I'm still new to use flutter, it is an interesting language. Just need to know.
#override
Widget build(BuildContext context){
return Center(
child : Image.asset(
"animated.gif"
)
);
}
If I build an animated image widget with Image.asset, is that possible to know when the animation finish, jump to the specific frame of the image just custom, and add a listener, or is there another way to achieve that?
The Image widget does not expose the progress of the animated asset.
However, you can use the lower level APIs to get more control.
If all you need is visibility into when frames are scheduled, you can work directly with the MultiFrameImageStreamCompleter. Look at the implementation of the Image widget for an example of how to get an image stream completer and use it.
Jumping to a specific animation frame is more tricky as the animation formats encodes deltas from previous frame and thus does not support random seek. One way to achieve that would be to decode and cache all frames, you can use the ui.Codec API to decode frames yourself and cache them. Note that doing this will consume a potentially large amount of memory.
Related
I searching an days for this question.
I want to Crop Images like that, in flutter:
GIF Source: https://github.com/ArthurHub/Android-Image-Cropper
The closest lib for this solution is the Image Lib, that lib offers manipulate images and crop, but i want to crop images in UI level like this gif. All libs I found dont offers that.
There is no widget that performs all that for you. However, I believe that it is possible to write that natively in flutter now. I don't have time at this particular moment to do it for you, but I can definitely point you in the right direction.
You're going to need to load the image in such a way that you can either draw it onto a canvas or use a RawImage to draw it rather than using the Image widget directly.
You need to figure out a co-ordinate system relative to the image
You'll need to find a way of drawing the crop indicator - you could do this either by drawing directly on the canvas or possibly using some combination of GestureDetector/Draggable/DropTarget. I'd suggest that sticking to Canvas might be the easiest to start.
Once the user has selected a part of the image, you need to translate the screen co-ordinates to picture co-ordinates.
You then have to create an off-screen canvas to draw the cropped image to. There are various transforms you'll have to do to makes sure the image ends up in the right place.
Once you've made the off-screen crop, you'll have to display the new image.
All of that is quite a lot of work, and probably a lot of finessing to get right.
Here's examples for a couple of the steps you'll need to do, but you'll have to figure out how to put them together.
Loading an image:
var byteData = await rootBundle.load("assets/image.jpg");
Uint8List lst = new Uint8List.view(byteData.buffer);
var codec = await UI.instantiateImageCodec(lst);
var nextFrame = await codec.getNextFrame();
var image = frameInfo.image;
Displaying an image on a canvas:
https://docs.flutter.io/flutter/dart-ui/Canvas/drawImageRect.html
https://docs.flutter.io/flutter/rendering/CustomPainter-class.html
Writing an image to a off-screen canvas:
ui.Image getCroppedImage(Image image, Rect src, Rect dst) {
var pictureRecorder = new ui.PictureRecorder();
Canvas canvas = new Canvas(pictureRecorder);
canvas.drawImageRect(image, src, dst, Paint());
return pictureRecorder.endRecording().toImage(dst.width.floor(), dst.height.floor());
}
You'll probably need to do something like this answer for getting the local coordinates of mouse/touch gestures.
Some advice - I'd start as simple as possible, not thinking about performance to start (i.e. draw everything each paint if needed, etc). Then once you get the basics working you can start thinking of optimization (i.e. using a RawImage, Transform, and Stack for the image and only re-drawing the selector, etc).
If you need any additional help let me know in a comment and I'll do my best to answer. Now that I've been writing about this a bit it does make me slightly curious to try implementing it so I may try at some point, but it probably won't be soon as I'm quite low on time at the moment. Good luck =D
The image_cropper plugin does exactly what you are looking for.
I'm currently working on a new app, and I want to add customized animations to it (not talking about activity transitions).
To show you exactly what I mean, take a look at this video at 2:30-2:33:
https://www.youtube.com/watch?v=XBMdjX5bbvk&nohtml5=False
You see the chest jumping to the screen and opens smoothly with beautiful animation?
I'd really like to know how can it be added to an Android app, is it a frame animation?
I mean, I can make this animation, in 2D, I just want to know how to add it (I'm using Android Studio) without causing memory overflow.
Thanks!
For you question:
You see the chest jumping to the screen and opens smoothly with
beautiful animation? I'd really like to know how can it be added to an
Android app, is it a frame animation?
I don't think it is a frame animation. I guess this has been implemented using OpenGL. You can find the official tutorial here.
