- UIImageView整体拉伸
UIImageView-contentMode
typedef NS_ENUM(NSInteger, UIViewContentMode) {
UIViewContentModeScaleToFill, // 默认 拉伸（会变形）
UIViewContentModeScaleAspectFit, // 等比例拉伸
UIViewContentModeScaleAspectFill, // 等比例填充
UIViewContentModeRedraw, // redraw on bounds change (这个不清楚)
UIViewContentModeCenter, // 下面的就是不拉伸按位置显示了
UIViewContentModeTop,
UIViewContentModeBottom,
UIViewContentModeLeft,
UIViewContentModeRight,
UIViewContentModeTopLeft,
UIViewContentModeTopRight,
UIViewContentModeBottomLeft,
UIViewContentModeBottomRight,
};
- UIImage局部拉伸
// 按4边间距显示不拉伸的区域
- (UIImage *)resizableImageWithCapInsets:(UIEdgeInsets)capInsets NS_AVAILABLE_IOS(5_0);
// 按2点拉伸 - (UIImage *)stretchableImageWithLeftCapWidth:(NSInteger)leftCapWidth topCapHeight:(NSInteger)topCapHeight;
- (UIImage *)resizableImageWithCapInsets:(UIEdgeInsets)capInsets resizingMode:(UIImageResizingMode)resizingMode;
// 拉伸模式
typedef NS_ENUM(NSInteger, UIImageResizingMode) {
UIImageResizingModeTile,//进行区域复制模式拉伸
UIImageResizingModeStretch,//进行渐变复制模式拉伸
};
3.UIImage修改大小
//内缩放，一条变等于最长边，另外一条小于等于最长边
-
(UIImage *)scaleToSize:(CGSize)newSize {
CGFloat width = self.size.width;
CGFloat height= self.size.height;
CGFloat newSizeWidth = newSize.width;
CGFloat newSizeHeight= newSize.height;
if (width <= newSizeWidth &&
height <= newSizeHeight) {
return self;
}if (width == 0 || height == 0 || newSizeHeight == 0 || newSizeWidth == 0) {
return nil;
}
CGSize size;
if (width / height > newSizeWidth / newSizeHeight) {
size = CGSizeMake(newSizeWidth, newSizeWidth * height / width);
} else {
size = CGSizeMake(newSizeHeight * width / height, newSizeHeight);
}
return [self drawImageWithSize:size];
} -
(UIImage *)drawImageWithSize: (CGSize)size {
CGSize drawSize = CGSizeMake(floor(size.width), floor(size.height));
UIGraphicsBeginImageContext(drawSize);[self drawInRect:CGRectMake(0, 0, drawSize.width, drawSize.height)];
UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return newImage;
}
