So I'm trying to create a very basic photo editor program in Java, using JavaFX. I got a brush and eraser working pretty well so far the following way:
package application;
import java.io.File;
import javax.imageio.ImageIO;
import javafx.application.Platform;
import javafx.embed.swing.SwingFXUtils;
import javafx.fxml.FXML;
import javafx.geometry.Point2D;
import javafx.scene.canvas.*;
import javafx.scene.control.*;
import javafx.scene.image.Image;
import javafx.scene.paint.Color;
import javafx.scene.shape.*;
public class EditorController {
private boolean eraser = false;
@FXML
private Canvas canvas;
@FXML
private ColorPicker colorPicker;
@FXML
private TextField brushSize;
@FXML
private TextField selectedTool;
private Point2D last = null;
public void initialize() {
GraphicsContext gc = canvas.getGraphicsContext2D();
canvas.setOnMouseReleased(e -> {last = null;});
canvas.setOnMouseClicked(e -> {
if (!eraser) {
double size = Double.parseDouble(brushSize.getText());
float mouseX = (float) e.getX();
float mouseY = (float) e.getY();
gc.fillOval(mouseX-(size/2), mouseY-(size/2), size, size);
}
});
canvas.setOnMouseDragged(e -> {
System.out.println(eraser);
double size = Double.parseDouble(brushSize.getText());
gc.setLineCap(StrokeLineCap.ROUND);
gc.setLineWidth(size);
float mouseX = (float) e.getX();
float mouseY = (float) e.getY();
if (last != null && !eraser) {
gc.strokeLine(last.getX(), last.getY(), mouseX, mouseY);
} else if (eraser) {
gc.clearRect(mouseX, mouseY, size, size);
}
last = new Point2D(mouseX, mouseY);
});
}
public void onSave() {
try {
Image snapshot = canvas.snapshot(null, null);
ImageIO.write(SwingFXUtils.fromFXImage(snapshot, null), "png", new File("paint.png"));
} catch (Exception e) {
System.out.println("Failed to save image: " + e);
}
}
public void onLoad() {
// not implemented yet
}
// not implemented yet
public void onUndo() { }
public void onRedo() { }
public void onSmaller() { }
public void onBigger() { }
public void onResetView() { }
public void onFitView() { }
public void onFillView() { }
public void onNewLayer() { }
public void onDeleteLayer() { }
public void onDuplicateLayer() { }
public void onGroupLayers() { }
public void onMergeLayers() { }
public void onAddMask() { }
public void onBrush() { eraser = false; selectedTool.setText("Brush"); }
public void onEraser() { eraser = true; selectedTool.setText("Eraser"); }
public void onExit() {
Platform.exit();
}
}
Now I want to have a feather/hardness value for the brush (like in photoshop) where I can draw a softer-looking line, but I'm not sure how to achieve it with JavaFX? Are there any tools within it for things like this?
So with a visual example: the brush on the left would be a feathered brush, the one on the right isn't (and that's what I have currently)
Simple drawing app.
It uses a radial gradient rendered to an image that is draw to the canvas, but you could just draw the gradient directly onto the canvas. A gradient is a paint so you can set it directly as an argument to setFill on a graphics context.
The solution in my example probably won't exactly give you the solution you are looking for, but perhaps you could tweak it for what you need.
It was a quick app I put together for demo purposes, it could be structured better if a more functional drawing app was required.
