Question

http://iphonedevelopertips.com/cocoa/how-to-mask-an-image.html 表格

页: 1 ToSave=[自封面:[UIImage conceptNamed:@”pic.jpg] withMask:[UIImage conceptNamed:@”sd-face-mask.png]];

www.un.org/Depts/DGACM/index_spanish.htm 在UIImage的景象观点

UIImageView *imgView = [[UIImageView alloc] initWithImage:imgToSave];
imgView.center = CGPointMake(160.0f, 140.0f);
[self.view addSubview:imgView];

。

[UIImagePNGRepresentation (img ToSave) written ToFile:[自发现UniqueSavePath]tomally:YES];

<>UIImagePNGRepresentation 回归NSData,其形象不同。

The output is inverse image mask. The area that was cut out in the app is now visible in the file. The area that was visible in the app is now removed. Visibility is opposite.

我的面罩旨在除表面外,消除一切。 UIImage看上去是正确的,但在我把它放在软盘上之后,档案却相反。这里的面貌已经消除,但除此之外还有一切。

让我知道,你是否能够帮助!

Answer 1

我的问题完全相同,当时我挽救了档案,但记忆中恢复的形象恰恰相反。

The culprit & the Solutions was UIImagePNGRepresentation(). 在将图像保存到磁盘之前,它就固定了应用图像,因此,我刚刚插入这一功能,作为制造隐蔽形象和归还形象的最后一步。

这可能不是最棘手的解决办法,但它行之有效。我从我的手里复制了一些法典,并对此加以压缩,但并不确定以下的法典是否与现在一样有效,如果不是这样的话,其接近......可能只是一些类型。

收到:

// MyImageHelperObj.h

@interface MyImageHelperObj : NSObject

+ (UIImage *) createGrayScaleImage:(UIImage*)originalImage;
+ (UIImage *) createMaskedImageWithSize:(CGSize)newSize sourceImage:(UIImage *)sourceImage maskImage:(UIImage *)maskImage;

@end





// MyImageHelperObj.m

#import <QuartzCore/QuartzCore.h>
#import "MyImageHelperObj.h"


@implementation MyImageHelperObj


+ (UIImage *) createMaskedImageWithSize:(CGSize)newSize sourceImage:(UIImage *)sourceImage maskImage:(UIImage *)maskImage;
{
    // create image size rect
    CGRect newRect = CGRectZero;
    newRect.size = newSize;

    // draw source image
    UIGraphicsBeginImageContextWithOptions(newRect.size, NO, 0.0f);
    [sourceImage drawInRect:newRect];
    UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();

    // draw mask image
    [maskImage drawInRect:newRect blendMode:kCGBlendModeNormal alpha:1.0f];
    maskImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

    // create grayscale version of mask image to make the "image mask"
    UIImage *grayScaleMaskImage = [MyImageHelperObj createGrayScaleImage:maskImage];
    CGFloat width = CGImageGetWidth(grayScaleMaskImage.CGImage);
    CGFloat height = CGImageGetHeight(grayScaleMaskImage.CGImage);
    CGFloat bitsPerPixel = CGImageGetBitsPerPixel(grayScaleMaskImage.CGImage);
    CGFloat bytesPerRow = CGImageGetBytesPerRow(grayScaleMaskImage.CGImage);
    CGDataProviderRef providerRef = CGImageGetDataProvider(grayScaleMaskImage.CGImage);
    CGImageRef imageMask = CGImageMaskCreate(width, height, 8, bitsPerPixel, bytesPerRow, providerRef, NULL, false);

    CGImageRef maskedImage = CGImageCreateWithMask(newImage.CGImage, imageMask);
    CGImageRelease(imageMask);
    newImage = [UIImage imageWithCGImage:maskedImage];
    CGImageRelease(maskedImage);
    return [UIImage imageWithData:UIImagePNGRepresentation(newImage)];
}

+ (UIImage *) createGrayScaleImage:(UIImage*)originalImage;
{
    //create gray device colorspace.
    CGColorSpaceRef space = CGColorSpaceCreateDeviceGray();
    //create 8-bit bimap context without alpha channel.
    CGContextRef bitmapContext = CGBitmapContextCreate(NULL, originalImage.size.width, originalImage.size.height, 8, 0, space, kCGImageAlphaNone);
    CGColorSpaceRelease(space);
    //Draw image.
    CGRect bounds = CGRectMake(0.0, 0.0, originalImage.size.width, originalImage.size.height);
    CGContextDrawImage(bitmapContext, bounds, originalImage.CGImage);
    //Get image from bimap context.
    CGImageRef grayScaleImage = CGBitmapContextCreateImage(bitmapContext);
    CGContextRelease(bitmapContext);
    //image is inverted. UIImage inverts orientation while converting CGImage to UIImage.
    UIImage* image = [UIImage imageWithCGImage:grayScaleImage];
    CGImageRelease(grayScaleImage);
    return image;
}

@end

Answer 2

在座标中,你穿戴面罩(黑色穿透和白块),或打着正反面的正常形象(白 let和黑块)。似乎出于某种原因,在把图像掩饰作为掩盖的正常形象。一种想法是使图形成为一种背景,然后形成从中挽救的形象。

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