How to use a objective-c library in monotouch

There are many nice objective-c libraries out there, and it you would loose precious time to port them in c#/monotouch.  But, with the new LinkWith attribute and the latest Monodevelop & Monotouch you can use a native library very easy.

I took for an example the iCarousel library from here wich is a great image gallery widget.

Ok, so these are the steps required:

- download the objective-c source code of iCarousel

- create a new project in Xcode ( i have Xcode 4.2 ), and call it for example "iCarousel". Choose the Cocoa Touch Static Library project type, like this:

replace the iCarousel.h and iCarousel.m files with the files from the downloaded source code.

Go to project settings.

In the "Build Settings" page, add the "i386" and "armv6" value to Architectures ( it must like like this:
"armv6 $(ARCHS_STANDARD_32_BIT)" )

Also change the "Valid Architectures" to i386 armv6 armv7.

Be sure to also change the "iOs deployment target" to the desired version.

Go to the "Build Phases" and add "-fno-objc-arc" as a value to all header files just under the "Compiler flags" ( apple select all them and press enter ).


Into the Link Binary With Libraries add:

• CoreGraphics
• UIKit
• QuartzCore

You're almost done now.  You need to only add a small script to compile for simulator also.
Insert in RunScript the fallowing script like in this screenshot:

# Version 2.0 (updated for Xcode 4, with some fixes)
# Changes:
#    - Works with xcode 4, even when running xcode 3 projects (Workarounds for apple bugs)
#    - Faster / better: only runs lipo once, instead of once per recursion
#    - Added some debugging statemetns that can be switched on/off by changing the DEBUG_THIS_SCRIPT variable to "true"
#    - Fixed some typos
#
# Purpose:
#   Create a static library for iPhone from within XCode
#   Because Apple staff DELIBERATELY broke Xcode to make this impossible from the GUI (Xcode 3.2.3 specifically states this in the Release notes!)
#   ...no, I don't understand why they did this!
#
# Author: Adam Martin - http://twitter.com/redglassesapps
# Based on: original script from Eonil (main changes: Eonil's script WILL NOT WORK in Xcode GUI - it WILL CRASH YOUR COMPUTER)
#
# More info: see this Stack Overflow question: http://stackoverflow.com/questions/3520977/build-fat-static-library-device-simulator-using-xcode-and-sdk-4

#################[ Tests: helps workaround any future bugs in Xcode ]########
#
DEBUG_THIS_SCRIPT="false"

if [ $DEBUG_THIS_SCRIPT = "true" ]
then
echo "########### TESTS #############"
echo "Use the following variables when debugging this script; note that they may change on recursions"
echo "BUILD_DIR = $BUILD_DIR"
echo "BUILD_ROOT = $BUILD_ROOT"
echo "CONFIGURATION_BUILD_DIR = $CONFIGURATION_BUILD_DIR"
echo "BUILT_PRODUCTS_DIR = $BUILT_PRODUCTS_DIR"
echo "CONFIGURATION_TEMP_DIR = $CONFIGURATION_TEMP_DIR"
echo "TARGET_BUILD_DIR = $TARGET_BUILD_DIR"
fi

#####################[ part 1 ]##################
# First, work out the BASESDK version number (NB: Apple ought to report this, but they hide it)
#    (incidental: searching for substrings in sh is a nightmare! Sob)

SDK_VERSION=$(echo ${SDK_NAME} | grep -o '.\{3\}$')

# Next, work out if we're in SIM or DEVICE

if [ ${PLATFORM_NAME} = "iphonesimulator" ]
then
OTHER_SDK_TO_BUILD=iphoneos${SDK_VERSION}
else
OTHER_SDK_TO_BUILD=iphonesimulator${SDK_VERSION}
fi

echo "XCode has selected SDK: ${PLATFORM_NAME} with version: ${SDK_VERSION} (although back-targetting: ${IPHONEOS_DEPLOYMENT_TARGET})"
echo "...therefore, OTHER_SDK_TO_BUILD = ${OTHER_SDK_TO_BUILD}"
#
#####################[ end of part 1 ]##################

#####################[ part 2 ]##################
#
# IF this is the original invocation, invoke WHATEVER other builds are required
#
# Xcode is already building ONE target...
#
# ...but this is a LIBRARY, so Apple is wrong to set it to build just one.
# ...we need to build ALL targets
# ...we MUST NOT re-build the target that is ALREADY being built: Xcode WILL CRASH YOUR COMPUTER if you try this (infinite recursion!)
#
#
# So: build ONLY the missing platforms/configurations.

if [ "true" == ${ALREADYINVOKED:-false} ]
then
echo "RECURSION: I am NOT the root invocation, so I'm NOT going to recurse"
else
# CRITICAL:
# Prevent infinite recursion (Xcode sucks)
export ALREADYINVOKED="true"

echo "RECURSION: I am the root ... recursing all missing build targets NOW..."
echo "RECURSION: ...about to invoke: xcodebuild -configuration \"${CONFIGURATION}\" -target \"${TARGET_NAME}\" -sdk \"${OTHER_SDK_TO_BUILD}\" ${ACTION} RUN_CLANG_STATIC_ANALYZER=NO"
xcodebuild -configuration "${CONFIGURATION}" -target "${TARGET_NAME}" -sdk "${OTHER_SDK_TO_BUILD}" ${ACTION} RUN_CLANG_STATIC_ANALYZER=NO BUILD_DIR="${BUILD_DIR}" BUILD_ROOT="${BUILD_ROOT}"

ACTION="build"

#Merge all platform binaries as a fat binary for each configurations.

