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

这是你在iphone中缝合图片的答案

根据我的经验,我可以给你一些说明:

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

- (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;
}

处理特定视图

你首先要导入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;
}

处理范围表单图像

CGRect captureRect = yourRect
CGRect 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)];

保存图像

保存在应用程序中

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

保存在相册中

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