/*

    File:  HybridImageView.m

    Abstract:  An NSView subclass that can toggle between OpenGL and Cocoa/Quartz rendering

    Version:  1.0

    Copyright:  © Copyright 2005 Apple Computer, Inc. All rights reserved.

    Disclaimer: IMPORTANT:  This Apple software is supplied to you by Apple Computer, Inc.

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    The Apple Software is provided by Apple on an "AS IS" basis.  APPLE MAKES NO

    WARRANTIES, EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION THE IMPLIED

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*/

#import "HybridImageView.h"

#import <OpenGL/OpenGL.h>

#import <OpenGL/gl.h>

#import <QuartzCore/CoreImage.h>

@interface HybridImageView (Internals)

- (NSPoint)originForCenteredImage;

- (void)drawUsingQuartzInRect:(NSRect)rect;

- (void)drawUsingOpenGLInRect:(NSRect)viewRect;

// OpenGL drawing support

- (NSOpenGLPixelFormat *)pixelFormat;

- (NSOpenGLContext *)openGLContext;

- (void)setupOpenGL;

- (void)updateMatrices;

- (void)clearGLContext;

- (CIContext *)CIContext;

@end

@implementation HybridImageView

// Initializes the attributes that HybridImageView adds to NSView.  This method is called by -initWithFrame:, and is also used by our Interface Builder palette.

- (void)initAddedProperties {

    [self setBackgroundColor:[NSColor colorWithDeviceRed:0.75 green:0.75 blue:0.75 alpha:1.0]];

}

- (id)initWithFrame:(NSRect)frame {

    self = [super initWithFrame:frame];

    if (self != nil) {

        [self initAddedProperties];

    }

    return self;

}

- (void)dealloc {

    [image release];

    [ciContext release];

    [openGLContext release];

    [pixelFormat release];

    [backgroundColor release];

    [super dealloc];

}

#pragma mark -

#pragma mark *** Key-Value Binding Support ***

+ (void)initialize {

    if (self == [HybridImageView class]) {

        // Declare the attributes of this class that should be shown in the Bindings inspector in Interface Builder.

        [self exposeBinding:@"backgroundColor"];

    }

}

#pragma mark -

#pragma mark *** NSView Method Overrides ***

- (BOOL)isOpaque {

    return YES;

}

- (void)drawRect:(NSRect)rect {

    if ([image isKindOfClass:[CIImage class]]) {

        [self drawUsingOpenGLInRect:rect];

    } else {

        [self drawUsingQuartzInRect:rect];

    }

}

#pragma mark -

#pragma mark *** Accessors ***

- (id)image {

    return [[image retain] autorelease];

}

- (void)setImage:(id)newImage {

    if (image != newImage) {

        [image release];

        image = [newImage retain];

        [self setNeedsDisplay:YES];

    }

}

- (NSColor *)backgroundColor {

    return backgroundColor;

}

- (void)setBackgroundColor:(NSColor *)newColor {

    if (newColor != nil && backgroundColor != newColor) {

        [backgroundColor release];

        backgroundColor = [newColor retain];

        [self setNeedsDisplay:YES];

    }

}

#pragma mark -

#pragma mark *** Archiving ***

// A view must know how to archive and unarchive itself in order to be placed in a custom Interface Builder palette.

- (void)encodeWithCoder:(NSCoder *)aCoder {

    [super encodeWithCoder:aCoder];

    if ([aCoder allowsKeyedCoding]) {

        [aCoder encodeObject:backgroundColor forKey:@"backgroundColor"];

    }

}

- (id)initWithCoder:(NSCoder *)aDecoder {

    self = [super initWithCoder:aDecoder];

    if (self) {

        if ([aDecoder allowsKeyedCoding]) {

            backgroundColor = [[aDecoder decodeObjectForKey:@"backgroundColor"] copy];

        }

    }

    return self;

}

@end

@implementation HybridImageView (Internals)

// Computes the appropriate origin for the composited image so that it will be centered in the view.

- (NSPoint)originForCenteredImage {

    if (image) {

        NSRect bounds = [self bounds];

        NSSize imageSize;

        if ([image isKindOfClass:[CIImage class]]) {

            // In general, it is usually necessary to allow for the possibility that the extent of a CIImage may be infinite.  In this example, however, we know we are dealing with a result image of finite size.

            CGRect extent = [image extent];

            imageSize = NSMakeSize(extent.size.width, extent.size.height);

        } else {

            imageSize = [image size];

        }

        return NSMakePoint(floor(0.5 * (bounds.size.width - imageSize.width)), floor(0.5 * (bounds.size.height - imageSize.height)));

    } else {

        return NSZeroPoint;

    }

}

// Draws the view's content using the Cocoa/Quartz API.

- (void)drawUsingQuartzInRect:(NSRect)rect {

    // If we're in OpenGL mode, switch back to regular Quartz drawing.

    if (openGLContext != nil) {

        // Suspend screen updates until the view has had the chance to redraw itself.

