本文介紹了如何在文本區上繪制?的處理方法,對大家解決問題具有一定的參考價值,需要的朋友們下面隨著小編來一起學習吧!
問題描述
我正在使用的程序只是通過在StackPane
上使用畫布層在文本或圖像上進行繪制。我想要完成的是,當我釋放鼠標MouseEvent.MOUSE_RELEASED
處理程序時,它會自動獲取畫布的快照,將圖像添加到ImageView Cover
并將其顯示在TextArea
的頂部,但它不能將更改添加到StackPane
類,即ImageView
。
我這里有一個程序,我將把它添加到我正在處理的另一個程序中,并且我計劃將主類TextCanvas
中的所有內容都從主項目中引入菜單控制器類。
主類TextCanvas.java:
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.util.logging.Level;
import java.util.logging.Logger;
import javafx.application.Application;
import javafx.beans.value.ChangeListener;
import javafx.beans.value.ObservableValue;
import javafx.embed.swing.SwingFXUtils;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.scene.Scene;
import javafx.scene.SnapshotParameters;
import javafx.scene.canvas.Canvas;
import javafx.scene.canvas.GraphicsContext;
import javafx.scene.control.Button;
import javafx.scene.control.ScrollPane;
import javafx.scene.control.TextArea;
import javafx.scene.control.Toggle;
import javafx.scene.control.ToggleButton;
import javafx.scene.control.ToggleGroup;
import javafx.scene.image.Image;
import javafx.scene.image.ImageView;
import javafx.scene.image.PixelReader;
import javafx.scene.image.PixelWriter;
import javafx.scene.image.WritableImage;
import javafx.scene.layout.BorderPane;
import javafx.scene.layout.StackPane;
import javafx.scene.layout.VBox;
import javafx.scene.paint.Color;
import javafx.stage.Screen;
import javafx.stage.Stage;
import javax.imageio.ImageIO;
public class TextCanvas extends Application
{
private ScrollPane Scroll = new ScrollPane();
Canvas Can = new Canvas(800, 400);
GraphicsContext GG = Can.getGraphicsContext2D();
TextArea TA = new TextArea();
ImageView Cover = new ImageView();
VBox ButtonBox = new VBox();
WordCanvas WC = new WordCanvas(Can, TA, GG);
@Override
public void start(Stage PrimaryStage)
{
ToggleGroup DrawErase = new ToggleGroup();
ToggleButton Draw = new ToggleButton("Draw");
ToggleButton Erase = new ToggleButton("Erase");
Button Clear = new Button("Clear");
Draw.setToggleGroup(DrawErase);
Erase.setToggleGroup(DrawErase);
double DotsPerInch = Screen.getPrimary().getDpi();
double W = DotsPerInch * 8.5;
double H = DotsPerInch * 11.0;
StackPane Stack = new WordCanvas(W, H);
WC.GetArea().setMaxWidth(W);
WC.GetArea().setMaxHeight(H);
WC.GetCan().setWidth(W);
WC.GetCan().setHeight(H);
DrawErase.selectedToggleProperty().addListener(new ChangeListener<Toggle>()
{
public void changed(ObservableValue<? extends Toggle> OV, Toggle TOld, Toggle TNew)
{
if(TNew == null)
{
GG.setStroke(Color.TRANSPARENT);
Stack.getChildren().remove(WC.GetCan());
}
else if(DrawErase.getSelectedToggle().equals(Draw))
{
GG.setStroke(Color.BLACK);
if(!Stack.getChildren().contains(WC.GetCan()))
{
Stack.getChildren().add(WC.GetCan());
}
}
else if(DrawErase.getSelectedToggle().equals(Erase))
{
GG.setStroke(Color.WHITE);
if(!Stack.getChildren().contains(WC.GetCan()))
{
Stack.getChildren().add(WC.GetCan());
}
}
}
});
Clear.setOnAction(new EventHandler<ActionEvent>()
{
@Override
public void handle(ActionEvent e)
