Charles Petzold

Multitasking on Windows Phone 7

cp@charlespetzold.com — Tue, 17 Aug 2010 13:15:40 GMT

That's the (somewhat provocative) title of a presentation I'll be delivering at the NYC .NET Developers Group on October 21, 2010. Details are here. This is the only public presentation on Windows Phone 7 currently on my schedule, and I plan to make the most of it.

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How to Insult a Writer

cp@charlespetzold.com — Mon, 16 Aug 2010 13:14:36 GMT

Don't you love getting a kick in the teeth first thing in the morning? That's what often happens to me when I read my email immediately after turning on the computer, even before my shower and breakfast. People send me emails that are obviously written in total innocence and with the purest of intentions, but like a clumsy oaf carrying a 2-by-4 beam, succeed in smashing me in the face and making me feel bad for the rest of the day.

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New Title! More Chapters!

cp@charlespetzold.com — Mon, 02 Aug 2010 15:37:43 GMT

According to the Microsoft Press blog, my book-in-progress Programming Windows Phone 7 Series now has a new title, Programming Windows Phone 7:

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The Disasters of Visual Design Tools

cp@charlespetzold.com — Fri, 16 Jul 2010 10:26:00 GMT

Many years ago — about the time that visual design tools were being introduced into our programming environments — I promised that I would never believe myself to be teaching programming if I were writing sentences like "Now drag the Button from the toolbox to the window." I am proud to say I have kept to that promise.

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Manipulation Events Update for the WP7 Beta

cp@charlespetzold.com — Wed, 14 Jul 2010 18:07:57 GMT

Always start with the good news: The good news is that the Manipulation events in the July beta of the Windows Phone 7 development tools no longer have the orientation problem I discussed in my blog entry Basic Manipulation Event Handling in Windows Phone 7 (at least with translation). You can flip the phone emulator sideways and translation coordinates don't need to be finagled. More good news: I am now able to get the emulator to recognize two fingers on my two touch screens, so I've been able to experiment with scaling as well as translation.

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Windows Phone 7 Development Tools Now in Beta

cp@charlespetzold.com — Tue, 13 Jul 2010 20:41:11 GMT

As of yesterday, Windows Phone 7 is in beta, which means there are updated development tools to be downloaded and installed.

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For Wendy Friedlander

cp@charlespetzold.com — Wed, 30 Jun 2010 19:29:20 GMT

Two summers ago I was working three days a week on a large WPF application at a company in New York City, and that's where I met Wendy Friedlander. Wendy brought several important skills to the project. Whereas I functioned as little more than a coder, Wendy revealed herself as a talented WPF programmer and much more besides. Her extensive practical experience in agile development practices, pair programming, and test-driven development helped the project enormously, and introduced me to modern team development strategies. Wendy was also one of the friendliest people I'd ever met and a joy to work with.

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Appearing on .NET Rocks

cp@charlespetzold.com — Sat, 26 Jun 2010 13:21:44 GMT

I will be appearing on a special Live Weekend edition of the Internet radio show .NET Rocks with hosts Carl Franklin and Richard Campbell. Many guests are scheduled; I'm slated for 9:00 – 10:00 AM Eastern Time on Sunday, June 27, 2010. Because it's live, you can call in and chat! Details are here:

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The Mathematics of Pathological Tennis

cp@charlespetzold.com — Fri, 25 Jun 2010 15:06:22 GMT

Many tennis fans seemed to enjoy the 5th set of the recent Wimbledon match between John Isner and Nicolas Mahut. In the absence of a tie-break for the final set, it went on for 138 games, finally ending at an unfathomable score of 70-68 with only one break of serve at the end.

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Orientation Strategies for Windows Phone 7

cp@charlespetzold.com — Wed, 16 Jun 2010 17:24:46 GMT

I've recently been thinking about ways to deal with orientation changes in Windows Phone 7. (That's when the user turns the phone sideways from portrait mode to landscape mode or back again.) I've also been working on the way-overlong chapter on data binding in my forthcoming book Programming Windows Phone 7, and it occurred to me that I might deal with orientation using data binding and data conversion techniques.

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Flip-Number Clock in Silverlight

cp@charlespetzold.com — Wed, 16 Jun 2010 16:18:04 GMT

I've seen some print ads recently that feature a phone with a simulation of 1960's style flip-number clock. Such a clock is fairly trivial in Silverlight:

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CompositionTarget.Rendering and RenderEventArgs

cp@charlespetzold.com — Fri, 11 Jun 2010 16:45:56 GMT

Sometimes it helps to read the .NET documentation even for a feature you think you know well. From WPF I knew about the CompositionTarget.Rendering event and I've also used it in Silverlight. The event is fired at the rate of video refresh and hence is ideal for performing animations. But just a couple days ago I re-read the documentation for the Silverlight version of the CompositionTarget.Rendering event and happened upon the following:

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Simulating Touch Inertia on Windows Phone 7

cp@charlespetzold.com — Sun, 06 Jun 2010 14:02:15 GMT

In Isaac Newton's Mathematical Principles of Natural Philosophy (1687), Definition 3 reads: "Inherent force of matter is the power of resisting which every body, so far as it is able, preserves in its state either of resting or of moving uniformly straight forward." (Cohen/Whitman translation, pg. 404) This is what we call "inertia." When you start an object moving with a little push or your hand, it will often continue moving for a little while until friction of some sort causes it to slow down and stop.

