App開發流程之影像處理工具類,app影像處理工具類
先羅列一下工具類中提供的方法:
/** * 根據原始view和毛玻璃樣式,擷取模糊視圖,並自動作為原view的subview(如果不需要作為子視圖,自行調用removeFromSuperview) */+ (UIView *)getBlurEffectViewWithOriginalView:(UIView *)originalView style:(ImageHelperBlurEffectStyle)style;/** * 根據原始映像和毛玻璃樣式,擷取新映像 */+ (UIImage *)getBlurEffectImageWithOriginalImage:(UIImage *)originalImage style:(ImageHelperBlurEffectStyle)style;/** * 根據原始映像,等比縮放係數,得到新映像 */+ (UIImage *)getImageWithOriginalImage:(UIImage *)originalImage scale:(CGFloat)scale;/** * 根據原始映像,等比縮放最大尺寸,得到新映像 */+ (UIImage *)getImageWithOriginalImage:(UIImage *)originalImage scaleMaxSize:(CGSize)scaleMaxSize;/** * 根據原始映像,等比縮放最大尺寸,得到新尺寸 */+ (CGSize)getImageSizeWithOriginalImage:(UIImage *)originalImage scaleMaxSize:(CGSize)scaleMaxSize;/** * 根據原始映像,完全填充尺寸,得到新映像 */+ (UIImage *)getImageWithOriginalImage:(UIImage *)originalImage fillSize:(CGSize)fillSize;/** * 根據原始映像,裁剪地區,得到新映像 */+ (UIImage *)getImageWithOriginalImage:(UIImage *)originalImage cutFrame:(CGRect)cutFrame;/** * 根據顏色,得到單位尺寸的純色新映像 */+ (UIImage *)getImageWithColor:(UIColor *)color;/** * 根據view,得到快照 */+ (UIImage *)getSnapshotWithView:(UIView *)view;/** * 全屏,但不包括狀態列 */+ (UIImage *)getFullScreenSnapshot;
說明:
1.擷取毛半透明效果(高斯模糊)映像
在iOS8以後,提供了類UIBlurEffect、UIVisualEffectView,可以方便的產生高斯模糊的視圖,然後只需要作為目標視圖的subview即可看到效果。在iOS7上需要自行實現,不過蘋果在WWDC 2013上提供了一個UIImage+ImageEffects的分類,可以產生高斯模糊的映像。將分類加入項目Categories目錄後,在ImageHelper中引用。因為UIBlurEffectStyle是在iOS8以後出現的,所以自訂了一個與其對應的枚舉類型ImageHelperBlurEffectStyle,以便在iOS7中也可以正常使用。實現代碼如下:
+ (UIView *)getBlurEffectViewWithOriginalView:(UIView *)originalView style:(ImageHelperBlurEffectStyle)style{ if (DeviceIOSVersionAbove(8)) { UIBlurEffectStyle blurStyle; switch (style) { case ImageHelperBlurEffectStyleExtraLight: { blurStyle = UIBlurEffectStyleExtraLight; break; } case ImageHelperBlurEffectStyleLight: { blurStyle = UIBlurEffectStyleLight; break; } case ImageHelperBlurEffectStyleDark: { blurStyle = UIBlurEffectStyleDark; break; } } UIBlurEffect *effect = [UIBlurEffect effectWithStyle:blurStyle]; UIVisualEffectView *effectView = [[UIVisualEffectView alloc] initWithEffect:effect]; effectView.frame = originalView.bounds; [originalView addSubview:effectView]; return effectView; } else { UIImage *originalImage = [self getSnapshotWithView:originalView]; UIImage *blurImage = [self getBlurEffectImageWithOriginalImage:originalImage style:style]; UIImageView *effectView = [[UIImageView alloc] initWithFrame:originalView.bounds]; [effectView setImage:blurImage]; [originalView addSubview:effectView]; return effectView; }}+ (UIImage *)getBlurEffectImageWithOriginalImage:(UIImage *)originalImage style:(ImageHelperBlurEffectStyle)style{ UIImage *newImage; switch (style) { case ImageHelperBlurEffectStyleExtraLight: { newImage = [originalImage applyExtraLightEffect]; break; } case ImageHelperBlurEffectStyleLight: { newImage = [originalImage applyLightEffect]; break; } case ImageHelperBlurEffectStyleDark: { newImage = [originalImage applyDarkEffect]; break; } } return newImage;}
2.提供了將映像等比例縮放的系列方法,以及裁剪的方法。基本思路就是在當前映像上下文中,指定繪製尺寸(即位元影像的尺寸),然後將相應映像繪製到指定位置,然後產生最終映像。例如裁剪映像範例程式碼:
