QUESTION :
According to my understanding if pixels per inch are increased on the screen, the content should only look better.
Now when I use my Mac I see a lot of programs which have blurry text when viewed on a Retina display. Why does every app need to be updated to work with retina display on mac?
Edit:
I wanted to add something more interesting, if you install Windows on a mac pro retina with all the latest drivers it would look absolutely gorgeous. The Win7 drivers support retina display really well and I don’t have to install applications on Win7 that support retina display specially.
So I feel that it is something which which is only done by OSx because everything works fine in Windows really.
ANSWER :
If PPI is increased, the app should look smaller. If it has to appear the same size as before then it needs to be suitably scaled. Now with vector graphics this is not a problem since these are resolution independent, but most apps employ a lot of bitmap/raster graphics resources which are resolution dependent. Scaling the latter can lead to varying amounts of blurriness depending on the image’s properties, the amount to be scaled, the scaling algorithm employed and so on.
FULL DISCLOSURE: I don’t know, here is what I think.
if you just up the resolution you get more screen real estate. However, if the display size stays the same everything gets a lot smaller. So, Apple put a display with a very large number of pixels and then turned down the dots per inch in the operating system to make everything take up more space, so in the end things seem the same size
Why does this make some apps look bad? I’m guessing they override GUI drawing api’s and the OS scales the resolution for these apps instead of the DPI which makes them look stretched.
If you use the “Best (Retina)” setting so that everything is pixel-doubled:
Images and icons look about the same because of integral scaling. But text in non-Retina apps looks clearly worse. The difference is that on a non-Retina display, text uses sub-pixel rendering. But with Retina, old apps use full-pixel anti-aliasing instead. (Those full pixels are then multiplied perfectly with integral scaling.)