How can I apply a clip-path after/during animation? - svg

I have a path in SVG defining a clipPath. Lines (tick marks) are drawn and clipped to the path.
When I perform an animation of the lines, they retain the original clipping. I would like them to be 're-clipped' at each stage of the animation.
Question: Is there an easy way to have the clipping performed during the transition?
Sample problem code:
http://jsfiddle.net/Q29TA/
When you click on the svg, it demonstrates the animation.
Relevant snippets:
d3.select( "#g-container" )
.selectAll( "line" )
.data( y.ticks( 10 ) )
.enter()
.append( "line" )
.attr( "x1", 0 ).attr( "x2", width )
.attr( "y1", y ).attr( "y2", y )
.attr( "class", "tick-marks" )
.attr( "clip-path", "url(#myclip)" );​
d3.select( "svg" )
.on("click", function() {
d3.selectAll(".tick-marks")
.transition().duration( 2500 )
.attr( "transform", "translate(0,30)" )
} )
I am open to new ways of doing this, but I can't hardcode an animation that recomputes the line's x1 and x2, since the clipPath could be anything.
Sample picture showing the aftermath of animation (I want the horizontal lines to meet the blue, diagonal line of the container):

It's better to use a single clip-path, just move the clip-path up to the container g element instead:
http://jsfiddle.net/dxZyq/

So (as you've discovered) it seems that clipping paths disregard the elements' transform properties. You could see it also happening – even without animation – if you apply your transform right when the elements are created:
.enter()
.append( "line" )
.attr( "transform", "translate(0,30)" )// <-- Same, "wrong" (i.e. undesired) clipping
.attr( "x1", 0 ).attr( "x2", width )
.attr( "y1", y ).attr( "y2", y )
.attr( "class", "tick-marks" )
.attr( "clip-path", "url(#myclip)" );​
From messing around, I've found that one way around this issue is grouping all the elements that need to move and translating just the group. You can see it here: http://jsfiddle.net/Q29TA/2/ (note, I'm just translating the group you created, which also has the blue path in it, so it's not quite right).
The other way of getting around it is not to apply the transform, and instead, move the lines by animating their y1 and y2: http://jsfiddle.net/Q29TA/1/

Related

Find original (x,y) new coordinates in fabric canvas

I am building a Warehouse map in 2D with fabricjs where I am displaying their racking systems as a series of rectangles.
As a first "layer/group", i add all bays as groups containing a rectangle and text, both positioned at the same (x,y). They also have both an angle set to fit their orientation in the space.
As a second "layer/group", i add groups containing a circle and text, representing the bay's number of issues. The (x,y) also fits the bays. This way, all my issues are always on top of the bays and the center of the group fits the rotated corner of the bay.
On the first paint, all is well aligned. Once they're shown on the page, the user can create new issues, so I am trying to position the issue group fitting the original (x,y), but since it can all be panned and zoomed, I am having a hard time positioning it where it should be.
I've been looking at their explanations about transforms, but I can't figure who the boss should be and thinking that having nested groups may also be why I am all mixed up.
By doing:
const gMatrix = matchingBay.group.calcTransformMatrix(false);
const targetToCanvas = fabric.util.transformPoint(matchingBay.aCoords.tl, gMatrix);
I am on the bay, but on the "group" corner, which is not what I am looking for. (x,y) will be one of the corners of the rectangle in the group, that may have been rotated.
By specifying the original (x,y) in this code will get me way off the actual painting zone.
So, my question is, how do I get the transformed (x,y) so I can add my issue group at those coordinates?
[EDIT]
As the suggestion of spring, it made me realize I can use the rotated rectangle's transforms to find its coordinates, so I tried:
const rect = matchingBay.getObjects()[BAY_RECTANGLE_INX];
const gMatrix = rect.calcTransformMatrix();
const targetToCanvas = fabric.util.transformPoint(rect.aCoords.bl, gMatrix);
Bottom left corner is where I wish to add the new Circle. After rotation, the bottom left is now the bottom right. But I am still off. As shown, the red circle should be on the corner. It looks like the rotation has not been applied.
qrDecompose gives me something that seems right:
{angle: -90, scaleX: 1, scaleY: -1, skewX: 0, skewY: 0, translateX: 6099.626027314769, translateY: 4785.016008065199 }
I realized that I was not thinking it the right way. Since I have the rectangle already in hands, I just had to get its own transformation and resolve the corner by my own, the following fixed my issue:
{
[...]
const rect = matchingBay.getObjects()[BAY_RECTANGLE_INX];
const gMatrix = rect.calcTransformMatrix();
const decomposed = fabric.util.qrDecompose(gMatrix);
const trans = fabric.util.transformPoint(new fabric.Point((decomposed.scaleX * -rect.width) / 2, (decomposed.scaleY * rect.height) / 2), gMatrix);
const top = trans.y;
const left = trans.x;
[...]
}
Since the matrix is bringing the center point of the rectangle, I can get the corner by substracting its width and height and then transforming the coordinates to find out where the matrix puts it.

