Android - Drawing to a PDF canvas from WebView

Question

I\'ve been having troubles getting PDF printing work on Android. What I\'m trying to do is render some HTML in WebView, then draw the WebView contents on a PDF canvas and fi

Answer 1

Summary: Don't modify the density, (it should be set on your device, probably to medium 160 dpi) instead, use scale. If you Just need Bitmaps of your HTML page in your PDF (No hyper-link function), this works. This is what your code is generating, with the following code:

    //Create PDF document

        PdfDocument doc = new PdfDocument();

        //Create A4 sized PDF page
        int my_width  = 595;
        int my_height = 842;

        PageInfo pageInfo = new PageInfo.Builder(my_width,my_height,1).create();
//      PageInfo pageInfo = new PageInfo.Builder(650,850,1).create();

        Page page = doc.startPage(pageInfo);

        WebView wv = (WebView) this.findViewById(R.id.webView1);

        Canvas canvas = page.getCanvas();
        WindowManager wm = (WindowManager) getSystemService(WINDOW_SERVICE);
        final DisplayMetrics displayMetrics = new DisplayMetrics();
        wm.getDefaultDisplay().getMetrics(displayMetrics);
        int    height  = displayMetrics.heightPixels;
        int    width   = displayMetrics.widthPixels;
        float  density = displayMetrics.density;
        int    wvWidth = wv.getWidth();
        int    wvHeight= wv.getHeight();
        float  wvScaleX= wv.getScaleX();
        float  wvScaleY= wv.getScaleY();

//      canvas.setDensity(100);//200 Bitmap.DENSITY_NONE
        int cdensity = canvas.getDensity();
        float scaleWidth = (float)width/(float)my_width;
        float scaleHeight = (float)height/(float)my_height;
        canvas.scale(scaleWidth, scaleHeight);
        Log.e("button1onClick","canvas width:" + canvas.getHeight() + " canvas height:" +  canvas.getWidth());
        Log.e("button1onClick","metrics width:" + width + " metrics height:" +  height + "metrics density:" +  density);
        Log.e("button1onClick"," wvWidth:" + wvWidth + " wvHeight:" +  wvHeight);
        Log.e("button1onClick"," scaleWidth: " + scaleWidth +
                " scaleHeight:" +  scaleHeight +" cdensity:" + cdensity);
        Paint paint = new Paint();
//      paint.setStyle(Style.FILL);
        paint.setColor(Color.RED);
        paint.setStyle(Paint.Style.STROKE);
        paint.setStrokeWidth(1);

        //Draw the webview to the canvas
        wv.draw(canvas);
        canvas.scale(1f, 1f);
        canvas.drawRect(0, 0, canvas.getWidth()-1,  canvas.getHeight()-1, paint);
        canvas.drawText("Direct drawn Red Rectangle to fill page canvas 0, 0," +
                canvas.getWidth() + "," + canvas.getHeight(), 100, 100, paint);

        doc.finishPage(page);

This works well (Hyper-links cannot work of course). More complex example: