Strange white line in my picture.

Discussion of application development using iX Developer, including but not limited to getting started, using the functions tab, properties, objects and installation.
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manuel
Posts: 1
Joined: Thu Dec 06, 2012 3:37 am

Strange white line in my picture.

Post by manuel »

Hi every one.

As i don't like, look of "shape fill/gradients"; i do my own gradient (linked file : rect4485.png)
rect4485.png
rect4485.png (4.55 KiB) Viewed 8427 times
I add it to my project with picture object. But strange whites lines show up :
2017-05-05 14_53_18-P797547 -.png
2017-05-05 14_53_18-P797547 -.png (34.42 KiB) Viewed 8427 times
Where did they came from ?
Not from alpha layer
I made a file "rvb 256.jpg" in rvb 256 colors no alpha layer whites lines show up to :(
Attachments
rvb 256.jpg
rvb 256.jpg (142.11 KiB) Viewed 8427 times

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Russ C.
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Re: Strange white line in my picture.

Post by Russ C. »

Hi Manuel

To start with it's important to understand that iX Developer and iX Runtime
(PC) uses WPF (which supports vector based graphics). However, the iX panels (running on Windows CE) does not support WPF.
This means that the graphics is converted from WPF/vector to raster graphics.

For the best result the picture should be in scaled 1:1 (and not stretched in anyway), otherwise the picture may become blury/fuzzy especially when transparent is selected.
The problem when pictures are stretched in iX Developer, is that iX converts the png picture to bitmap 565 format. iX panels does not support anti-aliasing/alpha channel so these pixels are converted as well.

This might result in a jagged appearance. Also, when reusing the same icon in different objects (with different sizes) will lead to that only one symbol is converted. This is then resized in runtime (which can result in lower quality). We have added a case in TFS about this:
Support Case 30555:Reusing pictures in iX application not optimal.

For best result pictures should be scaled 1:1 in iX Developer when transparency is used. Use the same resolution.

Pictures that is used in iX Developer (WinCE target) are converted to the bitmap 565 format in iX Developer when the project is built.
You can find all the pictures that are used in the real application in the "Symbols.zip" file in the BuildFiles folder in the iX project folder.

The difference is that on PC targets the original pictures are used in the application no matter how it's scaled/stretched, this will the application take care of during runtime.

On the Terminal/CE targets the pictures are already converted so when the transparency is applied you will get a fuzziness/blurriness.

This is how it works. I guess it are the limitations in .NET Compact framework that is responsible for this.
Remember that iX on PC, we have access to the full .NET framework with WPF support, which we don't have in our iX panels. Therefore graphics have to be handled in a different way.

Another problem could be the bit rate of pictures.
Remember that the panels mostly uses 16bit color (65k), make sure to reduce the number of colors when creating pictures to panels. Not doing so, might cause banding in large gradient areas of the image.
Here is a 24bit image, without modification:
(Embedded image moved to file: pic11942.jpg)
Here is that same image, displayed like the panel will display it, choosing the nearest color, notice the banding effect:
(Embedded image moved to file: pic04827.jpg)
But, by reducing the number of colors in an image manipulation program before you use it in iX Developer, the panel looks like this:
(Embedded image moved to file: pic05436.jpg)
In the picture above, we used error diffusion to reduce 24bit color to 16 bit by adding random raster noice to the picture.

I hope this helps and explains a little bit what is happening in the background when building the application.

Best,
Russ
Best regards,

Russ
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crisp90
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Joined: Tue Jul 03, 2018 4:14 am
Location: Mississauga, ON
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Re: Strange white line in my picture.

Post by crisp90 »

I did enjoy reading that thread. Thanks for sharing.

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