Question

我需要一个有效的android代码来将pdf文件打印到bmp中。我所拥有的代码能够打印，但文字非常模糊和缩小，以至于很难阅读。用于打印的设备很小，纸张宽度为384。印刷文本应清晰可读。

public class PdfToImage {

        private int ViewSize = 384;
        private String pdfErrorCode = null;
        private String pdfImageErrorCode = null;
        private String pdfImageSaveErrorCode = null;
        private String returnError = null;

        public String pdfToImage(File pdfFilePath) {
            PDFImage.sShowImages = true;
            PDFPaint.s_doAntiAlias = true;
            HardReference.sKeepCaches = true;
            try {
                RandomAccessFile pdfAccessFile = new RandomAccessFile(pdfFilePath,
                        "r");
                byte[] pdfData = new byte[(int) pdfAccessFile.length()];
                pdfAccessFile.readFully(pdfData);
                returnError = pdfLoadImages(pdfData);

                pdfErrorCode = "SUCCESS";

            } catch (Exception ignored) {
                pdfErrorCode = "PDF FILE NOT FOUND"; 
            }

            if (returnError.equals("PDF TO BMP CONVERSION SUCCESS")) {
                return pdfErrorCode;   
            } else {
                return "FAILED";
            }
        }

        @SuppressLint("NewApi")
        private String pdfLoadImages(final byte[] data) {

            try {
                ByteBuffer byteBuffer = ByteBuffer.NEW(data);
                PDFFile pdfFile = new PDFFile(byteBuffer);
                PDFPage pdfPage = pdfFile.getPage(1, true);

                final float scaleImage = ViewSize / pdfPage.getWidth() * 0.95f;
                Bitmap bitmapPdfPage = pdfPage.getImage(
                        (int) (pdfPage.getWidth() * scaleImage),
                        (int) (pdfPage.getHeight() * scaleImage), null, true, true);
                SaveImage(bitmapPdfPage, 1);

                ByteArrayOutputStream stream = new ByteArrayOutputStream();
                bitmapPdfPage.compress(Bitmap.CompressFormat.PNG, 100, stream);
                stream.reset();

                for (int i = 2; i <= pdfFile.getNumPages(); i++) {
                    pdfPage = pdfFile.getPage(i, true);
                    bitmapPdfPage = pdfPage.getImage(
                            (int) (pdfPage.getWidth() * scaleImage),
                            (int) (pdfPage.getHeight() * scaleImage), null, true,
                            true);
                    bitmapPdfPage.compress(Bitmap.CompressFormat.PNG, 100, stream);
                    SaveImage(bitmapPdfPage, i);
                    pdfImageErrorCode = "PDF TO BMP CONVERSION SUCCESS";
                }
                stream.close();
            } catch (Exception e) {
                Log.d("error", e.toString());
                pdfImageErrorCode = "PDF TO BMP CONVERSION FAILED";
            }
            System.gc();
            return pdfImageErrorCode;
        }

        private String SaveImage(Bitmap pdfBitmap, int pageNumber) {

            String sdcardPath = Environment.getExternalStorageDirectory()
                    .toString();
            File pdfDir = new File(sdcardPath + "/pdftobmp");
            pdfDir.mkdirs();

            String pdfToImageFileName = "pdf-" + pageNumber + ".png";
            File imageFile = new File(pdfDir, pdfToImageFileName);
            if (imageFile.exists())
                imageFile.delete();
            try {
                FileOutputStream outputStream = new FileOutputStream(imageFile);
                pdfBitmap.compress(Bitmap.CompressFormat.PNG, 90, outputStream);
                outputStream.flush();
                outputStream.close();
                pdfImageSaveErrorCode = "IMAGE SAVED";

            } catch (Exception e) {
                e.printStackTrace();
                pdfImageSaveErrorCode = "IMAGE NOT SAVED";
            }
            return pdfImageSaveErrorCode;
        }

    }

Answer 1

在这里，您将图像压缩到原始质量的1/10：

bitmapPdfPage.compress(Bitmap.CompressFormat.PNG, 10, stream);

为什么不尝试删除该行，或者将压缩调整为更高的值，比如90？

bitmapPdfPage.compress(Bitmap.CompressFormat.PNG, 90, stream);

修改

如果情况并非如此，那么我可以给你一些调试建议。

我想知道你的加载或保存代码是否导致了小而模糊的大小，所以如果我是你，我会在读取的行上放置一个调试断点/ p>
SaveImage(bitmapPdfPage, i);

然后，在变量列表中，您将能够找到bitmapPdfPage（在Android Studio中），并查看位图本身。如果位图在这里很小且模糊，那么可能会更新问题，知道它是不正确的加载代码。如果它很大并且您可以阅读文本，那么反之亦然，您知道它是位图保存代码的错误。

将PDF文件转换为BMP并打印

1 个答案: