Tuesday, April 16, 2013

Save Canvas to PNG file

Example to save canvas to file of PNG format using FileChooser.

Example to save canvas to file of PNG format using FileChooser
Example to save canvas to file of PNG format using FileChooser


package javafx_drawoncanvas;

import java.awt.image.RenderedImage;
import java.io.File;
import java.io.IOException;
import java.util.logging.Level;
import java.util.logging.Logger;
import javafx.application.Application;
import javafx.embed.swing.SwingFXUtils;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.scene.Group;
import javafx.scene.Scene;
import javafx.scene.canvas.Canvas;
import javafx.scene.canvas.GraphicsContext;
import javafx.scene.control.Button;
import javafx.scene.control.ColorPicker;
import javafx.scene.image.WritableImage;
import javafx.scene.input.MouseEvent;
import javafx.scene.layout.HBox;
import javafx.scene.layout.VBox;
import javafx.scene.paint.Color;
import javafx.stage.FileChooser;
import javafx.stage.Stage;
import javax.imageio.ImageIO;

/**
 * @web http://java-buddy.blogspot.com/
 */
public class JavaFX_DrawOnCanvas extends Application {
    
    final static int CANVAS_WIDTH = 400;
    final static int CANVAS_HEIGHT = 400;
    
    ColorPicker colorPicker;

    @Override
    public void start(final Stage primaryStage) {

        final Canvas canvas = new Canvas(CANVAS_WIDTH, CANVAS_HEIGHT);
        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.setStroke(colorPicker.getValue());
                graphicsContext.stroke();
            }
        });
        
        canvas.addEventHandler(MouseEvent.MOUSE_DRAGGED, 
                new EventHandler<MouseEvent>(){

            @Override
            public void handle(MouseEvent event) {
                graphicsContext.lineTo(event.getX(), event.getY());
                graphicsContext.setStroke(colorPicker.getValue());
                graphicsContext.stroke();
            }
        });

        canvas.addEventHandler(MouseEvent.MOUSE_RELEASED, 
                new EventHandler<MouseEvent>(){

            @Override
            public void handle(MouseEvent event) {

            }
        });

        Group root = new Group();
        
        Button buttonSave = new Button("Save");
        buttonSave.setOnAction(new EventHandler<ActionEvent>() {

            @Override
            public void handle(ActionEvent t) {
                FileChooser fileChooser = new FileChooser();
                
                //Set extension filter
                FileChooser.ExtensionFilter extFilter = 
                        new FileChooser.ExtensionFilter("png files (*.png)", "*.png");
                fileChooser.getExtensionFilters().add(extFilter);
              
                //Show save file dialog
                File file = fileChooser.showSaveDialog(primaryStage);
                
                if(file != null){
                    try {
                        WritableImage writableImage = new WritableImage(CANVAS_WIDTH, CANVAS_HEIGHT);
                        canvas.snapshot(null, writableImage);
                        RenderedImage renderedImage = SwingFXUtils.fromFXImage(writableImage, null);
                        ImageIO.write(renderedImage, "png", file);
                    } catch (IOException ex) {
                        Logger.getLogger(JavaFX_DrawOnCanvas.class.getName()).log(Level.SEVERE, null, ex);
                    }
                }
            }
            
        });
        
        HBox hBox = new HBox();
        hBox.getChildren().addAll(colorPicker, buttonSave);

        VBox vBox = new VBox();
        vBox.getChildren().addAll(hBox, canvas);
        root.getChildren().add(vBox);
        Scene scene = new Scene(root, 400, 425);
        primaryStage.setTitle("java-buddy.blogspot.com");
        primaryStage.setScene(scene);
        primaryStage.show();
    }

    public static void main(String[] args) {
        launch(args);
    }
    
    private void initDraw(GraphicsContext gc){
        
        colorPicker = new ColorPicker();
        
        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(colorPicker.getValue());
        gc.setStroke(colorPicker.getValue());
        gc.setLineWidth(1);
    }
    
}


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