# Calculate where the (multiple) built files are coming from:
CURRENTCONFIG_DEVICE_DIR=${SYMROOT}/${CONFIGURATION}-iphoneos
CURRENTCONFIG_SIMULATOR_DIR=${SYMROOT}/${CONFIGURATION}-iphonesimulator

echo "Taking device build from: ${CURRENTCONFIG_DEVICE_DIR}"
echo "Taking simulator build from: ${CURRENTCONFIG_SIMULATOR_DIR}"

CREATING_UNIVERSAL_DIR=${SYMROOT}/${CONFIGURATION}-universal
echo "...I will output a universal build to: ${CREATING_UNIVERSAL_DIR}"

# ... remove the products of previous runs of this script
#      NB: this directory is ONLY created by this script - it should be safe to delete!

rm -rf "${CREATING_UNIVERSAL_DIR}"
mkdir "${CREATING_UNIVERSAL_DIR}"

#
echo "lipo: for current configuration (${CONFIGURATION}) creating output file: ${CREATING_UNIVERSAL_DIR}/${EXECUTABLE_NAME}"
lipo -create -output "${CREATING_UNIVERSAL_DIR}/${EXECUTABLE_NAME}" "${CURRENTCONFIG_DEVICE_DIR}/${EXECUTABLE_NAME}" "${CURRENTCONFIG_SIMULATOR_DIR}/${EXECUTABLE_NAME}"

#########
#
# Added: StackOverflow suggestion to also copy "include" files
#    (untested, but should work OK)
#
if [ -d "${CURRENTCONFIG_DEVICE_DIR}/usr/local/include" ]
then
mkdir -p "${CREATING_UNIVERSAL_DIR}/usr/local/include"
# * needs to be outside the double quotes?
cp "${CURRENTCONFIG_DEVICE_DIR}/usr/local/include/"* "${CREATING_UNIVERSAL_DIR}/usr/local/include"
fi
fi

Okay.  Now you're ready to make the bindings :)  Just Clean & Build your project, and add the generated library file ( Attention! libiCarousel.a is in the in a folder Debug_universal or Release_universal) to your binding project in monotouch.  Be sure to make the LinkWith attribute look like this:

[assembly: LinkWith ("libiCarousel.a", LinkTarget.ArmV6 | LinkTarget.ArmV7 | LinkTarget.Simulator, ForceLoad = true, Frameworks="CoreGraphics QuartzCore UIKit")]

To make the bindings easier I'm using this little script based on the MonoMac parser class, that takes an objective-c header file and generate a c# binding interface for it.  It's not perfect, but it help's a lot.

After you make the binding interface, build your project, and the fresh new generated dll file in your projects :)

Happy coding!

Tapjoy publisher library for MonoTouch

Hello there monotouch users,

Tapjoy is a wonderful platform, but unfortunately they have not developed a library for monotouch users. And since C # is 10 times more beautiful and better for RAD than Objective-C, I decided to make it myself.

Basically I took the publishers library for XNA, and I adapted it for monotouch.

I hope this is helpful!

Download sources here.

Sample:

TapjoyConnect.Instance.TapjoyConnectCompleted += delegate(object sender, TapjoyConnectCompletedEventArgs e) 
{
 if( e.Succeeded )
  Console.WriteLine("tapjoy succeeded!");
 else
  Console.WriteLine("error; check your app id or secret key");
};
TapjoyConnect.Instance.RequestTapjoyConnect( APP_ID , SECRET_KEY );
   
   

A MonoTouch class for resize maintaining aspect ratio or crop your images

Hy guys,

I wrote a c# class for a personal project, and I'm sure it will be useful for you to. Very often we need to quickly resize an UIImage, using Thumb Resize maintaining aspect ratio or Crop Resize...

