PDFrenderer setting scale to screen

Question

Im using the code below to render a pdf. This is in a try/catch and works well, showing the pdf.

The problem is that the pdf file is too big for the screen. Does anyone know how to scale it down to fit please?

Thank you.

        imageView = (ImageView) findViewById(R.id.imagePDF);

        int REQ_WIDTH = imageView.getWidth();
        int REQ_HEIGHT = imageView.getHeight();

        Display display = getWindowManager().getDefaultDisplay();
        Point size = new Point();
        display.getSize(size);
        int width12 = size.x;
        int height12 = size.y;

        Bitmap bitmap = Bitmap.createBitmap(width12, height12, Bitmap.Config.ARGB_4444);

        File file = new File("/sdcard/Download/sample.pdf");


        PdfRenderer renderer = new PdfRenderer(ParcelFileDescriptor.open(file, ParcelFileDescriptor.MODE_READ_ONLY));

        if (currentPage < 0) {
            currentPage = 0;
        } else if (currentPage > renderer.getPageCount()) {
            currentPage = renderer.getPageCount();
        }

        int pages;

        pages = renderer.getPageCount();

        Matrix m = imageView.getImageMatrix();

        Rect rect = new Rect(0, 0, width12, height12);

        renderer.openPage(currentPage).render(bitmap, rect, m, PdfRenderer.Page.RENDER_MODE_FOR_DISPLAY);

        imageView.setImageMatrix(m);
        imageView.setImageBitmap(bitmap);
        imageView.invalidate();

imageView.setScaleType (ImageView.ScaleType.CENTER_INSIDE); <- this doesnt work, the pdf image still runs off the side of the screen — AesculusMaximus, Sep 17 '16 at 10:11
the Rect and Matrix are optional. What happens if you pass null for both? — Fletcher Johns, Sep 17 '16 at 11:06
This has set the width into the screensize, so thank you thats great! Do you know how I can maintain the proportions though. This has squeezed the width, I now need to squeeze the height. I hope this make sense? — AesculusMaximus, Sep 17 '16 at 11:18
I believe I need to find out the original dimensions of the pdf file somehow, then scale this down to inform the dimensions of the bitmap width and height — AesculusMaximus, Sep 17 '16 at 11:24

Fletcher Johns · Accepted Answer · 2016-09-17T12:09:47.917

4

You need to create a Bitmap that matches the aspect ratio of the Page. It's best to match the dimensions of the ImageView as well:

                PdfRenderer renderer = new PdfRenderer(ParcelFileDescriptor.open(file, ParcelFileDescriptor.MODE_READ_ONLY));
                PdfRenderer.Page page = renderer.openPage(0);
                int pageWidth = page.getWidth();
                int pageHeight = page.getHeight();
                float scale = Math.min((float) REQ_WIDTH / pageWidth, (float) REQ_HEIGHT / pageHeight);
                Bitmap bitmap = Bitmap.createBitmap((int) (pageWidth * scale), (int) (pageHeight * scale), Bitmap.Config.ARGB_8888);
                page.render(bitmap, null, null, PdfRenderer.Page.RENDER_MODE_FOR_DISPLAY);
                imageView.setImageBitmap(bitmap);

EDIT:

To avoid ImageView having width and height of 0, one solution is to post a Runnable containing the code:

imageView.post(new Runnable() {
    public void run() {
        // The above code goes here
    }
});

edited Sep 17 '16 at 12:09

answered Sep 17 '16 at 11:36

Fletcher Johns

1,236
15
20

This looks like it should work, but for some reason the REQ_WIDTH and REQ_HEIGHT values are 0? – AesculusMaximus Sep 17 '16 at 12:04
09-17 12:02:54.597 2358-2358/? W/InputEventReceiver﹕ Attempted to finish an input event but the input event receiver has already been disposed. 09-17 12:02:54.758 2358-2358/? W/System.err﹕ java.lang.IllegalArgumentException: width and height must be > 0 – AesculusMaximus Sep 17 '16 at 12:05
Your ImageView mustn't be fully inflated yet. Try: imageView.post(new Runnable() {public void run() {/*your code*/}}); – Fletcher Johns Sep 17 '16 at 12:06

PDFrenderer setting scale to screen

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