/*

 File: ImageView.m

 Abstract: ImageView 

 Version: 1.0

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 */ 

#import "ImageView.h"

#define kMargin 10.f

@implementation ImageView

// simple image view to display a given file

// uses ImageIO to open the image file

// handles image dpi and EXIF orientation...

// ---------------------------------------------------------------------------------------------------------------------

- (id)initWithFrame: (NSRect)frameRect

{

    // initialize

    if ((self = [super initWithFrame: frameRect]) != nil)

    {

    }

    return self;

}

// ---------------------------------------------------------------------------------------------------------------------

- (void) dealloc

{

    if (mImage)

        CGImageRelease(mImage);

    [mMeta release];

    [super dealloc];

}

// ---------------------------------------------------------------------------------------------------------------------

- (void) setImagePath: (NSString *)path

{

    // use ImageIO to get a CGImageRef for a file at a given path

    NSURL * url = [NSURL fileURLWithPath: path];

    // create the CGImageSourceRef

    CGImageSourceRef isr = CGImageSourceCreateWithURL((CFURLRef)url, NULL);

    if (isr)

    {

        // options for getting image and meta data

        // - create a 'cached' image

        // - allow float pixel data

        NSDictionary* options = [NSDictionary dictionaryWithObjectsAndKeys:

            (id)kCFBooleanTrue, (id)kCGImageSourceShouldCache,

            (id)kCFBooleanTrue, (id)kCGImageSourceShouldAllowFloat,

            NULL];

        // create image at index 0 (note that ImageIO supports multi-page TIFFs, GIFs, ...)

        CGImageRef image = CGImageSourceCreateImageAtIndex(isr, 0, (CFDictionaryRef)options);

        // get the meta data for the image at index 0

        NSDictionary* meta = (NSDictionary*)CGImageSourceCopyPropertiesAtIndex(isr, 0, (CFDictionaryRef)options);

        // keep image and meta-data

        [self setImage: image

          withMetadata: meta];

        CFRelease (isr);

    }

}

// ---------------------------------------------------------------------------------------------------------------------

- (void) setImage: (CGImageRef)image 

     withMetadata: (NSDictionary *)meta

{

    CGImageRetain(image);

    if (mImage)

        CGImageRelease(mImage);

    mImage = image;

    if (meta)

        [meta retain];

    [mMeta release];

    mMeta = meta;

    // update display

    [self setNeedsDisplay:YES];

}

// ---------------------------------------------------------------------------------------------------------------------

- (BOOL) isOpaque

{

    return YES;

}

// ---------------------------------------------------------------------------------------------------------------------

- (float) dpiWidth

{

    NSNumber*   val = [mMeta objectForKey:(id)kCGImagePropertyDPIWidth];

    float       dpi = [val floatValue];

    return (0 == dpi ? 72. : dpi);

}

// ---------------------------------------------------------------------------------------------------------------------

- (float) dpiHeight

{

    NSNumber*   val = [mMeta objectForKey: (id)kCGImagePropertyDPIHeight];

    float       dpi = [val floatValue];

    return (0 == dpi ? 72 : dpi);

}

// ---------------------------------------------------------------------------------------------------------------------

- (int) orientation

{

    NSNumber*   val = [mMeta objectForKey: (id)kCGImagePropertyOrientation];

    int orient = [val intValue];

    if (orient < 1 || orient > 8)

        orient = 1;

    return orient;

}

// ---------------------------------------------------------------------------------------------------------------------

- (CGAffineTransform) imageTransform

{

    // determine the image transform:

    // this honors: EXIF orientation, non-square-pixel dpi, ...

    float xdpi = [self dpiWidth];

    float ydpi = [self dpiHeight];

    int orient = [self orientation];

    float x = (ydpi > xdpi) ? ydpi/xdpi : 1;

    float y = (xdpi > ydpi) ? xdpi/ydpi : 1;

    float w = x * CGImageGetWidth(mImage);

    float h = y * CGImageGetHeight(mImage);

