Thursday, 23 February 2012

Touch4Apps Blog | posts about iPhone : iPad : iPod app development

When working with the video capture, the image buffer is not usually enough and we need to pick up the UIImage from the buffer.

UIImage ImageFromSampleBuffer (CMSampleBuffer sampleBuffer)
			{
				// Get the CoreVideo image
				using (var pixelBuffer = sampleBuffer.GetImageBuffer () as CVPixelBuffer){
					// Lock the base address
					pixelBuffer.Lock (0);
					// Get the number of bytes per row for the pixel buffer
					var baseAddress = pixelBuffer.BaseAddress;
					int bytesPerRow = pixelBuffer.BytesPerRow;
					int width = pixelBuffer.Width;
					int height = pixelBuffer.Height;
					var flags = CGBitmapFlags.PremultipliedFirst | CGBitmapFlags.ByteOrder32Little;
					// Create a CGImage on the RGB colorspace from the configured parameter above
					using (var cs = CGColorSpace.CreateDeviceRGB ())
					using (var context = new CGBitmapContext (baseAddress,width, height, 8, bytesPerRow, cs, (CGImageAlphaInfo) flags))
					using (var cgImage = context.ToImage ()){
						pixelBuffer.Unlock (0);
						return UIImage.FromImage (cgImage);
					}
				}
			}

 

Tags , , , ,
AddThis Social Bookmark Button

When working with UIDatePicker time mode, it is typical that the time is picked in UTC and it needs to be converted to the local time and DateTime representation for purposes of showing it, setting up an alarm and such.

 

NSDate sourceDate = picker.Date;
 
NSTimeZone sourceTimeZone = new NSTimeZone ("UTC");
NSTimeZone destinationTimeZone = NSTimeZone.LocalTimeZone;
 
int sourceGMTOffset = sourceTimeZone.SecondsFromGMT (sourceDate);
int destinationGMTOffset = destinationTimeZone.SecondsFromGMT (sourceDate);
int interval = destinationGMTOffset - sourceGMTOffset;
 
var destinationDate = sourceDate.AddSeconds (interval);
 
var dateTime = new DateTime(2001, 1, 1, 0, 0, 0).AddSeconds(destinationDate.SecondsSinceReferenceDate);

 

Happy coding!

 

Tags , , , ,
AddThis Social Bookmark Button

The standard UIPageControl does not allow custom sizes and colors for the page indicators. This is an implementation that fixes that.

 

using System;
using System.Drawing;
 
using MonoTouch.Foundation;
using MonoTouch.UIKit;
using MonoTouch.CoreGraphics;
 
namespace MonoTouch.UIKit.Extensions
{
	public enum PageControlType
	{
		OnFullOffFull,
		OnFullOffEmpty,
		OnEmptyOffFull,
		OnEmptyOffEmpty
	}
 
	public class PageControl : UIControl
	{
		private int numberOfPages;
		public int Pages 
		{ 
			get
			{
				return numberOfPages;
			}
 
			set
			{
				// make sure the number of pages is positive
				numberOfPages = Math.Max(0, value);
 
				// we then need to update the current page
				currentPage = Math.Min(Math.Max(0, currentPage), numberOfPages - 1);
 
				// correct the bounds accordingly
				this.Bounds = this.Bounds;
 
				// we need to redraw
				this.SetNeedsDisplay ();
 
				// depending on the user preferences, we hide the page control with a single element
				if (HidesForSinglePage && (numberOfPages < 2))
					this.Hidden = true;
				else
					this.Hidden = false;
			}
		}
 
		private int currentPage;
		public int CurrentPage 
		{ 
			get
			{
				return currentPage;
			}
 
			set
			{
				// no need to update in that case
				if (currentPage == value)
					return;
 
				// determine if the page number is in the available range
				currentPage = Math.Min(Math.Max(0, value), numberOfPages - 1);
 
				this.SetNeedsDisplay ();
			}
		}
 
		private bool hidesForSinglePage;
		public bool HidesForSinglePage 
		{ 
			get
			{
				return hidesForSinglePage;
			}
 
			set
			{
				hidesForSinglePage = value;
 
				// depending on the user preferences, we hide the page control with a single element
				if (hidesForSinglePage && (numberOfPages < 2))
					this.Hidden = true;
			}
		}
 
 
		public bool DefersCurrentPageDisplay { get; set; }
		public PageControlType ControlType  { get; set; }
		public UIColor OnColor { get; set; }
		public UIColor OffColor { get; set; }
 
		public float IndicatorDiameter { get; set; }
		public float IndicatorSpace { get; set; }
 
		private const float kDotDiameter = 4.0f;
		private const float kDotSpace = 12.0f;
 
		/// <summary>
		/// Initializes a new instance of the <see cref="ieMobile.PageControl"/> class.
		/// </summary>
		/// <param name='ct'>
		/// Ct.
		/// </param>
		/// <param name='frame'>
		/// Frame.
		/// </param>
		public PageControl (PageControlType ct, RectangleF rect) : base (rect)
		{
			ControlType = ct;
			DefersCurrentPageDisplay = false;
 
			this.BackgroundColor = UIColor.Clear;			
		}
 
		/// <summary>
		/// Sizes for number of pages.
		/// </summary>
		/// <returns>
		/// The for number of pages.
		/// </returns>
		/// <param name='pageCount'>
		/// Page count.
		/// </param>
		public SizeF SizeForNumberOfPages (int pageCount)
		{
			float diameter = (IndicatorDiameter > 0) ? IndicatorDiameter : kDotDiameter;
			float space = (IndicatorSpace > 0) ? IndicatorSpace : kDotSpace;
 
			return new SizeF(pageCount * diameter + (pageCount - 1) * space + 44.0f, Math.Max(44.0f, diameter + 4.0f));
		}
 
