java - How to convert a PDF page to an image in Android?

Question

All I need to do is take a (locally saved) PDF-document and convert one or all of it's pages to image format like JPG or PNG.

I've tried lot's of PDF Rendering/viewing solutions like APV PDF Viewer, APDFViewer, droidreader, android-pdf, MuPdf and many others but couldn't figure it out so far that how to convert a pdf-page into image?.

EDIT: Also I'd rather have a PDF to image converter than a PDF renderer that I need to edit to convert PDF to image.

Answer 1

To support API 8 and above, follow:

Using this library: android-pdfview and the following code, you can reliably convert the PDF pages into images (JPG, PNG):

DecodeServiceBase decodeService = new DecodeServiceBase(new PdfContext());
decodeService.setContentResolver(mContext.getContentResolver());

// a bit long running
decodeService.open(Uri.fromFile(pdf));

int pageCount = decodeService.getPageCount();
for (int i = 0; i < pageCount; i++) {
    PdfPage page = decodeService.getPage(i);
    RectF rectF = new RectF(0, 0, 1, 1);

    // do a fit center to 1920x1080
    double scaleBy = Math.min(AndroidUtils.PHOTO_WIDTH_PIXELS / (double) page.getWidth(), //
            AndroidUtils.PHOTO_HEIGHT_PIXELS / (double) page.getHeight());
    int with = (int) (page.getWidth() * scaleBy);
    int height = (int) (page.getHeight() * scaleBy);

    // you can change these values as you to zoom in/out
    // and even distort (scale without maintaining the aspect ratio)
    // the resulting images

    // Long running
    Bitmap bitmap = page.renderBitmap(with, height, rectF);

    try {
        File outputFile = new File(mOutputDir, System.currentTimeMillis() + FileUtils.DOT_JPEG);
        FileOutputStream outputStream = new FileOutputStream(outputFile);

        // a bit long running
        bitmap.compress(Bitmap.CompressFormat.JPEG, 100, outputStream);

        outputStream.close();
    } catch (IOException e) {
        LogWrapper.fatalError(e);
    }
}

You should do this work in the background i.e. by using an AsyncTask or something similar as quite a few methods take computation or IO time (I have marked them in comments).