How recursive animation works in below SVG - javascript

I am referring an svg animation given in below link
https://codepen.io/thinkdesign/pen/JybJOq
I am not able to understand how the recursion works here
var offset = 0;
var animation = function() {
offset -= 100;
pattern.animate({ x: offset }, 500, mina.ease, animation);
};
here we are changing x axis on each function call , so the x axis should go beyond screen at some point. Please help me understanding how this works

Nothing is moving across the page here. The x that is being moved here is the pattern's X offset. An SVG <pattern> is a fill that consists of a "tile" that is repeated infinitely in every direction. The <pattern> has an x and y attribute that tells the browser where to start the tiling from. Animating the pattern's x offset has the effect of making it look like the tile is continuously moving across your object.
Picture a rectangular window lying on a tiled floor. If you slide that window across the floor, it looks to you like the tile pattern moves through the window.

Related

Explain "SLIDER" drag and drop on protractor with a proper example

browser.actions().dragAndDrop(elem, target).perform();
I can clearly understand the above code but I cannot get how to specify this element and target.
Take this example
browser.actions().dragAndDrop(slider,{x:100, y:0}).perform();
In the website in which I'm working on, I cannot find any x, y or anything I can match with that and develop.
So it will be helpful if someone explains with some example for x and y so that I can relate to it and make I work.
The dragAndDrop() has two ways to work.
One starts with the element to drag. Here elem works as normal ElementFinder, so something like dragAndDrop(element(by.css('div.my-class')), target).perform();.
Now the target works in two ways: Either as another ElementFinder like in elem or as coordinates to move, starting from the position of elem, moving x pixels horizontally and y pixels vertically (plus to the right or top, minus to the left or bottom). So {x:100, y:0} will move your slider 100 pixels to the right from the starting position.
dragAndDrop(element(by.css('div.my-class')), {x:100, y:0}).perform(); will therefore move the element(by.css('div.my-class')) 100 pixels to the right.

three js video position inside sphere

I am using three js to display video where the user can move through the video using mouse, example here:
https://threejs.org/examples/?q=video#webgl_video_panorama_equirectangular
the code: https://github.com/mrdoob/three.js/blob/master/examples/webgl_video_panorama_equirectangular.html
Is there a way to display where user is watching (position and direction) inside container, something like this:
http://ignitersworld.com/lab/imageViewer.html
In the top left corner there is a little square showing current position. I would like to know position and direction in which view is facing (all in 2D)
How could I achieve that?
edit:
orientation has been solved.
I am looking for position on the layout within video, is this possible? Like on the picture: https://imgur.com/a/xsNYM
You can get the camera direction and calculate the angles. These angles will be your 2D orientation on a sphere:
var dir = camera.getWorldDirection();
var groundProjection = dir.clone().projectOnPlane(new THREE.Vector3(0,1,0))
var longitudeRadians = Math.atan2(groundProjection.x, groundProjection.z);
var latitudeRadians = Math.atan2(groundProjection.length(), dir.y)
// longitudeRadians is now an angle between -3.14 and 3.14
// latitudeRadians is now an angle between 0 and 3.14
Here is a running example: https://jsfiddle.net/holgerl/bqvdotps/

