Two videos and slides of the April Cocoaheads meeting is now available online. For details, see Scott Stevenson's blog entry. There's a total of some 750MB of material.

It featured Scott (seen above) on user interface design, and Joar (below) digging into the debugger.

I'm in the audience asking intelligent questions.

Tags: Cocoa, CocoaHeads, Mac OS X, Movies, Xcode

Alex Cone wins the prize for the geekiest name tag at the first Silicon Valley iPhone Developer meeting put together by Tim Burks.

Chi-Hua Chien of KPCB talked about the iFund, KPCB's $100 million fund for investing in new iPhone applications. The meeting was well-attended: probably close to 80 people there.

Tags: iPhone, Xcode

I managed to code myself into a corner writing my Mac application. IKImageBrowserView has some quirks and when I tried to reorganize the structure of my code, I couldn't get it to work at all. The changes were combined with Interface Builder alterations as well, so it was complicated.

I have an alternate approach, but I have to undo the changes I made. Subversion to the rescue. I have a subversion repository set up and so I can revert to a previous version. But how? The subversion functionality in XCode is very limited: it's really only any good for checking in new versions and looking at history. There is no way to see the structure of past versions and no way to revert any more than single files.

The answer was to tag the current version by copying it to the tags subversion folder and then check out the older version. I did all of that with snvx. It's a simple but functional GUI subversion client.

My subversion repository has moved from its old location that I set up with Tiger. I had hoped to be able to access it from my laptop over AFP, but locking does not work. So I moved it to an HTTP server-based repository. There are plenty of places on the web that detail how to set it up with Leopard, and it was simple to do. Next I need to figure out how to do ssh tunneling and I'll have a remote access solution.

Tags: Subversion, Xcode, Programming, Dead Ends

James Duncan Davidson has posted an interesting article about his meeting with Apple's Aperture team. He told them what irked him about Aperture as a photographer and they went off and fixed it. But how did they fix it?

I've looked a little at the internals of Aperture 2.0 and there are some striking differences between the two. It looks as if the whole core of the application has been rewritten.

Here is one thing I found. That diagram below is the data model for Aperture 1.5. The boxes represent information stored about things like versions, albums, vaults, adjustments etc., all the things that are carefully managed by Aperture and kept in a consistent state, all the things that are needed to display and manipulate images through the interface:

What matters is the number of lines in the diagram. I reckon there are about twenty. Each one is a relationship between the data in the boxes and many lines means much complexity and lots of work to keep things in order. And the impact of complexity grows very quickly as the number of items increases.

Now have a look at the data model for Aperture 2.0:

Still plenty of boxes, several more in fact, but hardly any lines. And only two are actual relationships, the two in the center representing inheritance instead. This means that Apple has eradicated the complexity inherent in the data model and moved it elsewhere, clearly to something faster.

This is at least partly why Aperture 2.0 is so much faster than Aperture 1.5. The other benefit of removing the complexity is that reliability should increase, so I'm hoping for a more stable, less buggy application.

For anyone wondering how I got hold of the data models for Aperture; it was easy. I just decompiled the .mom file in the application with Xcode.

Tags: Aperture, Cocoa, Core Data, Xcode

There are many changes in Cocoa beyond the obvious XCode enhancements and brand new Interface Builder. I have had scant time to delve into all of this, but Matt Gemmell has, and he has posted a long list of improvements that have been provided for us behind the scenes.

Behind the scenes views must be his forte because his about page reveals every last detail about him, down to the color of his underwear (well almost -- but it does mention socks).

Tags: Cocoa, Leopard, Socks, Xcode, Mac OS X

Leaves as artwork clearly represent the current frontier of web design. Now we have Versions, available as a beta that promises to make subversion easy to use on the Mac. That would be very nice since I use an assortment of tools right now and it is not a very satisfactory arrangement.

Linus argues that none of this is worth anything (the video is long but worth the time -- much clearer than reading the text of the talk). The comments are all over the map. That's a good sign that he is right. If the experience of users is so scattered that no-one can even agree what the problem is, then something is seriously wrong. What exists today is barely usable. It just doesn't feel that way because having anything is so much better than having nothing at all.

