QuickTime on Windows - Movies

Apple has a really good example class for MFC programming - CQuickTime -- very helpful!

I wanted to load a movie with a URL. There are a few good examples out there... so here's what I learned.

Movie LoadMovieFromURL( const UInt8* url, CFIndex len, Rect* bounds )
{  // you have to set the port first - MacSetPort, CreatePortAssociation 
    CFURLRef    urlRef  = ::CFURLCreateWithBytes( null, url, len, kCFStringEncodingUTF8, null );
    OSErr       error;
    
    if( null == urlRef )
        return null;
    
    Movie    movie        = null;
    Handle  dataRef;
    OSType  dataRefType;
    error = ::QTNewDataReferenceFromCFURL( urlRef, 0, &dataRef, &dataRefType );
    
    if( noErr == error )
      {
        short    movieId;
        error = ::NewMovieFromDataRef( &movie, 0, &movieId, dataRef, dataRefType );
        
        if( noErr == error )
          {
            ::GetMovieBox( movie, bounds );
          }
      }
    
    ::CFRelease( urlRef );
    
    return movie;
}

Before calling this routine, you need to set the graphics port. You can create a graphics port for your Windows HWND with CreatePortAssociation

With loading images, I didn't use a CFURLRef. I am here. Why? Just practicing how to skin cats many ways. Handy to know when things don't work.

I make the movie controller with the following routine:

MovieController MakeMovieController( Movie movie, CWnd* wnd, Rect* bounds )
{
    Rect    theMovieRect;
    CRect    box;
    
    ::SetMovieBox( movie, bounds );
    
    wnd->GetClientRect( box );
    
    theMovieRect.left    = 0;
    theMovieRect.top    = 0;
    theMovieRect.right  = box.Width();
    theMovieRect.bottom  = box.Height();
    
    // Attach a movie controller
    return ::NewMovieController( movie, &theMovieRect, mcTopLeftMovie );
}

This will put the movie in the top left corner of the CWnd. This works for me for now. I'm going to center the movie eventually.

Tags:
QuickTime Windows Movie MFC

QuickTime on Windows - Images

I've decided to use QuickTime for importing images, video and sound into the Windows application. The API is easy, familiar and cross platform. Plus, I get access to a wide range of media resource formats.

Loading an Image from a URL

GraphicsImportComponent LoadGraphicsImportFromURL( char* url, Rect* bounds )
{ // you need to make sure that you've set the port before calling
    Handle                  urlRef  = NULL;
    long                    urlLen  = (long) strlen( url );
    OSErr                   error   = noErr;
    GraphicsImportComponent gi      = NULL;
    
    error = PtrToHand( url, &urlRef, urlLen +1 );
    if( noErr == error )
      {
        error = GetGraphicsImporterForDataRef( urlRef, URLDataHandlerSubType, &gi );
        if( noErr == error )
          {
            GraphicsImportGetNaturalBounds( gi, bounds );
            
            CGrafPtr    port;
            GDHandle    gd;
            
            GetGWorld( &port, &gd );
            GraphicsImportSetGWorld( gi, port, gd );
            GraphicsImportSetGraphicsMode( gi, graphicsModeStraightAlpha, NULL );
          }
        DisposeHandle( urlRef );
      }
    
    return gi;  
    // you'll need to CloseComponent with this returned value 
    // when you are done with it.
}

Before calling this routine, you need to set the graphics port. You can create a graphics port for your Windows HWND with CreatePortAssociation

I use graphicsModeStraightAlpha so that png files (and other formats) draw well (for my purposes).

Drawing an Image

bool DrawGraphicsImport( GraphicsImportComponent gi, RECT* clientBox, Rect* bounds )
{
    if( (null == gi) || (null == clientBox) || (null == bounds) )
      {
        return false;
      }
    
    MatrixRecord  matrix;
    Rect          dstRect;
    float         width   = (float) ( clientBox->right - clientBox->left );
    float         height  = (float) ( clientBox->bottom - clientBox->top );
    
    if( ( 0.0f == width ) || ( 0.0f == height ) )
        return false;
    
    float         boundsWidth  = (float) ( bounds->right - bounds->left );
    float         boundsHeight = (float) ( bounds->bottom - bounds->top );
    
    if( ( 0.0f == boundsWidth ) || ( 0.0f == boundsHeight ) )
        return false;
    float         boundsAspect = boundsWidth / boundsHeight;
    
    float         dstWidth;
    float         dstHeight;
    
    
    dstWidth = height * boundsAspect;
    
    if( dstWidth > width )
      {
        dstWidth = width;
        dstHeight = width / boundsAspect;
      }
    else
      {
        dstHeight = height;
      }
    
    dstRect.left    = (short) (clientBox->left + (long) ( ( width - dstWidth ) * 0.5 ));
    dstRect.right    = (short) (dstRect.left + (long) dstWidth);
    dstRect.top      = (short) (clientBox->top + (long) ( ( height - dstHeight ) * 0.5 ));
    dstRect.bottom  = (short) (dstRect.top + (long) dstHeight);
    
    ::RectMatrix( &matrix, bounds, &dstRect );
    ::GraphicsImportSetMatrix( gi, &matrix );
    ::GraphicsImportDraw( gi );
    return true;
}

The clientBox is the HWND's client rect. Bounds is the natural bounds of the image. All I wanted to do here is to scale and center the image in an HWND. You'll notice that I don't need to pass the display context. If you want the image to draw to different contexts, you'll have to set the port for the image before drawing.

Tags: QuickTime Windows

Objective-C

In my recent update to Town Generator, I wanted to export an attributed string as html. Internally, Core Data stores the string as NSData which I convert into an NSAttributedString using an NSValueTransformer, NSUnarchiveFromDataTransformerName.

Nothing too unusual about all that - could easily been done with C or C++.

A cool thing about Objective-C is that you can extend any existing class by using categories - without subclassing the class.

So, I wrote a category for NSAttributedString as so:

@interface NSAttributedString ( TGDocumentAdditions )
- (NSString*) toHTML:(NSString*)pathToAttachments;
- (NSString*) toText;
@end

In the code that exports the comments to HTML, I don't need to do anything special to get the additional functionality. For example, with C++, I would have to subclass NSAttributedString and then I'd have to have a constructor that could restore the class from NSData... It starts to get messy (but not impossible).

NSAttributedString*   comments  = 
        [transformer transformedValue:[power valueForKey:@"comments"]];
[self appendTag:@"td" 
       contents:[comments toHTML:path] 
             to:html  
     attributes:nil];

By extending NSAttributedString by using a category, I can gain increased functionality without introducing a lot of coding overhead.

Tags: Objective C Cocoa