{
WC.GetGC().clearRect(0, 0, W, H);
Stack.getChildren().remove(WC.GetCover());
}
});
Button Snap = new Button("Snap");
Snap.setOnAction(new EventHandler<ActionEvent>()
{
@Override
public void handle(ActionEvent e)
{
Cover.setMouseTransparent(true);
WritableImage WImage = Can.snapshot(new SnapshotParameters(), null);
ByteArrayOutputStream Bos = new ByteArrayOutputStream();
try
{
ImageIO.write(SwingFXUtils.fromFXImage(WImage, null), "png", Bos);
}
catch(IOException ex)
{
Logger.getLogger(WordCanvas.class.getName()).log(Level.SEVERE, null, ex);
}
InputStream Fis = new ByteArrayInputStream(Bos.toByteArray());
Image Imos = new Image(Fis);
int IW = (int) Imos.getWidth();
int IH = (int) Imos.getHeight();
WritableImage OutputImage = new WritableImage(IW, IH);
PixelReader PReader = Imos.getPixelReader();
PixelWriter PWriter = OutputImage.getPixelWriter();
for (int y = 0; y < IH; y++)
{
for (int x = 0; x < IW; x++)
{
int argb = PReader.getArgb(x, y);
int r = (argb >> 16) & 0xFF;
int g = (argb >> 8) & 0xFF;
int b = argb & 0xFF;
if(r >= 0xCF && g >= 0xCF && b >= 0xCF)
{
argb &= 0x00FFFFFF;
}
PWriter.setArgb(x, y, argb);
}
}
if(!Stack.getChildren().contains(WC.GetCover()))
{
WC.GetCover().setImage(OutputImage);
Stack.getChildren().add(WC.GetCover());
}
else
{
WC.GetCover().setImage(OutputImage);
}
}
});
ButtonBox.getChildren().addAll(Draw, Erase, Clear, Snap);
BorderPane Border = new BorderPane();
Border.setCenter(Stack);
Border.setBottom(ButtonBox);
Scroll.setContent(Border);
Scroll.setFitToWidth(true);
Scroll.setFitToHeight(true);
Scene MainScene = new Scene(Scroll);
PrimaryStage.setMaximized(true);
PrimaryStage.setTitle("Practice Canvas");
PrimaryStage.setScene(MainScene);
PrimaryStage.show();
}
public static void main(String[] args)
{
launch(args);
}
}
包含文本區域和畫布的次要類:
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.util.logging.Level;
import java.util.logging.Logger;
import javafx.embed.swing.SwingFXUtils;
import javafx.event.EventHandler;
import javafx.geometry.Insets;
import javafx.scene.Cursor;
import javafx.scene.SnapshotParameters;
import javafx.scene.canvas.Canvas;
import javafx.scene.canvas.GraphicsContext;
import javafx.scene.control.TextArea;
import javafx.scene.image.Image;
import javafx.scene.image.ImageView;
import javafx.scene.image.PixelReader;
import javafx.scene.image.PixelWriter;
import javafx.scene.image.WritableImage;
import javafx.scene.input.MouseEvent;
import javafx.scene.layout.Background;
import javafx.scene.layout.BackgroundFill;
import javafx.scene.layout.CornerRadii;
import javafx.scene.layout.StackPane;
import javafx.scene.paint.Color;
import javax.imageio.ImageIO;
public class WordCanvas extends StackPane
{
private Canvas Can = new Canvas();
private GraphicsContext GC = Can.getGraphicsContext2D();
private TextArea Area = new TextArea();
private ImageView Cover = new ImageView();
double Width;
double Height;
public WordCanvas()
{
CreateUI();
}
public WordCanvas(double W, double H)
{
this.Width = W;
this.Height = H;