Tags: Subversion, Leaves, Xcode

The logging I have been doing is very primitive. I call NSLog() to see what I want to see and have to manually insert and remove these calls (or mess with comments) to control what is going on. It's time for something better. Looking around, I found a handy logging class at Borkware that does much of what I want called MLog.

It implements a logging system that includes the line number and source file name with each message. This is very useful for understanding what is happening when reading the logs. The change I made to that code was to add control over the logging level.

Here are the definitions for my version of MLog.h. I implement seven levels and add the ability to revert to standard NSLog() calls, or to remove all the logging code completely:

Macros take care of inserting the correct code and extracting the file name and line number from the preprocessor. The class implements two class methods: one for actually logging messages, and one for setting the current log level. The idea of the level control is that the minimum log level can be set either by an environment variable or by code and only messages logged at that level or above will be shown.

The Implementation includes a static variable that holds the current log level:

Initialization is done in the class initializer:

It reads the environment variable MLogMinLevel and uses that to set the initial level. The logging code compares the logging level passed to the method with the current level and ignores those below the minimum:

The level setter code is very simple:

To use the logging, I add lines like this to my code:

and it provides messages that look like this that include the level, the file name and the line number:

Since I provide logging control with an environment variable, I can quite easily create build configurations that behave differently. If I go to the Project menu and select Edit Project Settings I can duplicate the current Debug and Release configurations and make two new ones:

Clicking on on the Build tab lets me set these up:

I edit the preprocessor macros to include the symbols I need to control the logging system. The Release No Logging configuration sets __BTREMOVE-LOGGING, for instance. Once set up I can change the current configuration I want to build and run from the main XCode window just by selecting it:

For this to fully work I edit the custom scripts I added to copy the executable and run Aperture, since the build names have changed and there are more of them.

The other parts of this series can be found via the Cocoa page.

Tags: Aperture, Plug-ins, Cocoa, Random Wok, Xcode, Logging

Random Wok is only being compiled for Intel right now. I need a universal binary so that it will run on the PowerPC architecture as well. This is easy to change. I select the Random Wok target:

Then click on the Info button, and under the Architectures tab, select what I need:

That's all there is to it. Everything happens behind the scenes.

The other parts of this series can be found via the Cocoa page.

Tags: Aperture, Plug-ins, Random Wok, Cocoa, Xcode, Universal Binary

To use my Random Wok project I have to check it out. While the files are in the database they are inaccessible to normal file operations. I will do the check out in svnX.

I'm going to check out all the files in the trunk virtual folder to a new folder called Random Wok in my Documents/Progging/Working folder. First I create that new folder. Then in svnX I select the trunk virtual folder in the browser at the bottom click on the svn checkout button and select Working/Random Wok as the folder to check out to. svnX creates the folder for me and fills it with the files:

svnX has a browser built in for looking at working copies. Opening that shows me the working version I just checked out and lets me give it a more descriptive name:

Double-clikcing on the line shows me a browser that I can use to see the file status:

Now I can get back into XCode. I double click to open the XCode project that was checked out and set it up to use subversion. From the SCM menu I select Configure SCM... and set it up like this:

I change the build location and the location for intermediate files, and enable and select the SCM. I also found it necessary to clicked on Rebuild Code Sense Index for XCode to have the data it needs about my source files. To fully set up the build destination I select the target and change the Build Products Path for all configurations to be that Random Wok Folder:

Now the SCM tab for my project looks like this, showing the initial check-in:

Now I can enable the SCM status display by selecting the Random Wok project icon at the top of the XCode project list and control-clicking on the column header:

Now if I edit a file and save it I get a status change, M, showing modified:

Also shows up in the SCM smart folder on left:

Another thing I need to do is to tell snv that the pbxuser files are binary. This will prevent svn trying to merge them. To do that I go back into the terminal:

How does svn know where the repository is? There is a hidden folder called .svn in the checked out folder. In fact there are hidden .svn folders in all the folders.

Lastly I commit my updated version to the repository. I select all the files to update and from the menu use CMS > Commit Changes, and fill in the commit message:

With the files checked out I can compile and use my project just as I did before I used subversion. Each time I get to a good stopping point, I check in the files.

Eventually I will have a version that I want to release. And that means using svnX again.

The other parts of this series can be found via the Cocoa page.

