在iPhone App上將彩色照片轉換為黑白

Question

我的應用程序從iPhone或相機庫中拍攝照片。 然后是一個開關控件，可將其轉換為黑白照片。

當我執行開關控制時，它什么也沒做。

我不知道我的代碼出了什么問題。 我看過StackOverflow上的其他示例，但無法正常工作。 有人看到明顯的東西嗎？

這是我的頭文件，下面是我的實現文件。

//
//  ErdalKulguProjectViewController.h
//  ErdalKulguProject
//
//  Created by Kulgu, Erdal on 1/17/12.
//  Copyright 2012 __MyCompanyName__. All rights reserved.
//

#import <UIKit/UIKit.h>
#import <MediaPlayer/MediaPlayer.h>

@interface ErdalKulguProjectViewController : UIViewController <MPMediaPickerControllerDelegate, UIImagePickerControllerDelegate,UINavigationControllerDelegate> {
    IBOutlet UIImageView *chosenImage;
    IBOutlet UISwitch *toggleCamera;
    IBOutlet UISwitch *toggleBlackWhite;


}

-(IBAction)chooseImage:(id)sender;
- (UIImage *)convertImageToGrayScale:(UIImage *)image;

@property (nonatomic, retain) UIImageView *chosenImage;
@property (nonatomic,retain) UISwitch *toggleCamera; 
@property (nonatomic,retain) UISwitch *toggleBlackWhite;



@end

實施文件：

//
//  ErdalKulguProjectViewController.m
//  ErdalKulguProject
//
//  Created by Kulgu, Erdal on 1/17/12.
//  Copyright 2012 __MyCompanyName__. All rights reserved.
//

#import "ErdalKulguProjectViewController.h"

@implementation ErdalKulguProjectViewController

@synthesize chosenImage;
@synthesize toggleCamera; 
@synthesize toggleBlackWhite;
//@synthesize grayScale;


-(IBAction)chooseImage:(id)sender {
    UIImagePickerController *imagePicker; 
    imagePicker = [[UIImagePickerController alloc] init];



    if ([toggleCamera isOn]) { 
        imagePicker.sourceType=UIImagePickerControllerSourceTypeCamera;
    } else { 
        imagePicker.sourceType=UIImagePickerControllerSourceTypePhotoLibrary;

    } 
    imagePicker.delegate=self; 
    [[UIApplication sharedApplication] setStatusBarHidden:YES]; 
    [self presentModalViewController:imagePicker animated:YES]; 
    [imagePicker release];
}

- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info {
    [[UIApplication sharedApplication] setStatusBarHidden:NO]; 
    [self dismissModalViewControllerAnimated:YES]; 
    chosenImage.image=[info objectForKey: UIImagePickerControllerOriginalImage];



}

- (void)imagePickerControllerDidCancel: (UIImagePickerController *)picker {
    [[UIApplication sharedApplication] setStatusBarHidden:NO]; 
    [self dismissModalViewControllerAnimated:YES];
}





- (UIImage *)convertImageToGrayScale:(UIImage *)image
{
    // Create image rectangle with current image width/height
    CGRect imageRect = CGRectMake(0, 0, image.size.width, image.size.height);


    if ([toggleBlackWhite isOn]) { 


    } else { 


    } 


    // Grayscale color space
    CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceGray();

    // Create bitmap content with current image size and grayscale colorspace
    CGContextRef context = CGBitmapContextCreate(nil, image.size.width, image.size.height, 8, 0, colorSpace, kCGImageAlphaNone);

    // Draw image into current context, with specified rectangle
    // using previously defined context (with grayscale colorspace)
    CGContextDrawImage(context, imageRect, [image CGImage]);

    // Create bitmap image info from pixel data in current context
    CGImageRef imageRef = CGBitmapContextCreateImage(context);

    // Create a new UIImage object  
    UIImage *newImage = [UIImage imageWithCGImage:imageRef];

    // Release colorspace, context and bitmap information
    CGColorSpaceRelease(colorSpace);
    CGContextRelease(context);
    CFRelease(imageRef);

    // Return the new grayscale image
    return newImage;
}





/*
// The designated initializer. Override to perform setup that is required before the view is loaded.
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil {
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        // Custom initialization
    }
    return self;
}
*/

/*
// Implement loadView to create a view hierarchy programmatically, without using a nib.
- (void)loadView {
}
*/


/*
// Implement viewDidLoad to do additional setup after loading the view, typically from a nib.
- (void)viewDidLoad {
    [super viewDidLoad];
}
*/


/*
// Override to allow orientations other than the default portrait orientation.
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {
    // Return YES for supported orientations
    return (interfaceOrientation == UIInterfaceOrientationPortrait);
}
*/

- (void)didReceiveMemoryWarning {
    // Releases the view if it doesn't have a superview.
    [super didReceiveMemoryWarning];

    // Release any cached data, images, etc that aren't in use.
}

- (void)viewDidUnload {
    // Release any retained subviews of the main view.
    // e.g. self.myOutlet = nil;
}


- (void)dealloc {
    [chosenImage release];
    [toggleCamera release];
    [toggleBlackWhite release];
    [super dealloc];
}

@end

Answer 1

假設您的函數確實起作用，則需要在此處調用它：

- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info {
    [[UIApplication sharedApplication] setStatusBarHidden:NO]; 
    [self dismissModalViewControllerAnimated:YES]; 
    chosenImage.image=[info objectForKey: UIImagePickerControllerOriginalImage];

    //adjust the image if switch is toggled
    if ([toggleBlackWhite isOn]) chosenImage = [self convertImageToGrayScale:chosenImage];
}

然后顯示selectedImage。