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Great-Circle Arcs on the Sphere

cp@charlespetzold.com — Sat, 05 Jun 2010 19:53:00 GMT

If books are like children (and many authors think of them in that way), then 3D Programming for Windows: Three-Dimensional Graphics Programming for the Windows Presentation Foundation is like the brilliant child so full of promise who gets mowed down by a drunk driver on the way to prom.

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A Circular Gradient Brush for Silverlight

cp@charlespetzold.com — Sat, 05 Jun 2010 13:07:41 GMT

Yesterday I received an email asking if I knew how to create a circular gradient brush in Silverlight. Such a brush begins with one color and circles around to another color. It might possibly be animated like so:

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Basic Manipulation Event Handling in Windows Phone 7

cp@charlespetzold.com — Tue, 01 Jun 2010 13:09:40 GMT

A video display that responds to the touch of a single finger doesn't provide much more functionality than a mouse. But a display that responds to multiple fingers is potentially much more powerful in providing intimate interaction with visual objects.

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The Limits of float

cp@charlespetzold.com — Sun, 30 May 2010 12:00:58 GMT

One of the first things the veteran C# programmer notices when learning XNA programming is that all floating-point values are single-precision float rather than double-precision double. This not only reduces storage space (4 bytes each rather than 8 bytes) but also improves performance — at least in theory. (My extremely brief experimentation of the performance differential on the PC reveals something in the range of only about 5% improvement, but it may be more substantial on other devices.)

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Tripp Palin, 16, Sues Mom, Others

cp@charlespetzold.com — Fri, 28 May 2010 13:13:44 GMT

ANCHORAGE — Some kids celebrate their 16th birthdays with cake, presents, and friends. Tripp Palin celebrated his 16th birthday today by filing a groundbreaking lawsuit against six people, including his mother — standup comic and longtime reality-star Bristol Palin, 34.

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More Accelerometer Visualization on the Zune HD

cp@charlespetzold.com — Thu, 27 May 2010 14:02:00 GMT

If you're the type of person who enjoys conspiracy theories, you may be wondering if all this Windows Phone 7 hype is really just a ploy by Microsoft to get developers to buy more Zune HDs. It actually makes a little bit of sense: Having first been enticed into coding in C# for small devices, we then discover that no actual Windows Phone 7 devices are allowed outside the Redmond city limits except when accompanied by armed guards hired from Blackwater. Several times I've been in the same room as a phone but never closer than about 10 feet.

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Classical Music Being "Phased Out"

cp@charlespetzold.com — Sun, 23 May 2010 14:32:28 GMT

If you're one of those pathetic losers who still listens to classical music, it's time to let it go. Delete your Mahler MP3's, wipe your Wagner WMA's, burn your Copland CD's, smash your Vivaldi vinyl, and get yourself some Justin Bieber. I know it'll be painful at first. But with repeated listening your brain will soften into a pudding-like consistency, and soon you'll find yourself immersed in the warm blissful bath of his adorableness.

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SpinPaint for Windows Phone 7 (with a Rant about Touch)

cp@charlespetzold.com — Fri, 21 May 2010 10:38:13 GMT

Last week I had the opportunity to attend a two-day class on Microsoft Surface programming conducted by Dr. Neil Roodyn, and I enjoyed it immensely. Although we experimented mostly with the PC-based simulator included with the Surface SDK, we also had the opportunity to deploy our programs on actual Surface machines, which was a big thrill.

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Navigating the Windows Phone 7 Documentation

cp@charlespetzold.com — Thu, 06 May 2010 13:14:57 GMT

This is a subject that is not as simple as you might assume. Even if you've gone to the Windows Phone 7 portal and installed the development tools (which consist of Visual Studio 2010 Express for Windows Phone, the Windows Phone on-screen emulator, and XNA Game Studio 4.0), you're still going to need documentation and programming guides. The documentation is spread out in three separate locations in the MSDN Library, and this blog entry is a guide for finding what you need.

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“Programming Windows Phone 7” — Updated Source Code

cp@charlespetzold.com — Wed, 05 May 2010 20:50:45 GMT

An April Refresh of the Windows Phone 7 programming tools is now available. I've updated all the source code that accompanies the preview edition of my book Programming Windows Phone 7 Series and posted it here.