		/// <summary>
		/// Draws the rect.
		/// </summary>
		/// <param name='area'>
		/// Area.
		/// </param>
		/// <param name='formatter'>
		/// Formatter.
		/// </param>
		public override void Draw (RectangleF area)
		{
			base.Draw (area);
 
			// get the current context
			CGContext context = UIGraphics.GetCurrentContext ();
 
			// save the context
			context.SaveState ();
 
			// allow antialiasing
			context.SetAllowsAntialiasing (true);
 
			// get the caller's diameter if it has been set or use the default one 
			float diameter = (IndicatorDiameter > 0) ? IndicatorDiameter : kDotDiameter;
			float space = (IndicatorSpace > 0) ? IndicatorSpace : kDotSpace;
 
			// geometry
			RectangleF currentBounds = this.Bounds;
			float dotsWidth = this.Pages * diameter + Math.Max(0, this.Pages - 1) * space;
			float x = currentBounds.GetMidX () - dotsWidth / 2;
			float y = currentBounds.GetMidY () - diameter / 2;
 
			// get the caller's colors it they have been set or use the defaults
			CGColor onColorCG = OnColor != null ? OnColor.CGColor : UIColor.FromWhiteAlpha(1.0f, 1.0f).CGColor;
			CGColor offColorCG = OffColor != null ? OffColor.CGColor : UIColor.FromWhiteAlpha(0.7f, 0.5f).CGColor;
 
			// actually draw the dots
			for (int i = 0; i < Pages; i++)
			{
				RectangleF dotRect = new RectangleF (x, y, diameter, diameter);
 
				if (i == CurrentPage)
				{
					if (ControlType == PageControlType.OnFullOffFull || ControlType == PageControlType.OnFullOffEmpty)
					{
						context.SetFillColorWithColor (onColorCG);
						context.FillEllipseInRect(dotRect.Inset (-1.0f, -1.0f));
					}
					else
					{
						context.SetStrokeColorWithColor (onColorCG);
						context.StrokeEllipseInRect (dotRect);
					}
				}
				else
				{
					if (ControlType == PageControlType.OnEmptyOffEmpty || ControlType == PageControlType.OnFullOffEmpty)
					{
						context.SetStrokeColorWithColor (offColorCG);
						context.StrokeEllipseInRect (dotRect);
					}
					else
					{
						context.SetFillColorWithColor (offColorCG);
						context.FillEllipseInRect (dotRect.Inset (-1.0f, -1.0f));
					}
				}
 
				x += diameter + space;
			}
 
			// restore the context
			context.RestoreState ();
		}
 
		/// <summary>
		/// Toucheses the ended.
		/// </summary>
		/// <param name='touches'>
		/// Touches.
		/// </param>
		/// <param name='evt'>
		/// Evt.
		/// </param>
		public override void TouchesEnded (NSSet touches, UIEvent evt)
		{
			base.TouchesEnded (touches, evt);
 
			// get the touch location
			UITouch theTouch = touches.AnyObject as UITouch;
			PointF touchLocation = theTouch.LocationInView (this);
 
			// check whether the touch is in the right or left hand-side of the control
			if (touchLocation.X < (this.Bounds.Size.Width / 2))
				this.CurrentPage = Math.Max(this.CurrentPage - 1, 0) ;
			else
				this.CurrentPage = Math.Min(this.CurrentPage + 1, Pages - 1) ;
 
			// send the value changed action to the target
			this.SendActionForControlEvents (UIControlEvent.ValueChanged);
		}
	}
}

 

Usage is pretty simple.

 

var pageControl = new PageControl (PageControlType.OnFullOffFull, rectanglePosition);
pageControl.OnColor = UIColor.Blue;
pageControl.OffColor = UIColor.DarkGray;
pageControl.Pages = num of pages;

 

Happy coding!

 

 

Tags , , , ,
AddThis Social Bookmark Button

Ever had the problem installing any mpkg installer? Happened to me today, I received for no apparent reason information that JavaScript check failed during the iOS SDK installation. Was not able to resolve in a normal way, so had to hack a bit, here it is how (BTW works for any mpkg file, not only Xcode with iOS SDK).

1. extract the mpkg package with XAR (xar -xf path_to_your_installer.mpkg)
2. locate the dist file in the  content subdirectory (iPhoneSDKSL.dist in this case)
3. open it in some text editor (vi will be fine in this case)
4. check the volume check function there and just change to JS code to return true:

function volumeCheck()
{
return true;
}

function volumeCheck() { return true; }

5. close the text edit and save the file
6. repackage the mpkg back with XAR (xar -cf iOSDSDKInstall.mpkg path_to_the_extracted_location)
7. run the new package and all is well

BTW. if you use PathFinder app you can save lots of manual work, just right click the MPKG, select show content, then click the dist file and select open with and edit it in place. save it and that is it, PathFinder will repackage for you.

Happy hacking (in this case). 

 

AddThis Social Bookmark Button
AddThis Social Bookmark Button