CreateUI();
}
public WordCanvas(ImageView IV)
{
this.Cover = IV;
}
public WordCanvas(Canvas C, TextArea TA, GraphicsContext GG)
{
this.Can = C;
this.Area = TA;
this.GC = GG;
CreateUI();
}
public void CreateUI()
{
Caligraphy();
Imagination();
Color C = Color.STEELBLUE;
BackgroundFill BFill = new BackgroundFill(C, CornerRadii.EMPTY, Insets.EMPTY);
Background BGround = new Background(BFill);
this.getChildren().addAll(Area);
this.setBackground(BGround);
}
public void Caligraphy()
{
Area.setMaxWidth(Width);
Area.setMaxHeight(Height);
}
public void Imagination()
{
double CanvasWidth = GC.getCanvas().getWidth();
double CanvasHeight = GC.getCanvas().getHeight();
GC.setFill(Color.TRANSPARENT);
GC.fillRect(0, 0, Can.getWidth(), Can.getHeight());
GC.rect(0, 0, CanvasWidth, CanvasHeight);
GC.setLineWidth(3);
Can.addEventHandler(MouseEvent.MOUSE_ENTERED, new EventHandler<MouseEvent>()
{
@Override
public void handle(MouseEvent event)
{
Can.setCursor(Cursor.CROSSHAIR);
}
});
Can.addEventHandler(MouseEvent.MOUSE_EXITED, new EventHandler<MouseEvent>()
{
@Override
public void handle(MouseEvent event)
{
Can.setCursor(Cursor.DEFAULT);
}
});
Can.addEventHandler(MouseEvent.MOUSE_PRESSED, new EventHandler<MouseEvent>()
{
@Override
public void handle(MouseEvent event)
{
GC.beginPath();
GC.lineTo(event.getX(), event.getY());
GC.moveTo(event.getX(), event.getY());
GC.stroke();
}
});
Can.addEventHandler(MouseEvent.MOUSE_DRAGGED, new EventHandler<MouseEvent>()
{
@Override
public void handle(MouseEvent event)
{
GC.lineTo(event.getX(), event.getY());
GC.stroke();
}
});
Can.addEventHandler(MouseEvent.MOUSE_RELEASED, new EventHandler<MouseEvent>()
{
@Override
public void handle(MouseEvent event)
{
ImageView IV = new ImageView();
WordCanvas Stack = new WordCanvas(IV);
Cover.setMouseTransparent(true);
WritableImage WImage = Can.snapshot(new SnapshotParameters(), null);
ByteArrayOutputStream Bos = new ByteArrayOutputStream();
try
{
ImageIO.write(SwingFXUtils.fromFXImage(WImage, null), "png", Bos);
}
catch(IOException ex)
{
Logger.getLogger(WordCanvas.class.getName()).log(Level.SEVERE, null, ex);
}
InputStream Fis = new ByteArrayInputStream(Bos.toByteArray());
Image Imos = new Image(Fis);
int IW = (int) Imos.getWidth();
int IH = (int) Imos.getHeight();
WritableImage OutputImage = new WritableImage(IW, IH);
PixelReader PReader = Imos.getPixelReader();
PixelWriter PWriter = OutputImage.getPixelWriter();
for (int y = 0; y < IH; y++)
{
for (int x = 0; x < IW; x++)
{
int argb = PReader.getArgb(x, y);
int r = (argb >> 16) & 0xFF;
int g = (argb >> 8) & 0xFF;
int b = argb & 0xFF;
if(r >= 0xCF && g >= 0xCF && b >= 0xCF)
{
argb &= 0x00FFFFFF;
}
PWriter.setArgb(x, y, argb);
}
}
if(!Stack.getChildren().contains(Cover))
{
Cover.setImage(OutputImage);
Stack.getChildren().add(Cover);
}
else
{
Cover.setImage(OutputImage);
}
}
});
}
public void SetCan(Canvas C)
{
this.Can = C;
}
public Canvas GetCan()
{
return Can;
}
public void SetGC(GraphicsContext GG)
{
this.GC = GG;
}
public GraphicsContext GetGC()
