// Graphics Importer and Exporter Samples

// This example takes two images and composites them together

// demonstrating the use of different graphic modes

// Originally written by Sam Bushell for QuickTime "Live" '99

// WWDC 2000 Introduction to QuickTime

#include "MacShell.h"

void AlphaComposite( void )

{

    OSErr err = noErr;

    Handle hOpenTypeList = NewHandle(0);

    long  numTypes = 0;

    FSSpec  theFSSpec;

    GraphicsImportComponent backgroundImporter = 0, foregroundImporter = 0;

    Rect backgroundBounds, windowBounds, foregroundBounds;

    WindowPtr window = NULL;

    MatrixRecord matrix;

    RGBColor whiteColor;

    FixedPoint backgroundCenter;

    BuildGraphicsImporterValidFileTypes( hOpenTypeList, &numTypes );

    HLock( hOpenTypeList );

    // prompt for a background image.

    err = GetOneFileWithPreview(numTypes, (OSTypePtr)*hOpenTypeList, &theFSSpec, NULL);

    if (err) goto bail;

    err = GetGraphicsImporterForFile( &theFSSpec, &backgroundImporter );

    // prompt for a foreground image.

    err = GetOneFileWithPreview(numTypes, (OSTypePtr)*hOpenTypeList, &theFSSpec, NULL);

    if (err) goto bail;

    err = GetGraphicsImporterForFile( &theFSSpec, &foregroundImporter );

    err = GraphicsImportGetNaturalBounds( backgroundImporter, &backgroundBounds );

    windowBounds = backgroundBounds;

    OffsetRect( &windowBounds, 10, 45 );

    window = NewCWindow( NULL, &windowBounds, "\pAlpha Composite", true, documentProc, (WindowPtr)-1, true, 0);

    // set the graphics port for drawing the first image

    err = GraphicsImportSetGWorld( backgroundImporter, GetWindowPort( window ), NULL );

    // draw the background

    err = GraphicsImportDraw( backgroundImporter );

    pause();

    // center the foreground image over the background image

    // get the native size of the foreground image

    // offset the image to center it

    // set the rectangle in which to draw an image

    err = GraphicsImportGetNaturalBounds( foregroundImporter, &foregroundBounds );

    OffsetRect( &foregroundBounds, 

                (backgroundBounds.right - foregroundBounds.right) / 2,

                (backgroundBounds.bottom - foregroundBounds.bottom) / 2 );

    err = GraphicsImportSetBoundsRect( foregroundImporter,

                                       &foregroundBounds );

    // draw the foreground image over the background image,

    // using the default graphics mode, ditherCopy.

    err = GraphicsImportSetGWorld( foregroundImporter, GetWindowPort( window ), NULL );

    err = GraphicsImportDraw( foregroundImporter );

    pause();

    // redraw the background.

    err = GraphicsImportDraw( backgroundImporter );

    // draw the foreground using the transparent graphics mode, with white transparent.

    whiteColor.red = 0xffff;

    whiteColor.green = 0xffff;

    whiteColor.blue = 0xffff;

    err = GraphicsImportSetGraphicsMode( foregroundImporter,    // graphics importer instance

                                         transparent,           // graphics transfer mode to use for drawing

                                         &whiteColor );         // color to use for blending and transparent operations

    err = GraphicsImportDraw( foregroundImporter );

    pause();

    // redraw the background.

    err = GraphicsImportDraw( backgroundImporter );

    // draw the foreground using the straight alpha graphics mode.

    err = GraphicsImportSetGraphicsMode( foregroundImporter,        // graphics importer instance

                                         graphicsModeStraightAlpha, // graphics transfer mode to use for drawing

                                         NULL );

    err = GraphicsImportDraw( foregroundImporter );

    pause();

    // redraw the background.

    err = GraphicsImportDraw( backgroundImporter );

    // draw the foreground *rotated 30 degrees*, using the straight alpha graphics mode.

    err = GraphicsImportGetMatrix( foregroundImporter, &matrix );

    backgroundCenter.x = Long2Fix( backgroundBounds.right - backgroundBounds.left ) / 2;

    backgroundCenter.y = Long2Fix( backgroundBounds.bottom - backgroundBounds.top ) / 2;

    RotateMatrix( &matrix, Long2Fix(30), backgroundCenter.x, backgroundCenter.y );

    err = GraphicsImportSetMatrix( foregroundImporter, &matrix );

    err = GraphicsImportDraw( foregroundImporter );

bail:

    if ( backgroundImporter ) CloseComponent( backgroundImporter );

    if ( foregroundImporter ) CloseComponent( foregroundImporter );

    if ( hOpenTypeList) DisposeHandle( hOpenTypeList );

}