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David Tonhofer's questions

Martin Hope
David Tonhofer
Asked: 2025-02-12 19:17:16 +0800 CST
  • 6

O código:

import sys
import numpy as np

print(f"We are using Python {sys.version}", file=sys.stderr)
print(f"We are using numpy version {np.__version__}", file=sys.stderr)  # 2.2.1

def find_non_numpy_floats(x: any) -> bool:
    if not (isinstance(x, np.float64)):
        print(f"Found non-numpy.float64: {x} of type {type(x)}", file=sys.stderr)
        return False
    else:
        return True


w: np.ndarray = np.zeros((2, 2), dtype=np.float64)

np.vectorize(lambda x: find_non_numpy_floats(x))(w)

assert (np.all(np.vectorize(lambda x: isinstance(x, np.float64))(w))), "try to keep using the numpy floats"

Espero que Numpy.zeros gere uma matriz de Numpy float64, que não são iguais ao Python, floatse entendi corretamente (floats IEEE de 64 bits vs. algo específico do Python?)

Entretanto, o acima exposto resulta em:

We are using Python 3.13.1 (main, Dec  9 2024, 00:00:00) [GCC 14.2.1 20240912 (Red Hat 14.2.1-3)]
We are using numpy version 2.2.1
Found non-numpy.float64: 0.0 of type <class 'float'>
Found non-numpy.float64: 0.0 of type <class 'float'>
Found non-numpy.float64: 0.0 of type <class 'float'>
Found non-numpy.float64: 0.0 of type <class 'float'>

e um erro de asserção.

Por que isso acontece e como posso consertar isso (e se eu quiser?)

python
Martin Hope
David Tonhofer
Asked: 2024-10-06 22:20:30 +0800 CST
  • 9

Eu experimentei um pouco com os eventos enviados para um controle de botão JavaFX dependendo do que acontece com o ponteiro do mouse e gerei um diagrama de máquina de estado hierárquico (aproximado, já que meu editor não tem nenhuma noção de semântica) a partir disto:

Tudo isso é bem direto, basta rastrear o comportamento do estado inicial e ver o que acontece. Há uma sutileza aqui, pois o rótulo dentro do controle do botão também tem um papel a desempenhar, e ele gera MOUSE_ENTERED_TARGETeventos MOUSE_EXITED_TARGET(eu perguntei ao ChatGPT sobre isso e ele imprimiu uma resposta linda que estava bem errada 😂)

Máquina de estado hierárquica de controle de botão

A única questão que me deixa curioso é: por que sempre recebo dois MOUSE_ENTEREDou dois MOUSE_EXITEDeventos, um com consumed = falsee outro com consumed = true?

Código de exemplo

Aqui está o exemplo (quase mínimo). Ele apenas cria um botão que podemos pressionar manualmente para ver quais eventos são gerados:

Arquivocom.example.stack_overflow.Main.java

package com.example.stack_overflow;

import javafx.application.Application;
import javafx.event.ActionEvent;
import javafx.event.Event;
import javafx.geometry.Insets;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.input.MouseEvent;
import javafx.scene.layout.HBox;
import javafx.scene.layout.Pane;
import javafx.scene.layout.StackPane;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;

import java.util.Objects;

class PaneBuilder {

    private final StackPane stackPane;

    private static void log(String text) {
        System.out.println(text);
    }

    public PaneBuilder() {
        stackPane = buildCenteringStackPaneAroundButton(buildButton());
    }

    private static Button buildButton() {
        final var button = new Button("Click Me!");
        button.setMinWidth(120); // I think these are "120pt", why is there no "unit"?
        final var desc = "Button";
        button.addEventHandler(ActionEvent.ACTION, event -> {
            handleActionEvent(desc, event);
        });
        button.addEventHandler(MouseEvent.MOUSE_PRESSED, event -> {
            handleMouseEvent(desc, event);
        });
        button.addEventHandler(MouseEvent.MOUSE_RELEASED, event -> {
            handleMouseEvent(desc, event);
        });
        button.addEventHandler(MouseEvent.MOUSE_CLICKED, event -> {
            handleMouseEvent(desc, event);
        });
        button.addEventHandler(MouseEvent.MOUSE_ENTERED, event -> {
            handleMouseEvent(desc, event);
        });
        button.addEventHandler(MouseEvent.MOUSE_EXITED, event -> {
            handleMouseEvent(desc, event);
        });
        button.addEventHandler(MouseEvent.MOUSE_ENTERED_TARGET, event -> {
            handleMouseEvent(desc, event);
        });
        button.addEventHandler(MouseEvent.MOUSE_EXITED_TARGET, event -> {
            handleMouseEvent(desc, event);
        });
        button.armedProperty().addListener((obs, oldVal, newVal) -> log(desc + ": armed status changes: " + oldVal + " -> " + newVal));
        return button;
    }

