如何在javafx中绘制一条直线,在用户移动鼠标时自动更新?
因此,我知道如何做自由手线,但我想要一条直线,因此当用户单击一个点到用户释放鼠标的点时,当用户拖动鼠标时,端点应随鼠标移动,即类似于在绘画应用程序中绘制直线 目前正在使用此代码:如何在javafx中绘制一条直线,在用户移动鼠标时自动更新?,java,user-interface,javafx,Java,User Interface,Javafx,因此,我知道如何做自由手线,但我想要一条直线,因此当用户单击一个点到用户释放鼠标的点时,当用户拖动鼠标时,端点应随鼠标移动,即类似于在绘画应用程序中绘制直线 目前正在使用此代码: public class JavaFX_DrawOnCanvas extends Application { @Override public void start(Stage primaryStage) { Canvas canvas = new Canvas(400, 400);
public class JavaFX_DrawOnCanvas extends Application {
@Override
public void start(Stage primaryStage) {
Canvas canvas = new Canvas(400, 400);
final GraphicsContext graphicsContext = canvas.getGraphicsContext2D();
initDraw(graphicsContext);
canvas.addEventHandler(MouseEvent.MOUSE_PRESSED,
new EventHandler<MouseEvent>(){
@Override
public void handle(MouseEvent event) {
graphicsContext.beginPath();
graphicsContext.moveTo(event.getX(), event.getY());
graphicsContext.stroke();
}
});
canvas.addEventHandler(MouseEvent.MOUSE_DRAGGED,
new EventHandler<MouseEvent>(){
@Override
public void handle(MouseEvent event) {
graphicsContext.lineTo(event.getX(), event.getY());
graphicsContext.stroke();
}
});
canvas.addEventHandler(MouseEvent.MOUSE_RELEASED,
new EventHandler<MouseEvent>(){
@Override
public void handle(MouseEvent event) {
}
});
StackPane root = new StackPane();
root.getChildren().add(canvas);
Scene scene = new Scene(root, 400, 400);
primaryStage.setTitle("java-buddy.blogspot.com");
primaryStage.setScene(scene);
primaryStage.show();
}
public static void main(String[] args) {
launch(args);
}
private void initDraw(GraphicsContext gc){
double canvasWidth = gc.getCanvas().getWidth();
double canvasHeight = gc.getCanvas().getHeight();
gc.setFill(Color.LIGHTGRAY);
gc.setStroke(Color.BLACK);
gc.setLineWidth(5);
gc.fill();
gc.strokeRect(
0, //x of the upper left corner
0, //y of the upper left corner
canvasWidth, //width of the rectangle
canvasHeight); //height of the rectangle
gc.setFill(Color.RED);
gc.setStroke(Color.BLUE);
gc.setLineWidth(1);
}
}
public类JavaFX\u drawncanvas扩展应用程序{
@凌驾
公共无效开始(阶段primaryStage){
画布=新画布(400400);
final GraphicsContext GraphicsContext=canvas.getGraphicsContext2D();
initDraw(graphicsContext);
canvas.addEventHandler(MouseEvent.MOUSE_按下,
新的EventHandler(){
@凌驾
公共无效句柄(MouseeEvent事件){
graphicsContext.beginPath();
graphicsContext.moveTo(event.getX(),event.getY());
graphicsContext.stroke();
}
});
canvas.addEventHandler(MouseEvent.MOUSE_拖动,
新的EventHandler(){
@凌驾
公共无效句柄(MouseeEvent事件){
graphicsContext.lineTo(event.getX(),event.getY());
graphicsContext.stroke();
}
});
canvas.addEventHandler(MouseEvent.MOUSE_发布,
新的EventHandler(){
@凌驾
公共无效句柄(MouseeEvent事件){
}
});
StackPane root=新的StackPane();
root.getChildren().add(画布);
场景=新场景(根,400400);
setTitle(“java buddy.blogspot.com”);
初级阶段。场景(场景);
primaryStage.show();
}
公共静态void main(字符串[]args){
发射(args);
}
私有void initDraw(GraphicsContext gc){
double canvasWidth=gc.getCanvas().getWidth();
double canvasHeight=gc.getCanvas().getHeight();
gc.setFill(颜色为浅灰色);
gc.设定行程(颜色为黑色);
gc.设置线宽(5);
gc.fill();
气相色谱法(
0,//左上角的x
0,//左上角的y
画布宽度,//矩形的宽度
画布高度);//矩形的高度
gc.setFill(颜色为红色);
gc.设定行程(颜色为蓝色);
gc.设置线宽(1);
}
}
如何修改鼠标拖动事件以绘制直线而不是徒手 一般来说,我同意您的意见-使用。 但使用canvas,您可以实现相同的效果,如下所示:
public class JavaFX_DrawOnCanvas extends Application {
private Pair<Double, Double> initialTouch;
private Canvas layer = new Canvas();
@Override
public void start(Stage primaryStage) {
StackPane root = new StackPane();
Canvas canvas = new Canvas(400, 400);
final GraphicsContext graphicsContext = canvas.getGraphicsContext2D();
initDraw(graphicsContext);
canvas.addEventHandler(MouseEvent.MOUSE_PRESSED,
new EventHandler<MouseEvent>(){
@Override
public void handle(MouseEvent event) {
Canvas newLayer = new Canvas(400, 400);
GraphicsContext context = newLayer.getGraphicsContext2D();
initDraw(context);
layer = newLayer;
root.getChildren().add(0, newLayer);
initialTouch = new Pair<>(event.getSceneX(), event.getSceneY());
}
});
canvas.addEventHandler(MouseEvent.MOUSE_DRAGGED,
new EventHandler<MouseEvent>(){
@Override
public void handle(MouseEvent event) {
GraphicsContext context = layer.getGraphicsContext2D();
