1、给一个view截图
UIGraphicsBeginImageContextWithOptions(view.bounds.size, YES, 0.0);
[view.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *img = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
2、颜色转图片
+ (UIImage *)cl_imageWithColor:(UIColor *)color {
CGRect rect = CGRectMake(0.0f, 0.0f, 1.0f, 1.0f);
UIGraphicsBeginImageContext(rect.size);
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSetFillColorWithColor(context, [color CGColor]);
CGContextFillRect(context, rect);
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
returnimage;
}
3、判断图片类型
//通过图片Data数据第一个字节 来获取图片扩展名
- (NSString *)contentTypeForImageData:(NSData *)data
{
uint8_t c;
[data getBytes:&c length:1];
switch(c)
{
case0xFF:
return@"jpeg";
case0x89:
return@"png";
case0x47:
return@"gif";
case0x49:
case0x4D:
return@"tiff";
case0x52:
if([data length] < 12) {
returnnil;
}
NSString *testString = [[NSString alloc] initWithData:[data subdataWithRange:NSMakeRange(0, 12)] encoding:NSASCIIStringEncoding];
if([testString hasPrefix:@"RIFF"]
&& [testString hasSuffix:@"WEBP"])
{
return@"webp";
}
returnnil;
}
returnnil;
}
4、image圆角
- (UIImage *)circleImage
{
// NO代表透明
UIGraphicsBeginImageContextWithOptions(self.size, NO, 1);
// 获得上下文
CGContextRef ctx = UIGraphicsGetCurrentContext();
// 添加一个圆
CGRect rect = CGRectMake(0, 0, self.size.width, self.size.height);
// 方形变圆形
CGContextAddEllipseInRect(ctx, rect);
// 裁剪
CGContextClip(ctx);
// 将图片画上去
[self drawInRect:rect];
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
returnimage;
}
5、image拉伸
+ (UIImage *)resizableImage:(NSString *)imageName
{
UIImage *image = [UIImage imageNamed:imageName];
CGFloat imageW = image.size.width;
CGFloat imageH = image.size.height;
return[image resizableImageWithCapInsets:UIEdgeInsetsMake(imageH * 0.5, imageW * 0.5, imageH * 0.5, imageW * 0.5) resizingMode:UIImageResizingModeStretch];
}
6、取图片某一点的颜色
if(point.x < 0 || point.y < 0)returnnil;
CGImageRef imageRef = self.CGImage;
NSUInteger width = CGImageGetWidth(imageRef);
NSUInteger height = CGImageGetHeight(imageRef);
if(point.x >= width || point.y >= height)returnnil;
unsigned char *rawData = malloc(height * width * 4);
if(!rawData)returnnil;
CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
NSUInteger bytesPerPixel = 4;
NSUInteger bytesPerRow = bytesPerPixel * width;
NSUInteger bitsPerComponent = 8;
CGContextRef context = CGBitmapContextCreate(rawData,
width,
height,
bitsPerComponent,
bytesPerRow,
colorSpace,
kCGImageAlphaPremultipliedLast
| kCGBitmapByteOrder32Big);
if(!context) {
free(rawData);
returnnil;
}
CGColorSpaceRelease(colorSpace);
CGContextDrawImage(context, CGRectMake(0, 0, width, height), imageRef);
CGContextRelease(context);
int byteIndex = (bytesPerRow * point.y) + point.x * bytesPerPixel;
CGFloat red = (rawData[byteIndex] * 1.0) / 255.0;
CGFloat green = (rawData[byteIndex + 1] * 1.0) / 255.0;
CGFloat blue = (rawData[byteIndex + 2] * 1.0) / 255.0;
CGFloat alpha = (rawData[byteIndex + 3] * 1.0) / 255.0;
UIColor *result = nil;
result = [UIColor colorWithRed:red green:green blue:blue alpha:alpha];
free(rawData);
returnresult;
7、判断该图片是否有透明度通道
- (BOOL)hasAlphaChannel
{
CGImageAlphaInfo alpha = CGImageGetAlphaInfo(self.CGImage);
return(alpha == kCGImageAlphaFirst ||
alpha == kCGImageAlphaLast ||
alpha == kCGImageAlphaPremultipliedFirst ||
alpha == kCGImageAlphaPremultipliedLast);
}
8、获得灰度图
+ (UIImage*)covertToGrayImageFromImage:(UIImage*)sourceImage
{
int width = sourceImage.size.width;
int height = sourceImage.size.height;
CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceGray();
CGContextRef context = CGBitmapContextCreate (nil,width,height,8,0,colorSpace,kCGImageAlphaNone);
CGColorSpaceRelease(colorSpace);
if(context == NULL) {
returnnil;
}
CGContextDrawImage(context,CGRectMake(0, 0, width, height), sourceImage.CGImage);
CGImageRef contextRef = CGBitmapContextCreateImage(context);
UIImage *grayImage = [UIImage imageWithCGImage:contextRef];
CGContextRelease(context);
CGImageRelease(contextRef);
returngrayImage;
}
9、合并两个图片
+ (UIImage*)mergeImage:(UIImage*)firstImage withImage:(UIImage*)secondImage {
