2014/10/15 下午 10:04:59

iphone Programming Glossary: cg

Resizing UIimages pulled from the Camera also ROTATES the UIimage?

http://stackoverflow.com/questions/1260249/resizing-uiimages-pulled-from-the-camera-also-rotates-the-uiimage

myResizedImg I am using this to resize it UIImage resizeImage UIImage anImage width int width height int height CGImageRef imageRef anImage CGImage CGImageAlphaInfo alphaInfo CGImageGetAlphaInfo imageRef if alphaInfo kCGImageAlphaNone.. this to resize it UIImage resizeImage UIImage anImage width int width height int height CGImageRef imageRef anImage CGImage CGImageAlphaInfo alphaInfo CGImageGetAlphaInfo imageRef if alphaInfo kCGImageAlphaNone alphaInfo kCGImageAlphaNoneSkipLast.. to resize it UIImage resizeImage UIImage anImage width int width height int height CGImageRef imageRef anImage CGImage CGImageAlphaInfo alphaInfo CGImageGetAlphaInfo imageRef if alphaInfo kCGImageAlphaNone alphaInfo kCGImageAlphaNoneSkipLast..

Releasing CGImage (CGImageRef)

http://stackoverflow.com/questions/1263642/releasing-cgimage-cgimageref

CGImage CGImageRef I'm curious if I'm following proper memory management with CGImageRef which I'm passing through several.. CGImage CGImageRef I'm curious if I'm following proper memory management with CGImageRef which I'm passing through several methods.. CGImage CGImageRef I'm curious if I'm following proper memory management with CGImageRef which I'm passing through several methods since it's CG object I assume it doesn't support autorelease . Memory..

to drawRect or not to drawRect (when should one use drawRect/Core Graphics vs subviews/images and why?)

http://stackoverflow.com/questions/14659563/to-drawrect-or-not-to-drawrect-when-should-one-use-drawrect-core-graphics-vs-su

view need to be animated separately You have a relatively small view hierarchy so any perceived extra effort using CG isn't worth the gain You want to update pieces of the view without redrawing the whole thing The layout of your subviews.. drawRect against for performance reasons in general What about simple background images when do you create them with CG vs using a resizable png image A deep understanding of this subject may not be needed to make worthwhile apps but I don't..

CGImage/UIImage lazily loading on UI thread causes stutter

http://stackoverflow.com/questions/1815476/cgimage-uiimage-lazily-loading-on-ui-thread-causes-stutter

UIImage lazily loading on UI thread causes stutter My program displays a horizontal scrolling surface tiled with UIImageViews.. the scenes. Perhaps it is decompressing the JPEG data. Anyway the method is void forceLazyLoadOfImage UIImage image CGImageRef imgRef image.CGImage CGFloat currentWidth CGImageGetWidth imgRef CGFloat currentHeight CGImageGetHeight imgRef CGRect.. is decompressing the JPEG data. Anyway the method is void forceLazyLoadOfImage UIImage image CGImageRef imgRef image.CGImage CGFloat currentWidth CGImageGetWidth imgRef CGFloat currentHeight CGImageGetHeight imgRef CGRect bounds CGRectMake..

What's the difference between Quartz Core, Core Graphics and Quartz 2D?

http://stackoverflow.com/questions/1877987/whats-the-difference-between-quartz-core-core-graphics-and-quartz-2d

The Quartz 2D API is part of the Core Graphics framework so you may see Quartz referred to as Core Graphics or simply CG. I have a tendency of using Quartz and Core Graphics interchangeably when referring to 2 D drawing on the Mac iPhone even..

How to find the distance between two CG points?

http://stackoverflow.com/questions/1906511/how-to-find-the-distance-between-two-cg-points

to find the distance between two CG points When we touch with two fingers in a UIScrollView we get two CG points. I want to find the distane between them... to find the distance between two CG points When we touch with two fingers in a UIScrollView we get two CG points. I want to find the distane between them. Then like I do the pinch inside or outside . Then we will again get two.. Anyone have an idea how to do this iphone cocoa touch share improve this question Distance between p1 and p2 CGFloat xDist p2.x p1.x CGFloat yDist p2.y p1.y CGFloat distance sqrt xDist xDist yDist yDist Background Pythagorean theorem..

Drawing a PNG Image Into a Graphics Context for Blending Mode Manipulation

http://stackoverflow.com/questions/1936644/drawing-a-png-image-into-a-graphics-context-for-blending-mode-manipulation

a PNG Image Into a Graphics Context for Blending Mode Manipulation I need to draw a series of PNGs into a CG context so I can blend them together CGContextRef context UIGraphicsGetCurrentContext CGContextSetBlendMode context kCGBlendModeOverlay.. Context for Blending Mode Manipulation I need to draw a series of PNGs into a CG context so I can blend them together CGContextRef context UIGraphicsGetCurrentContext CGContextSetBlendMode context kCGBlendModeOverlay Currently I have my app.. draw a series of PNGs into a CG context so I can blend them together CGContextRef context UIGraphicsGetCurrentContext CGContextSetBlendMode context kCGBlendModeOverlay Currently I have my app working based on just drawing each image as a UIImageView..

