Java-将DPI设置为打印图像
我有一堆.jpg图像,我想以固定大小(厘米)打印它们(用墨水打印在纸上)。 假设image1.png是400x600像素,我想以300 dpi的速度打印它。 我尝试过使用PrinterJob和Printable实现,但似乎无法指定DPI。 以下是代码片段:Java-将DPI设置为打印图像,java,image,printing,dpi,Java,Image,Printing,Dpi,我有一堆.jpg图像,我想以固定大小(厘米)打印它们(用墨水打印在纸上)。 假设image1.png是400x600像素,我想以300 dpi的速度打印它。 我尝试过使用PrinterJob和Printable实现,但似乎无法指定DPI。 以下是代码片段: PrinterJob job = PrinterJob.getPrinterJob(); job.setPrintable(new PrintableDeck(cardDB)); PrintRequestAttributeSet attr
PrinterJob job = PrinterJob.getPrinterJob();
job.setPrintable(new PrintableDeck(cardDB));
PrintRequestAttributeSet attr = new HashPrintRequestAttributeSet();
attr.add(new PrinterResolution(300, 300, PrinterResolution.DPI));
attr.add(new MediaPrintableArea(8,21,210-16,296-42,MediaPrintableArea.MM));
attr.add(MediaSizeName.ISO_A4);
attr.add(new Copies(1));
attr.add(OrientationRequested.PORTRAIT);
attr.add(PrintQuality.HIGH);
//attr.add(Fidelity.FIDELITY_TRUE);
job.print(attr);
及
正如您在上面看到的,我有PageFormat.getImageableHeight()~842和PageFormat.getImageableWidth()~595。若页面为300dpi,我预计这些值会更高,约为3000x2500。
我错过了什么
非常感谢。这是我的代码,注意我使用的是Scalr
private String autoResizeImage(String image, int width, int dpi, String prefix) throws IllegalArgumentException, ImagingOpException, IOException {
File file = new File(image);
BufferedImage img = ImageIO.read(file);
BufferedImage result = Scalr.resize(img, Scalr.Method.SPEED, Scalr.Mode.FIT_TO_WIDTH, width, Scalr.OP_ANTIALIAS);
File outputfile = new File(prefix);
PNGEncodeParam penc = PNGEncodeParam.getDefaultEncodeParam(result);
double meter2inchRatio = 1d / 0.0254d;
int dim = (int) (dpi * meter2inchRatio) + 1;
penc.setPhysicalDimension(dim, dim, 1);
// resize orginal image
JAI.create("filestore", result, outputfile.getAbsolutePath(), "PNG", penc);
return outputfile.getAbsolutePath();
}
Java将图像的DPI设置为默认的Java 72dpi如果图像的元数据中没有先前定义的DPI,那么这比在Java 72dpi默认分辨率中将图像缩放到其维度要好,最好将300dpi分辨率添加到图像元数据中,因此,它将在正确的可打印区域尺寸中以更好的分辨率进行调整,也就是说,除了设置打印机分辨率、介质大小和介质可打印区域属性外,您还可以使用以下方法为保存的图像设置dpi: 以获得更好的图像视图质量和分辨率
private String autoResizeImage(String image, int width, int dpi, String prefix) throws IllegalArgumentException, ImagingOpException, IOException {
File file = new File(image);
BufferedImage img = ImageIO.read(file);
BufferedImage result = Scalr.resize(img, Scalr.Method.SPEED, Scalr.Mode.FIT_TO_WIDTH, width, Scalr.OP_ANTIALIAS);
File outputfile = new File(prefix);
PNGEncodeParam penc = PNGEncodeParam.getDefaultEncodeParam(result);
double meter2inchRatio = 1d / 0.0254d;
int dim = (int) (dpi * meter2inchRatio) + 1;
penc.setPhysicalDimension(dim, dim, 1);
// resize orginal image
JAI.create("filestore", result, outputfile.getAbsolutePath(), "PNG", penc);
return outputfile.getAbsolutePath();
}
private void saveGridImage(File output,BufferedImage gridImage) throws IOException {
output.delete();
final String formatName = "png";
for (Iterator<ImageWriter> iw = ImageIO.getImageWritersByFormatName(formatName); iw.hasNext();) {
ImageWriter writer = iw.next();
ImageWriteParam writeParam = writer.getDefaultWriteParam();
ImageTypeSpecifier typeSpecifier = ImageTypeSpecifier.createFromBufferedImageType(BufferedImage.TYPE_INT_RGB);
IIOMetadata metadata = writer.getDefaultImageMetadata(typeSpecifier, writeParam);
if (metadata.isReadOnly() || !metadata.isStandardMetadataFormatSupported()) {
continue;
}
setDPI(metadata);
final ImageOutputStream stream = ImageIO.createImageOutputStream(output);
try {
writer.setOutput(stream);
writer.write(metadata, new IIOImage(gridImage, null, metadata), writeParam);
} finally {
stream.close();
}
break;
}
}
private void setDPI(IIOMetadata metadata) throws IIOInvalidTreeException {
double INCH_2_CM = 2.54;
// for PMG, it's dots per millimeter
double dotsPerMilli = 1.0 * DPI / 10 / INCH_2_CM;
IIOMetadataNode horiz = new IIOMetadataNode("HorizontalPixelSize");
horiz.setAttribute("value", Double.toString(dotsPerMilli));
IIOMetadataNode vert = new IIOMetadataNode("VerticalPixelSize");
vert.setAttribute("value", Double.toString(dotsPerMilli));
IIOMetadataNode dim = new IIOMetadataNode("Dimension");
dim.appendChild(horiz);
dim.appendChild(vert);
IIOMetadataNode root = new IIOMetadataNode("javax_imageio_1.0");
root.appendChild(dim);
metadata.mergeTree("javax_imageio_1.0", root);
}
attr.add(new PrinterResolution(300, 300, PrinterResolution.DPI));
attr.add(new MediaPrintableArea(8,21,210-16,296-42,MediaPrintableArea.MM));
attr.add(MediaSizeName.ISO_A4);