Draw a border around shapes in the canvas with JavaFx

Question

I have drawn a straight line in a canvas and filled with a solid color. I want to border this straight line with a black colored border.

score 4 · Accepted Answer · answered Dec 09 '14 at 11:32

4

You can use two fillRect with different size and color

example:

final Canvas canvas = new Canvas(250,250);
GraphicsContext gc = canvas.getGraphicsContext2D();

gc.setFill(Color.BLUE);
gc.fillRect(0,0,100,20);
gc.setFill(Color.RED);
gc.fillRect(1,1,98,18);

answered Dec 09 '14 at 11:32

Mailkov

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What if it has an amoeba shape. Can't I get some shape property to draw the border. – Shantanu Chandra Dec 09 '14 at 11:35
in GraphicContext thereisn't a border function – Mailkov Dec 09 '14 at 11:39
If this answer helped you ... you can set as correct or upvote this – Mailkov Dec 09 '14 at 11:57

score 3 · Answer 2 · answered Dec 09 '14 at 20:44

In addition to filling your shape, also specify a stroke on the graphics context and ask it to stroke the shape.

Here is an example (adapted from the Oracle Canvas tutorial):

strokedshape

import javafx.application.Application;
import javafx.scene.*;
import javafx.scene.canvas.*;
import javafx.scene.paint.Color;
import javafx.stage.Stage;

public class CanvasStrokeDemo extends Application {
    @Override public void start(Stage stage) throws Exception {
        final Canvas canvas = new Canvas(250, 250);
        GraphicsContext gc = canvas.getGraphicsContext2D();

        // load the graphics context up with instructions to draw a shape.
        drawDShape(gc);

        // fill the shape.
        gc.setFill(Color.BLUE);
        gc.fill();

        // stroke an outline (border) around the shape.
        gc.setStroke(Color.GREEN);
        gc.setLineWidth(10);
        gc.stroke();

        stage.setScene(new Scene(new Group(canvas), Color.WHITE));    
        stage.show();
    }

    private void drawDShape(GraphicsContext gc) {
        gc.beginPath();
        gc.moveTo(50, 50);
        gc.bezierCurveTo(150, 20, 150, 150, 75, 150);
        gc.closePath();
    }

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

There is more information on the canvas drawing API in the GraphicsContext JavaDoc.

Draw a border around shapes in the canvas with JavaFx

2 Answers2