The code which creates the "feathered brush" is based on a gradient:
private RadialGradient createSoftBrushGradient(Color primaryColor) {
return new RadialGradient(
0, 0,
.5, .5,
.5,
true,
CycleMethod.NO_CYCLE,
new Stop(0, primaryColor),
new Stop(1, Color.TRANSPARENT)
);
}
import javafx.application.Application;
import javafx.beans.property.*;
import javafx.event.EventHandler;
import javafx.geometry.Insets;
import javafx.scene.Scene;
import javafx.scene.SnapshotParameters;
import javafx.scene.canvas.*;
import javafx.scene.control.*;
import javafx.scene.image.Image;
import javafx.scene.input.MouseEvent;
import javafx.scene.layout.*;
import javafx.scene.paint.*;
import javafx.scene.shape.Circle;
import javafx.stage.Stage;
public class SprayPaint extends Application {
private final IntegerProperty brushDiameter = new SimpleIntegerProperty();
private final ObjectProperty<Image> brushImage = new SimpleObjectProperty<>();
private final ToggleGroup brushHardnessSelection = new ToggleGroup();
private final RadioButton hardBrushSelection = new RadioButton();
private final RadioButton softBrushSelection = new RadioButton();
private final Circle hardBrush = new Circle();
private final Circle softBrush = new Circle();
private final SnapshotParameters snapshotParams = new SnapshotParameters();
private final Canvas canvas = new Canvas(600, 450);
@Override
public void start(Stage stage) {
snapshotParams.setFill(Color.TRANSPARENT);
Pane controls = createControls();
StackPane canvasHolder = new StackPane(canvas);
canvasHolder.setStyle("-fx-border-color: gray;");
canvasHolder.setMaxSize(Pane.USE_PREF_SIZE, Pane.USE_PREF_SIZE);
VBox layout = new VBox(
10,
controls,
canvasHolder
);
layout.setPadding(new Insets(10));
stage.setScene(new Scene(layout));
stage.show();
enableDrawing(canvas);
}
private void enableDrawing(Canvas canvas) {
EventHandler<MouseEvent> drawHandler = event -> {
Image brush = snapshotBrushImage();
GraphicsContext gc = canvas.getGraphicsContext2D();
gc.drawImage(
brush,
event.getX() - brushDiameter.doubleValue() / 2,
event.getY() - brushDiameter.doubleValue() / 2
);
};
canvas.setOnMousePressed(drawHandler);
canvas.setOnMouseDragged(drawHandler);
}
private Image snapshotBrushImage() {
if (brushImage.get() == null) {
if (hardBrushSelection == brushHardnessSelection.getSelectedToggle()) {
brushImage.set(snapshot(hardBrush));
} else { // soft brush selected
brushImage.set(snapshot(softBrush));
}
}
return brushImage.get();
}
private Image snapshot(Circle brushNode) {
return brushNode.snapshot(snapshotParams, null);
}
private Pane createControls() {
hardBrush.radiusProperty().bind(
brushDiameter.divide(2.0)
);
softBrush.radiusProperty().bind(
brushDiameter.divide(2.0)
);
hardBrushSelection.getStyleClass().addAll("toggle-button", "left-pill");
hardBrushSelection.getStyleClass().remove( "radio-button");
StackPane hardBrushGraphic = new StackPane(hardBrush);
hardBrushGraphic.setMinSize(40, 40);
hardBrushSelection.setGraphic(hardBrushGraphic);
hardBrushSelection.setToggleGroup(brushHardnessSelection);
softBrushSelection.getStyleClass().addAll( "toggle-button", "right-pill");
softBrushSelection.getStyleClass().remove( "radio-button");
StackPane softBrushGraphic = new StackPane(softBrush);
softBrushGraphic.setMinSize(40, 40);
softBrushSelection.setGraphic(softBrushGraphic);
softBrushSelection.setToggleGroup(brushHardnessSelection);
hardBrushSelection.setSelected(true);
HBox brushSelectionPanel = new HBox(hardBrushSelection, softBrushSelection);
Slider brushDiameterSlider = new Slider(8, 40, 20);
brushDiameterSlider.setMajorTickUnit(4);
brushDiameterSlider.setMinorTickCount(0);
brushDiameterSlider.setShowTickMarks(true);
brushDiameter.setValue((int) Math.round(brushDiameterSlider.getValue()));
brushDiameterSlider.valueProperty().addListener((observable, oldValue, newValue) ->
brushDiameter.setValue((int) Math.round(newValue.doubleValue()))
);
Label fontSizeLabel = new Label();
fontSizeLabel.textProperty().bind(
brushDiameter.asString()
);
ColorPicker colorPicker = new ColorPicker();
hardBrush.fillProperty().bind(
colorPicker.valueProperty()
);
colorPicker.valueProperty().addListener((observable, oldColor, newColor) ->
softBrush.setFill(
createSoftBrushGradient(newColor)
)
);
colorPicker.setValue(Color.NAVY);
brushDiameter.addListener((observable, oldValue, newValue) ->
brushImage.set(null)
);
colorPicker.valueProperty().addListener((observable, oldValue, newValue) ->
brushImage.set(null)
);
brushHardnessSelection.selectedToggleProperty().addListener((observable, oldValue, newValue) ->
brushImage.set(null)
);
Button clear = new Button("Clear");
clear.setOnAction(e ->
canvas.getGraphicsContext2D().clearRect(
0, 0, canvas.getWidth(), canvas.getHeight()
)
);
HBox controlPanel = new HBox(
10,
colorPicker,
brushSelectionPanel,
new Label("Diameter: "),
brushDiameterSlider,
fontSizeLabel,
clear
);
controlPanel.setMinWidth(450);
controlPanel.setMinHeight(Pane.USE_PREF_SIZE);
return controlPanel;
}
private RadialGradient createSoftBrushGradient(Color primaryColor) {
return new RadialGradient(
0, 0,
.5, .5,
.5,
true,
CycleMethod.NO_CYCLE,
new Stop(0, primaryColor),
new Stop(1, Color.TRANSPARENT)
);
}
}
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