I have an svg which has multiple stroked paths, and a rectangle shape behind them that has the shape of the paths cut out of them. Effectively, the stroked paths should be "plugging the holes" in the rectangle shape.
The reason for this is that I would like to animate the paths so that they are erased, revealing what is underneath through the holes in the rectangle shape.
That's all well and good, and the animation works fine. The problem is that there is a hairline-thin space between the holes and the outside of the path strokes, so you can see what is underneath even while the paths are still there. You can see a screen capture of that here:
How do I avoid this happening? The space is not in the svg, because making it bigger on the page still has the space hairline thin:
I figure it has something to do with the aliasing, but have no idea how to combat it. I can't just apply a thicker stroke to the paths, because then the stroke starts to bleed into the other shapes, as seen here:
What else is there to do?
You could use a mask instead of a clip-path, since masks allow using the stroke to define the masked area.
<mask id="strokemask" maskContentUnits="objectBoundingBox"
x="0" y="0" width="100%" height="100%">
<circle cx="0.5" cy="0.5" r="0.1" stroke="white" fill="white"
stroke-width="0.02"/>
<circle cx="0.5" cy="0.5" r="0.15" stroke="white" fill="none"
stroke-width="0.03"/>
<circle cx="0.5" cy="0.5" r="0.22" stroke="white" fill="none"
stroke-width="0.05"/>
<circle cx="0.5" cy="0.5" r="0.3" stroke="white" fill="none"
stroke-width="0.06"/>
</mask>
Here's a live example of an animated mask that uses some stroked circles.
Related
I'm trying to find tools to render a group of overlapping shapes so that within the group the fill acts as opaque (so the overlapped circle outlines are not shown), but at the same time the fills of group members are transparent to any background layers underneath.
I hope this picture will make it clearer:
What I'm able to accomplish is a bunch of circles with empty fills (d in the image). What I would like to achieve (h in the image) is circle outlines being hidden in the overlaps so that the layering in the outlined circle group is clear, but the group as a whole having a transparent fill so that the background layer (blue-filled bubbles in the picture) is visible.
The perimeter of the circles in the group would be determined by data and possibly dynamic so I guess they need to be identifiable as separate objects, so I cannot turn them into some kind of compound path to get what I need.
From what I found, this cannot be done in SVG or CSS alone, so I wonder if there is some knock-out filter or any kind of solution within Pixi.js or general WebGL that would allow me to set a different transparency behaviour within the layer and different towards other layers.
Something like this perhaps.
You can add more circles as desired. The mask circles overlap each other but as a whole when applied to the rectangle the masked parts are transparent.
<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"
width="100%" height="100%" viewBox="0 0 200 200" >
<defs>
<mask id="circle-mask" width="1" height="1" maskContentUnits="objectBoundingBox" maskUnits="objectBoundingBox">
<circle cx="0.2" cy="0.2" r="0.1" stroke="white" stroke-width="0.01"/>
<circle cx="0.3" cy="0.3" r="0.1" stroke="white" stroke-width="0.01"/>
</mask>
</defs>
<circle cx="30" cy="60" r="20" fill="blue" fill-opacity="0.5"/>
<rect width="200" height="200" mask= "url(#circle-mask)" fill="blue"/>
</svg>
I'm new to the svg library (HTML5 svg tag and related) and trying to learn. I'm working on a little diagram editor in VueJS using svg. I know how to create a rectangle and even a path from one rectangle/circle/etc to another, but I'm not unclear how to approach creating a path that starts and ends at the same rectangle (i.e., a loop) - something like this
I don't care that much where the start and end points intersect the rectangle, though I'd prefer they were relatively close to one another or at least on the same edge of the rectangle.
Thanks for any nudges in the right direction.
Just create a <path> that consists of a bezier curve whose control points form a rectangle.
<svg viewBox="0 0 100 100">
<rect x="50" y="10" width="50" height="40" fill="#4472c4"/>
<path d="M 50,20 C 10,20 10,40, 50,40" fill="none" stroke="red"/>
<!-- Show grey lines to indicate the bezier control points -->
<line x1="50" y1="20" x2="10" y2="20" fill="none" stroke="lightgrey" stroke-width="0.5"/>
<line x1="50" y1="40" x2="10" y2="40" fill="none" stroke="lightgrey" stroke-width="0.5"/>
</svg>
Having used Postscript for years, I am now learning SVG. There is a feature of PS that I have not been able to replicate so far: zero-width lines. In PS, a line with zero width is always visible: PostScript converts zero line width to the smallest printable width. On the screen, when zooming they never get any thinkness, yet are visible no matter the scale. I have used them when I wanted to render very thin lines, without worring about the final resolution I was going to use, and they turned out really useful.
However, in the official SVG docs (https://www.w3.org/TR/svg-strokes/) it says that:
A zero value causes no stroke to be painted. A negative value is invalid.
Is there a way in SVG to build zero-width lines in the sense of PostScript?
As Robert said, the nearest thing to what you want in SVG is vector-effect="non-scaling-stroke". This fixes the stroke width at 1 no matter how the SVG is scaled.
This works on Chrome and Firefox (and probably Opera - haven't checked), but AFAIK not IE/Edge.
<svg viewBox="0 0 100 100">
<rect x="10" y="10" width="80" height="80"
fill="none" stroke="black" stroke-width="1"
vector-effect="non-scaling-stroke"/>
</svg>
Note that antialiasing will come into play depending on the position of the lines. The position will be affected by the scale.
If your lines are rectilinear (horizontal or vertical), you might also want to use shape-rendering="crispEdges". This will turn off antialiasing for the shape on which it is used, resulting in sharp one-pixel lines.
<svg viewBox="0 0 100 100">
<rect x="10" y="10" width="80" height="80"
fill="none" stroke="black" stroke-width="1"
vector-effect="non-scaling-stroke" shape-rendering="crispEdges"/>
</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'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).