/*

     File: ViewController.m

 Abstract: 

  Version: 1.3

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 */

#import "ViewController.h"

#import "EAGLView.h"

#define DEG2RAD (M_PI/180.0f)

// These enums match the button tags in the nib

enum {

    BUTTON_BRIGHTNESS,

    BUTTON_CONTRAST,

    BUTTON_SATURATION,

    BUTTON_HUE,

    BUTTON_SHARPNESS,

    NUM_BUTTONS

};

@implementation ViewController

@synthesize slider;

@synthesize tabBar;

- (void)viewDidLoad

{

    int b, i;

    // Select first tab by default

    tabBar.selectedItem = [tabBar.items objectAtIndex:0];

    // Create a bitmap context for rendering the tabBar buttons

    // Usually, button images are loaded from disk, but these simple shapes can be procedurally generated.

    // UITabBar only needs the alpha channel of these images.

    CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();

    CGContextRef context = CGBitmapContextCreate(nil, 30, 30, 8, 0, colorSpace, kCGImageAlphaPremultipliedFirst);

    CGImageRef theCGImage;

    // Draw with white round strokes

    CGContextSetLineCap(context, kCGLineCapRound);

    CGContextSetRGBStrokeColor(context, 1.0, 1.0, 1.0, 1.0);

    CGContextSetRGBFillColor(context, 1.0, 1.0, 1.0, 1.0);

    CGContextSetLineWidth(context, 2.0);

    for (b = 0; b < NUM_BUTTONS; b++)

    {

        CGContextClearRect(context, CGRectMake(0, 0, 30, 30));

        switch(b)

        {

            case BUTTON_BRIGHTNESS:

            {

                const CGFloat line[8*4] = {

                    15.0, 6.0, 15.0, 4.0,

                    15.0,24.0, 15.0,26.0,

                     6.0,15.0,  4.0,15.0,

                    24.0,15.0, 26.0,15.0,

                    21.5,21.5, 23.0,23.0,

                     8.5, 8.5,  7.0, 7.0,

                    21.5, 8.5, 23.0, 7.0,

                     8.5,21.5,  7.0,23.0,                   

                };

                // A circle with eight rays around it

                CGContextStrokeEllipseInRect(context, CGRectMake(10.5, 10.5, 9.0, 9.0));

                for (i = 0; i < 8; i++)

                {

                    CGContextMoveToPoint(context, line[i*4+0], line[i*4+1]);

                    CGContextAddLineToPoint(context, line[i*4+2], line[i*4+3]);

                    CGContextStrokePath(context);                   

                }

                break;

            }

            case BUTTON_CONTRAST:

            {

                // A circle with the right half filled

                CGContextStrokeEllipseInRect(context, CGRectMake(4.0, 4.0, 22.0, 22.0));

                CGContextAddArc(context, 15.0, 15.0, 11.0, -M_PI/2.0, M_PI/2.0, false);

                CGContextFillPath(context);

                break;

            }

            case BUTTON_SATURATION:

            {

                CGGradientRef gradient;

                const CGFloat stripe[3][12] = {

                    { 0.3,0.3,0.3,0.15, 1.0,0.0,0.0,0.70,  5, 5, 7, 25 }, 

                    { 0.5,0.5,0.5,0.25, 0.0,1.0,0.0,0.75, 12, 5, 6, 25 },

                    { 0.2,0.2,0.2,0.10, 0.0,0.0,1.0,0.65, 18, 5, 7, 25 },

                };

                // Red/Green/Blue gradients, inside a rounded rect

                for (i = 0; i < 3; i++)

                {

                    gradient = CGGradientCreateWithColorComponents(colorSpace, stripe[i], NULL, 2);

                    CGContextSaveGState(context);

                    CGContextClipToRect(context, CGRectMake(stripe[i][8], stripe[i][9], stripe[i][10], stripe[i][11]));

                    CGContextDrawLinearGradient(context, gradient, CGPointMake(15, 5), CGPointMake(15, 25), 0);

                    CGContextRestoreGState(context);

                    CGGradientRelease(gradient);

                }

                CGContextMoveToPoint(context, 4, 15);

                CGContextAddArcToPoint(context, 4, 4, 15, 4, 4);

