OS X Graphics Display

jaredbkt

Registered
Does Mac OS X use vector graphics to draw the images on screen? I know that OpenGL is the main rendering engine, but I tought that because the icons can resize so smoothly they might be vector. Anyone know? Thanks.
 
OSX’s graphic system is very complex and powerful.

Graphic compositing is done by "Quartz" - which is based on display PDF - which is not yet Open GL accelerated (“Quartz Extreme”_which means OpenGL accelerated Quartz compositing is a feature in Jaguar) - every window is stored in a buffer and does not to be redrawn if windows overlap etc. - the windowserver keeps everything in that buffer.

But to come back to your question: No - icons are not vector-graphics but 128x128 pixel bitmap pictures that are scaled down by quartz
 
what is the difference between pixel-bitmap and vector? I am in need of enlightenment. also, are there any other types of images besides those two?
 
Originally posted by xaqintosh
what is the difference between pixel-bitmap and vector? I am in need of enlightenment. also, are there any other types of images besides those two?

There are generally two types of images - pixelbased (like TIFF, JPEG, GIF etc) and vector-based (EPS etc) - pixel-images consist of pixels describing the color for every pixel in the image. Vector-images are using lines and fills to describe a picture - so what’s the difference for the user?

At example you have 2 images - one is a bitmap-image and the other is vectorbased and there are about a size of 200x200 pixel (which does not apply for the vectorbased image anyways but lets say you have two windows open with every image and they are exactly the same size) - if you now zoom the image to 200% in the bitmap-image you see that the quality goes down (like in the example) because the program you are using have to stretch 1 pixel to 4 pixel - but on the vector-based image the quality remains - your program recalculates all lines and fills.

So thats great - why not use vector images for photos?
Because a vecor-image has to be created from strokes and fills and is commonly used for drawings - and bitmap images are used for photos

Any more questions? :)

original.jpg
Original, 100% Zoom
bitmap2x.jpg
Bitmap, 200% Zoom
vector2x.jpg
Vector, 200% Zoom
illu.jpg
Outlines

You see that the resized bitmap-image looks jagged and you see at the vector-image that it has not lost quality (uhm.. and that i need to have to spend more work on smooth lines ;) ) and on the last image you see that the vector-image consits of lines and fills

(Like always: sorry for my english)
 
let me splain a little further for ya :)

pixel based images are basically images made up of dots, this is where you see dpi and ppi from dots per inch and pixels per inch, since dots make up the image if you enlarge it you will basically see larger dots, and thus if you enlarge a pixel image you lose detail, also the more dots you have the more detail you have, and the more dots you have per inch (in printing) the more clear an image appears

vector based images are images made up of lines and shapes and the what not based on mathematics. since the image is based on mathematics, there is no loss in detail as the image size increases, just the detail itself will become larger.

vector graphics can indeed be used for a photograph, in fact genuine fractals does this, in one way and streamline does this in another, genuine fractals is a program that converts pixel based images into vector based with the purpose of enlarging an image and keeping as much clarity as possible, but you will still not get a clear image as you are still working with a pixel based image from the outset, and you cant create detail out of nothing when enlarging ;) as for streamline it is a conversion program for the purpose of using the graphic in a vector program like illustrator and is used more with line drawings and the such that you would scan in

as far as the operating system and the icons go, i could have sworn that the icons were pdf driven and vector based themselves, because it seems you can make them larger than 128x128 and still look quite clear (ever try the icon screen saver?) anyways im probably wrong :) im just going by the way they look to me as a graphic designer :)
 
Originally posted by BuddahBobb
let me splain a little further for ya :)
as far as the operating system and the icons go, i could have sworn that the icons were pdf driven and vector based themselves, because it seems you can make them larger than 128x128 and still look quite clear (ever try the icon screen saver?) anyways im probably wrong :) im just going by the way they look to me as a graphic designer :)

The icons in macosx are generally stored in various resolutions in an .icns file in the application's bundle - the sizes are 16x16, 32x32,64x64,96x96 and 128x128 and quartz calculates the steps between this sizes (if there is only one 128x128 icon quartz theoretically would also calculates the other sizes)

If you try the shareware Iconograher (you can get it at versiontracker.com) you see that icons consists of pixel-based images at sizes up to 128x128
 
It's an inside joke from another Forum.

Bobb- You might want to revise your sig for here. Admin's not quite as lenient as Kenji as far as cursing is concerned.
 
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