如何在JavaFX中停止动画GIF？

Question

我想在我的项目中使用动画GIF,但我不知道如何停止循环动画.我的意思是,我希望GIF只玩一次.

谢谢!

Answer 1

我还没有完成GIF动画,甚至没有意识到JavaFX会有启动和停止它们的方法.如果你想用图像做任何动画,我建议你自己一帧一帧地做.这样您就可以完全控制它,并且您的图像中只能有256种颜色.

我在Mike的博客中阅读了一篇关于使用JavaFX创建Sprite动画的非常好的文章.

这很容易做到.您只需扩展Transition类,向其添加ImageView并实现Transition的Interpolate方法.

编辑:哦,顺便说一句,GIF有一个循环标志,告诉他们要么循环播放,要么不循环播放.换句话说:理论上你可以修改GIF文件的循环属性.仅在理论上,因为我只是尝试指定只播放一次而在JavaFX中它仍然在无限循环中播放,而在FireFox中它播放一次.顺便说一句,JavaFX似乎不支持动画PNG(APNG),它支持超过256种颜色.因此自动图像动画功能非常有限.最好自己做动画.

我希望有人能提出更好的东西,但这里有一个关于如何完全控制你的gif的示例代码.

import java.awt.image.BufferedImage;
import java.net.URISyntaxException;

import javafx.animation.Interpolator;
import javafx.animation.Transition;
import javafx.application.Application;
import javafx.embed.swing.SwingFXUtils;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.image.Image;
import javafx.scene.image.ImageView;
import javafx.scene.image.WritableImage;
import javafx.scene.layout.HBox;
import javafx.stage.Stage;
import javafx.util.Duration;

/**
 * Requires GifDecoder from here: http://www.java2s.com/Code/Java/2D-Graphics-GUI/DecodesaGIFfileintooneormoreframes.htm
 */
public class AnimatedGifDemo extends Application {

    @Override
    public void start(Stage primaryStage) throws URISyntaxException {

        HBox root = new HBox();

        // TODO: provide gif file, ie exchange banana.gif with your file
        Animation ani = new AnimatedGif(getClass().getResource("banana.gif").toExternalForm(), 1000);
        ani.setCycleCount(10);
        ani.play();

        Button btPause = new Button( "Pause");
        btPause.setOnAction( e -> ani.pause());

        Button btResume = new Button( "Resume");
        btResume.setOnAction( e -> ani.play());

        root.getChildren().addAll( ani.getView(), btPause, btResume);

        Scene scene = new Scene(root, 1600, 900);

        primaryStage.setScene(scene);
        primaryStage.show();

    }

    public static void main(String[] args) {
        launch(args);
    }

    public class AnimatedGif extends Animation {

        public AnimatedGif( String filename, double durationMs) {

            GifDecoder d = new GifDecoder();
            d.read( filename);

            Image[] sequence = new Image[ d.getFrameCount()];
            for( int i=0; i < d.getFrameCount(); i++) {

                WritableImage wimg = null;
                BufferedImage bimg = d.getFrame(i);
                sequence[i] = SwingFXUtils.toFXImage( bimg, wimg);

            }

            super.init( sequence, durationMs);
        }

    }

    public class Animation extends Transition {

        private ImageView imageView;
        private int count;

        private int lastIndex;

        private Image[] sequence;

        private Animation() {
        }

        public Animation( Image[] sequence, double durationMs) {
            init( sequence, durationMs);
        }

        private void init( Image[] sequence, double durationMs) {
            this.imageView = new ImageView(sequence[0]);
            this.sequence = sequence;
            this.count = sequence.length;

            setCycleCount(1);
            setCycleDuration(Duration.millis(durationMs));
            setInterpolator(Interpolator.LINEAR);

        }

        protected void interpolate(double k) {

            final int index = Math.min((int) Math.floor(k * count), count - 1);
            if (index != lastIndex) {
                imageView.setImage(sequence[index]);
                lastIndex = index;
            }

        }

        public ImageView getView() {
            return imageView;
        }

    }

}

它提供暂停/恢复按钮进行测试.你需要的还有Gif解码器代码和动画banana.gif.