Reader Q&A – PDFs in iOS

I got a question from a reader last night who was looking at some code from one of my Xamarin seminars.

Ryan asked about how to extract the content from a pdf file, draw on it, and email it in iOS.

One way to do this is using Core Graphics, as shown in the following snippet:

If you have a question feel free to contact me through my blog. I get lots of questions like this, but I do my best to respond to them all.

Load a Collada File in Scene Kit

My friend @lobrien (whose blog you should read if you don’t already) was asking about loading Collada filesĀ in Scene Kit, so I whipped up a quick example:

In the Xamarin Studio solution pad, the folder containing the Collada file has a .scnassets suffix, and the model has a build action of SceneKitAsset:

solution pad

Given this, the model is rendered as shown below:


There’s also a Collada build action as well. I’ve never used that option though. If someone wants to elaborate on what that does (perhaps supporting animations embedded in Collada files? just a guess) please add a comment here.

Updated Scratch Ticket Code

Someone asked a question in the Xamarin forums last week about the scratch ticket code I wrote a while back, so I decided to update it to work with the unified API and show how to get an image from the view, which is what the person in the forums was asking for.

One thing I find super useful in Xamarin Studio is the ability to see the image at runtime in the debugger (similar to what you’d get in Xamarin Sketches), as shown below:

image from view

You can get the updated code from my repo:

Visual Studio Code with Xamarin on a Mac

Microsoft just announced a new cross-platform editor that has many of the features of Visual Studio called Visual Studio Code. I downloaded it on my Mac to try out with a Xamarin.iOS project and see if it works. I was pleased discover it works out of the box (as far as I can tell on a first look).

Visual Studio Code works against files and folders. When you open a folder where a Xamarin.iOS project lives, all the files load fine and features such as links to references and even intellisense on iOS classes work great.

Here’s a class that implements a UIView subclass for example showing intellisenseĀ on CALayer:


You can download Visual Studio Code at:

NGraphics in a Xamarin Sketch

Frank Krueger published a new open source graphics library called NGraphics today. As with everything Frank does it looks pretty awesome. It even has its own editor where you can type in code and live preview the output. So you probably won’t need what I’m about to show you, but I was curious if it would work with Xamarin Sketches (just for kicks).

Sure enough, all I had to do was add LoadAssembly calls to reference NGraphics assemblies in the sketch and add the assemblies to the sketchname.sketchcs.Resources folder alongside the sketchcs file. Then, since Frank includes methods to return native image types, such as NSImage on Mac, I can leverage the sketch visualizers in Xamarin Studio to get a live preview.

Here’s Frank’s sample code to draw a house in a sketch: