我创建了一个简单的JavaFX图像编辑器。有两个ImageView实例(对于原始图像，打开一个，对于已编辑图像，打开一个)。

一种方法将WritableImage转换为灰度。

问题是，转换所需的时间大约是Swing执行相同任务所需时间的两倍。知道为什么吗？@FXML

void loadImage(ActionEvent event) {

FileChooser fileChooser = new FileChooser();

File file = fileChooser.showOpenDialog(Main.primaryStage);

if (file != null) {

Image image = new Image("file:" + file.getAbsolutePath());

imViewOrig.setImage(image);

PixelReader pr = imViewOrig.getImage().getPixelReader();

WritableImage wi = new WritableImage(

pr,

(int)imViewOrig.getImage().getWidth(),

(int)imViewOrig.getImage().getHeight());

imViewEdit.setImage(wi);

}

}

@FXML

void greyscale(ActionEvent event) {

PixelReader pr = imViewOrig.getImage().getPixelReader();

PixelWriter pw = ((WritableImage)imViewEdit.getImage()).getPixelWriter();

long beginTime = System.currentTimeMillis();

for (int x = 0; x < imViewEdit.getImage().getWidth(); x++) {

for (int y = 0; y < imViewEdit.getImage().getHeight(); y++) {

Color c = pr.getColor(x, y);

double avg = (c.getRed() + c.getGreen() + c.getBlue()) / 3.;

Color grey = new Color(avg, avg, avg, c.getOpacity());

pw.setColor(x, y, grey);

}

}

System.out.println(System.currentTimeMillis() - beginTime + "ms");

}

秋千代码：

public void greyscale() {

long beginTime = System.currentTimeMillis();

for (int x = 0; x < image.getWidth(); x++) {

for (int y = 0; y < image.getHeight(); y++) {

Color c = new Color(image.getRGB(x, y));

int avg = (c.getRed() + c.getGreen() + c.getBlue()) / 3;

Color grey = new Color(avg, avg, avg);

image.setRGB(x, y, grey.getRGB());

}

}

repaint();

System.out.println(System.currentTimeMillis() - beginTime + "ms");

}

最佳答案

在快速测试中，如果仅执行int计算而不是操纵Color对象，则它的工作速度将提高10倍左右。与AWT Color类相比，JavaFX Color类的实现要丰富得多。我想这要付出额外的开销。int width = (int)image.getWidth();

int height = (int)image.getHeight();

int[] pixels = new int[width * height];

WritablePixelFormat pixelFormat = PixelFormat.getIntArgbPreInstance();

pr.getPixels(0, 0, width, height, pixelFormat, pixels, 0, width);

int[] newPixels = new int[pixels.length];

for (int i = 0 ; i < pixels.length; i++) {

int c = pixels[i];

int a = c & 0xFF000000 ;

int r = (c >> 16) & 0xFF ;

int g = (c >> 8) & 0xFF ;

int b = c & 0xFF ;

int gray = (r+g+b) / 3 ;

newPixels[i] = a | (gray << 16) | (gray << 8) | gray ;

}

pw.setPixels(0, 0, width, height, pixelFormat, newPixels, 0, width);