    CGAffineTransform ctms[8] = {

    { x, 0, 0, y, 0, 0},  //  1 =  row 0 top, col 0 lhs  =  normal

    {-x, 0, 0, y, w, 0},  //  2 =  row 0 top, col 0 rhs  =  flip horizontal

    {-x, 0, 0,-y, w, h},  //  3 =  row 0 bot, col 0 rhs  =  rotate 180

    { x, 0, 0,-y, 0, h},  //  4 =  row 0 bot, col 0 lhs  =  flip vertical

    { 0,-x,-y, 0, h, w},  //  5 =  row 0 lhs, col 0 top  =  rot -90, flip vert

    { 0,-x, y, 0, 0, w},  //  6 =  row 0 rhs, col 0 top  =  rot 90

    { 0, x, y, 0, 0, 0},  //  7 =  row 0 rhs, col 0 bot  =  rot 90, flip vert

    { 0, x,-y, 0, h, 0}   //  8 =  row 0 lhs, col 0 bot  =  rotate -90

    };

    return ctms[orient-1];

}

// ---------------------------------------------------------------------------------------------------------------------

- (CGAffineTransform) imageTransformToFitView

{

    // make sure the entire image fits...

    CGRect imageRect = CGRectMake(0., 0., CGImageGetWidth(mImage), CGImageGetHeight(mImage));

    CGAffineTransform ctm = [self imageTransform];

    CGSize ctmdSize = CGRectApplyAffineTransform(imageRect, ctm).size;

    // keep a small border

    NSSize destSize = NSInsetRect([self bounds], kMargin, kMargin).size;

    // scale to fit in view rect

    float scale = MIN(destSize.width / ctmdSize.width, destSize.height / ctmdSize.height);

    ctm = CGAffineTransformConcat(ctm, CGAffineTransformMakeScale(scale, scale));

    return ctm;

}

// ---------------------------------------------------------------------------------------------------------------------

- (void) drawRect: (NSRect)rect

{

    // draw the background...

    [[NSColor colorWithCalibratedRed: 0.75 

                               green: 0.75

                                blue: 0.75

                               alpha: 1.0] set];

    [NSBezierPath fillRect: [self bounds]];

    // ... and the image

    if (mImage)

    {

        CGContextRef context = (CGContextRef)[[NSGraphicsContext currentContext] graphicsPort];

        if (context)

        {

            CGContextSaveGState(context);

            NSRect viewBounds = [self bounds];

            size_t width  = CGImageGetWidth(mImage);

            size_t height = CGImageGetHeight(mImage);

            CGRect imageRect = {{0,0}, {width,height}};

            // determine transform - fit to view,  EXIF orientation, non-square-pixel dpi, ...

            CGAffineTransform ctm = [self imageTransformToFitView];

            // center in view rect

            CGSize ctmdSize = CGRectApplyAffineTransform(imageRect, ctm).size;

            ctm.tx += viewBounds.origin.x + (viewBounds.size.width  - ctmdSize.width)/2;

            ctm.ty += viewBounds.origin.y + (viewBounds.size.height - ctmdSize.height)/2;

            CGContextConcatCTM(context, ctm);

            // want faster resizing?

            // if we are in live-resizing we use a faster image scaling (kCGInterpolationNone)

            if (mLiveResizing)

            {

                CGInterpolationQuality qual = CGContextGetInterpolationQuality(context);

                CGContextSetInterpolationQuality(context, kCGInterpolationNone);

                CGContextDrawImage (context, imageRect, mImage );

                CGContextSetInterpolationQuality(context, qual);

            } else

            {

                // use default interpolation quality 

                CGContextDrawImage(context, imageRect, mImage);

            }

            CGContextRestoreGState(context);

        }

    }

}

// ---------------------------------------------------------------------------------------------------------------------

- (void)viewWillStartLiveResize

{

    mLiveResizing = YES;

}

// ---------------------------------------------------------------------------------------------------------------------

- (void)viewDidEndLiveResize

{

    mLiveResizing = NO;

    // at the end of a live resize - redraw. This time it will be in higher quality

    [self display];

}

@end