If you want to make simple 2d animations, you can use the AnimationDrawable api provided by android. You basically need frames for the sequence of animations and then you can create the animation using the following code:
// you would need an `ImageView` object as a placeholder for the animation
ImageView mMascotView = findViewById(...);
// prepare the animation object ..
AnimationDrawable mMascotAnimation = new AnimationDrawable();
final int frameTime = 250; // time in milliseconds
// adding the frames to the animation object. You can specify different
// times for each of these in milliseconds
mMascotAnimation.addFrame(getResources().getDrawable(R.drawable.frame1),frameTime);
mMascotAnimation.addFrame(getResources().getDrawable(R.drawable.frame2),frameTime);
mMascotAnimation.addFrame(getResources().getDrawable(R.drawable.frame3),frameTime);
// make it loop infinitely ..
mMascotAnimation.setOneShot(false);
// set the background of the `ImageView` as the `AnimationDrawable`object ..
mMascotView.setBackground(mMascotAnimation);
// start the animation ..
mMascotAnimation.start();
Note: You should not call the AnimationDrawable.start()inside the onCreate() method of the activity. The views are not ready yet. You should use the callback on onWindowFocusChanged() method and start the animation there:
#Override
public void onWindowFocusChanged (boolean hasFocus)
{
//Start animation here
if(hasFocus) {
mMascotAnimation.start();
}
}
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);
}
Is there any API to listen for a particular frame during an animation of a Sprite in CreateJS? There was kind of a way to trigger events at particular frames in a Flash MovieClip, but not sure how to do this in CreateJS.
I could achieve this by listening to the change event of the Sprite while it animates, check the currentFrame on each event, check if the frame index is the one to which I want to react, BUT, this seems rather laboured, and means I have to hard code to an index instead of a frame label.
Interestingly, the _animations property of a Sprite seems to be intended to be private, so although I can use this property to ascertain the length of the animation, again, would still have to hard code to a index value. (Out of curiosity, why not have mySprite.length() API? Flash's MovieClip has a number of frames prop...).
Is there a way to make frame labels in CreateJS? In the docs here, I can see the use of:
instance.gotoAndStop("frameName");
...but I don't see any documentation on how to set frame labels in a SpriteSheet for a particular animation sequence, or how to retrieve the index of the frame associated with a frame label.
Thanks for your help!
The gotoAndStop and gotoAndPlay methods both allow for a frame number or animation name (not frame name). You can label animations when you create a SpriteSheet, but you can not otherwise make named keyframes inside of animations.
To determine the keyframe, you could check the currentAnimationFrame (doc) on your main tick function, or listen for the change event (doc) from the Sprite.
sprite.on("tick", function() {
if (sprite.currentAnimationFrame == 10) {
// do something
}
});
Note that depending on your app framerate, you might have to store the previous frame, and check if the playhead has passed a certain frame, as EaselJS may skip frames depending on the speed of playback.
--
The length property is a good idea, but it would likely have to be a method that you pass in an animation name. I have logged an issue on the EaselJS GitHub
Coming from the iOS world where we have UIImageView and the property animationImages:
http://developer.apple.com/library/ios/documentation/UIKit/Reference/UIImageView_Class/Reference/Reference.html#//apple_ref/occ/instp/UIImageView/animationImages
Where animationImages is just an array of arbitrary animation frames. You specify the images (maybe 15), then set the total animation time (maybe 4 seconds) in one of the other properties, then just start the anim and the images in animationImages will play sequentially over the specified time with an even frame rate.
How would I do the same with WP7/Silverlight? This all Expression Blend seems wonderful, but I just can't find a way to animate the image source (I'm guessing it might be impossible). How would I do the same? Should I add a unique image object for each frame in the animation, then play around with visibility/opacity properties and manually have to create all the spaced out key frames? That sounds like a lot of extra work + overhead and not a nice way to go...
http://www.windowsphonegeek.com/articles/WP7-Animations-in-depthndash-Overview-and-Getting-Started
http://www.wearerighteous.com/wp7-development/xaml-animation-in-silverlight-for-windows-phone-7/
http://www.windowspresentationfoundation.com/?p=712
Try out these links. Especially the first one, I think the first one resolve all you doubts. In wp7 we can go for two options either XAML based (static) animations / or with the help of C# code. By using blend u can create all sot of static animation with out any issue. Here the animation is working on the basis of page frames. If u are interested in learning more about Animation try this too;
http://msdn.microsoft.com/en-us/library/cc189019(v=vs.95).aspx
You can actually animate the Image.Source property here's a tutorial.
Animating Images in WP7