Resizing and rotation on svg (Raphael.js) creates jumping

I've been working on this problem for days. I am trying to implement a "free transform" tool for svgs. Similar to that of Raphael.FreeTransform or how you would move/rotate/scale images in MS Word. (Yes, I am aware there are libraries) The following jSFiddle displays my problem: https://jsfiddle.net/hLjvrep7/12/
There are 5 functions in the jsFiddle: rotate-t. shrink-t, grow-t, shrink, grow. The functions suffixed with '-t' also apply the current rotation transformation. e.g.:
grow-t
rect.attr({height : height * 1.25, width : width * 1.25}).transform('r' + degree);
grow
rect.attr({height : height * 1.25, width : width * 1.25});
Once an svg is rotated, then scaled. If you try to rotate the svg again (after scale), the svg jumps. To see this, go top the fiddle:
Hit rotate-t twice. Svg should rotate a total of 30 degrees from the rectangles origin.
Hit grow (not grow-t) twice. Note the top left position of the svg stays the same.
Hit rotate-t once. Note the svg jumps to a different position, then rotates.
Note hitting rotate-t subsequent times will continue to rotate the image around the origin (which is what I want the first time rotate-t is clicked)
One solution I had was to apply the current rotation transformation whenever changing the height and width. This fixes my previous problem, but introduces another problem. To see an example of this, go to the fiddle, and:
Hit rotate-t twice.
Hit grow-t a couple times. Notice the svg grows, but the top left position of the rectangle moves. That's a problem for me. I want the svg to grow without the top left corner to move.
Notes on using the jsFiddle:
Any combination of rotate-t, grow-t, shrink-t will exhibit the ideal rotation behavior (about the origin, no jumping). But this also demonstrates the undesired growing and shrinking (top left position moved when svg is on angle).
Any combination pf rotate-t, grow, shrink will exhibit the ideal scaling behavior (top left corner of svg doesn't move). But this also demonstrates the undesired rotation property (will jump around after different rotations and scales).
Bottom line: I want to be able to the svg rotate around the origin. Then grow the image, while the top left position remains the same. Then rotate the svg again, around the origin without any jumping.
I am aware the how the transform function impacts the local coordinate system of the svg. I'm leaning towards using rotate-t, grow, shrink combo and simply apply some x-y offsets to remove the "jumping" effect. I would imagine there must be some sort of offset I could apply to avoid jumping or shifting during rotation or scaling, but its not clear to me how to calculate such offsets. Any help would be appreciated.
Please don't hesitate to ask anymore questions. Like I said, I've been digging into this for days. Clearly, I don't understand it all, but am somewhat intimate with what's happening and happy to explain anything in more detail.
My solutions for scale, rotate, move back and front etc:
$scope.back = function () {
if($scope.currentImage !==null) {
if($scope.currentImage.prev!=undefined) {
var bot = $scope.currentImage.prev;
$scope.currentImage.insertBefore(bot);
ft.apply();
}
}
};
//Function for moving front
$scope.front = function () {
if($scope.currentImage !==null) {
if($scope.currentImage.next!=undefined) {
var top = $scope.currentImage.next;
if($scope.currentImage.next.node.localName == "image")
$scope.currentImage.insertAfter(top);
ft.apply();
}
}
};
//ZOOM
$scope.zoomIn = function () {
if ($scope.currentImage!= null) {
var ft = paper.freeTransform($scope.currentImage);
if(ft.attrs.scale.y<4) {
$scope.currentImage.toFront();
ft.attrs.scale.y = ft.attrs.scale.y *(1.1);
ft.attrs.scale.x = ft.attrs.scale.x *(1.1);
ft.apply();
ft.updateHandles();
}
}
};

