I'm working on a PHP script that generates a jpg wallpaper from an SVG-file according to the screen resolution of the visitor. The wallpaper consists of a circular gradient (rectangle) background and a path on top of it. How would you go about centering the path horizontally and vertically to the rectangle? Remember that the rectangle's size and proportions are not a constant. Should I separate the background and path to different svg files or is there an easy way to center paths? Maybe a framework?
This is easilly achieved by using nested <svg> elements and the preserveAspectRatio attribute. Put your background in the outer svg and your path in the inner one.
<?xml version="1.0" encoding="UTF-8"?>
<svg xmlns="http://www.w3.org/2000/svg" version="1.1" width="100%" height="100%">
<rect id="background" width="100%" height="100%" fill="grey"/>
<svg preserveAspectRatio="xMidYMid meet" viewBox="0 0 30 40" width="100%" height="100%">
<g>
<circle cx="15" cy="20" r="10" fill="yellow"/>
<circle cx="12" cy="17" r="1.5" fill="black"/>
<circle cx="18" cy="17" r="1.5" fill="black"/>
<path d="M 10 23 A 8 13 0 0 0 20 23" stroke="black" stroke-width="2" fill="none"/>
</g>
</svg>
</svg>
Run this snippet and try resizing the window.
To get this to work, all you need to ensure is that the viewBox attribute on the inner <svg> element is correctly set.
If you know the coordinates of the paths, you could take the total of the x/y coordinates and divide by the number of coordinates, this will give you the average position for the coordinate set. Then, offset each coordinate by the coordinates for half the width/height of the square, plus any offset, minus the difference between the center of the coordinate set and half the width/height of the square.
This should result in your coordinates being centered within the square, I think (it is rather early here, and I've just started my first coffee, so I could be wrong). This is of course assuming you know all the variables in play (the width/height of the square, any offset applied and the coordinates of the path).
Related
I'd like to create a responsive SVG that consists of an image clipped by a polygon.
The image needs to preserve its aspect ratio and get cropped, while the polygon needs to adapt in width to its container but preserve the same height.
I don't want the whole thing to scale homothetically.
visual explanation of the issue
If I set preserveAspectRatio="none" to the svg, the polygon stretches like planned, but the image is then distorted. I've tried setting preserveAspectRatio="xMidYmid slice" to the image, but since the svg is set not to have its aspect ratio preserved it doesn't work as planned.
Here's my current code:
<svg viewBox="0 0 1440 810" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">
<defs>
<clipPath id="clip">
<polygon points="0 750,1440 810,1440 60,0 0" />
</clipPath>
</defs>
<g aria-hidden="true" clip-path="url(#clip)">
<image
opacity="0.75"
preserveAspectRatio="xMinYMid slice"
xlink:href="https://upload.wikimedia.org/wikipedia/commons/thumb/6/6e/Monasterio_Khor_Virap%2C_Armenia%2C_2016-10-01%2C_DD_25.jpg/2880px-Monasterio_Khor_Virap%2C_Armenia%2C_2016-10-01%2C_DD_25.jpg"
/>
</g>
</svg>
Thanks in advance for your help.
This is the only thing preventing me from understanding how the coordination system works...
<svg version="1.1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"
width="600" height="400" x="0" y="0">
<text x="0" y="0">
<tspan>✉</tspan>
</text>
</svg>
If the y-axis points down why does y="0" start from the outside of the viewport? Shouldn't it start right at the top edge? It blows my logic away...
The x-axis points to the right and it starts right in the left edge of the viewport, now this is logic and normal behavior.
Why does the y-axis behave like this? Or why make one start from the outside and the other not? What is the logic behind this? Unless I'm misunderstanding how it works...
It's all in the SVG specification
the initial coordinate system has the origin at the top/left with the x-axis pointing to the right and the y-axis pointing down
The origin for text is basically the bottom left corner of the glyph for left-to-right text.
For most uses of Latin text (i.e., writing-mode:lr, text-anchor:start and alignment-baseline:baseline) the alignment-point in the glyph will be the intersection of left edge of the glyph cell (or some other glyph-specific x-axis coordinate indicating a left-side origin point) with the Latin baseline of the glyph.
