I would like to two show a Chart and also present an url with a link to a bigger Chart. The small preview-image looks and works fine:
<canvas id="image"></canvas>
var ct1 = document.getElementById("image").getContext("2d");
ct1.canvas.width = document.getElementById("image").offsetWidth;
ct1.canvas.height = document.getElementById("image").offsetHeight;
var Chart1 = new Chart(ct1).Line(lineChartData1,options);
The canvas is wrapped in a div, that's why offsetWidth and offsetHeight (to fill this additional div-element). Cause of the responsive-design there is no fixed image. Anyway, this works perfectly. For the URL to the "bigger" image I want to have the URL. I know the toDataURL() will help.
var url = document.getElementById("image").toDataURL();
document.write(url);
There are two disturbing problems with it:
The URL with this way exisists and, but the image has no content.
I also want to give the canvas-image a new size, like I managed with ct1.canvas.width and ct1.canvas.height, but it seems I cannot add this to the toDataURL.
What's wrong with the code?
Okay, I think I got it. Chart.js is animating the charts, so the toDataURL() I mentioned in my first question rendered only an empty image. We have to initiate the toDataURL, not before the animation is done. We handle that with the options:
var options = {
onAnimationComplete: done
}
and a tiny function:
function done() {
console.log('done');
var url=document.getElementById("canvas").toDataURL();
document.getElementById("canvas_link").href=url;
}
I think that's all.
Related
I need to dynamically add groups of multiple groups of images to the canvas, these "multi-group" will react differently depending on which of he contained groups has been dragged over by another group. I need these multi-groups to be able to be selected, rotated and dragged around the screen.
Ive chosen to use FabricJS and create images using fabric.Image.fromURL, manipulate, then add them to the canvas in a callback function. To add multiple images to a group, you nest more images in cascading callback functions as shown in this tutorial
I cant find a way to get a reference to a group of images created this way so I can add another group of images. Declaring a variable before any calls to fabric.Image.fromURL and trying to assign a reference to a created image doesnt work. The only way Ive got something working is a horrible desparate hack of adding such a group to the canvas then setting it as the active object then creating a new group and adding that active object to the group, this is soooo wrong and I dont think it will work for 3 groups. Heres my last coding attempt;
fabric.Image.fromURL('images/icon_station.png', function(img) {
var img1 = img;
fabric.Image.fromURL('images/icon_curve.png', function(img) {
img.set({left: 64,top: 64,angle: -90});
var img2 = img;
fabric.Image.fromURL('images/icon_curve.png', function(img) {
var img3 = img;
var tile_loop = new fabric.Group([img1, img2, img3]);
tile_loop.set({left: 0, top: 0, height: 64, width: 64});
canvas.add(tile_loop).setActiveObject(tile_loop);
});
});
});
fabric.Image.fromURL('images/icon_station.png', function(img) {
img.set({left: 64,top: 64});
var img1 = img;
fabric.Image.fromURL('images/icon_straight.png', function(img) {
img.set({left: 64,top: 64});
var img2 = img;
fabric.Image.fromURL('images/icon_curve.png', function(img) {
img.set({left: 64,top: 64});
var img3 = img;
var tile_loop = new fabric.Group([img1,img2,img3,canvas.getActiveObject()]);
tile_loop.set({left: 128, top: 128, height: 128, width: 128});
canvas.add(tile_loop);
});
});
});
The only other way Ive seen is to load images into html tags and create them in fabric from the tags, like this
var imgElement = document.getElementById('my-img');
var imgInstance = new fabric.Image(imgElement, {left: 100,top: 100});
canvas.add(imgInstance);
but that seems like a last resort work around, I would prefer to load images up directly in fabricjs.
Ive tried to do this in Phaser but it doesnt do groups of groups, Fabric has all the other stuff I need so I would like to stay with it, its a shame it does these weird ways of handling images.
Any help is much appreciated, if all else fails Ill use the last resort, it would be great to find a clever correct way.
I created an example in JSFiddle;
http://jsfiddle.net/d7bjbpfb/
Here is the problem :
I have a canvas, and four (would be more in future, but 4 for testing...anyway, doesn't matter) images that can be "poped" into the canvas by clicking on it.
Each image can be present multiple times in the canvas.
So far, poping is working fine, images are draggable... But I can't add some resize or zIndex function as I can only select the last image add to the canvas.
In a ideal world, I would like, by clicking/dragging an image, put it on top of the canvas, and kinda "select" it, so that I can connect the resize functions to the image.
But with the array of images, I can't manage to identify properly the item dragged, and can't use (or don't manage to use) the selectors.
Thank you.
