Sorry if the title was misleading, it's the closest approximation I could come up with, haha.
Okay so I'm using FabricJS for a proof-of-concept for a fabric-printing client, and they require 300PPI images (i.e, freaking huge). Now, if you check the JsFiddle I've popped in below you'll see the tiling is done with some while loops which seem to work fine, except for the fact that the whole browser freezes while loading, meaning I can't even stick up a loader icon.
Have I done something horribly wrong, or is that just sorta how it works? The long loading times are fine as long as I can a) put up a loader and b) it doesn't, uh, "He's dead, Jim!" my Chrome. I'm getting the images with base64, if that helps at all.
Cheers everyone!
EDIT For context, here's one of the functions that creates a pattern from an uploaded file:
function renderMirror(){
showLoader();
var isFullRows = false;
var rowIndex = 0;
var totalHeight = 0;
while(isFullRows == false){
// let's start with filling up the row's columns. start the width at zero.
var totalWidth = 0;
var isFullCols = false;
var colIndex = 0;
if(rowIndex % 2){
var isRowMirrored = false;
}else{
var isRowMirrored = true;
}
while(isFullCols == false){
colIndex++
if(rowIndex == 1){
console.log('row');
}
if(totalWidth >= canvas.width){
isFullCols = true;
}
if(colIndex % 2){
var isColMirrored = false;
}else{
var isColMirrored = true;
}
canvas.add(new fabric.Rect({
left: totalWidth,
top: totalHeight,
fill: pattern,
flipX: isColMirrored,
flipY: isRowMirrored,
height: newImgHeight,
width: newImgWidth,
selectable: false
}));
totalWidth+= newImgWidth;
// safeguard
if(colIndex > 100){
isFullCols = true;
}
}
// now instantiate the row.
rowIndex++;
if(totalHeight >= canvas.height){
isFullRows = true;
}
totalHeight+= newImgHeight;
// safeguard
if(rowIndex > 100){
isFullRows = true;
}
}
hideLoader();
}
The whole thing is here, if you'd like to have a proper look?
I've experienced something similar to generate PDF at 300. I tried two different solutions:
Using webWorkers which will do the heavy work on the background and is not going to freeze the browser, however this approach was a little bit slower in my use case.
The second approach I took was create an endpoint where I get just the base 64 image and then with that data of the image I generate a PDF using imagemagick to create the PDF at 300 DPI also I create a virtual canvas with JS to generate the real size of the image from a scaled canvas in order to make it a little bit faster as well.
Related
I have six floors of a building drawn on a canvas with fabric.js. In order to show only one floor, I do this:
building.selectFloor = function(floorId){
for (var i = 0; i < floors.length; i++){
if (floorId == floors[i].name){
floors[i].visible = true;
}else{
floors[i].visible = false;
}
}
canvas.renderAll();
};
But nothing changes - all floors are still visible. The floors set to visible = false don't disappear until renderAll() is called later on a window resize:
$(window).resize(setSize);
setSize();
function setSize(){
viewportWidth = $(window).width();
viewportHeight = $(window).height();
$appContainer.css({ "width": viewportWidth, "height": viewportHeight});
canvas.setDimensions({ width: viewportWidth, height: viewportHeight });
if (canvas.building){
canvas.building.center();
canvas.building.scaleX = canvas.building.scaleY = (viewportWidth + viewportHeight) / (1920 + 1080);
canvas.renderAll();
}
}
but then they do disappear. Why is one renderAll() working, and the other not? I've tried wrapping the non-functioning renderAll() in a window.timeOut to see if a delay helps, but no luck.
Ok - so I figured it out in the end: building is a group which appears to be getting cached by some internal fabric magic, and the cached version is being rendered instead of the updated version. To render the updated version you have to do this
canvas.building.set('dirty', true);
canvas.renderAll();
Hope that helps someone on down the line.
EDIT
Turns out there's an easier solution still:
canvas.building.objectCaching = false
There is a new version that changed the format to:
canvas.requestRenderAll();
This worked for me in later versions:
// for one canvas
myCanvas.objectCaching = false;
// for all canvas
fabric.Object.prototype.objectCaching = false;
// in both case it still needs to be re-rendered
myCanvas.renderAll();
ps: using version 4.2.0
You have to update (at least in the new version) object properties with object.set({...}) or set object.dirty = true in order to make the cache system recognize the change in the object properties. Disabling cache might not be the best idea, it has been included for a reason. canvas.requestRenderAll(); then works as intended.
I've been looking around a lot of JavaScript answers but I haven't found one that really answers my problem yet. What I'm trying to do is load an image, grab the pixel data, perform an analysis, and then load another image to repeat the process.