                CGContextAddArcToPoint(context, 26, 4, 26, 15, 4);

                CGContextAddArcToPoint(context, 26, 26, 15, 26, 4);

                CGContextAddArcToPoint(context, 4, 26, 4, 15, 4);

                CGContextClosePath(context);

                CGContextStrokePath(context);

                break;

            }

            case BUTTON_HUE:

            {

                CGGradientRef gradient;

                CGFloat hue[8];

                const int angle = 4;

                // A radial gradient, inside a circle

                for (i = 0; i < 360; i+=angle)

                {

                    float x = cosf((i+angle*0.5)*DEG2RAD)*10+15;

                    float y = sinf((i+angle*0.5)*DEG2RAD)*10+15;

                    float r = (i    )/180.0; if (r > 1.0) r = 2.0-r;

                    float g = (i+120)/180.0; if (g > 2.0) g = g-2.0; else if (g > 1.0) g = 2.0-g;

                    float b = (i+240)/180.0; if (b > 3.0) b = 4.0-b; else if (b > 2.0) b = b-2.0; else b = 2.0-b;

                    float a = (i+ 90)/180.0; if (a > 2.0) a = a-2.0; else if (a > 1.0) a = 2.0-a;

                    hue[0] = hue[4] = r;

                    hue[1] = hue[5] = g;

                    hue[2] = hue[6] = b;

                    hue[3] = a*0.5;

                    hue[7] = a*0.75;

                    gradient = CGGradientCreateWithColorComponents(colorSpace, hue, NULL, 2);

                    CGContextSaveGState(context);

                    CGContextMoveToPoint(context, 15, 15);

                    CGContextAddArc(context, 15, 15, 10, i*DEG2RAD, (i+angle)*DEG2RAD, false);

                    CGContextClosePath(context);

                    CGContextClip(context);

                    CGContextDrawLinearGradient(context, gradient, CGPointMake(x, y), CGPointMake(15, 15), 0);                  

                    CGContextRestoreGState(context);

                    CGGradientRelease(gradient);

                }

                CGContextStrokeEllipseInRect(context, CGRectMake(4.0, 4.0, 22.0, 22.0));

                break;

            }

            case BUTTON_SHARPNESS:

            {

                int x, y;

                // A gradient checkerboard, inside a rounded rect

                for (x = 5; x < 25; x+=2)

                {

                    float b = (x - 5)/19.0*0.5+0.375;

                    if (b > 0.75) b = 0.75;

                    else if (b < 0.5) b = 0.5;

                    for (y = 5; y < 25; y+=2)

                    {

                        float k = ((x ^ y) & 2) ? b : 1.0-b;

                        CGContextSetRGBFillColor(context, k, k, k, k);

                        CGContextFillRect(context, CGRectMake(x, y, 2, 2));

                    }

                }

                CGContextSetRGBFillColor(context, 1.0, 1.0, 1.0, 1.0);

                CGContextMoveToPoint(context, 4, 15);

                CGContextAddArcToPoint(context, 4, 4, 15, 4, 4);

                CGContextAddArcToPoint(context, 26, 4, 26, 15, 4);

                CGContextAddArcToPoint(context, 26, 26, 15, 26, 4);

                CGContextAddArcToPoint(context, 4, 26, 4, 15, 4);

                CGContextClosePath(context);

                CGContextStrokePath(context);

                break;

            }

        }

        theCGImage = CGBitmapContextCreateImage(context);

        ((UITabBarItem *)[tabBar.items objectAtIndex:b]).image = [UIImage imageWithCGImage:theCGImage];

        CGImageRelease(theCGImage);

    }

    CGContextRelease(context);

    CGColorSpaceRelease(colorSpace);

}

- (void)dealloc

{

    self.slider = nil;

    self.tabBar = nil;

    [super dealloc];

}

- (void)sliderAction:(id)sender

{

    // Redraw the view with the new settings

    [((EAGLView*)self.view) drawView];

}

- (void)tabBar:(UITabBar *)tabBar didSelectItem:(UITabBarItem *)item

{

    // Recenter the slider (this application does not accumulate multiple filters)

    [self.slider setValue:1.0 animated:YES];

    // Redraw the view with the new settings

    [((EAGLView*)self.view) drawView];

}

@end