Tags: Subversion, Xcode, Random Wok, Checking Out

For a long time I have wanted to implement a version control system. The attraction is being able to gain control over my code without simply making duplicates of the project folders. In particular I want to be able to fork and merge different code bases and roll back to working versions. As soon as I involve anyone else in the development process (even testers), it is no longer just me and all this becomes a necessity.

So I am going to install subversion and move my active projects over to it. I have been reading up on subversion for a while on and off, and think that I understand it well enough to implement it and blog it. For the record I'm using XCode 2.4.1, subversion 1.4.3, Mac OS X 10.4.8. Since the interaction among these changes, bugs get fixed, and features get added, not all of this article will stand the test of time.

I'm going to concern myself with just a local repository. I don't need remote access yet, so that will do. This decision means that I don't have to deal with Apache, WebDAV, and a host of other issues that make the set up complex.

A significant cause of confusion is the number of folder hierarchies that have to be understood and managed in the setting up and running of subversion. So to make what I am doing crystal clear, I have some diagrams to illustrate and am using color to differentiate the parts.

I have to work with three different folder hierarchies, so I better get organized.

The first hierarchy is my current project, Random Wok. Its project folder is called Random Wok and its path is Documents/Progging/Cocoa/Aperture/. Inside Random Wok is the XCode project file, the Build folder, and all the source files and resources. Once I have put the project into my repository I will mothball the Random Wok folder. Currently I create new versions by duplicating the Random Wok folder and numbering them. These files and folders are yellow:

The second hierarchy is a new one. To use subversion I will put my code into a folder called trunk that lives inside a virtual folder hierarchy inside subversion repository. That repository (implemented inside a folder) will itself be one of a number, all organized into a real folder hierarchy on my hard drive. As per the subversion documentation, I will also have a branches folder and a releases folder at the same level as the trunk folder. So my first step is to create a folder Documents/Progging/Repositories on my hard drive. That is the real folder that will hold all my repositories. The first one will be called Random Wok Repository and will hold one project. These files and folders will be red.

The third hierarchy I have to concern myself with is that of the checked-out code. I will be checking my code out of the repository to this new location, building and debugging it, and finally checking it back in again when I am happy with the result. If I want I can then delete the code, because it's all in the repository. I create a folder called Working in Documents/Progging and another called Builds. Working is where I will check the source out to and will be green. Builds is where I will have all the Build folders live. I want to be able to keep the builds separate from the code. Inside Builds I create a folder called Random Wok. Inside that is where the builds and temporary files will be kept. The Build files and folders will be blue.

Now I need a copy of subversion. Subversion is actually a collection of utilities, svn and svnadmin being the two I will use the most. I download a prebuilt binary from Coding Monkeys and run the installer. That puts the binaries into /usr/local/bin:

To make using these simpler I set the PATH variable in the current tcsh shell invocation to /usr/local/bin with setenv by typing setenv PATH /usr/local/bin.

Next I need to run svnadmin to create my first repository:

And there it is:

Now I run svn once so it will create a folder called .subversion in my home directory:

Much more information follows that. In the .subversion folder is a config file. I edit this using TextWrangler with File > Open Hidden... and selecting Enable: All Files. In the [miscellany] section I modify the list of global-ignores so that it looks like this (it's actually all on one line):

The modifications make subversion ignore some extra XCode files that I don't care about. I don't include the *.pbxuser files as some people do. That is because those per-user values include the custom executable settings that I need to launch Aperture. Here is the hierarchy so far:

Next I need to set up the repository and import a project.

The other parts of this series can be found via the Cocoa page.

Tags: Subversion, Cocoa, Xcode, Random Wok

Writing Random Wok and other code is always a very punctuated experience. I decide what to implement next, then read and take notes, then figure out what I think I need to do, then write the code, then debug, then blog. Sometimes a lot of time is spent during the reading and figuring out stages as I try to understand either how something is done, or, knowing how it is done, trying to understand how to do it that way in my code.