My problem is that I can't preload all of the images because this script has to be able to work on large amounts of images and preloading could be too resource heavy. So I'm stuck trying to load a new image each time through a loop, but I'm stuck with a race condition between the image loading and the script drawing it to the canvas's context. At least I'm pretty sure that's what is happening because the script will work fine with the images precached (for example if I refresh after loading the page previously).
As you'll see there are several lines of code commented out because I'm incredibly new to JavaScript and they weren't working the way I thought they would, but I didn't want to forget about them if I needed the functionality later.
This is the snippet of code that I believe is giving rise to the problem:
EDIT: So I got my function to work after following a suggestion
function myFunction(imageURLarray) {
var canvas = document.getElementById('imagecanvas');
console.log("Canvas Grabbed");
if (!canvas || !canvas.getContext) {
return;
}
var context = canvas.getContext('2d');
if (!context || !context.putImageData) {
return;
}
window.loadedImageCount = 0;
loadImages(context, canvas.width, canvas.height, imageURLarray, 0);
}
function loadImages(context, width, height, imageURLarray, currentIndex) {
if (imageURLarray.length == 0 || imageURLarray.length == currentIndex) {
return false;
}
if (typeof currentIndex == 'undefined') {
currentIndex = 0;
}
var currentimage = new Image();
currentimage.src = imageURLarray[currentIndex];
var tempindex = currentIndex;
currentimage.onload = function(e) {
// Function code here
window.loadedImageCount++;
if (loadedImageCount == imageURLarray.length) {
// Function that happens after all images are loaded here
}
}
currentIndex++;
loadImages(context, width, height, imageURLarray, currentIndex);
return;
}
Maybe this will help:
currentimage.onload = function(e){
// code, run after image load
}
If it is necessary to wait for the image to load, the following code will load the next image (currentIndex is your "img" variable):
var loadImages = function(imageURLarray, currentIndex){
if (imageURLarray.length == 0 || imageURLarray.length == currentIndex) return false;
if (typeof currentIndex == 'undefined'){
currentIndex = 0;
}
// your top code
currentimage.onload = function(e){
// code, run after image load
loadImages(imageURLArray, currentIndex++);
}
}
Instead of a "for" loop, use for example this function:
loadImages(imageURLarray);
Maybe try this:
http://jsfiddle.net/jnt9f/
Setting onload handler before setting img src will make sure the onload event be fired even the image is cached
var $imgs = $(),i=0;
for (var img = 0; img < imageURLarray.length; img++) {
$imgs = $imgs.add('<img/>');
}
var fctn = (function fctn(i){
$imgs.eq(i).on('load',function(){
//do some stuff
//...
fctn(++i);
}).attr('src',imageURLarray[i]);
})(0);
Actually...a lot of developers are pointing here to detect when images are done loading after a jQuery event..
https://github.com/desandro/imagesloaded
If you can determine when the event triggers your images to load (for example, adding an Id or class onto the page right before your images begin to load), then you should be able to blend that in with this plug-in on github.
Good Luck!
I'm learning javascript by using the easeljs library to make a simple game, for school lessons.
I want to make a crosshair give some feedback to the player by showing a small animation while you are pointing at your target, using a hittest I made.
However, when the crosshair touches the target, the animation (should be two little triangles pointing to the middle of the crosshair) seems to be stuck on it's first frame.
Here is a bit of my code, I put both of these functions inside a ticker function. The functions do what they're supposed to do (I checked by sending a message to the console.log), but I think the animation is reset as soon as the variable "hitTestControle" is set to true, at every tick.
If you want to check out all of the code, here is a link to the "game":
http://athena.fhict.nl/users/i279907/achtergrond/achtergrond.html
function hitTest() {
if(distance(crossHair, block) < 60) {
hitTestControle = true;
} else {
hitTestControle = false;
console.log(hitTestControle);
}
}
function hitTestControl() {
if(hitTestControle == true) {
crossHair.gotoAndPlay("move");
console.log("hit");
} else {
crossHair.gotoAndPlay("stop");
}
}
PS: There also seems to be something wrong with this hittest I used.
function distance() {
var difx = blok.x - crossHair.x;
var dify = blok.y - crossHair.y;
return Math.sqrt( (difx * difx) + (dify * dify) );
}
It looks like you're starting the animation... setting it to the first frame and starting it... every time hitTestControle is true. Since hitTestControle will be true as long as you're hovering over the target, the animation will never reach the second frame.
What you need to do is start the animation when you transition from hitTestControle = false to hitTestControle = true, but once that happens you just let it play automatically.