EDIT : some code
var imgCpt = 0;
var image = [];
function addDetails(img) {
imgCpt++;
var imageObj = new Image();
imageObj.onload = function() {
image[imgCpt] = new Kinetic.Image({
x: 0,
y: 0,
image: imageObj,
draggable: true,
id:image[imgCpt]
});
image[imgCpt].setX((stage.getWidth()/2) - (image[imgCpt].getWidth()/2));
image[imgCpt].setY((stage.getHeight()/2) - (image[imgCpt].getHeight()/2));
eval(image[imgCpt]).on('click', function() {
alert(eval(imgCpt));
});
layer.add(image[imgCpt]);
stage.add(layer);
};
imageObj.src = 'uploads/'+img;
}
I've already tried different solutions : multiple layer, and acting on it instead of acting on image, working with shapes filled with image instead of image, but it's always the same problem : I can't get the id of the concerned element (instead of the id of the last insert element)
This version works with array, but I tried yersterday to build the image id with eval(); without more success.
Thank you for your help
EDIT² : sorry to insist, but I would really be glad to have some assistance on this point, even if I think it's more JS related than pure KineticJS related.
Thank you.
Ok Guys, just solved the problem :
eval("image["+imgCpt+"].on('click', function() {alert("+imgCpt+");});");
Instead of :
eval(image[imgCpt]).on('click', function() {
alert(eval(imgCpt));
});
Now time to set a true action behind the click.
Thank you for helping ;)
I have been trying to put an image with a hyperlink on it into a google apps script ui. I first thought of using createAnchor(), but that only allows text. Then I thought of using a button, but as far as I know you cannot open a new tab/window and redirect in a callback function.
I also tried createHTML(), but the element is not handled by it as yet.
I have seen people overlay transparent buttons over images, but still have same issue in callback.
My research has not found an answer to this. Does anyone have any solutions/examples?
Thanks
This worked for me on Chrome20 and IE9
// Container for box and results
var imageContainer = app.createFlexTable();
// Setup the button
var button = app.createButton("ImageButton");
button.setStyleAttribute("background", "url(dontshowimagehere.JPG) no-repeat");
button.setStyleAttribute("position", "absolute");
button.setStyleAttribute("color", "transparent");
button.setStyleAttribute('zIndex','1');
button.setStyleAttribute("border", "0px solid black");
imageContainer.setWidget(0, 0, button);
// image to click
var image = app.createImage("image.jpg").setId(imageId);
imageContainer.setWidget(1,0, image);
The image has a slight (3px) offset. If important, this looks to fix it http://www.w3schools.com/css/css_positioning.asp (use relative for the flex table and top etc for the image and button)
Did you try a transparent Anchor overlaying the image?
function doGet() {
var app = UiApp.createApplication().setTitle("Image Anchor");
var panel = app.createAbsolutePanel().setWidth('50%').setHeight('50%');
var image = app.createImage().setUrl("https://lh6.googleusercontent.com/-v0Q3gPQz03Q/T_y5gcVw7LI/AAAAAAAAAF8/ol9uup7Xm2g/s512/GooglePlus-512-Red.png").setStyleAttribute("width", "28px").setStyleAttribute("height", "28px");
var anchor = app.createAnchor("?", "https://plus.google.com/u/1/116085534841818923812/posts").setHeight("28px").setWidth("28px").setStyleAttribute("opacity", "0.1").setTarget("blank");
panel.add(image,100,50);
panel.add(anchor,100,50);
app.add(panel);
return app.close();
}
app.createAbsolutePanel()
.add(app.createImage('https://www.google.com/images/logos/google_logo_41.png'))
.add(app.createAnchor('','https://www.google.co.uk/intl/en/about/')
.setStyleAttributes({position:'absolute',top:'0px',left:'0px',width:'201px',height:'47px',opacity:'0'}))
This is a tested one. It works fine.
It doesn't work with positioning the image (as 'absolute').
It doesn't work with .setHorizontalAlignment(UiApp.HorizontalAlignment.CENTER)
I don't believe this is possible with the widgets available. I would suggest altering your UI's design to utilize an Anchor widget instead.
Use HTML Box if you are coding directly on your page. Click "Edit" to edit your page and go to "Insert>HTML Box" in your menu. It will accept javascript too! There are a few caveats - when using javascript, HTML Box will not accept links...too bad, but too many exploits there.
