I'm having issues with all the animations on the page lagging when I choose to display this picture. I have tried displaying it with fadeIn, visibility, animate:opacity, display:block, and no matter which way I reveal it still causes the browser to choke. There has to be a way around this. (I've also tried preloading the image and it makes no difference!)
Is it just the size of the image?
http://jsfiddle.net/ZJpmT/2/
I suspect it is the image size. Doing a quick test showed that a fadeIn with a duration of 5 seconds, could be shown, but using a duration of 1 second wouldn't show any fade effect at all, but just show the the image at once.
Animating an image which is 1MB in size isn't what you want to do. If you really need this image to be that large, try to add a background to each frame, which matches the pages background and save it as JPG. That could reduce the size a bit, but it's not guaranteed that it will stop the browser from choking.
Related
I have a QML GridView, with a huge number of simple icons in it. The number can be in the millions, but only around a thousand will be visible at the same time, and there are only a few dozen types of images, so I guess they should be cached well.
If I use PNG images, everything is fine. The startup time is relatively long, but after everything is rendered, the application runs fine even on low-spec machines, and scrolling / resizing / zooming in the GridView is also fast and smooth.
However, if I use SVG instead, it slows my system down significantly. Even after everything is rendered, the responsiveness of the application is horrible, even GUI elements unrelated to the GridView are showing significant lag, the mouse cursor can barely be moved, etc. I thought after they are rendered, SVGs are presented just as any other image. Why must the CPU be busy if I don't even interact with them? And, most importantly, is there anything I can do about it? The same thing happens if I have SVG images containing nothing but a single rectangle, and use the same image in every cell. So it must mean the objects themselves are doing something.
"The number can be in the millions" and *"The startup time is relatively long"- those statement warrant a discussion about the design of your data model and bitmap caching strategy. But you didn't provide any code. So the following is a guess.
I'm not sure if you are loading the SVG images in C++ code or through QML, but I suspect you aren't setting the sourceSize (width and height) properties when you import your SVG. Hence, it's getting mapped into memory at a much larger size than it's getting rendered at. That is, it's eating up a lot more memory than it was with pre-sized PNG files. Or perhaps it's getting mapped in at a smaller size and Qt is is spending a lot of time having to resize these images at runtime as it scrolls in/out of view.
Open up one of your SVG files with notepad and look at at the attribute to see what the import size is.
In any case, try making sure your sourceSize.width and sourceSize.height match your render width/height.
Image {
id: icon
anchors.centerIn: parent
source: "cloud.svg"
sourceSize.width: 50
sourceSize.height: 50
width: 50
height: 50
}
Loading SVG's is an expensive operation...
Gridview manage dynamic objects.. creating visible items and destroying invisible items each time ....so, must render SVG each time you move the grid
One very bad idea is use that:
GridVIew{
cacheBuffer : 6000
//create 6000 items ...long startup time and memory expensive
...
}
This is a much better option:
Image {
id: icon
asynchronous : true //load image in asyncronus thread
sourceSize.width: width //scale as item size
sourceSize.height: height //scale as item size
...
}
If the load is too slow, you can add something like "LOADING..." text in the item background...
I have a window displaying a video stream with a twitter feed as an overlay.
When a new tweet is displayed, the current tweet animates out using a rotate animation and the next tweet is rotated into view. The animations are performed using a RotateTransition.
The app also switches between different cameras to display different streams. To give an indication of when the app switches to the next camera, I have a progressbar that fills using a Timeline object.
This works well, until I resize the window. The rotate animations start to flicker, along with the progressbars as they gradually fill.
As a test, I disabled the video stream, to see what's happening. The 'artifact' doesn't occur then and I can resize as much as I want. If I play the stream and don't resize, everything works well.
The video player is based on VLCJ, but the actual pixels are drawn on a WritableImage in an Imageview.
See the following images that illustrate the problem.
At the bottom right you can see 2 different progress bars (a ProgresBar and a ProgressIndicator).
A part of the flickering result is still visible below the second image. It somehow stays visible, probably because the area doesn't get redrawn.
Any idea what makes the flickering happen? Is there anything I can do to fix or avoid this?
I tried some VM options in IntelliJ: -Dsun.java2d.d3d=true -Dprism.forceGPU=true to somehow enable hardware acceleration, but that doesn't seem to help.
Disabling the progressbar fill animation doesn't help either.
I had a similar problem with some arcs and shapes that would flicker when its attributes / sizes were changed.
The solution to my problem was to make sure that the methods used to change the shapes were called from inside the JavaFX thread.
Platform.runLater(() -> {
arc.setStartAngle(30);
arc.setLength(45);
}
Here's my current layout:
The layout above works fine pre iphone6 but once the view is set to iphone6+ then you get:
FYI Those images look like the same size because of how they are displayed in sof. Click the image itself and you'll the actual size/scale of the image.
I get why that this is happening because my text areas are staying in the same place on the image while the image has actually changed in size (respecting aspect ratio). So my question is, how do I get these text fields to move in respect to the image behind it getting larger while still keeping their relative position & size against the image?
Try removing the vertical text Days, Hrs, and Mins the image and use that as the background image.
Then make 3 separate images one for each Days, Hrs, and Mins.
From there use auto layout to do the following:
[Days image][00] [Hrs image][01] [Mins image][02]
I have a trigger that changes the background of a div to an animated gif
I would like the javascript to force the image to animate again every time it is set as the background, however it currently only loops once and then displays the last frame after that.
Any ideas?
I tried adding ?v=1 but it seems that that causes a delay as the image loads again. I would prefer to have the image saved in cache but trigger the animation to restart
It seemed so simple just a day ago, but I can't figure it out:
How do I center an image on a page, giving it fixed % margins (10% on all sides) and still have it scale with the window on resize?
It's very important that the page and the image display well on all platforms, without scrollers (!).
The page itself is very simple and only contains the image (which on different versions of the page has different dimensions), and a bar on the top with a link to send it to another page.
The max size of the image would be 1500x1000px, no minimum size.
I wholeheartedly hope someone can help me out with this, thanks so much!
Best way to do that is using JavaScript. Get the window size, subscribe for window.onresize event and update the image size and position accordingly.
Using CSS only will NOT work, because any position properties depend on the container. In your case the container is the window, which will size itself based on the content. This creates a sort of circular dependency (window size depends on the image, the image size and position depend on the window size).
For information about getting the exact available window size in cross-browser way you could check this post: Get the size of the screen, current web page and browser window - haven't done that in a while to provide you with exact code.
Also note that you don't mention keeping the aspect ratio of the image. If it should not be maintained there is no way to do it HTML/CSS only, because all operations with them do maintain AR of images.