JavaFX：图像被缩放到 25%，然后被打印。

Question

我正在尝试使用 JavaFX api 打印图像。不幸的是，它正在剪切图像的一部分，大约 25%，然后将其拉伸到整个 A4 页面并打印。我在打印代码上做错了什么。无论打印机是什么，我如何指示将图像适合打印页面。请告诉我。

代码：

 public void printThis() {

        System.out.println("I was called");
        // note you can use overloaded forms of the Image constructor
        // if you want to scale, etc
        String path = "resources/img/printouts/image.png";
        Image image = new Image(getClass().getResource(path).toExternalForm());
        ImageView imageView = new ImageView(image);
        new Thread(() -> printImage(imageView)).start();
    }

    public void printImage(ImageView image) {
        Printer printer = Printer.getDefaultPrinter();
        PrinterJob printJob = PrinterJob.createPrinterJob(printer);
        PageLayout pageLayout = printJob.getJobSettings().getPageLayout();
        //PageLayout pageLayout = printer.createPageLayout(Paper.A4, PageOrientation.PORTRAIT, Printer.MarginType.DEFAULT);
        printJob.getJobSettings().setPageLayout(pageLayout);
        if (printJob != null) {
            boolean success = printJob.printPage(image);
            if (success) {
                printJob.endJob();
            }
        }
    }

请让我知道我做错了什么。谢谢你。 :-)

Answer 1

您可以在printImage 方法中添加以下代码：

image.setPreserveRatio(true);
image.setFitHeight(pageLayout.getPrintableHeight());
image.setFitWidth(pageLayout.getPrintableWidth());

这将打印缩放到可以放入pageLayout.getPrintableWidth() x pageLayout.getPrintableHeight() 的矩形中的最大尺寸的图像，保留比例，请参阅ImageView.preserveRation。

Answer 2

如果我理解正确，您想在任意打印机上以任何方向、纸张尺寸等打印图像。图像不应被裁剪或按比例更改，但应尽可能多地填充纸可以吗？对吗？

所以，我做了一个简单的例子来说明你是如何做到的。您需要以宽度和高度缩放图像，但两个缩放值应该相同（保留比例）。您需要打印机的可打印区域（默认纸张大小），然后您就可以计算出正确的值。

import javafx.application.Application;
import javafx.print.PageLayout;
import javafx.print.Printer;
import javafx.print.PrinterJob;
import javafx.scene.Node;
import javafx.scene.image.Image;
import javafx.scene.image.ImageView;
import javafx.scene.transform.Scale;
import javafx.stage.Stage;

public class ImagePrint extends Application {

    @Override
    public void start(Stage stage) {
        Image image = new Image("https://openclipart.org/image/800px/svg_to_png/93337/road08.png");
        ImageView imageView = new ImageView(image);
        new Thread(() -> printImage(imageView)).start();
    }

    public void printImage(Node node) {

        Printer printer = Printer.getDefaultPrinter();
        PageLayout pageLayout = printer.getDefaultPageLayout();
        System.out.println("PageLayout: " + pageLayout);

        // Printable area
        double pWidth = pageLayout.getPrintableWidth();
        double pHeight = pageLayout.getPrintableHeight();
        System.out.println("Printable area is " + pWidth + " width and "
                + pHeight + " height.");

        // Node's (Image) dimensions
        double nWidth = node.getBoundsInParent().getWidth();
        double nHeight = node.getBoundsInParent().getHeight();
        System.out.println("Node's dimensions are " + nWidth + " width and "
                + nHeight + " height");

        // How much space is left? Or is the image to big?
        double widthLeft = pWidth - nWidth;
        double heightLeft = pHeight - nHeight;
        System.out.println("Width left: " + widthLeft
                + " height left: " + heightLeft);

        // scale the image to fit the page in width, height or both
        double scale = 0;

        if (widthLeft < heightLeft) {
            scale = pWidth / nWidth;
        } else {
            scale = pHeight / nHeight;
        }

        // preserve ratio (both values are the same)
        node.getTransforms().add(new Scale(scale, scale));

        // after scale you can check the size fit in the printable area
        double newWidth = node.getBoundsInParent().getWidth();
        double newHeight = node.getBoundsInParent().getHeight();
        System.out.println("New Node's dimensions: " + newWidth
                + " width " + newHeight + " height");

        PrinterJob job = PrinterJob.createPrinterJob();
        if (job != null) {
            boolean success = job.printPage(node);
            if (success) {
                job.endJob();
                System.exit(0);
            }
        }
    }

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