Rotating a shape in KineticJS seems to move it out of sync with it's group

I am working on some image viewing tools in KineticJS. I have a rotate tool. When you move the mouse over an image, a line appears from the centre of the image to the mouse position, and then when you click and move, the line follows and the image rotates around that point, in sync with the line. This works great.
My issue is, I have the following set up:
Canvas->
Stage->
Layer->
GroupA->
GroupB->
Image
This is because I draw tabs for options on GroupA and regard it as a container for the image. GroupB is used because I flip GroupB to flip the image ( and down the track, any objects like Text and Paths that I add to the image ), so that it flips but stays in place. This all works well. I am also hoping when I offer zoom, to zoom groupb and thus zoom anything drawn on the image, but for groupA to create clipping and continue to support drag buttons, etc.
The object I am rotating, is GroupA. Here is the method I call to set up rotation:
this.init = function(control)
{
console.log("Initing rotate for : " + control.id());
RotateTool.isMouseDown = false;
RotateTool.startRot = isNaN(control.getRotationDeg()) ? 0 : control.getRotationDeg();
RotateTool.lastAngle = control.parent.rotation() / RotateTool.factor;
RotateTool.startAngle = control.parent.rotation();
this.image = control.parent;
var center = this.getCentrePoint();
RotateTool.middleX = this.image.getAbsolutePosition().x + center.x;
RotateTool.middleY = this.image.getAbsolutePosition().y + center.y;
this.image.x(this.image.x() + center.x - this.image.offsetX());
this.image.y(this.image.y() + center.y - this.image.offsetY());
this.image.offsetX(center.x);
this.image.offsetY(center.y);
}
getCentrePoint is a method that uses trig to get the size of the image, based on the rotation. As I draw a line to the centre of the image, I can tell it's working well, to start with. I've also stepped in to it and it always returns values only slightly higher than the actual width and height, they always look like they should be about what I'd expect, for the angle of the image.
Here is the code I use on mouse move to rotate the image:
this.layerMouseMove = function (evt, layer)
{
if (RotateTool.isRotating == false)
return;
if (!Util.isNull(this.image) && !Util.isNull(this.line))
{
if (Item.moving && !RotateTool.isRotating)
{
console.log("layer mousemove item moving");
RotateTool.layerMouseUp(evt, layer);
}
else
{
var pt = this.translatePoint(evt.x, evt.y);
var x = pt.x;
var y = pt.y;
var end = this.getPoint(x, y, .8);
RotateTool.line.points([this.middleX, this.middleY, end.x, end.y]);
RotateTool.line.parent.draw();
RotateTool.sign.x(x - 20);
RotateTool.sign.y(y - 20);
var angle = Util.findAngle({ x: RotateTool.startX, y: RotateTool.startY }, { x: x, y: y }, { x: RotateTool.middleX, y: RotateTool.middleY });
var newRot = (angle) + RotateTool.startAngle;
RotateTool.image.rotation(newRot);
console.log(newRot);
}
}
}
Much of this code is ephemeral, it's maintaining the line ( which is 80% of the length from the centre to my mouse, as I also show a rotate icon, over the mouse.
Sorry for the long windedness, I'm trying to make sure I am clear, and that it's obvious that I've done a lot of work before asking for help.
So, here is my issue. After I've rotated a few times, when I click again, the 'centre' point that the line draws to, is way off the bottom right of my screen, and if I set a break point, sure enough, the absolute position of my groups are no longer in sync. This seems to me like my rotation has moved the image in the manner I hoped, but moved my group off screen. When I set offsetX and offsetY, do I need to also set it on all the children ? But, it's the bottom child I can see, and the top group I set those things on, so I don't really understand how this is happening.
I do notice my image jumps a few pixels when I move the mouse over it ( which is when the init method is called ) so I feel like perhaps I am just out slightly somewhere, and it's causing this flow on effect. I've done some more testing, and my image always jumps slightly up and to the right when I move the mouse over it, and the rotate tool continues to work reliably, so long as I don't move the mouse over the image again, causing my init method to call. It seems like every time this is called, is when it breaks. So, I could just call it once, but I'd have to associate the data with the image then, for the simple reason that once I have many images, I'll need to change my data as my selected image changes. Either way, I'd prefer to understand and resolve the issue, than just hide it.
Any help appreciated.

What is causing my canvas drawing to break and skip at certain values (2^15, for one)?

I'm working on a 2d canvas-based app using EaselJS where the user can move indefinitely on the xy-plane by dragging the background. Think google maps, except the background is a repeating tile.
The code for the movement is very simple and looks something like this:
// container - the createjs.Container being panned
// background - a createjs.Shape child of container, on which the
// background is drawn
background.onPress = function(evt) {
var x = evt.stageX, y = evt.stageY;
evt.onMouseMove = function(evt) {
// the canvas is positioned in the center of the window, so the apparent
// movement works by changing the registration point of the container in
// the opposite direction.
container.regX -= evt.stageX - x;
container.regY -= evt.stageY - y;
x = evt.stageX;
y = evt.stageY;
stage.update();
};
evt.onMouseUp = function(evt) {
// Here the background would be redrawn based on the new container coords.
// However the issue occurs even before the mouse is released.
background.redraw();
stage.update();
};
};
All works as expected until reaching 32678px (2^15) on either axis. What occurs is different in different browsers, but the point where it first happens is the same.
In Firefox, it will suddenly shift a large chunk of pixels (~100) rather than 1. It will then happen again at 65538 (2^16+2), perhaps more after that, but I haven't witnessed it. After the trouble points, the drag will continue smoothly, as expected, but remaining shifted.
In Chrome, the effect is more dramatic. The drawing breaks and results in repeated ~100px wide "stripes" of the background across the page at 32768, and does not correct itself on redraw.
Oddly, the numbers in EaselJS don't reflect the issue. The only change in the container's transform matrix is the tx or ty incrementing by 1. No other matrices change. It seems as though EaselJS is getting all the numbers right.
Can anyone shed any light this issue?
Edit:
I worked around this problem by redrawing parts of the container using a calculated regX/regY, rather than attempting to translate very large regX/regY coords on the canvas.
This question may be related
What is the maximum size for an HTML canvas?
From what I gather browsers use short int to store canvas sizes with 32,767 being the maximum possible value.
Links possibly related to your issue,
Mozilla - HTML5 Canvas slow/out of memory
https://stackoverflow.com/a/12535564/149636

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