CGImageRef firstImageRef = firstImage.CGImage;
CGFloat firstWidth = CGImageGetWidth(firstImageRef);
CGFloat firstHeight = CGImageGetHeight(firstImageRef);
CGImageRef secondImageRef = secondImage.CGImage;
CGFloat secondWidth = CGImageGetWidth(secondImageRef);
CGFloat secondHeight = CGImageGetHeight(secondImageRef);
CGSize mergedSize = CGSizeMake(MAX(firstWidth, secondWidth), MAX(firstHeight, secondHeight));
UIGraphicsBeginImageContext(mergedSize);
[firstImage drawInRect:CGRectMake(0, 0, firstWidth, firstHeight)];
[secondImage drawInRect:CGRectMake(0, 0, secondWidth, secondHeight)];
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
returnimage;
}
10、为imageView添加倒影
CGRect frame = self.frame;
frame.origin.y += (frame.size.height + 1);
UIImageView *reflectionImageView = [[UIImageView alloc] initWithFrame:frame];
self.clipsToBounds = TRUE;
reflectionImageView.contentMode = self.contentMode;
[reflectionImageView setImage:self.image];
reflectionImageView.transform = CGAffineTransformMakeScale(1.0, -1.0);
CALayer *reflectionLayer = [reflectionImageView layer];
CAGradientLayer *gradientLayer = [CAGradientLayer layer];
gradientLayer.bounds = reflectionLayer.bounds;
gradientLayer.position = CGPointMake(reflectionLayer.bounds.size.width / 2, reflectionLayer.bounds.size.height * 0.5);
gradientLayer.colors = [NSArray arrayWithObjects:
(id)[[UIColor clearColor] CGColor],
(id)[[UIColor colorWithRed:1.0 green:1.0 blue:1.0 alpha:0.3] CGColor], nil];
gradientLayer.startPoint = CGPointMake(0.5,0.5);
gradientLayer.endPoint = CGPointMake(0.5,1.0);
reflectionLayer.mask = gradientLayer;
[self.superview addSubview:reflectionImageView];
11、画水印
// 画水印
- (void) setImage:(UIImage *)image withWaterMark:(UIImage *)mark inRect:(CGRect)rect
{
if([[[UIDevice currentDevice] systemVersion] floatValue] >= 4.0)
{
UIGraphicsBeginImageContextWithOptions(self.frame.size, NO, 0.0);
}
//原图
[image drawInRect:self.bounds];
//水印图
[mark drawInRect:rect];
UIImage *newPic = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
self.image = newPic;
}
12、获取一个视频的第一帧图片
NSURL *url = [NSURL URLWithString:filepath];
AVURLAsset *asset1 = [[AVURLAsset alloc] initWithURL:url options:nil];
AVAssetImageGenerator *generate1 = [[AVAssetImageGenerator alloc] initWithAsset:asset1];
generate1.appliesPreferredTrackTransform = YES;
NSError *err = NULL;
CMTime time = CMTimeMake(1, 2);
CGImageRef oneRef = [generate1 copyCGImageAtTime:time actualTime:NULL error:&err];
UIImage *one = [[UIImage alloc] initWithCGImage:oneRef];
returnone;
13、UIView背景颜色渐变
UIView *view = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 320, 100)];
[self.view addSubview:view];
CAGradientLayer *gradient = [CAGradientLayer layer];
gradient.frame = view.bounds;
gradient.colors = [NSArray arrayWithObjects:(id)[[UIColor blackColor] CGColor], (id)[[UIColor whiteColor] CGColor], nil];
[view.layer insertSublayer:gradient atIndex:0];
14、UIImage和base64互转
// view分类方法
- (NSString *)encodeToBase64String:(UIImage *)image {
return[UIImagePNGRepresentation(image) base64EncodedStringWithOptions:NSDataBase64Encoding64CharacterLineLength];
}
- (UIImage *)decodeBase64ToImage:(NSString *)strEncodeData {
NSData *data = [[NSData alloc]initWithBase64EncodedString:strEncodeData options:NSDataBase64DecodingIgnoreUnknownCharacters];
return[UIImage imageWithData:data];
}
15、将一个image保存在相册中
UIImageWriteToSavedPhotosAlbum(image, nil, nil, nil);
或者
#import
[[PHPhotoLibrary sharedPhotoLibrary] performChanges:^{
PHAssetChangeRequest *changeRequest = [PHAssetChangeRequest creationRequestForAssetFromImage:image];
changeRequest.creationDate = [NSDate date];
} completionHandler:^(BOOL success, NSError *error) {
if(success) {
NSLog(@"successfully saved");
}
else{
NSLog(@"error saving to photos: %@", error);
}
}];
16、修改cell.imageView的大小
UIImage *icon = [UIImage imageNamed:@""];
CGSize itemSize = CGSizeMake(30, 30);
UIGraphicsBeginImageContextWithOptions(itemSize, NO ,0.0);
CGRect imageRect = CGRectMake(0.0, 0.0, itemSize.width, itemSize.height);
[icon drawInRect:imageRect];
cell.imageView.image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
17、
