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/**
* 根据颜色绘制一张图片 可以用来设置button不同状态下的背景颜色
*
* @param color color
* @param size size
*
* @return 返回绘制的image
*/
+ (UIImage *)imageWithColor:(UIColor *)color size:(CGSize)size
{
CGRect rect = CGRectMake(0, 0, size.width, size.height);
UIGraphicsBeginImageContext(rect.size);
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSetFillColorWithColor(context, [color CGColor]);
CGContextFillRect(context, rect);
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return image;
}
/**
* 裁剪image
*
* @param rect 裁剪的rect
* @param image 要裁剪的image
*
* @return 返回裁剪之后的image
*/
+ (UIImage*)subImageInRect:(CGRect)rect withImage:(UIImage *)image
{
CGImageRef subImageRef = CGImageCreateWithImageInRect(image.CGImage, rect);
CGRect smallBounds = CGRectMake(0, 0, CGImageGetWidth(subImageRef), CGImageGetHeight(subImageRef));
UIGraphicsBeginImageContext(smallBounds.size);
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextDrawImage(context, smallBounds, subImageRef);
UIImage* smallImage = [UIImage imageWithCGImage:subImageRef];
UIGraphicsEndImageContext();
CFRelease(subImageRef);
return smallImage;
}
// 缩放从顶部开始平铺图片
+ (UIImage *)imageScaleAspectFillFromTop:(CGSize)frameSize withImage:(UIImage *)image
{
CGFloat screenScale = [UIScreen mainScreen].scale;
CGFloat radio = image.size.height / image.size.width;
CGFloat height = frameSize.height / radio;
UIImage *adjustedImg = [self scaleToSize:CGSizeMake(frameSize.width * screenScale, height) withImage:image];
// 裁剪
CGRect rect = CGRectMake(0, 0, frameSize.width * screenScale,frameSize.width * screenScale);
adjustedImg = [self subImageInRect:rect withImage:adjustedImg];
return adjustedImg;
}
/**
* 等比例缩放图片
*
* @param size size
* @param image 要缩放的image
*
* @return 返回缩放的image
*/
+ (UIImage *)scaleToSize:(CGSize)size withImage:(UIImage *)image
{
CGFloat width = CGImageGetWidth(image.CGImage);
CGFloat height = CGImageGetHeight(image.CGImage);
float verticalRadio = size.height*1.0/height;
float horizontalRadio = size.width*1.0/width;
float radio = 1;
if(verticalRadio>1 && horizontalRadio>1)
{
radio = verticalRadio > horizontalRadio ? horizontalRadio : verticalRadio;
}
else
{
radio = verticalRadio < horizontalRadio ? verticalRadio : horizontalRadio;
}
width = width*radio;
height = height*radio;
int xPos = (size.width - width)/2;
int yPos = (size.height-height)/2;
// 创建一个bitmap的context
// 并把它设置成为当前正在使用的context
UIGraphicsBeginImageContext(size);
// 绘制改变大小的图片
[image drawInRect:CGRectMake(xPos, yPos, width, height)];
// 从当前context中创建一个改变大小后的图片
UIImage* scaledImage = UIGraphicsGetImageFromCurrentImageContext();
// 使当前的context出堆栈
UIGraphicsEndImageContext();
// 返回新的改变大小后的图片
return scaledImage;
}
+ (UIImage *)imageFillSize:(CGSize)viewsize withImage:(UIImage *)image
{
CGSize size = image.size;
CGFloat scalex = viewsize.width / size.width;
CGFloat scaley = viewsize.height / size.height;
CGFloat scale = MAX(scalex, scaley);
UIGraphicsBeginImageContext(viewsize);
CGFloat width = size.width * scale;
CGFloat height = size.height * scale;
float dwidth = ((viewsize.width - width) / 2.0f);
float dheight = ((viewsize.height - height) / 2.0f);
CGRect rect = CGRectMake(dwidth, dheight, size.width * scale, size.height * scale);
[image drawInRect:rect];
UIImage *newimg = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return newimg;
}
/**按照指定宽度按比例缩放图片**/
+ (UIImage *)zoomImage:(UIImage *)sourceImage targetWidth:(CGFloat)defineWidth
{
UIImage *newImage = nil;
CGSize imageSize = sourceImage.size;
CGFloat width = imageSize.width;
CGFloat height = imageSize.height;
CGFloat targetWidth = defineWidth;
CGFloat targetHeight = height / (width / targetWidth);
CGSize size = CGSizeMake(targetWidth, targetHeight);
CGFloat scaleFactor = 0.0;
CGFloat scaledWidth = targetWidth;
CGFloat scaledHeight = targetHeight;
CGPoint thumbnailPoint = CGPointMake(0.0, 0.0);
if(CGSizeEqualToSize(imageSize, size) == NO){
CGFloat widthFactor = targetWidth / width;
CGFloat heightFactor = targetHeight / height;
if(widthFactor > heightFactor){
scaleFactor = widthFactor;
}
else{
scaleFactor = heightFactor;
}
scaledWidth = width * scaleFactor;
scaledHeight = height * scaleFactor;
if(widthFactor > heightFactor){
thumbnailPoint.y = (targetHeight - scaledHeight) * 0.5;
}else if(widthFactor < heightFactor){
thumbnailPoint.x = (targetWidth - scaledWidth) * 0.5;
}
}
UIGraphicsBeginImageContext(size);
CGRect thumbnailRect = CGRectZero;
thumbnailRect.origin = thumbnailPoint;
thumbnailRect.size.width = scaledWidth;
thumbnailRect.size.height = scaledHeight;
[sourceImage drawInRect:thumbnailRect];
newImage = UIGraphicsGetImageFromCurrentImageContext();
if(newImage == nil){
NSLog(@"scale image fail");
}
UIGraphicsEndImageContext();
return newImage;
}