    public Pane getPane() {
        return stackPane;
    }

    private static StackPane buildCenteringStackPaneAroundButton(Button button) {
        final var stackPane = new StackPane();
        stackPane.setAlignment(Pos.CENTER);
        final var hbox = buildHBoxAroundVBoxAroundButton(button);
        final var insets = new Insets(20, 20, 20, 20); // I guess those are "20points"
        StackPane.setMargin(hbox, insets);
        stackPane.getChildren().add(hbox);
        return stackPane;
    }

    private static HBox buildHBoxAroundVBoxAroundButton(Button button) {
        final var hbox = new HBox();
        hbox.setAlignment(Pos.CENTER);
        hbox.getChildren().add(buildVBoxAroundButton(button));
        return hbox;
    }

    private static VBox buildVBoxAroundButton(Button button) {
        final var vbox = new VBox();
        vbox.setAlignment(Pos.CENTER);
        vbox.getChildren().add(button);
        return vbox;
    }

    private static void appendEventDesc(StringBuilder buf, Event event) {
        buf.append("\n   Type          : " + event.getEventType());
        buf.append("\n   Class         : " + event.getClass().getName());
        buf.append("\n   Consumed      : " + event.isConsumed());
        buf.append("\n   Source class  : " + event.getSource().getClass().getName());
        buf.append("\n   Event         : " + Objects.toIdentityString(event));
    }

    public static void handleMouseEvent(String desc, MouseEvent event) {
        final var buf = new StringBuilder("Mouse event in " + desc);
        appendEventDesc(buf, event);
        log(buf.toString());
    }

    public static void handleActionEvent(String desc, ActionEvent event) {
        final var buf = new StringBuilder("Action event in " + desc);
        appendEventDesc(buf, event);
        log(buf.toString());
    }
}

public class Main extends Application {

    @Override
    public void start(Stage stage) {
        stage.setTitle("Button Example");
        stage.setScene(new Scene(new PaneBuilder().getPane()));
        stage.sizeToScene();
        stage.show();
    }

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

}

E o POM para construir e executar o acima. O programa deve ser executado com o objetivo Maven javafx:rundo plugin JavaFX Maven

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>com.example</groupId>
    <artifactId>stack_overflow</artifactId>
    <version>1.0-SNAPSHOT</version>

    <!-- RUNNING VIA MAVEN + JAVAFX PLUGIN IN IDE: -->
    <!--   'Main Menu' > 'Run' > 'Run Maven Goal' > 'Plugins' > 'JavaFx Maven Plugin' > 'javafx:run' -->
    <!--   This will invoke the goal "javafx:run" of the "javafx-maven-plugin". -->
    <!--   With the 'Run New Maven Goal' menu entry, you can define that goal, and it will appear in the -->
    <!--   context menu as 'right-mouse-button menu' > 'run maven' > 'javafx:run' -->

    <!-- RUNNING VIA MAVEN IN COMMAND LINE w/o leaving the IDE (no need for OpenJDX SDK): -->
    <!-- Right-click on the project window and select "Open Terminal at the current Maven module path". -->
    <!-- Enter the command "mvn javafx:run" or for debugging output "mvn -X javafx:run". -->
    <!-- This will invoke the goal "javafx:run" of the "javafx-maven-plugin". -->

    <properties>

        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>

        <!-- This is the latest OpenJavaFX version on 2024-09-26 (version of 2024-09-16) -->
        <!-- https://mvnrepository.com/artifact/org.openjfx/javafx-controls -->

        <javafx.version>23</javafx.version>

        <javafx.plugin.version>0.0.8</javafx.plugin.version>
        <compiler.plugin.version>3.13.0</compiler.plugin.version>
        <exec.plugin.version>3.4.1</exec.plugin.version>
        <dependency.plugin.version>3.8.0</dependency.plugin.version>
        <main.class>com.example.stack_overflow.Main</main.class>

        <java.compiler.source.version>21</java.compiler.source.version>
        <java.compiler.target.version>21</java.compiler.target.version>

    </properties>

    <dependencies>
        <!-- https://mvnrepository.com/artifact/org.openjfx/javafx-controls -->
        <dependency>
            <groupId>org.openjfx</groupId>
            <artifactId>javafx-controls</artifactId>
            <version>${javafx.version}</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.openjfx/javafx-fxml -->
        <dependency>
            <groupId>org.openjfx</groupId>
            <artifactId>javafx-fxml</artifactId>
            <version>${javafx.version}</version>
        </dependency>
    </dependencies>

