2014/10/15 下午 10:11:20

iphone Programming Glossary: measuring

Scaling AR pictures based on the distance from the camera

http://stackoverflow.com/questions/11913355/scaling-ar-pictures-based-on-the-distance-from-the-camera

proper perspective when you don 脌 stand directly in front of them. I think I have achieved that goal more or less. By measuring the initial heading from the iPhone to a picture I can decide about the rotation angle of the pictures as viewed by the..

Detect touches only on non-transparent pixels of UIImageView, efficiently

http://stackoverflow.com/questions/13291919/detect-touches-only-on-non-transparent-pixels-of-uiimageview-efficiently

goes on you may have to convert the point before checking the pixel data. Appears to work pretty quickly to me. I was measuring approx. 0.1 0.4 ms for this method call. It doesn't do the interior space and is probably not optimal. share improve this..

Bluetooth LE RSSI for proximity detection iOS

http://stackoverflow.com/questions/15687332/bluetooth-le-rssi-for-proximity-detection-ios

things like 'at the keyboard' and 'relocated' moved away through a specific door openning or direction. Likewise measuring a field by randomly dancing through the room changing orientation a lot does work well once the receiver antenna lobes got..

Large scrolling background in OpenGL ES

http://stackoverflow.com/questions/217822/large-scrolling-background-in-opengl-es

OpenGL implementation would be smart enough to discard the invisible portion of the background but according to some measuring code I wrote it looks like background takes 7 ms to draw on average and 84 ms at maximum. This is measured in the simulator...

Navigation bar show/hide

http://stackoverflow.com/questions/2926914/navigation-bar-show-hide

view subclass override its touchesEnded withEvent method and count how many touches you get in a duration of time by measuring the time between two consecutive taps perhaps with timeIntervalSinceDate . Or test the result from touch tapCount . If you..

Corelocation framework does not produce accurate distances

http://stackoverflow.com/questions/3118773/corelocation-framework-does-not-produce-accurate-distances

ignores height or just doing some better filtering on the points you use. I'm struggling to find a reliable way of measuring location distance speed with the iPhone 3GS . and iPad or Touch is just going to be worse I guess. If you can drop me a..

finding location of specific characters in UILabel on iPhone

http://stackoverflow.com/questions/3191049/finding-location-of-specific-characters-in-uilabel-on-iphone

with a custom image iphone coordinates uilabel character cgpoint share improve this question The basic tools for measuring text on iPhone are in UIStringDrawing.h but none of them do what you need. You will basically have to iterate through substrings.. but none of them do what you need. You will basically have to iterate through substrings one character at a time measuring each. When a line wraps the result is taller split after the last character that did not wrap and add the line height to..

Measure network traffic programmatically on iPhone

http://stackoverflow.com/questions/4313358/measure-network-traffic-programmatically-on-iphone

network traffic programmatically on iPhone I'm interested in measuring the network traffic for my application. Ideally I would need to separate wireless from 3G network traffic. I can't seem..

iPhone - Backgrounding to poll for events

http://stackoverflow.com/questions/4656214/iphone-backgrounding-to-poll-for-events

know if this is the approach of the apps you mentioned before but it works for me. Hope I could help Update After measuring the time of the BG task there was a surprise. The BG Task is limited to 600 seconds. This is the exact minimum time of the..

Iphone - when to calculate heightForRowAtIndexPath for a tableview when each cell height is dynamic?

http://stackoverflow.com/questions/4823197/iphone-when-to-calculate-heightforrowatindexpath-for-a-tableview-when-each-cel

the sizeWithFont methods on the relevant string to do the calculations. This is quicker than building a view and then measuring the result. Note that if you change the height of a cell you will need to either reload the whole table with reloadData..

programatically measuring carrier's signal strength in iPhone device

http://stackoverflow.com/questions/4954389/programatically-measuring-carriers-signal-strength-in-iphone-device

measuring carrier's signal strength in iPhone device I am developing a non appstore app. I want to read the carrier's signal strength..

iPhone - What does the gyroscope measures? Can I get an absolute degree measurement in all axis?

