Scaling SVG image element when image is another SVG file

Question

I am making a tool where I need a possibility to add an image into existing SVG. This image can be both Bitmap file and another SVG file. So I do it using element, like this:

<image x="100" y="100" width="200" height="100" preserveAspectRatio="none" xlink:href="image.jpg">

I need this image to fit to width/height I specified (I don't care about the original size of an image), that's why I set preserveAspectRatio to "none". And it works fine with bitmaps. However when I try the same code with another SVG image, it is not scaled. The preserverAspectRatio description says that viewBox should be set on this image element, however it doesn't help - the image is not scaled.

Here is the code which, as far as I understand should work:

<image x="100" y="100" width="200" height="100" viewBox="0 0 200 100" preserveAspectRatio="none" xlink:href="clock.svg">

And here is source of the clock.svg:

<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" version="1.1" id="Map">
<path d="M8.179,20.115c-0.478,0.277-0.642,0.889-0.365,1.366c0.275,0.479,0.889,0.642,1.365,0.366c0.479-0.275,0.643-0.888,0.367-1.367C9.27,20.004,8.658,19.84,8.179,20.115zM9.18,12.239c-0.479-0.276-1.09-0.112-1.366,0.366s-0.111,1.09,0.365,1.366c0.479,0.276,1.09,0.113,1.367-0.366C9.821,13.126,9.657,12.516,9.18,12.239zM8.625,17.043c-0.001-0.552-0.448-0.999-1.001-1c-0.553,0-1,0.448-1,1c0,0.553,0.449,1,1,1C8.176,18.043,8.624,17.596,8.625,17.043zM16.312,3.957V3.031h1c0.275,0,0.5-0.225,0.5-0.5v-0.5c0-0.275-0.225-0.5-0.5-0.5h-3.625c-0.275,0-0.5,0.225-0.5,0.5v0.5c0,0.275,0.225,0.5,0.5,0.5h1v0.926C7.819,4.381,2.376,10.068,2.374,17.042C2.376,24.291,8.251,30.166,15.5,30.169c7.249-0.003,13.124-5.878,13.125-13.127C28.624,10.067,23.181,4.38,16.312,3.957zM15.5,27.166C9.909,27.157,5.385,22.633,5.375,17.042C5.385,11.451,9.909,6.927,15.5,6.917c5.59,0.01,10.115,4.535,10.124,10.125C25.615,22.633,21.091,27.157,15.5,27.166zM12.062,22.998c-0.478-0.275-1.089-0.111-1.366,0.367c-0.275,0.479-0.111,1.09,0.366,1.365c0.478,0.277,1.091,0.111,1.365-0.365C12.704,23.887,12.54,23.275,12.062,22.998zM12.062,11.088c0.479-0.276,0.642-0.888,0.366-1.366c-0.276-0.478-0.888-0.642-1.366-0.366s-0.642,0.888-0.366,1.366C10.973,11.2,11.584,11.364,12.062,11.088zM22.822,13.971c0.478-0.275,0.643-0.888,0.366-1.366c-0.275-0.478-0.89-0.642-1.366-0.366c-0.479,0.278-0.642,0.89-0.366,1.367C21.732,14.083,22.344,14.247,22.822,13.971zM15.501,23.92c-0.552,0-1,0.447-1,1c0,0.552,0.448,1,1,1s1-0.448,1-1C16.501,24.367,16.053,23.92,15.501,23.92zM19.938,9.355c-0.477-0.276-1.091-0.111-1.365,0.366c-0.275,0.48-0.111,1.091,0.366,1.367s1.089,0.112,1.366-0.366C20.581,10.245,20.418,9.632,19.938,9.355zM23.378,16.042c-0.554,0.002-1.001,0.45-1.001,1c0.001,0.552,0.448,1,1.001,1c0.551,0,1-0.447,1-1C24.378,16.492,23.929,16.042,23.378,16.042zM22.823,20.115c-0.48-0.275-1.092-0.111-1.367,0.365c-0.275,0.479-0.112,1.091,0.367,1.367c0.477,0.275,1.089,0.112,1.365-0.366C23.464,21.004,23.3,20.391,22.823,20.115zM15.501,8.167c-0.552,0-1,0.448-1,1l-0.466,7.343l-3.004,1.96c-0.478,0.277-0.642,0.889-0.365,1.366c0.275,0.479,0.889,0.642,1.365,0.366l3.305-1.676c0.055,0.006,0.109,0.017,0.166,0.017c0.828,0,1.5-0.672,1.5-1.5l-0.5-7.876C16.501,8.614,16.053,8.167,15.501,8.167zM18.939,22.998c-0.479,0.276-0.643,0.888-0.366,1.367c0.275,0.477,0.888,0.642,1.366,0.365c0.478-0.276,0.642-0.889,0.366-1.365C20.028,22.886,19.417,22.723,18.939,22.998zM11.197,3.593c-0.836-1.04-2.103-1.718-3.541-1.718c-2.52,0-4.562,2.042-4.562,4.562c0,0.957,0.297,1.843,0.8,2.576C5.649,6.484,8.206,4.553,11.197,3.593zM27.106,9.014c0.503-0.733,0.8-1.619,0.8-2.576c0-2.52-2.043-4.562-4.562-4.562c-1.438,0-2.704,0.678-3.541,1.717C22.794,4.553,25.351,6.484,27.106,9.014z" fill="#000000" fill-opacity="1" stroke="#DDDDDD" stroke-width="0.5" stroke-opacity="1"/>

I want this clock to be scaled and occupy all the 200x100 rectangle, but it is not. I would be very grateful if anybody could help.

Answer 1

From the 'image' element definition in the SVG 1.1 spec:

The value of the ‘viewBox’ attribute to use when evaluating the ‘preserveAspectRatio’ attribute is defined by the referenced content. For content that clearly identifies a viewBox (e.g. an SVG file with the ‘viewBox’ attribute on the outermost svg element) that value should be used. For most raster content (PNG, JPEG) the bounds of the image should be used (i.e. the ‘image’ element has an implicit ‘viewBox’ of '0 0 raster-image-width raster-image-height'). Where no value is readily available (e.g. an SVG file with no ‘viewBox’ attribute on the outermost svg element) the ‘preserveAspectRatio’ attribute is ignored, and only the translation due to the ‘x’ & ‘y’ attributes of the viewport is used to display the content.

What the spec tells you is that the referenced svg (your clock.svg) should define it's coordinate system (aka 'viewBox').