/*  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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            expressly stated in this notice, no other rights or licenses, express or implied,

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

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*/

/* SampleCIView.m - simple OpenGL based CoreImage view */

#import "SampleCIView.h"

#import <OpenGL/OpenGL.h>

#import <OpenGL/gl.h>

static CGRect centerSizeWithinRect(CGSize size, CGRect rect);

@implementation SampleCIView

+ (NSOpenGLPixelFormat *)defaultPixelFormat

{

    static NSOpenGLPixelFormat *pf;

    if (pf == nil)

    {

    /* 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

    };

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

    }

    return pf;

}

- (void)dealloc

{

    //NSLog(@"[SampleCIView dealloc]");

    [_image release];

    [_context release];

    [super dealloc];

}

- (CIImage *)image

{

    return [[_image retain] autorelease];

}

- (void)setImage:(CIImage *)image dirtyRect:(CGRect)r

{

    if (_image != image)

    {

    [_image release];

    _image = [image retain];

    if (CGRectIsInfinite (r))

        [self setNeedsDisplay:YES];

    else

        [self setNeedsDisplayInRect:*(NSRect *)&r];

    }

}

- (void)setImage:(CIImage *)image

{

    [self setImage:image dirtyRect:CGRectInfinite];

}

- (void)setCleanRect:(CGRect)cleanRect

{

    _cleanRect = cleanRect;

}

- (void)setDisplaySize:(CGSize)displaySize

{

    _displaySize = displaySize;

}

- (void)prepareOpenGL

{

    long parm = 1;

    /* Enable beam-synced updates. */

    [[self openGLContext] setValues:&parm forParameter:NSOpenGLCPSwapInterval];

    /* 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);

    glClearColor (0.0f, 0.0f, 0.0f, 0.0f);

    glHint (GL_TRANSFORM_HINT_APPLE, GL_FASTEST);

}

- (void)viewBoundsDidChange:(NSRect)bounds

{

#pragma unused(bounds)

    /* For subclasses. */

}

- (void)updateMatrices

{

    NSRect r = [self bounds];

    if (!NSEqualRects (r, _lastBounds))

    {

    [[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 ();

    _lastBounds = r;

    [self viewBoundsDidChange:r];

    }

}

- (void)drawRect:(NSRect)r

{

    CGRect ir, rr;

    CGImageRef cgImage;

    [[self openGLContext] makeCurrentContext];

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

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

    if (_context == nil)

    {

    NSOpenGLPixelFormat *pf;

    pf = [self pixelFormat];

    if (pf == nil)

        pf = [[self class] defaultPixelFormat];

    _context = [[CIContext contextWithCGLContext: CGLGetCurrentContext()

             pixelFormat: [pf CGLPixelFormatObj] options: nil] retain];

    }

    ir = CGRectIntegral (*(CGRect *)&r);

    if ([NSGraphicsContext currentContextDrawingToScreen])

    {

    [self updateMatrices];

    /* Clear the specified subrect of the OpenGL surface then

     * render the image into the view. Use the GL scissor test to

     * clip to * the subrect. Ask CoreImage to generate an extra

     * pixel in case * it has to interpolate (allow for hardware

     * inaccuracies) */

    rr = CGRectIntersection (CGRectInset (ir, -1.0f, -1.0f),

                 *(CGRect *)&_lastBounds);

    glScissor (ir.origin.x, ir.origin.y, ir.size.width, ir.size.height);

    glEnable (GL_SCISSOR_TEST);

    glClear (GL_COLOR_BUFFER_BIT);

    if ([self respondsToSelector:@selector (drawRect:inCIContext:)])

    {

        [self drawRect:*(NSRect *)&rr inCIContext:_context];

    }

    else if (_image != nil)

    {

        // use the commented out method if you don't want to perform scaling

        //[_context drawImage:_image atPoint:rr.origin fromRect:rr];

        CGRect where = centerSizeWithinRect(_displaySize, *(CGRect *)&_lastBounds);

        [_context drawImage:_image inRect:where fromRect:_cleanRect];

    }

    glDisable (GL_SCISSOR_TEST);

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

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

     * flushBuffer]. */

    glFlush ();

    }

    else

    {

    /* Printing the view contents. Render using CG, not OpenGL. */

    if ([self respondsToSelector:@selector (drawRect:inCIContext:)])

    {

        [self drawRect:*(NSRect *)&ir inCIContext:_context];

    }

    else if (_image != nil)

    {

        cgImage = [_context createCGImage:_image fromRect:ir];

        if (cgImage != NULL)

        {

        CGContextDrawImage ([[NSGraphicsContext currentContext]

                     graphicsPort], ir, cgImage);

        CGImageRelease (cgImage);

        }

    }

    }

}

@end

static CGRect centerSizeWithinRect(CGSize size, CGRect rect)

{

    float delta;

    if( CGRectGetHeight(rect) / CGRectGetWidth(rect) > size.height / size.width ) {

        // rect is taller: fit width

        delta = rect.size.height - size.height * CGRectGetWidth(rect) / size.width;

        rect.size.height -= delta;

        rect.origin.y += delta/2;

    }

    else {

        // rect is wider: fit height

        delta = rect.size.width - size.width * CGRectGetHeight(rect) / size.height;

        rect.size.width -= delta;

        rect.origin.x += delta/2;

    }

    return rect;

}