我正在将不同大小的图像加载到内容区域中,并且由于它们按比例调整大小,因此图像的任何给定两边与内容区域的边界之间通常存在间隙。
我将此图像顶部的一个矩形图层调整,调整不透明度,以更改下面背景图像的可见度。我希望此过滤器与图像的大小相匹配。
这是元素的定义方式:
<td id="svgContentCell">
<svg id="svg" width="1000" height="750" version="1.1" onload="Init()" xmlns="http://www.w3.org/2000/svg" xmlns:xlink= "http://www.w3.org/1999/xlink"
onmousedown="onMouseDown(evt)" onmousemove="onMouseMove(evt)" onmouseup="onMouseUp(evt)" >
<image id="background" x="0" y="0" width="100%" height="100%" xlink:href=""></image>
<rect id="filter" x="0" y="0" width="100%" height="100%" fill="rgb(255, 255, 255)" fill-opacity="0"></rect>
</svg>
</td>
我认为使用Javascript会相对简单,但是我无法检索有关background
图像大小的任何有用数据。客户端宽度属性返回0.
var bg = document.getElementById('background');
var scrollWidth = bg.scrollWidth; // result: 0
var clientWidth = bg.clientWidth; // result: 0
var offsetWidth = bg.offsetWidth; // result: 0
var width = bg.getAttribute("width"); // result: 100%
// edit: BoundingClientRect() returns size of container not the scaled image.
var bg = document.getElementById("background");
var rect = bg.getBoundingClientRect();
var height = rect.height; // result: 750
var width = rect.width; // result: 1000
// I can retrieve the **unscaled** image dimensions like this
var bg = document.getElementById('background');
var address = bg.getAttribute('xlink:href');
var original = new Image();
original.src = address;
var unscaledWidth = original.width;
var unscaledHeight = original.height;
有没有人知道我可以获得缩放background
图片的实际像素宽度和高度的方法,以便我可以适当调整filter
元素的大小?
答案 0 :(得分:2)
答案 1 :(得分:0)
正如罗伯特·朗森(Robert Longson)似乎是一个可靠的来源,表示没有办法检索这个,我编写了自己的函数来计算它。
function calculateScaledImage() {
// Get the container dimensions
var bg = document.getElementById("background");
var rect = bg.getBoundingClientRect();
var cHeight = rect.height; // result: 750
var cWidth = rect.width; // result: 1000
// Get the unscaled dimensions
var address = bg.getAttribute('xlink:href');
// Create new image with URL to get unscaled dimension (not displayed)
var original = new Image();
original.src = address;
var oWidth = original.width;
var oHeight = original.height;
// New dimensions and ratio for scaling
var nWidth;
var nHeight;
var ratio;
var isWide = false;
// Is the empty space going to be on sides or top
if (oWidth > oHeight) {
isWide = true;
// I found that if the height exceeded the container it scaled it differently
if (oHeight > cHeight)
{
isWide = false;
}
}
var filter = document.getElementById('filter');
if (isWide) {
ratio = cWidth / oWidth;
nWidth = oWidth * ratio;
nHeight = oHeight * ratio;
var adjustment = (cHeight - nHeight) / 2;
filter.setAttribute("y", adjustment);
filter.setAttribute("x", 0);
filter.setAttribute("width", nWidth);
filter.setAttribute("height", nHeight);
}
else {
ratio = cHeight / oHeight;
nHeight = oHeight * ratio;
nWidth = oWidth * ratio;
var adjustment = (cWidth - nWidth) / 2;
filter.setAttribute("x", adjustment);
filter.setAttribute("y", 0);
filter.setAttribute("width", nWidth);
filter.setAttribute("height", nHeight);
}
}
答案 2 :(得分:-2)
你可以试试这个
var height = document.getElementById('myimage').offsetHeight;
var width = document.getElementById('myimage').offsetWidth;