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Sharpness/Contrast on large screens
#1
Hello Mike,

I'm using the Windows 10 version of MobileSheets on a computer with a 27" monitor, with a resolution of 1920x1080.  The issue is when I open the music to play, it is best described as "soft focus", with lots of shading/aliasing and a white/black contrast ratio that is painful.  

I can overlay mobilesheets with Foxit, Adobe Reader, or Sumantra and they are quite sharp and legible, but not mobile sheets.  I'm guessing the rendering engine is trying to do the best it can when scaling down, but scaling up is not the engines best trick.  

Any chance of a rendering engine, or configuration changes to better suit the big screens?  

Thanks,
JWR
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#2
JWR,

To be honest, I'm really not sure why you are seeing that kind of difference. I have a 3440x1440 monitor and sheet music looks sharp on it. There aren't major differences between Adobe and MobileSheets on my computer. I do see some small rendering differences such as the thickness of text and lines, and I'm curious if things will look different when I switch to rendering the pages using Win2D.  I don't think this is a problem with the PDF library I'm using to render the pages, so it's possible there is something with how I'm displaying the images that are rendered. I think I'll need to see screenshot of the differences you are seeing though to understand better what the problem is. It would also help if I had a copy of the PDF you are using, unless you are seeing this issue with every PDF you've tried.

On a side note, if you go to Settings->Display Settings->Render Preference and switch the value, does that make any difference?

Mike
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#3
Hi again Mike,

Can you check your "Page color tones".  I always set that on PDF readers, as I do not often do well with white backgrounds, I had immediately set it to grey when I ran through settings.  

For me, with "none" chosen it is ok, not as clear as the dedicated readers but you can never get them exact.  But that white is harsh in general.  With "sepia" chosen it is a washed out yellow more than the ambered brown one would expect this I'm using now.  With either of "Grey" or "Cool" it is as it every pixel has been lit too it's whitest tone.  That is probably why I'm seeing the Halo effect.   

I'm using a Dell SE2719H right now, it is new and bought for purpose as the music stand.  I'll put another monitor on there this afternoon to see if it's the monitor not speaking correctly with MobileSheets.

Thanks,
JWR
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#4
Have you calibrated that monitor? I normally have to turn down the brightness and contrast a lot on monitors as they always have them way too high. A lot of times they also use picture modes that result in far too much sharpness being applied, and can cause graphical artifacts. 

I switched between all of the page tones and didn't really see any differences in how the page was rendered on my monitor. I'm currently using #FFF2D1 for Sepia. I can experiment with other colors if you believe there is a better color to use. I believe I originally tried #704214 but it was far too dark and the notes on the sheet music didn't stand out at all. 

Please let me know if you can try adjusting the settings on that monitor to see if it improves the quality of the images in MobileSheets. I usually rely on TFT Central, as they do a thorough analysis of most monitors and provide some rough values to help users get started with their calibration. I found a review for the U2719D, but could not find one for the SE2719H. It is here if you want to see it: https://www.tftcentral.co.uk/reviews/dell_u2719d.htm

They also provide ICC calibration profiles so that the colors are correct on the monitor. I applied this for my monitor, and while at first it takes a little getting used to, it does result in accurate color representation.

Another thing to consider is that C# UWP applications use DirectX to render everything (it's how Microsoft implements it under the hood). Other applications you are referencing may use GDI+ or other approaches to rendering. What kind of graphics card do you have in that computer?

Mike
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#5
For any programmers out there, this is the algorithm I use for shading the pages to apply the color tone to the bitmap of the page:

Code:
public static void Shade(byte[] pixels, int width, int height, int color)
{
    double red = ((color >> 16) & 0xFF) / 255.0;
    double green = ((color >> 8) & 0xFF) / 255.0;
    double blue = (color & 0xFF) / 255.0;
    const int whiteEnough = 0xE0;
    for (int x = 0; x < width; ++x)
    {
        for (int y = 0; y < height; ++y)
        {
            int index = x * 4 + y * width * 4;

            if (pixels[index] > whiteEnough && pixels[index + 1] > whiteEnough &&
                pixels[index + 2] > whiteEnough)
            {
                // Ignore alpha which is the last byte. WriteableBitmap uses BGRA
                pixels[index + 2] = (byte)(pixels[index + 2] * red);
                pixels[index + 1] = (byte)(pixels[index + 1] * green);
                pixels[index] = (byte)(pixels[index] * blue);
            }
        }
    }
}

I don't know if there is a better algorithm to color the background without distorting the image in any negative way, but I'm always open to recommendations.

Thanks,
Mike
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#6
For windows, the normal recommendation when using the Delphi programming language is to use ScanLine rather than pixels (it is much faster/efficient).
I've no idea whether this capability exists in C# or on an android system i.e. you might be better sticking with what you are doing, especially if you are happy with the current speed.

Geoff
Samsung Galaxy Tab A6
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#7
Wow, nice support, code shown for peer review, very nice.  

First, I'm using a standard "W5 Pro" Atom z8750 stick like this: https://www.amazon.com/Intel-Z8350-Windo...B07MB9TC33 they are sold under many names but all the same.  The concept being that I want a big screen and big screens are everywhere, why play with a tablet?  Travel with a PC stick and you are up and running in a heart beat and have even less to carry around than the tablet guy.  Also they are cheap as chips and readily available.

I had properly calibrated the monitor with a light gun, but then again, it's purpose is to be a music stand so I reset it to my own best case and now it is ok.  It might be a bit dark for a movie or word processor, but that isn't what it's there to be.

I would prefer to have the ability to define my own colours in the page colour tones as I usually use a salmon pink with a deep grey text when reading (I read alot and that is easiest on my eyes, but I'm probably the only one who would choose that preset). 

Thanks Mike for now I'll wish list more options on page colour tone, and move on.

JR
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#8
Adding support for additional color tones along with the ability for the user to pick their own color is on my long list of things to do. I look forward to the day when the list starts shrinking instead of growing Wink

Mike
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