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Where’s the Grown-Up Version of Zune?

cp@charlespetzold.com — Wed, 05 May 2010 12:38:48 GMT

I was installing the Zune desktop software on a newly rebuilt partition when it asked me to enter "three of your favorite artists," so I quickly typed in one of my very favorite composers:

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XNA 3D on the Zune HD?

cp@charlespetzold.com — Tue, 04 May 2010 17:32:53 GMT

Last Wednesday, I gave a lunchtime presentation about Windows Phone 7 programming at Devscovery 2010 NYC, and among the little demos was a simple 3D cube coded in XNA that rotates around the X, Y, and Z axes in a confusing manner. Here it is running on the on-screen phone emulator:

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Listening to the “Shutter Island” Soundtrack

cp@charlespetzold.com — Fri, 30 Apr 2010 16:00:00 GMT

I couldn't believe the musical howler in Chapter 5 of Dennis Lehane's 2003 novel Shutter Island. It's 1954 and U.S. Marshall Teddy Daniels is investigating an odd disappearance from an isolated insane asylum. When Teddy pays a visit to the home of chief-of-staff Dr. Cawley, Cawley puts a record on a phonograph. Lehane describes the music as "a balm of strings and piano." Teddy's partner asks "Brahms?" Cawley answers, "Mahler."

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Introducing PhoniePoint version 1E-10

cp@charlespetzold.com — Thu, 29 Apr 2010 02:12:03 GMT

I have this vision of one day walking into a room full of programmers eager to learn about Windows Phone 7 programming. I'm empty handed, but then I pull a phone from my pocket, hook it up to the projector, and use that phone to do my entire presentation — the (now traditional) mix of slides, sample code, and incredibly useful insights.

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Inventing the “Three-Finger Salute”

cp@charlespetzold.com — Fri, 16 Apr 2010 14:07:17 GMT

Everybody knows that IBM engineer David Bradley invented the Ctrl-Atl-Delete key combination used to reboot the IBM PC. But who first described this key combination as the "three-finger salute"?

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Visualizing the Windows Phone Accelerometer (on a Zune HD)

cp@charlespetzold.com — Mon, 05 Apr 2010 18:19:26 GMT

In early 1975, Bill Gates and Paul Allen were writing a BASIC interpreter for the MITS Altair 8800 computer, an early personal computer kit that had recently become available in extremely limited quantities. (Ed Roberts, the creator of the Altair, died last week and received a prestigious front-page obituary in the New York Times.) Gates and Allen didn't actually have one of the very rare Altairs to test their code; instead, they had written an emulator of the Intel 8080 microprocessor on the Harvard DEC PDP-10, and they were using that emulator to run this BASIC interpreter. On the night before Allen was flying to Albuquerque to meet with Ed Roberts and show him their work, Gates was nervous about possible flaws in their emulator: "If I got one of those opcodes wrong, this thing is just not gonna work." (Stephen Manes and Paul Andrews, Gates: How Microsoft's Mogul Reinvented an Industry — and Made Himself the Richest Man in America, Doubleday, 1993, pg. 73-74) But the BASIC interpreter booted up and ran.

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Using VertexPositionTexture on Windows Phone

cp@charlespetzold.com — Tue, 30 Mar 2010 11:10:55 GMT

I was having a helluva time with XNA 3D for Windows Phone applying a simple Texture2D to a simple model constructed using VertexPositionTexture and BasicEffect. The program would deploy on the phone emulator, all the DLLs would be loaded, and then Visual Studio's Output window would display:

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New Book: “Programming Windows Phone 7 Series”

cp@charlespetzold.com — Mon, 15 Mar 2010 12:00:00 GMT

I am pleased to announce the publication later this year of a new book Programming Windows Phone 7 Series:

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Pants on the Ground: The Silverlight Application

cp@charlespetzold.com — Sat, 23 Jan 2010 17:24:51 GMT

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Dear EarthLink Customer Support

cp@charlespetzold.com — Wed, 13 Jan 2010 12:37:09 GMT

Dear EarthLink Customer Support,

This blog entry may seem like an unusual way to get in touch with you, but I've run out of options. You don't accept postal mail or phone calls, and your Support Center Feedback page generates an email to external_feedback@lists.corp.earthlink.net, which your email system bounces! I've considered visiting your office in Atlanta and demanding to see a corporate representative, but I suspect I'll only find myself in a crowd of many thousands of other crazed dissatisfied customers wailing in agony in your lobby.

