Java可以使用JavaFX或Swing来实现画图板功能。下面是一个简单的示例代码,演示如何使用JavaFX实现一个简单的画图板:
import javafx.application.Application; import javafx.scene.Scene; import javafx.scene.canvas.Canvas; import javafx.scene.canvas.GraphicsContext; import javafx.scene.input.MouseButton; import javafx.scene.input.MouseEvent; import javafx.scene.layout.VBox; import javafx.scene.paint.Color; import javafx.stage.Stage; public class DrawingBoard extends Application { private double startX, startY, endX, endY; @Override public void start(Stage primaryStage) { Canvas canvas = new Canvas(800, 600); GraphicsContext gc = canvas.getGraphicsContext2D(); gc.setStroke(Color.BLACK); gc.setLineWidth(1.0); canvas.addEventHandler(MouseEvent.MOUSE_PRESSED, event -> { if (event.getButton() == MouseButton.PRIMARY) { startX = event.getX(); startY = event.getY(); } }); canvas.addEventHandler(MouseEvent.MOUSE_DRAGGED, event -> { if (event.getButton() == MouseButton.PRIMARY) { endX = event.getX(); endY = event.getY(); gc.clearRect(0, 0, canvas.getWidth(), canvas.getHeight()); gc.strokeRect(startX, startY, endX - startX, endY - startY); } }); VBox root = new VBox(canvas); Scene scene = new Scene(root, 800, 600); primaryStage.setTitle("Drawing Board"); primaryStage.setScene(scene); primaryStage.show(); } public static void main(String[] args) { launch(args); } }
运行这段代码,将会弹出一个窗口,你可以在窗口内点击并拖动鼠标左键来绘制矩形。