Manually drawing a gradient in iPhone apps?

http://stackoverflow.com/questions/227005/manually-drawing-a-gradient-in-iphone-apps

even gradient between them over an arbitrarily sized area I am guessing you would create a UIView subclass and use the CG drawing methods in the drawRect method. I just don't know which ones or if there are any pitfalls to watch out for like..

UISplitViewController and complex view hierarchy

http://stackoverflow.com/questions/2640225/uisplitviewcontroller-and-complex-view-hierarchy

to which you are returning they do not autorotate instead the UISplitView which has failed to be removed due to a CG exception continues to respond to the rotation instead causing horrible rendering bugs that can't be just dealt with . At..

Determining the Colorspace of a UIImage

http://stackoverflow.com/questions/4168972/determining-the-colorspace-of-a-uiimage

it uses the RGB colorspace or not. Is there an easy way to do this without manipulating pixel data I know there's some CGColorSpace functions but none of them seem to do this just create colorspaces and manipulate them and much more advanced.. in advance. iphone uiimage cgcolorspace share improve this question You have to get the color space through CGImage. You can do it with the following line of functions properties @property nonatomic readonly CGImageRef CGImage CGColorSpaceRef.. space through CGImage. You can do it with the following line of functions properties @property nonatomic readonly CGImageRef CGImage CGColorSpaceRef CGImageGetColorSpace CGImageRef image So to get the color space of an image you'd do CGColorSpaceRef..

iOS “ current graphics context” - What is that

http://stackoverflow.com/questions/4772392/ios-current-graphics-context-what-is-that

The OS needs a place to save information such as drawing state which you don't want to specify in every single CG drawing command such as in which bitmap or view to draw the scale or other transform to use the last color you specified.. bitmap or view to draw the scale or other transform to use the last color you specified etc. The context tells each CG call where to find all this stuff for your current drawing call. Give a different context to the exact same drawing call..

How to render a radial gradient onto a new UIImage on an iphone

http://stackoverflow.com/questions/5617113/how-to-render-a-radial-gradient-onto-a-new-uiimage-on-an-iphone

GraphicsImaging Conceptual drawingwithquartz2d dq_shadings dq_shadings.html And it made me think i need to use CGShadingRef or CGGradientRef and use UIImage's 'imageWithCGImage' constructor to go from the CG to a UIImage... but i can't.. Conceptual drawingwithquartz2d dq_shadings dq_shadings.html And it made me think i need to use CGShadingRef or CGGradientRef and use UIImage's 'imageWithCGImage' constructor to go from the CG to a UIImage... but i can't figure out how... dq_shadings.html And it made me think i need to use CGShadingRef or CGGradientRef and use UIImage's 'imageWithCGImage' constructor to go from the CG to a UIImage... but i can't figure out how. Any suggestions greatly appreciated iphone..

How to draw a transparent stroke (or anyway clear part of an image) on the iPhone

http://stackoverflow.com/questions/629409/how-to-draw-a-transparent-stroke-or-anyway-clear-part-of-an-image-on-the-iphon

Yes nothing original but it's part of something larger . I have a UIImageView where the user draws by creating a CGContextRef and the various CG draw functions. I primarily draw strokes lines with the function CGContextAddLineToPoint Now.. it's part of something larger . I have a UIImageView where the user draws by creating a CGContextRef and the various CG draw functions. I primarily draw strokes lines with the function CGContextAddLineToPoint Now my issue is this The user can.. draws by creating a CGContextRef and the various CG draw functions. I primarily draw strokes lines with the function CGContextAddLineToPoint Now my issue is this The user can draw lines of various colors. I want to give him the ability to use..

Is programmatically inverting the colors of an image possible?

http://stackoverflow.com/questions/6672517/is-programmatically-inverting-the-colors-of-an-image-possible

width and height as integers since we'll be using them as array subscripts etc and this'll save a whole lot of casting CGSize size self.size int width size.width int height size.height Create a suitable RGB alpha bitmap context in BGRA colour.. self.size int width size.width int height size.height Create a suitable RGB alpha bitmap context in BGRA colour space CGColorSpaceRef colourSpace CGColorSpaceCreateDeviceRGB unsigned char memoryPool unsigned char calloc width height 4 1 CGContextRef.. int height size.height Create a suitable RGB alpha bitmap context in BGRA colour space CGColorSpaceRef colourSpace CGColorSpaceCreateDeviceRGB unsigned char memoryPool unsigned char calloc width height 4 1 CGContextRef context CGBitmapContextCreate..

Detect if CGPoint within polygon

http://stackoverflow.com/questions/8952476/detect-if-cgpoint-within-polygon

if CGPoint within polygon I have a set of CGPoints which make up a polygon shape how can I detect if a single CGPoint is inside.. if CGPoint within polygon I have a set of CGPoints which make up a polygon shape how can I detect if a single CGPoint is inside or outside of the polygon Say the shape.. if CGPoint within polygon I have a set of CGPoints which make up a polygon shape how can I detect if a single CGPoint is inside or outside of the polygon Say the shape was a triangle and the CGPoint was moving hoizontally how could I..