{
return GC;
}
public void SetArea(TextArea TA)
{
this.Area = TA;
}
public TextArea GetArea()
{
return Area;
}
public ImageView GetCover()
{
return Cover;
}
}
在主類中,Snap按鈕處理程序確實按我希望的那樣工作,但我想要的是,在輔助類中,Even處理程序自動創建快照并執行主類中的Snap按鈕所做的事情。但是我都沒試過,它甚至不接受this.getChildren().add(Cover)
。
另一個小問題是,我希望WritableImage
通過更優雅的解決方案自動變得透明。User@珠海給出了一個完美工作的解決方案here,但我更喜歡不需要讀完每個像素的更短的解決方案。現有的PNG文件確實可以正常工作,但當我制作自己的PNG文件時,它們不是透明的。
推薦答案
不清楚為什么每次繪制都要創建畫布,玩父級的子級,以及每次都需要捕獲屏幕并創建圖像。
您只是想在文本區域上進行繪制,所以在文本區域上有一塊畫布,您可以在上面繪制。畫布的mouseTransparentProperty
可用于確定哪個層獲得輸入。
public class TextCanvas extends Application {
private GraphicsContext gc;
@Override
public void start(Stage primaryStage) {
TextArea textArea = new TextArea();
Canvas canvas = createCanvas();
ToggleButton draw = new ToggleButton("Draw");
ToggleButton erase = new ToggleButton("Erase");
ToggleGroup drawErase = new ToggleGroup();
draw.setToggleGroup(drawErase);
erase.setToggleGroup(drawErase);
drawErase.selectedToggleProperty().addListener((ov, oldV, newV) -> {
if (newV == null) {
gc.setStroke(Color.TRANSPARENT);
canvas.setMouseTransparent(true);
} else if (drawErase.getSelectedToggle().equals(draw)) {
System.out.println("Fd");
gc.setStroke(Color.BLACK);
canvas.setMouseTransparent(false);
} else if (drawErase.getSelectedToggle().equals(erase)) {
gc.setStroke(Color.WHITE);
canvas.setMouseTransparent(false);
}
});
Button clear = new Button("Clear");
clear.setOnAction(e -> gc.clearRect(0, 0, canvas.getWidth(), canvas.getHeight()));
CheckBox cb = new CheckBox("Show canvas");
cb.setSelected(true);
canvas.visibleProperty().bind(cb.selectedProperty());
VBox buttonBox = new VBox(draw, erase, clear, cb);
StackPane stack = new StackPane(textArea, canvas);
ScrollPane scrollPane = new ScrollPane(stack);
scrollPane.setFitToHeight(true);
canvas.widthProperty().bind(scrollPane.widthProperty());
canvas.heightProperty().bind(scrollPane.heightProperty());
stack.setBackground(new Background(new BackgroundFill(Color.STEELBLUE, CornerRadii.EMPTY, Insets.EMPTY)));
BorderPane border = new BorderPane();
border.setCenter(scrollPane);
border.setBottom(buttonBox);
primaryStage.setMaximized(true);
primaryStage.setTitle("Practice Canvas");
primaryStage.setScene(new Scene(border));
primaryStage.show();
}
private Canvas createCanvas() {
Canvas canvas = new Canvas();
gc = canvas.getGraphicsContext2D();
gc.setLineWidth(3);
canvas.setOnMouseEntered(event -> canvas.setCursor(Cursor.CROSSHAIR));
canvas.setOnMouseExited(event -> canvas.setCursor(Cursor.DEFAULT));
canvas.setOnMousePressed(event -> {
gc.beginPath();
gc.lineTo(event.getX(), event.getY());
gc.moveTo(event.getX(), event.getY());
gc.stroke();
});
canvas.setOnMouseDragged(event -> {
gc.lineTo(event.getX(), event.getY());
gc.stroke();
});
canvas.setMouseTransparent(true);
return canvas;
}
public static void main(String[] args) {
launch(args);
}
}
編輯:我添加了一個復選框來切換畫布的可見性。您必須明確您的使用要求,了解每個用戶操作對每個模式執行的操作。在任何情況下,這應該足夠玩了。
另外,使用適當的Java命名約定:局部變量、(非常量)字段名和方法參數應以小寫開頭。
這篇關于如何在文本區上繪制?的文章就介紹到這了,希望我們推薦的答案對大家有所幫助,