面膜白色列于iPhone PNG图像
题
我知道已经有上2个相关的职位,但目前还不清楚......
因此,情况是这样的...
我具有由来自在网络上的URL请求的UIImage
文件的png
。
是否有可能掩盖了白色所以它变得透明?
我的一切都与CGImageCreateWithMaskingColors
到目前为止已经试过,返回一个白图像...
任何帮助球员将是珍贵:)
解决方案
因为我发现了一个解决方案,它的正常工作,我回答我的问题,我真的相信,这将是有用的,具有同样需要很多人好了。
首先,我认为这将是很好的通过类别致以UIImages
:
<强>的UIImage + Utils.h 强>
#import <UIKit/UIKit.h>
@interface UIImage (Utils)
- (UIImage*)imageByClearingWhitePixels;
@end
<强>的UIImage + Utils.m 强>
#import "UIImage+Utils.h"
@implementation UIImage (Utils)
#pragma mark Private Methods
- (CGImageRef) CopyImageAndAddAlphaChannel:(CGImageRef) sourceImage {
CGImageRef retVal = NULL;
size_t width = CGImageGetWidth(sourceImage);
size_t height = CGImageGetHeight(sourceImage);
CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
CGContextRef offscreenContext = CGBitmapContextCreate(NULL, width, height, 8, 0, colorSpace, kCGImageAlphaPremultipliedFirst);
if (offscreenContext != NULL) {
CGContextDrawImage(offscreenContext, CGRectMake(0, 0, width, height), sourceImage);
retVal = CGBitmapContextCreateImage(offscreenContext);
CGContextRelease(offscreenContext);
}
CGColorSpaceRelease(colorSpace);
return retVal;
}
- (UIImage *) getMaskedArtworkFromPicture:(UIImage *)image withMask:(UIImage *)mask{
UIImage *maskedImage;
CGImageRef imageRef = [self CopyImageAndAddAlphaChannel:image.CGImage];
CGImageRef maskRef = mask.CGImage;
CGImageRef maskToApply = CGImageMaskCreate(CGImageGetWidth(maskRef),CGImageGetHeight(maskRef),CGImageGetBitsPerComponent(maskRef),CGImageGetBitsPerPixel(maskRef),CGImageGetBytesPerRow(maskRef),CGImageGetDataProvider(maskRef), NULL, NO);
CGImageRef masked = CGImageCreateWithMask(imageRef, maskToApply);
maskedImage = [UIImage imageWithCGImage:masked];
CGImageRelease(imageRef);
CGImageRelease(maskToApply);
CGImageRelease(masked);
return maskedImage;
}
#pragma mark Public Methods
- (UIImage*)imageByClearingWhitePixels{
//Copy image bitmaps
float originalWidth = self.size.width;
float originalHeight = self.size.height;
CGSize newSize;
newSize = CGSizeMake(originalWidth, originalHeight);
UIGraphicsBeginImageContext( newSize );
[self drawInRect:CGRectMake(0,0,newSize.width,newSize.height)];
UIImage* newImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
//Clear white color by masking with self
newImage = [self getMaskedArtworkFromPicture:newImage withMask:newImage];
return newImage;
}
@end
最后,我能够使用这样的:(后,我已导入当然UIImage+Utils.h
)
UIImage *myImage = [...]; //A local png file or a file from a url
UIImage *myWhitelessImage = [myImage imageByClearingWhitePixels]; // Hooray!
其他提示
这是不是真的有可能,至少没有简单的方法,当然也没有API调用。它基本上是通常用Photoshop进行图像编辑的问题。具有透明背景大多数图像创建的方式。
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