Placement of SVG circle that lacks center coordinates

djvanderlaan's d3.js Planetarium first defines a "sun" circle at the center of the SVG area:
svg.append("circle").attr("r", 20).attr("cx", w/2)
.attr("cy", h/2).attr("class", "sun")
and then defines two orbits around the sun (with code slightly rearranged for clarity here):
var planets = [
{ R: 300, r: 5, speed: 5, phi0: 90},
{ R: 150, r: 10, speed: 2, phi0: 190}
];
var container = svg.append("g")
.attr("transform", "translate(" + w/2 + "," + h/2 + ")")
container.selectAll("g.planet").data(planets).enter().append("g")
.attr("class", "planet")
.each(function(d, i) {
d3.select(this).append("circle").attr("class", "orbit")
.attr("r", d.R)
d3.select(this).append("circle").attr("r", d.r).attr("cx",d.R)
.attr("cy", 0).attr("class", "planet");
});
The first circle in each group--the "orbit" circle--is never given center coordinates cx and cy. That's not just in the source code; I looked at the "orbit" circles in the inspectors in three browsers, and there is no cx or cy for the orbit circles. However, these circles are centered on the center of the SVG area, i.e. on x=w/2, y=h/2. How does the browser know where to place these circles? Does it inherit cx and cy from the enclosing g element? From the "sun"?
Yes, all svg elements inherit the transform and scale of their parent svg:g elements. You can use this to set a local center, as done here, or to play with scale and rotate with fine precision (since setting these all with the transform attribute can sometimes lead to unexpected results).
Often, people place their circle elements inside a parent g and position the g without ever setting cx/cy because a circle defaults to centering on the center of its parent. This isn't the case with svg:rect elements, which have to be offset to "center" them.

How to avoid fade-out on scaled CCSprite without cancelling anti-aliasing?

I have 3 sprites. Left edge, right edge, and repeating center which has 1 pixel width but is scaled up. The problem is that the scaled sprite fades out the farther away it is from the center:
I've tried using CCTexture's setAliasTexParameters but the result doesn't look good:
How do I get the antialiased looks in the first picture but without the fade out problem?
You could try this on the sprite:
// These parameters set the texture properties:
// minifying filter - linear interpolation,
// magnification filter - linear interpolation,
// texture repeat in S direction,
// texture repeat in T direction (*)
ccTexParams params = {GL_LINEAR, GL_LINEAR, GL_REPEAT, GL_REPEAT};
[sprite.texture setTexParams:&params];
// This explicitly sets the contentSize of the sprite to (10, 200),
// but also sets the "window to the texture" to this rectangle:
[sprite setTextureRect:CGRectMake(0, 0, 10, 200)];
You have to tweak these settings, but hope you get it.
You don't have to scale the sprite.
(*) For S and T check this: Difference between U V and S T texture coordinates

transition a circle into a line by unrolling it with SVG and d3

For a project we are trying to make a circle into a line (and back again) while it is rotating along a linear path, much like a tire rotates and translates when rolling on a road, or a curled fore finger is extended and recurled into the palm.
In this Fiddle, I have a static SVG (the top circle) that rotates along the linear black path (which is above the circle, to mimic a finger extending) that is defined in the HTML.
I also use d3 to generate a "circle" that is made up of connected points (and can unfurl if you click on/in the circle thanks to #ChrisJamesC here ), and is translated and rotated
in the function moveAlongLine when you click on the purple Line:
function moveAlongLine() {
circle.data([lineData])
.attr("transform", "translate(78.5,0) rotate(-90, 257.08 70) ")
.duration(1000)
circle.on("click", transitionToCircle)
}
The first problem is that the .duration(1000) is not recognized and throws a Uncaught TypeError: Object [object Array] has no method 'duration' in the console, so there is a difference between the static definition of dur in SVG and dynamically setting it in JS/D3, but this is minor.
The other is should the transform attributes be abstracted from one another like in the static circle? in the static circle, the translate is one animation, and the rotation is another, they just have the same star and duration, so they animate together. How would you apply both in d3?
The challenge that I can not get, is how to let it unroll upwards(and also re-roll back), with the static point being the top center of the circle also being the same as the leftmost point on the line.
these seem better:
I should try to get the unfurl animation to occur while also rotating? This seems like it would need to be stepwise/sequential based...
Or Consider an octogon (defined as a path), and if it were to rotate 7 of the sides, then 6, then 5.... Do this for a rather large number of points on a polyhedron? (the circle only needs to be around 50 or so pixels, so 100 points would be more than enough) This is the middle example in the fiddle. Maybe doing this programmatically?
Or This makes me think of a different way: (in the case of the octogon), I could have 8 line paths (with no Z, just an additional closing point), and transition between them? Like this fiddle
Or anything todo with keyframes? I have made an animation in Synfig, but am unsure ho get it to SVG. The synfig file is at http://specialorange.org/filedrop/unroll.sifz if you can convert to SVG, but the xsl file here doesn't correctly convert it for me using xsltproc.
this seems really complicated but potential:
Define a path (likely a bézier curve with the same number of reference points) that the points follow, and have the reference points dynamically translate as well... see this for an concept example
this seems complicated and clunky:
Make a real circle roll by, with a growing mask in front of it, all while a line grows in length
A couple of notes:
The number of points in the d3 circle can be adjusted in the JS, it is currently set low so that you can see a bit of a point in the rendering to verify the rotation has occurred (much like the gradient is in the top circle).
this is to help students learn what is conserved between a number line and a circle, specifically to help learn fractions. For concept application, take a look at compthink.cs.vt.edu:3000 to see our prototype, and this will help with switching representations, to help you get a better idea...
I ended up using the same function that generates the circle as in the question, and did a bit of thinking, and it seemed like I wanted an animation that looked like a finger unrolling like this fiddle. This lead me to the math and idea needed to make it happen in this fiddle.
The answer is an array of arrays, with each nested array being a line in the different state, and then animate by interpolating between the points.
var circleStates = [];
for (i=0; i<totalPoints; i++){
//circle portion
var circleState = $.map(Array(numberOfPoints), function (d, j) {
var x = marginleft + radius + lineDivision*i + radius * Math.sin(2 * j * Math.PI / (numberOfPoints - 1));
var y = margintop + radius - radius * Math.cos(2 * j * Math.PI / (numberOfPoints - 1));
return { x: x, y: y};
})
circleState.splice(numberOfPoints-i);
//line portion
var lineState = $.map(Array(numberOfPoints), function (d, j) {
var x = marginleft + radius + lineDivision*j;
var y = margintop;
return { x: x, y: y};
})
lineState.splice(i);
//together
var individualState = lineState.concat(circleState);
circleStates.push(individualState);
}
and the animation(s)
function all() {
for(i=0; i<numberOfPoints; i++){
circle.data([circleStates[i]])
.transition()
.delay(dur*i)
.duration(dur)
.ease("linear")
.attr('d', pathFunction)
}
}
function reverse() {
for(i=0; i<numberOfPoints; i++){
circle.data([circleStates[numberOfPoints-1-i]])
.transition()
.delay(dur*i)
.duration(dur)
.ease("linear")
.attr('d', pathFunction)
}
}
(Note: This should be in comments but not enough spacing)
Circle Animation
Try the radial wipe from SO. Need to tweak it so angle starts at 180 and ends back at same place (line#4-6,19) and move along the X-axis (line#11) on each interation. Change the <path... attribute to suit your taste.
Line Animation Grow a line from single point to the length (perimeter) of the circle.
Sync both animation so that it appears good on all browsers (major headache!).

