iphone - 创建特定大小的 UIImage

Question

如何从头开始创建 UIImage。具体来说，我想创建一个大小为 320x50 的 UIImage。然后，我希望能够在该图像上绘制特定颜色的多边形。

Answer 1

这里给你一个答案stitch picture in iphone

根据我的经验，我可以给你一些注意事项:

比例尺

- (UIImage *)scaleImage:(UIImage *)image toScale:(float)scaleSize{ UIGraphicsBeginImageContext(CGSizeMake(image.size.width*scaleSize,image.size.height*scaleSize); [image drawInRect:CGRectMake(0, 0, image.size.width * scaleSize, image.size.height *scaleSize)]; UIImage *scaledImage = UIGraphicsGetImageFromCurrentImageContext(); UIGraphicsEndImageContext(); return scaledImage;}

调整大小

- (UIImage *)reSizeImage:(UIImage *)image toSize:(CGSize)reSize{ UIGraphicsBeginImageContext(CGSizeMake(reSize.width, reSize.height)); [image drawInRect:CGRectMake(0, 0, reSize.width, reSize.height)]; UIImage *reSizeImage = UIGraphicsGetImageFromCurrentImageContext(); UIGraphicsEndImageContext(); return reSizeImage;}

处理特定 View

你必须先导入 QuzrtzCore.framework

-(UIImage*)captureView:(UIView *)theView{ CGRect rect = theView.frame;  UIGraphicsBeginImageContext(rect.size);  CGContextRef context = UIGraphicsGetCurrentContext();  [theView.layer renderInContext:context];  UIImage *img = UIGraphicsGetImageFromCurrentImageContext();  UIGraphicsEndImageContext();  return img;}

处理范围形式的图像

CGRect captureRect = yourRectCGRect viewRect = self.view.frame;UIImage *viewImg;UIImage *captureImg;UIGraphicsBeginImageContext(viewRect.size); CGContextRef context = UIGraphicsGetCurrentContext(); [self.view.layer renderInContext:context]; viewImg = UIGraphicsGetImageFromCurrentImageContext(); UIGraphicsEndImageContext();captureImg = [UIImage imageWithCGImage:CGImageCreateWithImageInRect(viewImg.CGImage, captureRect)];

保存图片

保存在应用中

NSString *path = [[NSHomeDirectory() stringByAppendingPathComponent:@"Documents"] stringByAppendingPathComponent:@"image.png"];[UIImagePNGRepresentation(image) writeToFile:path atomically:YES];

保存在相册

CGImageRef screen = UIGetScreenImage();UIImage* image = [UIImage imageWithCGImage:screen];CGImageRelease(screen);UIImageWriteToSavedPhotosAlbum(image, self, nil, nil);