2014/10/15 下午 10:08:48

iphone Programming Glossary: factors

Detecting noise via mic while playing a song on iPhone

http://stackoverflow.com/questions/11993844/detecting-noise-via-mic-while-playing-a-song-on-iphone

and has higher influence. Since you should be able to detect the volume you should be able to add some correction factors. But since this is a natural problem I guess every algorithm will have this problem. Another solution would be to subtract..

obtaining the rotation and size of a UIImageView based on its transformation matrices

http://stackoverflow.com/questions/1379811/obtaining-the-rotation-and-size-of-a-uiimageview-based-on-its-transformation-mat

work forward to generate a matrix that scales and rotates and then use that to figure out how to extract the scale factors and rotations analytically. A scaling matrix to scale by Sx in the X axis and Sy in the Y axis looks like this ﹖x 0 Sy A.. to conclude that tan R Sx.sin R Sx.cos R b a and therefore R atan b a And now we know R we can extract the scale factors by using the main diagonal a Sx.cos R and therefore Sx a cos R d Sy.cos R and therefore Sy d cos R So you now know Sx Sy..

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

In what situations do you reach for drawRect Core Graphics that could also be accomplished with subviews What factors lead you to that decision How Why is drawing in one custom view recommended for buttery smooth table cell scrolling yet..

How do I programatically zoom a UIScrollView?

http://stackoverflow.com/questions/172255/how-do-i-programatically-zoom-a-uiscrollview

Designing the iPhone interface in a nib or in code?

http://stackoverflow.com/questions/1816964/designing-the-iphone-interface-in-a-nib-or-in-code

question I was once very strongly against using Interface Builder in my own projects. This was due to a number of factors. I started first working with the Xcode tools when the iPhone SDK was back in beta around March 2008 and since I didn't..

UIKeyboardFrameBeginUserInfoKey & UIKeyboardFrameEndUserInfoKey

http://stackoverflow.com/questions/3332364/uikeyboardframebeginuserinfokey-uikeyboardframeenduserinfokey

the start frame of the keyboard in screen coordinates. These coordinates do not take into account any rotation factors applied to the window 䏭 contents as a result of interface orientation changes. Thus you may need to convert the rectangle.. the end frame of the keyboard in screen coordinates. These coordinates do not take into account any rotation factors applied to the window 䏭 contents as a result of interface orientation changes. Thus you may need to convert the rectangle..

iPhone — the input parameter to UIView's sizeThatFits method

http://stackoverflow.com/questions/4016316/iphone-the-input-parameter-to-uiviews-sizethatfits-method

from the bounds property. But there are tricky situations during layout when the best size depends on not quite static factors. Take a text label for example. It may be flowed in one or more lines and the number of lines may depend on the maximum..

Getting displacement from accelerometer data with Core Motion

http://stackoverflow.com/questions/4449565/getting-displacement-from-accelerometer-data-with-core-motion

up the right low pass filtering. I cannot give a general value but as a rule of thumb experimenting with filtering factors between 0.2 and 0.8 will be a good starting point. The right value depends on the business case you need for instance what..

Slight zoom on MKCoordinateRegion?

http://stackoverflow.com/questions/4724176/slight-zoom-on-mkcoordinateregion

always jumping zooming in to far and clipping my pins. EDIT Quick tests showing the results of different scaling factors on the region SCALE FACTOR V region.span.latitudeDelta upper.latitude lower.latitude 0.9 region.span.longitudeDelta..

Default UITableViewCellStyleSubtitle font size?

http://stackoverflow.com/questions/4775107/default-uitableviewcellstylesubtitle-font-size

in code so if you want some guaranteed fixed values you'd better do that as size values may vary depending on many factors cell's style sdk version os version etc . I've tested on simulator with 4.2 SDK version and got following results no extra..

Choosing between the two - Interface Builder OR creating via code

http://stackoverflow.com/questions/6385516/choosing-between-the-two-interface-builder-or-creating-via-code

I create my UI iphone xcode cocoa touch interface builder share improve this question There are a number of factors that can influence your choice. It can come down to personal taste but there are some advantages to using Interface Builder...

CoreAudio AudioTimeStamp.mHostTime clock frequency?

http://stackoverflow.com/questions/675626/coreaudio-audiotimestamp-mhosttime-clock-frequency

multiply by ns2HTimeFactor instead of dividing by hTime2nsFactor . Of course it is a waste of time to re calculate the factors each time you need them. Those factors are constant they will never change while the system is running. Thus you can calculate.. by hTime2nsFactor . Of course it is a waste of time to re calculate the factors each time you need them. Those factors are constant they will never change while the system is running. Thus you can calculate them somewhere near the start of.. again. In Cocoa I'd recommend to write yourself a static class for everything above. You can calculate the conversion factors for either conversion in the void initialize method of the class. Cocoa guarantees that this method is for sure automatically..

Using UIPinchGestureRecognizer to scale uiviews in single direction

http://stackoverflow.com/questions/6759028/using-uipinchgesturerecognizer-to-scale-uiviews-in-single-direction

your affine transform piece.transform CGAffineTransformScale piece transform hScale vScale with different scaling factors. One way to calculate them is the following define an ivar in your class to store the lastTouchPosition in your gesture..

Is there a good charting library for iPhone? [closed]

http://stackoverflow.com/questions/769749/is-there-a-good-charting-library-for-iphone

or custom backgrounds iphone cocoa touch cocoa charts core plot share improve this question One of the many factors that motivated the Core Plot project was the lack of good plotting frameworks on the iPhone. Core Plot also encompases many..

Cost of message dispatch in Objective-C

http://stackoverflow.com/questions/907843/cost-of-message-dispatch-in-objective-c

premature optimization. You might not want to do a lot of it in an inner loop but the algorithms you choose and other factors will have a much bigger factor on how fast your code is. If it is too slow use a profiler and go from there. share improve..