[dgatwood]

I'm trying to use MobileSheets (paid version) for reading conducting scores on a large-screen (25") Android 14 tablet (Megapad), and I'm having some problems that look like a software bug.  Specifically, the rendering resolution is inadequate for the display:

• Staff lines have inconsistent spacing
  
• Text in vector PDFs is blurry with holes in 'e' almost missing, etc.
  

It looks like the app is rendering at a fixed resolution based on page size times some constant value, rather than computing the rendering resolution based on screen size and display resolution, and is failing to use subpixel rendering, resulting in very crude scaling quality.

Equally puzzling:

• The resolution seems to be based on page size instead of screen size.  The original file, which had an 8.5x11 page size, was completely unreadable.  Changing the page size to 11x17 made it passable (barely).
  
• The content resolution in portrait mode (one page at a time) is no better than in landscape mode (two pages at a time).
  
• Zooming in results in jagged lines and text, i.e. zooming in doesn't let you see details that aren't being rendered when zoomed out.
  
• Quality is poor even with rasterized PDFs at 300 DPI.
  

Based on this, it looks like MobileSheets is downscaling to maybe 20–30 DPI, regardless of zoom settings, number of pages shown, etc.  This occurs regardless of whether the render preference is set to "Quality" or "Fast", though in fast mode, 2-up display becomes even more unreadable.

I don't have these problems when viewing the PDF in the Drive app.  Zooming in works as expected — a little lag, but readable.

Could you please add a mode that renders at a higher resolution for displaying scores?  When viewing an 11"x17" page with 27 staves on the screen, we need all the quality we can get.  ?

[Zubersoft]

You're making a lot of incorrect assumptions about a lot of things:

1) MobileSheets gets the raw PDF page size, figures out the scaling factor to make it fit the screen (based on the scale display settings) and then calls into the PDF library asking it to render the page at that scale level. The PDF library handles generating the image, and this is generally a very high quality rendering that properly handles vector based graphics and such.
2) The PDF library handles all of the low level details for how pages are rendered. Subpixel rendering doesn't apply because I'm just displaying an entire bitmap
3) You can switch between two PDF libraries by changing Settings->Display Settings->Render Preference
4) If you want high quality zooming, you can enable it, but it means the pages will be re-rendered at the higher resolution, so it's not as seamless. Just open your score, tap the center of the screen to bring up the overlay, tap the second icon at the bottom left, tap "Zoom/Pan Settings" and enable the option for high-quality zooming
5) MobileSheets does not render at 20-30 DPI. That's complete nonsense - the PDF library will handle a 300 DPI page correctly.

You really do get what you pay for with the device. Megapad tablets are not known to be particularly high quality. Two things really matter for how sharp the images are - the resolution of the display combined with the density of the screen (the pixels per inch). I can only assume that device has a low resolution and a low density. On my Samsung Galaxy Tab S8 Ultra, for example, the pages are rendered with extremely good detail and sharpness (when using good quality PDFs).

Mike

[dgatwood]

You're making a lot of incorrect assumptions about a lot of things:

1) MobileSheets gets the raw PDF page size, figures out the scaling factor to make it fit the screen (based on the scale display settings) and then calls into the PDF library asking it to render the page at that scale level. The PDF library handles generating the image, and this is generally a very high quality rendering that properly handles vector based graphics and such.
2) The PDF library handles all of the low level details for how pages are rendered. Subpixel rendering doesn't apply because I'm just displaying an entire bitmap
3) You can switch between two PDF libraries by changing Settings->Display Settings->Render Preference
4) If you want high quality zooming, you can enable it, but it means the pages will be re-rendered at the higher resolution, so it's not as seamless. Just open your score, tap the center of the screen to bring up the overlay, tap the second icon at the bottom left, tap "Zoom/Pan Settings" and enable the option for high-quality zooming
5) MobileSheets does not render at 20-30 DPI. That's complete nonsense - the PDF library will handle a 300 DPI page correctly.

You really do get what you pay for with the device. Megapad tablets are not known to be particularly high quality. Two things really matter for how sharp the images are - the resolution of the display combined with the density of the screen (the pixels per inch). I can only assume that device has a low resolution and a low density. On my Samsung Galaxy Tab S8 Ultra, for example, the pages are rendered with extremely good detail and sharpness (when using good quality PDFs).

Mike

Mea culpa.  I just re-added the original file, and apparently my memory was faulty, or else the zoom level was slightly different before for some reason.  There's no quality difference between the 8.5x11 and 11.17 vector PDFs.

To be clear, when I spoke of subpixel rendering, I meant in the PDF library.  But I"m seeing a lack of subpixel rendering in Drive, too, so I guess Android just doesn't support it on this particular flat panel.   

So I guess the only real issue is that when I feed in a 300 DPI pre-rasterized PDF and show it on the screen, the PDF library is downscaling the raster images to screen resolution, so even when you zoom in, the quality doesn't improve.  I don't see an option for high-quality zooming in the Zoom/Pan Settings.

Ah.  If I enable fast rendering, I do, and yeah, that's a lot better.  ?

Sadly, I've found zero tablets on the market of similar size that have higher res, and their 32-inch tablet won't rotate flat and doesn't use a standard VESA mount, so I can't make it rotate flat.  The largest tablets that are greater than 1080p seem to be 15.6 inches, which isn't nearly big enough for a score that's designed to be on up to 11x17 paper.

Guess I'll suffer with this hardware until someone makes a large tablet that's actually good.

[Zubersoft]

You should be able to enable high-quality zooming regardless of which Render Preference setting is selected. That should also significantly improve the rendering quality if you zoom in a lot. Just recognize that this will slow down the rendering and it uses more memory as a much larger image is rendered. When high-quality zooming is disabled, the canvas is just scaled, which is much faster, but the quality is worse (as it's just like zooming in on an image in an application like paint).

Mike