        [[self window] disableScreenUpdatesUntilFlush];

        [self clearGLContext];

    }

    // Fill with the background color.

    [[self backgroundColor] set];

    NSRectFill(rect);

    if ([image isKindOfClass:[NSBitmapImageRep class]]) {

        NSBitmapImageRep *bitmapImageRep = (NSBitmapImageRep *)image;

        // Create a temporary NSImage from the NSBitmapImageRep, and use it to composite the bitmap into the window.

        NSImage *nsImage = [[NSImage alloc] initWithSize:[bitmapImageRep size]];

        [nsImage addRepresentation:bitmapImageRep];

        NSSize imageSize = [nsImage size];

        [nsImage drawAtPoint:[self originForCenteredImage] fromRect:NSMakeRect(0, 0, imageSize.width, imageSize.height) operation:NSCompositeSourceOver fraction:1.0];

        [nsImage release];

    }

}

// Draws the view's content using OpenGL and Core Image.

- (void)drawUsingOpenGLInRect:(NSRect)viewRect {

    if ([image isKindOfClass:[CIImage class]]) {

        NSPoint imageOrigin = [self originForCenteredImage];

        // If we're in Cocoa/Quartz mode, switch to OpenGL drawing.

        if (openGLContext == nil) {

            // Suspend screen updates until the view has had the chance to redraw itself.

            [[self window] disableScreenUpdatesUntilFlush];

        }

        [[self openGLContext] makeCurrentContext];

        [self updateMatrices];

        // Fill with background color.

        float r, g, b, a;

        [[[self backgroundColor] colorUsingColorSpaceName:NSDeviceRGBColorSpace] getRed:&r green:&g blue:&b alpha:&a];

        glClearColor(r, g, b, a);

        glClear (GL_COLOR_BUFFER_BIT);

        // Composite the image using a CIContext.

        [[self CIContext] drawImage:image atPoint:*(CGPoint *)&imageOrigin fromRect:[image extent]];

        /* Flush the OpenGL command stream. If the view is double

         * buffered this should be replaced by [[self openGLContext]

         * flushBuffer]. */

        glFlush ();

    }

}

- (NSOpenGLPixelFormat *)pixelFormat {

    /* Making sure the context's pixel format doesn't have a recovery

     * renderer is important - otherwise CoreImage may not be able to

     * create deeper context's that share textures with this one. */

    static const NSOpenGLPixelFormatAttribute attr[] = {

        NSOpenGLPFAAccelerated,

        NSOpenGLPFANoRecovery,

        NSOpenGLPFAColorSize, 32,

        0

    };

    if (pixelFormat == nil) {

        pixelFormat = [[NSOpenGLPixelFormat alloc] initWithAttributes:(void *)&attr];

    }

    return pixelFormat;

}

- (NSOpenGLContext *)openGLContext {

    // create a context the first time through

    //

    if (openGLContext == nil) {

        openGLContext = [[NSOpenGLContext alloc] initWithFormat:[self pixelFormat] shareContext:nil];

        [openGLContext setView:self];

        [openGLContext makeCurrentContext];

        [self setupOpenGL];

    }

    return openGLContext;

}

- (void)setupOpenGL {

    /* Make sure that everything we don't need is disabled. Some of these

     * are enabled by default and can slow down rendering. */

    glDisable (GL_ALPHA_TEST);

    glDisable (GL_DEPTH_TEST);

    glDisable (GL_SCISSOR_TEST);

    glDisable (GL_BLEND);

    glDisable (GL_DITHER);

    glDisable (GL_CULL_FACE);

    glColorMask (GL_TRUE, GL_TRUE, GL_TRUE, GL_TRUE);

    glDepthMask (GL_FALSE);

    glStencilMask (0);

    glHint (GL_TRANSFORM_HINT_APPLE, GL_FASTEST);

}

- (void)updateMatrices {

    NSRect r = [self bounds];

    [[self openGLContext] update];

    /* Install an orthographic projection matrix (no perspective)

     * with the origin in the bottom left and one unit equal to one

     * device pixel. */

    glViewport (0, 0, r.size.width, r.size.height);

    glMatrixMode (GL_PROJECTION);

    glLoadIdentity ();

    glOrtho (0, r.size.width, 0, r.size.height, -1, 1);

    glMatrixMode (GL_MODELVIEW);

    glLoadIdentity ();

}

- (void)clearGLContext {

    if (openGLContext != nil) {

        if ([openGLContext view] == self) {

            [openGLContext clearDrawable];

        }

        [ciContext release];

        ciContext = nil;

        [openGLContext release];

        openGLContext = nil;

    }

}

- (CIContext *)CIContext {

    /* Allocate a CoreImage rendering context using the view's OpenGL

     * context as its destination if none already exists. */

    if (ciContext == nil) {

    ciContext = [[CIContext contextWithCGLContext: CGLGetCurrentContext() pixelFormat:[[self pixelFormat] CGLPixelFormatObj] options: nil] retain];

    }

    return ciContext;

}

@end