x="195" y="112" text-anchor="end" font-family="&quot;Arial&quot;" font-size="10px" stroke="none" fill="#000000" style="-webkit-tap-highlight-color: rgba(0, 0, 0, 0); text-anchor: end; font-family: 'Fontin Sans', Fontin-Sans, sans-serif; font-size: 11px; font-style: normal; font-variant: normal; font-weight: normal; font-stretch: normal; line-height: normal;" font="11px 'Fontin Sans', Fontin-Sans, sans-serif"><tspan dy="4" style="-webkit-tap-highlight-color: rgba(0, 0, 0, 0);">400</tspan></text> 
    <text x="195" y="66" text-anchor="end" font-family="&quot;Arial&quot;" font-size="10px" stroke="none" fill="#000000" style="-webkit-tap-highlight-color: rgba(0, 0, 0, 0); text-anchor: end; font-family: 'Fontin Sans', Fontin-Sans, sans-serif; font-size: 11px; font-style: normal; font-variant: normal; font-weight: normal; font-stretch: normal; line-height: normal;" font="11px 'Fontin Sans', Fontin-Sans, sans-serif"><tspan dy="4" style="-webkit-tap-highlight-color: rgba(0, 0, 0, 0);">450</tspan></text> 
    <text x="195" y="20" text-anchor="end" font-family="&quot;Arial&quot;" font-size="10px" stroke="none" fill="#000000" style="-webkit-tap-highlight-color: rgba(0, 0, 0, 0); text-anchor: end; font-family: 'Fontin Sans', Fontin-Sans, sans-serif; font-size: 11px; font-style: normal; font-variant: normal; font-weight: normal; font-stretch: normal; line-height: normal;" font="11px 'Fontin Sans', Fontin-Sans, sans-serif"><tspan dy="4" style="-webkit-tap-highlight-color: rgba(0, 0, 0, 0);">500</tspan></text> 
    <path fill="none" stroke="#000000" d="M200.5,480L200.5,20M196,480.5L201,480.5M196,434.5L201,434.5M196,388.5L201,388.5M196,342.5L201,342.5M196,296.5L201,296.5M196,250.5L201,250.5M196,204.5L201,204.5M196,158.5L201,158.5M196,112.5L201,112.5M196,66.5L201,66.5M196,20.5L201,20.5" style="-webkit-tap-highlight-color: rgba(0, 0, 0, 0);"></path> 
    <rect x="100" y="20" width="15" height="460" rx="0" ry="0" fill="none" stroke="#000" style="-webkit-tap-highlight-color: rgba(0, 0, 0, 0);"></rect> 
    <rect x="85" y="250" width="15" height="230" rx="0" ry="0" fill="none" stroke="#000" style="-webkit-tap-highlight-color: rgba(0, 0, 0, 0);"></rect> 
    <rect x="115" y="250" width="15" height="230" rx="0" ry="0" fill="none" stroke="#000" style="-webkit-tap-highlight-color: rgba(0, 0, 0, 0);"></rect> 
    </svg> 

的问题是我没有被设置帆布的宽度和高度，以作为SVG已校正的图像尺寸相同的设置在画布高度和宽度。

Answer 1

您必须明确定义svg图像的width和height。 例如

<svg height="150" width="150" xmlns="http://www.w3.org/2000/svg" version="1.1"> 
    <rect width="150" height="150" fill="green" stroke-width="10" stroke="black"/> 
</svg> 

看到http://jsfiddle.net/372gtsw9/