Scaling a rotated object to fit specific rect

How can I find the scale ratio a rotated Rect element in order fit it in a bounding rectangle (unrotated) of a specific size?
Basically, I want the opposite of getBoundingClientRect, setBoundingClientRect.
First you need to get the transform applied to the element, with <svg>.getTransformToElement, together with the result of rect.getBBox() you can calculate the actual size. Width this you can calculate the scale factor to the desired size and add it to the transform of the rect. With this I mean that you should multiply actual transform matrix with a new scale-matrix.
BUT: This is a description for a case where you are interested in the AABB, means axis aligned bounding box, what the result of getBoundingClientRect delivers, for the real, rotated bounding box, so the rectangle itself in this case, you need to calculate (and apply) the scale factor from the width and/or height.
Good luck…
EDIT::
function getSVGPoint( x, y, matrix ){
var p = this._dom.createSVGPoint();
p.x = x;
p.y = y;
if( matrix ){
p = p.matrixTransform( matrix );
}
return p;
}
function getGlobalBBox( el ){
var mtr = el.getTransformToElement( this._dom );
var bbox = el.getBBox();
var points = [
getSVGPoint.call( this, bbox.x + bbox.width, bbox.y, mtr ),
getSVGPoint.call( this, bbox.x, bbox.y, mtr ),
getSVGPoint.call( this, bbox.x, bbox.y + bbox.height, mtr ),
getSVGPoint.call( this, bbox.x + bbox.width, bbox.y + bbox.height, mtr ) ];
return points;
};
with this code i one time did a similar trick... this._dom refers to a <svg> and el to an element. The second function returns an array of points, beginning at the top-right edge, going on counter clockwise arround the bbox.
EDIT:
the result of <element>.getBBox() does not include the transform that is applied to the element and I guess that the new desired size is in absolute coordinates. So the first thing you need to is to make the »BBox« global.
Than you can calculate the scaling factor for sx and sy by:
var sx = desiredWidth / globalBBoxWidth;
var sy = desiredHeight / globalBBoxHeight;
var mtrx = <svg>.createSVGMatrix();
mtrx.a = sx;
mtrx.d = sy;
Than you have to append this matrix to the transform list of your element, or concatenate it with the actual and replace it, that depends on you implementation. The most confusion part of this trick is to make sure that you calculate the scaling factors with coordinates in the same transformation (where absolute ones are convenient). After this you apply the scaling to the transform of the <element>, do not replace the whole matrix, concatenate it with the actually applied one, or append it to the transform list as new item, but make sure that you do not insert it before existing item. In case of matrix concatenation make sure to preserve the order of multiplication.
The last steps depend on your Implementation, how you handle the transforms, if you do not know which possibilities you have, take a look here and take special care for the DOMInterfaces you need to implement this.

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