Try changing your hitTestControl() function to something like this:
function hitTestControl() {
if(hitTestControle == true && alreadyOverHit == false) {
crossHair.gotoAndPlay("move");
alreadyOverHit = true;
console.log("hit");
} else {
crossHair.gotoAndPlay("stop");
alreadyOverHit = false;
}
}
In other words, only start the animation once, during the first frame you're detecting a hit, and then don't touch it unless you move off the target and back on.
I am trying to figure out how to sequence the train animation so I can offset and rotate each wagon in turn around curves, for example, in Route_51 (click Test>Run[twice]) in this display. Needs Chrome or other HTML5 compliant browser.
Here is my so far 'non-complying' code (using KineticJs):
function animate(nr,path,incr,train,dirX,dirY){
var steps,offsetX,offsetY,count,a;
steps = Math.round(path[nr][2] / incr);
offsetX = path[nr][2]/steps;
offsetY = path[nr][3]/steps;
count = 0;
stage.onFrame(function(frame){
layer = train[0].getLayer();
if(count < steps){
for(a=0; a<train.length; a+=1){
incrX = train[a].getX() + offsetX * -dirX;
incrY = train[a].getY() - offsetY * -dirY;
train[a].setX(incrX);
train[a].setY(incrY);
}
layer.draw();
count += 1;
}
else{
stage.stop();
nr += 1;
if(path[nr]){
animate(nr,path,incr,train,dirX,dirY);
}
}
});
stage.start();
}
I don't seem to be able to grasp the logic (getting old).
All help appreciated. Thanks.
It seems a certain amount of time has to pass before some kind of logic emerges.
In this case it was that each loco/wagon needed its own fully incremented path for the starts and optionally finishes to be staggered. Here is a screenshot of the train in motion with the "normal" scale view inset. Room for improvement of course especially with curve coordinates.
For the animation visit http://glasier.hk and follow the KJS link.
it is the first time for me to explore jQuery and gameQuery for building games using JavaScript, so am asking about sth that might look very naive, but really i cant get it.
i am developing a game like Space Invader, the detection for collision between player missile and enemies not working.
This is my code:
the definition for my Enemy class
function Enemy(node){
this.node = $(node);
this.pts_value = 0;
return true;
}
this is the code i use to add ten enemy sprite next to each other. the enemies move together to the left and the right
$.each(new Array(10), function(index, value) {
$("#enemy_group").addSprite("enemy2_"+index,{animation: enemies[2],
posx: index * 55, posy: 0, width: 48, height: 48})
$("#enemy2_"+index).addClass("enemy");
$("#enemy2_"+index)[0].enemy = new Enemy($("#enemy2_"+index));
$("#enemy2_"+index)[0].pts_value = 150;
});
so when i need to move the enemies, i move the enemies together, i move the group that includes all the sprites "#enemy_group"
if(ENEMY_TO_RIGHT){
var enemiesNewPos = (parseInt($("#enemy_group").css("left"))) + ENEMY_SPEED;
if(enemiesNewPos < PLAYGROUND_WIDTH - 550){
$("#enemy_group").css("left", ""+enemiesNewPos+"px");
} else {
ENEMY_TO_RIGHT = false;
}
} else {
var enemiesNewPos = (parseInt($("#enemy_group").css("left"))) - ENEMY_SPEED;
if(enemiesNewPos > 0){
$("#enemy_group").css("left", ""+enemiesNewPos+"px");
} else {
ENEMY_TO_RIGHT = true;
}
}
finally for collision detection, i want to remove the enemy sprite that the players missile has hit, each missile sprite has an added class names ".playerMissiles"
$(".playerMissiles").each(function(){
var posy = parseInt($(this).css("top"));
if(posy < 0){
$(this).remove();
return;
}
$(this).css("top", ""+(posy - MISSILE_SPEED)+"px");
//Test for collisions
var collided = $(this).collision(".enemy, .group");
if(collided.length > 0){
//An enemy has been hit!
collided.each(function(){
$(this).setAnimation(enemies[0], function(node){$(node).remove();});
})
}
});
i was following the documentation tutorial on the gameQuery website.
any help appreciated, thanks,
I can't see any problem with your code. I can only give you a few pointers:
Did you create "enemy_group" with the addGroup function?
Is "enemy_group" nested in something special like a custom div ? for the collision detection to work you need a chain of parent composed only of sprites and groups (and tiles map)
Is "enemy_group" nested in a sprite, if so it's a bad idea because you will need to add the selector for this sprite in your methode call and this sprite will be included in the colliding element list.
The same goes for the ".playerMissiles"
Just to be sure what version of gameQuery and jQuery do you use? The last version from gitHub is unstable and I wouldn't recomend using it, user 0.5.1 instead.
You could use jquery collision plugin, so you avoid doid the logic by yourself.
Hope this helps. Cheers