使图像适合打印区域

我需要用Java打印图像。 所以我实现了Printable接口的print()方法。 但是打印机总是只打印一些原始图像。 如何使图像适合打印区域（A4），这样打印机能够打印整个图像，而不是它们的一部分？ 现在我的代码看起来像这样：

 public int print(Graphics graphics, PageFormat pageFormat, int pageIndex) throws PrinterException { if (pageIndex >= images.size()) { return Printable.NO_SUCH_PAGE; } RenderedImage image; Graphics2D graphics2D = (Graphics2D) graphics; image = new NullOpImage((RenderedImage) images.get(pageIndex), null, null, OpImage.OP_IO_BOUND); double x = (pageFormat.getImageableWidth() - image.getWidth())/2 + pageFormat.getImageableX(); double y = (pageFormat.getImageableHeight() - image.getHeight())/2 + pageFormat.getImageableY(); graphics2D.drawRenderedImage(image, AffineTransform.getTranslateInstance(x, y)); return PAGE_EXISTS; } 

Answer 1

您需要缩小图像以适合可用区域。

 private int currentPage = -1; private Image cachedScaledImage = null; public double getScaleFactor(int iMasterSize, int iTargetSize) { double dScale = 1; if (iMasterSize > iTargetSize) { dScale = (double) iTargetSize / (double) iMasterSize; } else { dScale = (double) iTargetSize / (double) iMasterSize; } return dScale; } public double getScaleFactorToFit(BufferedImage img, Dimension size) { double dScale = 1; if (img != null) { int imageWidth = img.getWidth(); int imageHeight = img.getHeight(); dScale = getScaleFactorToFit(new Dimension(imageWidth, imageHeight), size); } return dScale; } public double getScaleFactorToFit(Dimension original, Dimension toFit) { double dScale = 1d; if (original != null && toFit != null) { double dScaleWidth = getScaleFactor(original.width, toFit.width); double dScaleHeight = getScaleFactor(original.height, toFit.height); dScale = Math.min(dScaleHeight, dScaleWidth); } return dScale; } public int print(Graphics graphics, PageFormat pageFormat, int pageIndex) throws PrinterException { if (pageIndex >= images.size()) { return Printable.NO_SUCH_PAGE; } RenderedImage image; Graphics2D graphics2D = (Graphics2D) graphics; int width = (int)Math.round(pageFormat.getImageableWidth()); int height = (int)Math.round(pageFormat.getImageableHeight()); if (currentPage != pageIndex || cachedScaledImage == null) { currentPage = pageIndx; image = new NullOpImage((RenderedImage) images.get(pageIndex), null, null, OpImage.OP_IO_BOUND); BufferedImage imageCopy = new BufferedImage(image.getWidth(), image.getHeight(), BufferedImage.TYPE_INT_ARGB); Graphics2D g2d = imageCopy.createGraphics(); g2d.drawImage(imageCopy, 0, 0, null); g2d.dispose(); double scaleFactor = getScaleFactorToFit(new Dimension(image.getWidth(), image.getHeight()), new Dimension(width, height)); int imageWidth = (int)Math.round(image.getWidth() * scaleFactor); int imageHeight = (int)Math.round(image.getHeight() * scaleFactor); double x = ((pageFormat.getImageableWidth() - imageWidth) / 2) + pageFormat.getImageableX(); double y = ((pageFormat.getImageableHeight() - imageHeight) / 2) + pageFormat.getImageableY(); cachedScaledImage = imageCopy.getScaledInstance(imageWidth, imageHeight, Image.SCALE_SMOOTH); } graphics2D.drawRenderedImage(cachedScaledImage, AffineTransform.getTranslateInstance(x, y)); return PAGE_EXISTS; }