A quick example to crop and resize an image from 768x507 to 300x300:

//load a test image, with size: 768x507
UIImage img = UIImage.FromFile("test.jpg");
//initiate the resizer class
ImageResizer resizer = new ImageResizer(img);
//crop resize 
resizer.CropResize( 300,300 );
//and that's it! The image is resized & croped to exactly 300x300
UIImage croppedImage = resizer.ModifiedImage;

Or resize maintaining ratio to a maximum of 200x200:

//load a test image, with size: 768x507
UIImage img = UIImage.FromFile("test.jpg");
//initiate the resizer class
ImageResizer resizer = new ImageResizer(img);
//crop resize 
resizer.RatioResize( 200,200 ); //now it has 200x132
//and that's it! 
UIImage croppedImage = resizer.ModifiedImage;

Also you can scale it to 120% for example

//load a test image, with size: 768x507
UIImage img = UIImage.FromFile("test.jpg");
//initiate the resizer class
ImageResizer resizer = new ImageResizer(img);
//crop resize 
resizer.Scale( 120 ); //now it has 922x608
//and that's it! 
UIImage croppedImage = resizer.ModifiedImage;

So, here it is!

using System;
using MonoTouch.UIKit;
using System.Drawing;
using MonoTouch.CoreGraphics;
namespace Test
{
 public enum CropPosition
 {
  Start, Center, End
 }
 
 public class ImageResizer
 {
  UIImage initialImage  = null;
  UIImage modifiedImage = null;
  
  public ImageResizer ( UIImage image )
  {
   this.initialImage         = image;
   this.modifiedImage = image;
  }
  
  
  /// <summary>
  /// strech resize
  /// </summary>
  public void Resize( float width, float height )
  {
   UIGraphics.BeginImageContext( new SizeF( width, height ) );
   //
   modifiedImage.Draw( new RectangleF( 0,0, width, height ) );
   modifiedImage = UIGraphics.GetImageFromCurrentImageContext();
   //
   UIGraphics.EndImageContext();
  }
  
  public void RatioResizeToWidth( float width )
  {
   Console.WriteLine("resize to width: " + width  );
   var cur_width = modifiedImage.Size.Width;
   if( cur_width > width )
   {
    var ratio  = width / cur_width;
    var height = modifiedImage.Size.Height * ratio;
    //resize
    Resize( width, height );
   }
  }
  
  public void RatioResizeToHeight( float height )
  {
   Console.WriteLine("resize to height: " + height  );
   var cur_height = modifiedImage.Size.Height;
   if( cur_height > height )
   {
    var ratio = height / cur_height;
    var width = modifiedImage.Size.Width * ratio;
    //
    Resize( width, height );
   }
  }
  
  /// <summary>
  /// resize maintaining ratio
  /// </summary>
  public void RatioResize( float max_width, float max_height )
  {
   if( max_width > max_height )
   {
    RatioResizeToWidth ( max_width  );
    RatioResizeToHeight( max_height );
   }
   else
   {
    RatioResizeToHeight( max_height );
    RatioResizeToWidth ( max_width  );
   }
  }
  
  /// <summary>
  /// scaling the image with a given procent value
  /// </summary>
  public void Scale( float procent )
  {
   var width  = modifiedImage.Size.Width  * (procent / 100);
   var height = modifiedImage.Size.Height * (procent / 100);
   Resize( width, height );
  }
  
  /// <summary>
  /// default crop resize, set on center
  /// </summary>
  public void CropResize( float width, float height )
  {
   CropResize(width, height, CropPosition.Center );
  }
  
  /// <summary>
  /// resize and crop to a specific location
  /// </summary>
  public void CropResize( float width, float height, CropPosition position )
  {
   SizeF ImgSize = modifiedImage.Size;
   //
   if( ImgSize.Width  < width  ) width  = ImgSize.Width;
   if( ImgSize.Height < height ) height = ImgSize.Height;
   //
   float crop_x = 0;
   float crop_y = 0;
   if( ImgSize.Width / width < ImgSize.Height / height )
   {
    //scad din width
    RatioResizeToWidth( width );
    ImgSize = modifiedImage.Size;
    //compute crop_y
    if( position == CropPosition.Center ) crop_y = (ImgSize.Height / 2) - (height / 2);
    if( position == CropPosition.End    ) crop_y = ImgSize.Height - height;
   }
   else
   {
    //change height
    RatioResizeToHeight( height );
    ImgSize = modifiedImage.Size;
    //calculeaza crop_x
    if( position == CropPosition.Center ) crop_x = (ImgSize.Width / 2) - (width / 2);
    if( position == CropPosition.End    ) crop_x = ImgSize.Width - width;
   }
   //create new contect
   UIGraphics.BeginImageContext( new SizeF( width, height ) );
   CGContext context =  UIGraphics.GetCurrentContext();
   //crops the new context to the desired height and width
   RectangleF clippedRect = new RectangleF( 0, 0, width, height );
   context.ClipToRect(clippedRect);
   //draw my image on the context
   RectangleF drawRect = new RectangleF( -crop_x, -crop_y, ImgSize.Width, ImgSize.Height );
   modifiedImage.Draw( drawRect );
   //save the context in modifiedImage
   modifiedImage = UIGraphics.GetImageFromCurrentImageContext();
   //close the context
   UIGraphics.EndImageContext();
   
  }
 

  public UIImage InitialImage 
  {
   get 
   {
    return this.initialImage;
   }
  }

  public UIImage ModifiedImage 
  {
   get 
   {
    return this.modifiedImage;
   }
  }
 }
}