If you are coding in apps script, you could try to place the image on a panel and use absolute panel and position your link over your image. Another method could be to use the .setStyleAttribute for CSS styling and utilize the zIndex parameter to place a panel over top of your image....like so:
var panel = app.createSimplePanel();
// add your image to the simple panel or whatever panel you wish to choose in your GUI
var popPanel = app.createSimplePanel()
.setStyleAttribute('top','Y')
.setStyleAttribute('left','X')
.setStyleAttribute('zIndex','1')
.setStyleAttribute('position','fixed');
// add your anchor to the popPanel
app.add(panel).add(popPanel);
Not 100% sure if you can make this panel transparent, but you could try something like:
.setStyleAttribute('background',transparent')
or change the opacity via:
.setStyleAttribute('opacity','.5')
Hopes this gives you a few ideas!
I managed to do it with a single Anchor object and using CSS3.
It works on Chrome, I did not test it in other Browsers.
gui.createAnchor("", false, "$DESTINATION_URL$")
.setStyleAttributes({ "display":"block",
"width":"$IMAGE_WIDTH_IN_PIXEL$",
"height":"$IMAGE_HEIGHT_IN_PIXEL$",
"background":"url($URL_OF_THE_IMAGE$)",
"background-size":"100% 100%",
"background-repeat":"no-repeat" })
Of course you have to replace the $......$ with your data.
Thierry
If you first create all your HTML in a string, you can then replace the content of a page with the HTML you want like this:
var myString = 'the html you want to add, for example you image link and button';
var page = SitesApp.getSite('example.com', 'mysite').getChildByName('targetpage');
var upage = page.setHtmlContent('<div>' + myString + '</div>');
I am a beginner programmer in javascript. I don't use jQuery! And I want to make a simple game.
I am loading multiple images into canvas using
imageObj.onload = function(){}
I am using a keylistener for multiple keypresses so that the images could move on the diagonal while pressing both up and left keys by using smth like this:
function keydown_handler(e){my_key[String.fromCharCode(e.keyCode)] =
true; Move();}
My problem is that when I press the keys and move the images on the canvas the image flickers. I suppose this is because it loads the image every time I press a key. If this is true how can I load an image ONCE into memory and then RECALL that image from memory and change it's coordinates?
Thank you!
Well, what you really need to do is to create a render loop with javascript using requestAnimationFrame(), and render with the canvas element. Here's a really basic example of rendering with HTML5:
<!DOCTYPE html>
<html>
<body>
<canvas id="gameCanvas" width="800px" height="600px"></canvas>
<script type="text/javascript">
var canvas = document.getElementById('gameCanvas');
var context = canvas.getContext('2d');
var myImage = new Image();
var myImage.onload=function(){init();};
var myImage.src='location/of/image.png';
var imageX = 0, imageY = 0;
function render()
{
window.requestAnimationFrame(render);
// clear canvas
canvas.width = canvas.width;
context.drawImage(myImage, imageX, imageY);
imageX++;
imageY++;
}
function init()
{
window.requestAnimationFrame(render);
}
</script>
</body>
</html>
There will never be flicker when you're rendering through a canvas since the browser is already double buffering that rendering surface; and manually double buffering the canvas will actually produce a significant drop in framerate. What you're probably encountering (if you're rendering through a canvas) is tearing of the frame. Using requestAnimationFrame will resolve the tearing problem by essentially v-syncing the render (since it waits until the end of code execution to render).
Hopefully this will help you get started on the right path for rendering with HTML5.
What you are referring to is a very common problem when dealing with animations. The issue has less to do with what is stored in memory and more to do with the way an animation must be redrawn each time something changes. The most common method for avoiding this flickering issue is known as double buffering.
I have never done this using HTML5 specifically but after a quick search I found this article that may help you.
https://stackoverflow.com/a/2864533/594558
Is there a way to add an image in my main app, so that it is on top off a popWindow? The equivalent of the Z-index should render it on top.
So, I've got a popWindow and I want to add an image on top of the popWindow.
If in my main app I use:
var floatingImage:Image = new Image;
floatingImage.source = image_path;
floatingImage.y = 200;
floatingImage.x = 200;
addChild(floatingImage);
Then the image is on top of main App, but it is still below my popWindow.
I would add the image directly to the popWindow, but I'm using FlashEff 2, and for some reason the effect won't work if I have an image in the popUp. So, I thought that I would add the image in the main app and have it float above the popWindow.
Another possibility might be to check somehow if the popWindow is open and then add the image directly to the popWindow.
If anyone has any suggestions, I'd love to hear them.
Thank you.
-Laxmidi
Not really recommended but here is the code. This won't work well with UIComponents just DisplayObjects.
[Embed(source="assets/MyImage.png")]
private var MyImage:Class;
protected function button1_clickHandler(event:MouseEvent):void
{
var image:DisplayObject = new MyImage();
stage.addChild(image);
}