Objective c 图像在处理后旋转。如何才能正确地执行此操作?
我的问题是:UIImage在处理后会旋转 我使用一个名为Objective c 图像在处理后旋转。如何才能正确地执行此操作?,objective-c,uiimage,quartz-graphics,Objective C,Uiimage,Quartz Graphics,我的问题是:UIImage在处理后会旋转 我使用一个名为ProcessHelper的助手类进行图像处理。此类有两种方法: + (unsigned char *) convertUIImageToBitmapRGBA8:(UIImage *) image; + (UIImage *) convertBitmapRGBA8ToUIImage:(unsigned char *)rawData withWidth:(int) width
ProcessHelper
的助手类进行图像处理。此类有两种方法:
+ (unsigned char *) convertUIImageToBitmapRGBA8:(UIImage *) image;
+ (UIImage *) convertBitmapRGBA8ToUIImage:(unsigned char *)rawData
withWidth:(int) width
withHeight:(int) height;
实施
+ (unsigned char *) convertUIImageToBitmapRGBA8:(UIImage *) image {
NSLog(@"Convert image [%d x %d] to RGBA8 char data", (int)image.size.width,
(int)image.size.height);
CGImageRef imageRef = [image CGImage];
NSUInteger width = CGImageGetWidth(imageRef);
NSUInteger height = CGImageGetHeight(imageRef);
CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
unsigned char *rawData = malloc(height * width * 4);
NSUInteger bytesPerPixel = 4;
NSUInteger bytesPerRow = bytesPerPixel * width;
NSUInteger bitsPerComponent = 8;
CGContextRef context = CGBitmapContextCreate(rawData,
width,
height,
bitsPerComponent,
bytesPerRow,
colorSpace,
kCGImageAlphaPremultipliedLast | kCGBitmapByteOrder32Big);
CGColorSpaceRelease(colorSpace);
CGContextDrawImage(context, CGRectMake(0, 0, width, height), imageRef);
CGContextRelease(context);
return rawData;
}
+ (UIImage *) convertBitmapRGBA8ToUIImage:(unsigned char *) rawData
withWidth:(int) width
withHeight:(int) height {
CGContextRef ctx = CGBitmapContextCreate(rawData,
width,
height,
8,
width * 4,
CGColorSpaceCreateDeviceRGB(),
kCGImageAlphaPremultipliedLast );
CGImageRef imageRef = CGBitmapContextCreateImage (ctx);
UIImage* rawImage = [UIImage imageWithCGImage:imageRef];
CGContextRelease(ctx);
free(rawData);
return rawImage;
}
我
开始时,我获得像素数据:
rawData = [ProcessHelper convertUIImageToBitmapRGBA8:image];
接下来我进行一些处理:
-(void)process_grayscale {
int byteIndex = 0;
for (int i = 0 ; i < workingImage.size.width * workingImage.size.height ; ++i)
{
int outputColor = (rawData[byteIndex] + rawData[byteIndex+1] + rawData[byteIndex+2]) / 3;
rawData[byteIndex] = rawData[byteIndex + 1] = rawData[byteIndex + 2] = (char) (outputColor);
byteIndex += 4;
}
workingImage = [ProcessHelper convertBitmapRGBA8ToUIImage:rawData
withWidth:CGImageGetWidth(workingImage.CGImage)
withHeight:CGImageGetHeight(workingImage.CGImage)];
}
-(无效)处理\u灰度{
int byteIndex=0;
对于(int i=0;i
在此之后,我将workingImage
返回到父类,并且UIImageView
显示返回的图像,但大小较旧,我的意思是:前面的图像是WxH,后面的图像是WxH,但旋转(应该是HxW,旋转后)。我想使图像不旋转
当我从ipad编辑照片时就会发生这种情况。屏幕截图还可以,来自类似互联网背景的图像也可以
如何正确执行此操作?使用
UIGraphicsPushContext(ctx);[image drawInRect:CGRectMake(0,0,宽度,高度)];UIGraphicsPopContext()代码>而不是CGContextDrawImage
CGContextDrawImage
将垂直翻转图像
或者在调用CGContextDrawImage
之前缩放和转换上下文(谢谢您的帮助;)现在每个图像都颠倒了,我不知道为什么。现在我可以翻转它了,一切正常,但我不知道为什么图像并没有原始旋转。