http://stackoverflow.com/questions/5112536/iphone-what-does-the-gyroscope-measures-can-i-get-an-absolute-degree-measurem

with the gyroscope using Core Motion. After a few tests this is my question. What information is exactly the gyroscope measuring absolute angles I mean suppose I hold my phone in portrait at exactly 90 degrees and start sampling. These may be not the..

how do I calculate heightForRowAtIndexPath when the cell is not even constructed yet?

http://stackoverflow.com/questions/5294356/how-do-i-calculate-heightforrowatindexpath-when-the-cell-is-not-even-constructed

Draw Line with gesture

http://stackoverflow.com/questions/6436990/draw-line-with-gesture

NSValue valueWithCGPoint gR locationInView gR.view Points addObject value holderView setNeedsDisplay NSLog @ End of measuring and I will use the points in Points to draw line above all the subviews in void drawRect CGRect rect NSLog @ Entered Draw..

Need to find Distance using Gyro+Accelerometer

http://stackoverflow.com/questions/6647314/need-to-find-distance-using-gyroaccelerometer

find the total displacement you just do dl sqrt dx dx dy dy dz dz Gyroscope is not necessary for this but if you are measuring linear distances you can use the gyroscope reading to control that rotation of the device was not too large. If rotation..

Detecting iPhone mute switch in iOS 5

http://stackoverflow.com/questions/8158087/detecting-iphone-mute-switch-in-ios-5

switch in iOS 5 . However I have I tried a technique mentioned elsewhere to detect this by playing an audio file and measuring its runtime. However even though my iPhone was muted the audio file still played the entire duration. I'm using AVAudioPlayer..

How can I get a precise time, for example in milliseconds in Objective-C?

http://stackoverflow.com/questions/889380/how-can-i-get-a-precise-time-for-example-in-milliseconds-in-objective-c

precision. In order to calculate millisecond time accuracy you can do Get a current time for where you want to start measuring from NSDate date NSDate date do work... Find elapsed time and convert to milliseconds Use modifier to conversion since receiver..

What's the difference between frame and layout in Interface builder's size inspector?

http://stackoverflow.com/questions/914102/whats-the-difference-between-frame-and-layout-in-interface-builders-size-inspe

case. What is the difference iphone interface builder share improve this question When lining controls up and measuring their distances from each other it's often desirable to think about the controls' locations in terms of the visual space.. is the name Interface Builder uses for this concept. The layout rectangle is useful to look at for applications of measuring and sizing. The Apple Human Interface Guidelines might make the statement that Two push buttons aligned vertically and horizontally..

Measuring velocity via iPhone SDK

http://stackoverflow.com/questions/1994018/measuring-velocity-via-iphone-sdk

velocity via iPhone SDK I need to implement a native iPhone app to measure the velocity of the phone basically a speedometer..

Measuring time the vehicle takes to accelerate in iPhone

http://stackoverflow.com/questions/4654864/measuring-time-the-vehicle-takes-to-accelerate-in-iphone

time the vehicle takes to accelerate in iPhone How to measure time the vehicle takes to accelerate from 0 to 100 km h 0..

Measuring the UITableView Scrolling Performance - iphone

http://stackoverflow.com/questions/5459708/measuring-the-uitableview-scrolling-performance-iphone

the UITableView Scrolling Performance iphone I am trying to measure the scrolling performance for my UITableView between..

Measuring time Interval Since Now

http://stackoverflow.com/questions/6144966/measuring-time-interval-since-now

time Interval Since Now anyone know or can provide some example code relating to timeIntervalSinceNow method... I need..

Draw Line with gesture

http://stackoverflow.com/questions/6436990/draw-line-with-gesture

the points in Points to draw line above all the subviews in void drawRect CGRect rect NSLog @ Entered Draw In Rect if Measuring UIColor redColor setStroke UIBezierPath pathToDraw UIBezierPath bezierPath for int n 1 n Points count 1 n NSValue value..

How to measure true FPS performance of OpenGL ES?

http://stackoverflow.com/questions/6586635/how-to-measure-true-fps-performance-of-opengl-es

was a way to get that FPS value. The real one. How iphone objective c ios opengl es share improve this question Measuring OpenGL ES performance by framerate may not be the best approach . I've taken to recording frame time myself which seems..