+ (UIImage *)getImageWithOriginalImage:(UIImage *)originalImage cutFrame:(CGRect)cutFrame{ CGSize newSize = cutFrame.size; UIGraphicsBeginImageContext(newSize); [originalImage drawInRect:CGRectMake(-cutFrame.origin.x, -cutFrame.origin.y, cutFrame.size.width, cutFrame.size.height)]; UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext(); UIGraphicsEndImageContext(); return newImage;}
3.截屏方法
需要用到方法:
UIGraphicsBeginImageContextWithOptions(CGSize size, BOOL opaque, CGFloat scale)。第一個參數仍然是指定映像上下文繪製尺寸;第二個參數指定是否不透明;第三個為等比例縮放係數,如果為0.0,表示與裝置主畫面的係數一致。
CALayer的renderInContext:(CGContextRef)ctx方法,將圖層全部渲染到某個上下文中,建議為當前映像上下文。最後得到映像。
+ (UIImage *)getSnapshotWithView:(UIView *)view{ UIGraphicsBeginImageContextWithOptions(view.bounds.size, YES, 0.0); [view.layer renderInContext:UIGraphicsGetCurrentContext()]; UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext(); UIGraphicsEndImageContext(); return newImage;}+ (UIImage *)getFullScreenSnapshot{ return [self getSnapshotWithView:[UIApplication sharedApplication].keyWindow];}
全屏時候,不包括狀態列,因為狀態列不在應用的window上,無法直接擷取。但是可以通過私人Api拿到系統截屏映像,在此不展開探究。
測試內容
UIImage *icon = LOADIMAGE(AppIcon); UIImage *testImg; testImg = [ImageHelper getImageWithOriginalImage:icon scale:2]; LOG(@"%@", testImg); testImg = [ImageHelper getImageWithOriginalImage:icon scaleMaxSize:CGSizeMake(100, 90)]; LOG(@"%@", testImg); testImg = [ImageHelper getImageWithOriginalImage:icon fillSize:CGSizeMake(100, 90)]; LOG(@"%@", testImg); testImg = [ImageHelper getImageWithOriginalImage:icon cutFrame:CGRectMake(10, 10, 50, 50)]; LOG(@"%@", testImg); testImg = [ImageHelper getImageWithColor:COLOR(255, 120, 100)]; LOG(@"%@", testImg); testImg = [ImageHelper getSnapshotWithView:self.view]; LOG(@"%@", testImg); testImg = [ImageHelper getFullScreenSnapShot]; LOG(@"%@", testImg); testImg = [ImageHelper getBlurEffectImageWithOriginalImage:testImg style:ImageHelperBlurEffectStyleDark]; LOG(@"%@", testImg); UIView *coverView = [ImageHelper getBlurEffectViewWithOriginalView:[UIApplication sharedApplication].keyWindow style:ImageHelperBlurEffectStyleDark];
2016-09-13 19:05:11.995 base[33087:2301853] <UIImage: 0x7ffaf97e8d00>, {120, 120}2016-09-13 19:05:11.997 base[33087:2301853] <UIImage: 0x7ffaf97e9610>, {90, 90}2016-09-13 19:05:11.999 base[33087:2301853] <UIImage: 0x7ffaf950a330>, {100, 90}2016-09-13 19:05:12.001 base[33087:2301853] <UIImage: 0x7ffaf9463630>, {50, 50}2016-09-13 19:05:12.002 base[33087:2301853] <UIImage: 0x7ffaf950a330>, {1, 1}2016-09-13 19:05:12.007 base[33087:2301853] <UIImage: 0x7ffaf96004b0>, {375, 667}2016-09-13 19:05:12.013 base[33087:2301853] <UIImage: 0x7ffaf950a330>, {375, 667}2016-09-13 19:05:12.040 base[33087:2301853] <UIImage: 0x7ffaf9506f30>, {375, 667}
1.可以單步調試代碼,查看testImg映像內容:
2.[ImageHelper getSnapshotWithView:self.view];這行代碼中的self.view產生快照後,尺寸為{375, 667},但如果在viewDidLoad方法中加入代碼:
self.edgesForExtendedLayout = UIRectEdgeNone;
重新輸出的尺寸為{375, 603},因為edgesForExtendedLayout屬性預設為UIRectEdgeAll,這在處理UI布局時候需要注意。後續記錄的UIViewContoller父類也會提到。
base項目已更新:git@github.com:ALongWay/base.git