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1859 Books: Harriet Beecher Stowe’s “The Minister’s Wooing”

cp@charlespetzold.com — Thu, 31 Dec 2009 18:26:54 GMT

The Fugitive Slave Act of 1850 was perhaps the most politically explosive piece of legislation ever passed by the United States Congress. As part of the Compromise of 1850, the Fugitive Slave Act ostensibly did little more than strengthen a concept that was imbedded in the Constitution: that a "Person held to Service or Labour in one State" upon "escaping into another, shall ... be delivered up on Claim of the Party to whom such Service or Labour may be due." (Article IV, Section 2)

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Silverlight Apps that Resize Themselves

cp@charlespetzold.com — Thu, 17 Dec 2009 18:01:08 GMT

Yesterday I was working on a Silverlight application that adjusted its size within the browser page when I began encountering erratic behavior. Turns out I hadn't taken account of the zooming feature implemented in recent versions of Internet Explorer (and other browsers), and now I'm not sure I should need to.

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Experimental Embedding of Silverlight Apps in Blog Entries

cp@charlespetzold.com — Tue, 15 Dec 2009 16:53:13 GMT

Commonly, blog entries that discuss Silverlight programming contain a link to a separate HTML or ASPX file that contains the actual Silverlight application. I want to start embedding Silverlight applications right in my blog entries. Since I wrote my own blogging software — it's a Windows Forms application called BlogHack and it's as sloppy as the name suggests — I figured it wouldn't be too difficult.

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Listening to Cecilia Bartoli’s “Sacrificium”

cp@charlespetzold.com — Mon, 07 Dec 2009 13:00:00 GMT

Castration is not a pleasant topic. Even manly men — those who courageously run into burning buildings or jump out of airplanes — are known to whimper and cringe at the very thought of a sharpened knife hovering somewhat below belt level.

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Coding for Multi-Touch for Silverlight 3

cp@charlespetzold.com — Tue, 01 Dec 2009 18:41:22 GMT

Two weeks ago, at the second-day keynote at the Microsoft Professional Developers Conference (PDC), Windows and Windows Live Division President Steven Sinofsky told us that Microsoft would be giving everyone there a new Acer notebook computer. He got a big round of applause. Nothing quite excites a roomful of programmers more than free hardware.

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Text Deformation Based on Bézier Splines

cp@charlespetzold.com — Sun, 29 Nov 2009 18:44:04 GMT

In previous blog entries I showed how to use a WPF program (called TextOutlineGenerator and available from here) to generate text outlines that you can then use in Silverlight programs for some interesting effects. This morning I woke up with an idea to deform a whole character string based on two Bézier curves.

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1859 Books: Charles Darwin’s “On the Origin of Species”

cp@charlespetzold.com — Tue, 24 Nov 2009 12:00:00 GMT

It had long been observed that animals and other living things are particularly well-adapted to the environments in which they live. Prior to November 24, 1859 — 150 years ago today — the best explanation for this amazing phenomenon was that they had been designed specifically for that purpose.

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Seeds Across the Oceans

cp@charlespetzold.com — Mon, 23 Nov 2009 19:45:57 GMT

How do plants get from one land mass to another? Here's one plausible answer from a man who actually performed the necessary experiments:

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1859 Books: Charles Dickens’ “A Tale of Two Cities”

cp@charlespetzold.com — Sat, 21 Nov 2009 19:00:00 GMT

In Oscar Wilde's The Importance of Being Earnest (1895) when the very proper and stuffy Lady Bracknell learns that Jack was found as a baby in a hand-bag in the cloak-room at Victoria Station, she is understandably shocked: “I confess I feel somewhat bewildered by what you have just told me. To be born, or at any rate bred, in a hand-bag, whether it had handles or not, seems to me to display a contempt for the ordinary decencies of family life that reminds one of the worst excesses of the French Revolution.”

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Text Morphing but with Decomposed Outlines

cp@charlespetzold.com — Fri, 13 Nov 2009 12:44:43 GMT

I'm not quite sure how to describe this Silverlight program. It contains two text strings of approximately equal linegth for which I've generated flattened PathGeometry objects using a WPF program I've described in a previous blog entry. The character outlines of each text string thus consist of a series of tiny lines. By animating these little lines back and forth between the two outlines, the text strings seem to morph into each other, but in a rather unusual way.

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Displaying Text at Angles

cp@charlespetzold.com — Thu, 12 Nov 2009 18:55:06 GMT

I'm not sure if this TV trend is for real, or whether I'm just noticing it more, but I think there's been an increase in the past year or so of text displayed with perspective effects — not necessarily 3D text had has depth and body, but regular flat 2D text that appears to occupy a 3D space. One example is the titles on Fringe that seem to be attached to the sides of buildings, but I've also seen text in TV commercials where the words seem to meet at angles.

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Random Globules This Time

cp@charlespetzold.com — Mon, 02 Nov 2009 23:59:20 GMT

After I posted a blog entry on writing a random-rectangle program for Silverlight, I added a comment with links to Win16 and Win32 random-rectangle programs. It's really amazing to see how fast those old programs run on modern machines!

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