    <build>
        <plugins>

            <!-- Standard Java Compiler Plugin -->
            <!-- https://maven.apache.org/plugins/maven-compiler-plugin/ -->
            <!-- https://mvnrepository.com/artifact/org.apache.maven.plugins/maven-compiler-plugin -->

            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>${compiler.plugin.version}</version>
                <configuration>
                    <source>${java.compiler.source.version}</source>
                    <target>${java.compiler.target.version}</target>
                </configuration>
            </plugin>

            <!-- Special Plugin to run JavaFX programs -->
            <!-- https://github.com/openjfx/javafx-maven-plugin -->
            <!-- https://mvnrepository.com/artifact/org.openjfx/javafx-maven-plugin -->
            <!-- If you run the plugin's goal on the command line with the '-X' option like so: -->
            <!-- mvn -X javafx:run -->
            <!-- you will see the command line the plugin builds, which looks as follows, with ++ replaced by double dash -->

            <plugin>
                <groupId>org.openjfx</groupId>
                <artifactId>javafx-maven-plugin</artifactId>
                <version>${javafx.plugin.version}</version>
                <configuration>
                    <mainClass>${main.class}</mainClass>
                    <options>
                        <option>-ea</option>
                    </options>
                </configuration>
            </plugin>

        </plugins>
    </build>
</project>

Executar este programa abre esta janela:

insira a descrição da imagem aqui

Se agora seguirmos o caminho vermelho indicado com o ponteiro do mouse, clicarmos com o mouse e movermos o ponteiro do mouse para fora do botão novamente:

insira a descrição da imagem aqui

obtemos as seguintes alterações no valor do armedatributo e eventos emitidos pelo botão. Note o double MOUSE_ENTEREDcom consumed= false, então true.

Entrando no controle do botão:

Mouse event in Button
   Type          : MOUSE_ENTERED
   Class         : javafx.scene.input.MouseEvent
   Consumed      : false
   Source class  : javafx.scene.control.Button
   Event         : javafx.scene.input.MouseEvent@2ebee20a
Mouse event in Button
   Type          : MOUSE_ENTERED
   Class         : javafx.scene.input.MouseEvent
   Consumed      : true
   Source class  : javafx.scene.control.Button
   Event         : javafx.scene.input.MouseEvent@2ebee20a

Inserindo o rótulo do controle do botão:

Mouse event in Button
   Type          : MOUSE_ENTERED_TARGET
   Class         : javafx.scene.input.MouseEvent
   Consumed      : false
   Source class  : javafx.scene.control.Button
   Event         : javafx.scene.input.MouseEvent@5d41df9f

Ao clicar, observe a mudança no status de armed.

Mouse event in Button
   Type          : MOUSE_PRESSED
   Class         : javafx.scene.input.MouseEvent
   Consumed      : false
   Source class  : javafx.scene.control.Button
   Event         : javafx.scene.input.MouseEvent@3df998ed
Button: armed status changes: false -> true
Mouse event in Button
   Type          : MOUSE_RELEASED
   Class         : javafx.scene.input.MouseEvent
   Consumed      : false
   Source class  : javafx.scene.control.Button
   Event         : javafx.scene.input.MouseEvent@241a11d5
Action event in Button
   Type          : ACTION
   Class         : javafx.event.ActionEvent
   Consumed      : false
   Source class  : javafx.scene.control.Button
   Event         : javafx.event.ActionEvent@3d8fce01
Button: armed status changes: true -> false
Mouse event in Button
   Type          : MOUSE_CLICKED
   Class         : javafx.scene.input.MouseEvent
   Consumed      : false
   Source class  : javafx.scene.control.Button
   Event         : javafx.scene.input.MouseEvent@505036ef

Saindo do rótulo do controle do botão:

Mouse event in Button
   Type          : MOUSE_EXITED_TARGET
   Class         : javafx.scene.input.MouseEvent
   Consumed      : false
   Source class  : javafx.scene.control.Button
   Event         : javafx.scene.input.MouseEvent@2d496725

Saindo do controle de botão:

Mouse event in Button
   Type          : MOUSE_EXITED
   Class         : javafx.scene.input.MouseEvent
   Consumed      : false
   Source class  : javafx.scene.control.Button
   Event         : javafx.scene.input.MouseEvent@59a94fe0
Mouse event in Button
   Type          : MOUSE_EXITED
   Class         : javafx.scene.input.MouseEvent
   Consumed      : true
   Source class  : javafx.scene.control.Button
   Event         : javafx.scene.input.MouseEvent@59a94fe0
javafx