This is an issue for xamarin.uwp and FFImageLoading, but it reproduces only in UWP.
The issue with optimized files by Photoshop.
I optimized my images on a server with Photoshop. I exported them with option Smaller File (8-bit) after it I got black color in UWP (ios and android are ok).
When I deleted downsample parameters for CachedImage(FFImageLoading control) then transparency was back.
Example:
And files before optimization and after it
https://github.com/luberda-molinet/FFImageLoading/wiki/Xamarin.Forms-API
Says that the CachedImage class does not support transparency on iOS or Windows Phone. Perhaps since the article was written iOS support has been added but not yet UWP.
It's a bug, please make a separate issue on project site. It's related to this:
8 bit PNG can have no more than 256 colors. A part of the PNG file structure holds pointers to 256 colors and then each pixel in the image gets its color from one of those pointers. Thus each pixel only consumes one bytem its 0-255 value pointing to its color on the palette. On the other hand, a 32 bit PNG is 4 bytes per pixel and each pixel can represent a different ARGB color value.
Pixel Format
// Edit I created it: https://github.com/luberda-molinet/FFImageLoading/issues/986
Related
I was trying to use a coloured texture (PNG 24/RGB) for a POI (bicycle_parking) and it was not being rendered. It was added properly as a texture, it just won't be rendered on the POI.
After some testing I came to believe that POIs only accept grayscale textures that can later be filled up with a color. Is this right?
I also found out that the icon needs to be of a specific size (I got it working only at 32x32 pixels and 512x512, but the scaling did not make it look good). Is there any information regarding this?
Now I have a grayscale icon (mostly white) but the fill color does not change the white as expected. This is as far as I got..
Here's a set of icons similar to the ones I need to render into POIs
How could I achieve adding this type of icons as the texture of a POI? Workarounds/hacks are welcome as well :)
Thanks!
The texture of the Poi must have a size that is a power of 2 and goes from 32x32 up until 512x512. Also make sure that the colour code of that image is RGB anything else wont work. For the best visual result you have to create 3 sets of pngs for different screen densities, for example see heatmap_legend.png then look at heatmap_legend#2x.png and heatmap_legend#3x.png, you can find them in the "common" folder.
So turns out that the color wasn't a problem after all. It was quite tricky to get one image working, but once I had the image working, adding color to it and saving the PNG worked just fine.
The problem with the image size I experienced is still happening. You need to export it in 32x32, 64x64 or 96x96 in order to StyleEditor not to crash when opening the file.
I've been playing with jssor sliders, specifically with different-size-photo-slider. It works when I run the demo version, but when I add my own jpegs, generated by Aperture on OS X from RAW format, those images never finish loading. The loading animated icon just stays forever. The files and pixel sizes are not different from the jssor images. It looks like my jpegs fail to be resized. I tried both Safari and Firefox. Any ideas?
Thanks.
It looks like when I export from Aperture with the default colormap, which is sRGB IEC611966-2.1, javascript has problems resizing the picture. Using, or maybe just changing to, Adobe 1998 or Generic RGB makes things work fine. BTW. the source is Nikon raw file with sRGB color map.
I am currently working in XNA 4.0 trying to render a font that I got. The font is rendered with this:
spriteBatch.DrawString(this.font, this.text, new Vector2(10, 10), this.color);
But some of my letters gets blurry and low quality (See image)
I have tried to change the SamplerState of the GraphicDevice but that does not seem to improve anything.
-Update-
After testing one of the ideas were XNA would compress the text and in that case loosing quality i tried out to create my own font texture instead of generating one using a .spritefont. And then sending that into the contentloader, the results I managed to get was just slightly larger text but with the same artifacts.
See Image
And I was now wondering if the problem still can have to do with compressing problems or if there could be another issue making the font get a lower quality in the program compared to using it ouside the program.
The way I am currently loading my font is using
font= ContentManager.Load<SpriteFont>(FontPath);
It's because XNA uses compression for spritefonts. The possible workarounds are:
Use Nuclex framework, which includes an alternative font importer;
Make your own font texture, following the instructions from Shawn Hargreaves's blog;
In your SpriteFont definition, double the size of generated font, then draw it at half its size.
I am using PNG type image with transparent background in picturebox control with stretch Mode in Windows CE. But in pocket pc device it shows wrong behaviour. I provide its screen shot below:
How can I resolve it?
As you've discovered, ARGB transparency isn't supported in the CF. You need to change your image and then use ColorKey transparency. See the answers to this question for more links.
looks to me like you have used an alpha type png RGBA, which is not displayable by your code and its converted to RGB so just displays your background colour as one rectangle.
Greg.
So I have two images set to fill the screen - one at 320x480 (iPhone 3) and the other at 640x960 (iPhone 4).
img.png (320x480)
img#2x.png (640x960)
In Interface Builder, I have img.png set to fill the view (it shouldn't be filling the iPhone 4 view, though, right?), and when I build and run, it is notably too small.
So, when I do the opposite, setting img#2x.png as the img, a giant blue question mark fills the view. The project still builds and the image fills the screen, but is very pixelated as if it has been rescaled. It shouldn't have been rescaled, though, as it is the higher resolution.
Now using...
img.png (640x960)
img#2x.png (320x480)
I've also tried switching which file takes the #2x suffix, but that has not helped either. With the smaller file taking the #2x suffix, and setting the image view to img.png, it shows up way larger than the view canvas, but way too small when on the phone. With the smaller file still having the #2x suffix, I tried switching the view to the new img#2x.png and once again got the oversized, pixelated question mark in IB and a low res full-screen image when deployed to the phone.
I also made sure that my view size was set to 640x960 in the size inspector. What else should I be doing?
Don't use #2x when specifying the image name. Just use the base name of the image (so in your case, just img). iOS will do the magic behind the scenes to use the 2x version if it's on a retina display and the regular version otherwise (including when you use a xib to lay out your interface).
The displayed dimensions of the image will always be the dimensions of the non-2x image. The retina display just displays 2 pixels for every 1 which is why the scale is 2.0 and you have to double the dimensions of the original image. So your view size in IB should be 320x480.
Edit
If IB is being finicky, especially in Xcode 4, just try deleting the xib and starting over. Sometimes it gets a bit corrupted and doesn't know what to do with itself. I've had to do this on one or two occasions, and it seems that it worked for the OP as well.