context.clearRect(0, 0, layer.getWidth(), layer.getHeight());
context.strokeLine(initialTouch.getKey(), initialTouch.getValue(), event.getSceneX(), event.getSceneY());
}
});
root.getChildren().add(canvas);
Scene scene = new Scene(root, 400, 400);
primaryStage.setScene(scene);
primaryStage.show();
}
private void initDraw(GraphicsContext gc){
double canvasWidth = gc.getCanvas().getWidth();
double canvasHeight = gc.getCanvas().getHeight();
gc.setFill(Color.LIGHTGRAY);
gc.setStroke(Color.BLACK);
gc.setLineWidth(5);
gc.fill();
gc.strokeRect(
0, //x of the upper left corner
0, //y of the upper left corner
canvasWidth, //width of the rectangle
canvasHeight); //height of the rectangle
gc.setFill(Color.RED);
gc.setStroke(Color.BLUE);
gc.setLineWidth(1);
}
public static void main(String[] args) {
launch(args);
}
}
public类JavaFX\u drawncanvas扩展应用程序{
私人接触;
私有画布层=新画布();
@凌驾
公共无效开始(阶段primaryStage){
StackPane root=新的StackPane();
画布=新画布(400400);
final GraphicsContext GraphicsContext=canvas.getGraphicsContext2D();
initDraw(graphicsContext);
canvas.addEventHandler(MouseEvent.MOUSE_按下,
新的EventHandler(){
@凌驾
公共无效句柄(MouseeEvent事件){
画布新层=新画布(400400);
GraphicsContext上下文=newLayer.getGraphicsContext2D();
initDraw(上下文);
层=新层;
root.getChildren().add(0,newLayer);
initialTouch=新对(event.getSceneX(),event.getSceneY());
}
});
canvas.addEventHandler(MouseEvent.MOUSE_拖动,
新的EventHandler(){
@凌驾
公共无效句柄(MouseeEvent事件){
GraphicsContext上下文=layer.getGraphicsContext2D();
clearRect(0,0,layer.getWidth(),layer.getHeight());
strokeLine(initialTouch.getKey(),initialTouch.getValue(),event.getSceneX(),event.getSceneY());
}
});
root.getChildren().add(画布);
场景=新场景(根,400400);
初级阶段。场景(场景);
primaryStage.show();
}
私有void initDraw(GraphicsContext gc){
double canvasWidth=gc.getCanvas().getWidth();
double canvasHeight=gc.getCanvas().getHeight();
gc.setFill(颜色为浅灰色);
gc.设定行程(颜色为黑色);
gc.设置线宽(5);
gc.fill();
气相色谱法(
0,//左上角的x
0,//左上角的y
画布宽度,//矩形的宽度
画布高度);//矩形的高度
gc.setFill(颜色为红色);
gc.设定行程(颜色为蓝色);
gc.设置线宽(1);
}
公共静态void main(字符串[]args){
发射(args);
}
}
所以,基本上您需要为每条新线创建单独的层并使用它。请注意,新添加的层必须添加到根子级的0索引处,因为否则主画布的事件处理程序将停止处理事件。一般来说,我同意您的意见-使用。 但使用canvas,您可以实现相同的效果,如下所示:
public class JavaFX_DrawOnCanvas extends Application {
private Pair<Double, Double> initialTouch;
private Canvas layer = new Canvas();
@Override
public void start(Stage primaryStage) {
StackPane root = new StackPane();
Canvas canvas = new Canvas(400, 400);
final GraphicsContext graphicsContext = canvas.getGraphicsContext2D();
initDraw(graphicsContext);
canvas.addEventHandler(MouseEvent.MOUSE_PRESSED,
new EventHandler<MouseEvent>(){
@Override
public void handle(MouseEvent event) {
Canvas newLayer = new Canvas(400, 400);
GraphicsContext context = newLayer.getGraphicsContext2D();
initDraw(context);
layer = newLayer;
root.getChildren().add(0, newLayer);
initialTouch = new Pair<>(event.getSceneX(), event.getSceneY());
}
});
canvas.addEventHandler(MouseEvent.MOUSE_DRAGGED,
new EventHandler<MouseEvent>(){
@Override
public void handle(MouseEvent event) {
GraphicsContext context = layer.getGraphicsContext2D();
context.clearRect(0, 0, layer.getWidth(), layer.getHeight());
context.strokeLine(initialTouch.getKey(), initialTouch.getValue(), event.getSceneX(), event.getSceneY());
}
});
root.getChildren().add(canvas);
Scene scene = new Scene(root, 400, 400);
primaryStage.setScene(scene);
primaryStage.show();
}
private void initDraw(GraphicsContext gc){
double canvasWidth = gc.getCanvas().getWidth();
double canvasHeight = gc.getCanvas().getHeight();
gc.setFill(Color.LIGHTGRAY);
gc.setStroke(Color.BLACK);
gc.setLineWidth(5);
gc.fill();
gc.strokeRect(
0, //x of the upper left corner
0, //y of the upper left corner
canvasWidth, //width of the rectangle
canvasHeight); //height of the rectangle
gc.setFill(Color.RED);
gc.setStroke(Color.BLUE);
gc.setLineWidth(1);
}
public static void main(String[] args) {
launch(args);
}
}
public类JavaFX\u drawncanvas扩展应用程序{
私人接触;
私有画布层=新画布();
@凌驾
公共无效开始(阶段primaryStage){
StackPane root=新的StackPane();
画布=新画布(400400);
final GraphicsContext GraphicsContext=canvas.getGraphicsContext2D();
initDraw(graphicsContext);
canvas.addEventHandler(MouseEvent.MOUSE_按下,
新的EventHandler(){
@结束