I go to several offline and online resources to get my curiosity satisfied, my brain overloaded, and my questions answered. Here is a short list of where I go, in order of attack:

1. XCode's Built-in Help and Documentation

My first stop is XCode, Apple's IDE for Cocoa development. XCode has a great deal of information built in: more than a gigabyte of Reference Library, in fact. Access to it all is via XCode's Help menu:

The documentation for XCode itself is found via the XCode Help item. The full developer reference library opens in a viewing window via Documentation:

The documentation window has two modes of searching. If you don't know how these work you will not find things and be very confused. Access the modes by clicking on the magnifying glass:

API search is immediate and needs no carriage return. The window below the search box shows the matches in order of fit. Click on one and I have the document in the lower pane. Double click and it opens in a separate window.

Full-Text Search is not immediate. I must press carriage return for anything to happen. And then the scope of the search is controlled by the selection in the library browser on the left:

My search for NSNull will only be carried out for documentation on Carbon in this case. I have to leave the Reference Library line at the top selected if I want to see all the documents (as I normally do).

The help menu also has two search items that work on selected text. Find selected text in documentation and Find selected text in API reference. An option double click on a word also takes me to Find selected text in API reference. I use this all the time.

Another very handy shortcut is to command double click on a word. That takes me to the definition in the code. This can be very useful because the context and comments in the code can often tell more than the documentation:

I set the languages that are searched via the Configure Options button on the toolbar:

I don't do C++ or Java and this prevents anything about them from showing up. Updates come out periodically. I have auto-checking enabled in the preferences:

So that I get update notifications:

And when a new set of documentation is available, 250 MB or so later, I have it.

Finally, I have access to the Man pages at the bottom of XCode's Help menu. I don't type "man" into a terminal: it is all there in the XCode documentation package.

2. Spotlight

The next place I go is Spotlight. I have all of the developer material indexed so spotlight will locate example code, saved web pages, and all kinds of other documents on my hard drive.

3. Cocoadev

Then I go to the web. Cocoadev is a WikiWikiWeb site containing a huge amount of user-contributed advice, code, explanations, links, and other material. It is easy to search, and you can contribute your own comments.

4. Cocoabuilder

Cocoabuilder is an archive of all of the postings to the Apple XCode, Cocoa, and Macosxdev mailing lists. There is a lot of Apple input on there. You can't post here. To post questions, sign up for the appropriate mailing lists at http://lists.apple.com/.

5. Borkware Quickies

Borkware and its associated Quickies page is a great place to find some of more useful and less documented ways of doing things. It's the creation of Mark Dalrymple, author of several Unix and Mac programming books and teacher at the Big Nerd Ranch.

6. Google

Finally, I Google what I am looking for. That will catch all kinds of things, including hits on the core foundation code, and open source efforts to duplicate parts of the Mac OS.

Tags: Cocoa, Resources, Xcode, Documentation

The user interface for the plugin is a single window. It's a combination of elements put there by Aperture and elements put there by the plugin. So far I have not defined an interface or hooked it up, so there has been nothing to see when the plugin is used except the Aperture elements.

In XCode the resources folder holds the user interface files:

And it is the nib file that describes the interface and contains instances of the objects it uses. Double-clicking on the nib file opens Interface Builder and shows the current Settings View:

I can remove that message, resize the window and add whatever I need to that view to implement the user controls. After some dragging and dropping, and more dragging, and more dragging, I came up with this:

It's not 100% there, but is good enough to get me to the next stage. The string format pop-up is populated with the four ways of creating the random string, but the length pop-up that follows is not. That will need to be filled dynamically by code depending on which choice of format is made.

It took me a little while to figure out how to add new items to a pop-up menu. Either drag a new one (called "Item") from the menu palette, or much more easily, just option drag an existing one.

Some of the interface elements will be disabled when they are not in use. For instance there is no letter case option if Numeric is chosen, so that will go gray. And if Salt is not selected then the Generate button and the text field will be gray and disabled.

The Example file name at the bottom will change dynamically as the user selects and types so they can see an example of the format. It will include the prefix and postfix strings in their proper positions and the random string in the middle.

I added the None strings in the text fields as placeholders in Interface Builder via the Attributes pane of the Inspector. They will appear whenever nothing is present in the field.

The next step is to join the user interface elements to the code and make them do something useful.

The other parts of this series can be found via the Cocoa page.

Tags: Aperture, Plug-ins, Cocoa, Random Wok, Interface, Xcode