default baseline is in text downside, can use attr dominant-baseline change baseline, here is mdn example
<svg viewBox="0 0 200 120" xmlns="http://www.w3.org/2000/svg">
<path d="M20,20 L180,20 M20,50 L180,50 M20,80 L180,80" stroke="grey" />
<text dominant-baseline="auto" x="30" y="20">Auto</text>
<text dominant-baseline="middle" x="30" y="50">Middle</text>
<text dominant-baseline="hanging" x="30" y="80">Hanging</text>
</svg>
The client asked to scale the drawing down so I added width/height and viewBox to the SVG element. The problem is that some elements are scaled differently than others. The structure of the svg is like this:
<svg width="100%" height="100%" viewBox="0 50 700 200">
<defs>...</defs>
<g id="group-ab">
Here are the boxes (drawn with polyline) that are scaled correctly, both in their own group (group-a, group-b)
</g>
<g id="group-a-id">
<text>A</text>
<circle id="group-a-id-bg-circle"></circle>
</g>
<g id="group-B-id">
<text>B</text>
<circle id="group-b-id-bg-circle"></circle>
</g>
<path id="group-a-pattern" d="..."></path>
<path id="group-b-pattern" d="..."></path>
</svg>
The path is the pattern for the pieces. It seems that everything that isn't under the group "group-ab" isn't scaled correctly, see the image below. Normally (when not using viewBox) the pattern fills up the boxes and the A/B are centered with the boxes (same translates are done to them).
Why is this happening? One would think that it doesn't matter if elements are within groups or not if svg is scaled.
I want to create a SVG graphic that loads an external SVG file, stores it as a symbol into its defs section and uses this symbol in the main section:
<svg width="1000" height="1000">
<defs>
<symbol id="sym1" width="50" height="50" viewBox="0 0 45 45">
<svg width="45" height="45">
<rect x="0" y="0" width="45" height="45" style="stroke:red;stroke-width:1;fill:none"/>
</svg>
</symbol>
</defs>
<rect x="100" y="100" width="50" height="50" style="stroke:black;stroke-width:1;fill:none"/>
<use x="100" y="100" xlink:href="#sym1"></use>
</svg>
http://jsfiddle.net/tx0rpxdf/4/
One frame condition is that I cannot change the inner SVG element, because it will be loaded from an external file.
The symbol should have a size of 50x50, so I define its width and height accordingly. I know that the inner SVG element has a size of 45x45, so I define its viewBox as "0 0 45 45".
To test the usage of the symbol, I create a black rectangle of size 50x50 and place a symbol instance at the same position. The lines should match.
But they don't match using Chrome (Chromium) on Debian Jessie. Even worse, it produces different results in Firefox and Opera.
What's the problem here and how can I produce the correct result in all browsers that support SVG?
There are a couple of issues:
a <rect> with width/height 45 and a stroke-width of 1 is not 45 user units wide, it's 46 user units wide as the stroke pokes out inside by 0.5 of a unit and outside by 0.5 of a unit on each edge. If you can't change the inner <svg> element then you won't be able to fix this issue though.
drawing two shapes one on top of another will not make one hide another as there will be antialiasing in effect. shape-rendering="optimizeSpeed" can prevent this.
I'm making some pointers by hand coding svgs. I have defined a polygon using points in a 100x100 square and gotten the aspect ratio that I want by setting the width and height attributes of the outer SVG element. Here is a jsfiddle of the graphic: http://jsfiddle.net/62WpR/.
Unfortunately, the text is being compressed by the width and height attributes. Is there any way to use these without compressing text, or doing something silly like applying a transform to it?
If this is not possible, I guess I will have to define paths in a coordinate space with the final aspect ratio that I want. Disappointing.
Solved it kind of.
By setting the viewbox to a 1:2 ratio and using transforms on both of the polygons in the svg, I was able to get the dimensions I wanted. As long as the dimensions in the CSS are set to a 2:1 ratio, the graphic will display right.
I have also made judicious use of the preserveAspectRatio property to keep the image at the same aspect ratio. I'm only setting the width in the CSS: http://jsfiddle.net/62WpR/3/
<svg baseProfile="full" contentScriptType="text/ecmascript" contentStyleType="text/css" id="svg" preserveAspectRatio="xMinYMin meet" version="1.2" viewBox="0 0 100 50" xmlns="http://www.w3.org/2000/svg">
<g transform="scale(1 .5)" stroke-linejoin="bevel" stroke="black">
<polygon vector-effect="non-scaling-stroke" fill="#666" id="tab" points="20.0,95.0 5.0,50.0 20.0,5.0 90.0,5.0 95.0,15.0 95.0,85.0 90.0,95.0"></polygon>
<polygon vector-effect="non-scaling-stroke" fill="#FFEA00" id="insert" points="25.0,95.0 10.0,50.0 25.0,5.0" visibility="visible"></polygon>
</g>
<text fill="white" font-size="30" text-anchor="middle" x="60" y="36">999</text>
</svg>