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,獲取模糊視圖,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; /** * 根據原始圖像和毛玻璃樣式,獲取新圖像 */ + (UIImage *)getBlurEffectImageWithOriginalImage:(UIImage *)originalImage style:(ImageHelperBlurEffectStyle)style; /** * 根據原始圖像,等比縮放系數,得到新圖像 */ + (UIImage *)getImageWithOriginalImage:(UIImage *)originalImage scale:(CGFloat)scale; /** * 根據原始圖像,等比縮放最大尺寸,得到新圖像 */ + (UIImage *)getImageWithOriginalImage:(UIImage *)originalImage scaleMaxSize:(CGSize)scaleMaxSize; /** * 根據原始圖像,等比縮放最大尺寸,得到新尺寸 */ + (CGSize)getImageSizeWithOriginalImage:(UIImage *)originalImage scaleMaxSize:(CGSize)scaleMaxSize; /** * 根據原始圖像,完全填充尺寸,得到新圖像 */ + (UIImage *)getImageWithOriginalImage:(UIImage *)originalImage fillSize:(CGSize)fillSize; /** * 根據原始圖像,裁剪區域,得到新圖像 */ + (UIImage *)getImageWithOriginalImage:(UIImage *)originalImage cutFrame:(CGRect)cutFrame; /** * 根據顏色,得到單位尺寸的純色新圖像 */ + (UIImage *)getImageWithColor:(UIColor *)color; /** * 根據view,得到快照 */ + (UIImage *)getSnapshotWithView:(UIView *)view; /** * 全屏截圖,但不包括狀態欄 */ + (UIImage *)getFullScreenSnapshot;
說明:
1.獲取毛玻璃效果(高斯模糊)圖像
在iOS8以后,提供了類UIBlurEffect、UIVisualEffectView,可以方便的生成高斯模糊的視圖,然后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,可以生成高斯模糊的圖像。將分類加入項目Categories目錄后,在ImageHelper中引用。因為UIBlurEffectStyle是在iOS8以后出現的,所以自定義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.提供了將圖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圖像上下文中,指定繪制尺寸(即位圖的尺寸),然后將相應圖像繪制到指定位置,然后生成最終圖像。例如裁剪圖像示例代碼:
+ (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圖像上下文繪制尺寸;第二個參數指定是否不透明;第三個為等比例縮放系數,如果為0.0,表示與設備主屏幕的系數一致。
CALayer的renderInContext:(CGContextRef)ctx方法,將圖層全部渲染到某個上下文中,建議為當前圖像上下文。最后得到圖像。
+ (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]; }
全屏截圖時候,不包括狀態欄,因為狀態欄不在應用的window上,無法直接獲取。但是可以通過私有Api拿到系統截屏圖像,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圖像內容:
2.[ImageHelper getSnapshotWithView:self.view];這行代碼中的self.view生成快照后,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屬性默認為UIRectEdgeAll,這在處理UI布局時候需要注意。后續記錄的UIViewContoller父類也會提到。
base項目已更新:git@github.com:ALongWay/base.git
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2016.09.14更新
1.修改了UIGraphicsBeginImageContext為UIGraphicsBeginImageContextWithOptions方法,設置不透明為NO,scale系數為0.0。即處理后為高質量的圖像,包括原圖alpha值。截屏方法區別在於沒有包括透明度值
2.圖像裁剪方法更新:
+ (UIImage *)getImageWithOriginalImage:(UIImage *)originalImage cutFrame:(CGRect)cutFrame { CGImageRef cgimageRef = CGImageCreateWithImageInRect(originalImage.CGImage, cutFrame); UIImage *newImage = [UIImage imageWithCGImage:cgimageRef]; CGImageRelease(cgimageRef); return newImage; }
裁剪區域可以任意設定。之前的方法,當偏移區域加上裁剪區域沒有覆蓋原圖全部區域時候,圖像在上下文中繪制會失敗。
3.增加了圖像合並方法,可以合並任意數量的圖像
+ (UIImage *)getImageMergedWithOriginalImageArray:(NSArray<ImageHelperMergeImage *> *)imageArray { if (!imageArray || imageArray.count == 0) { return nil; } ImageHelperMergeImage *firstMergeImage = [imageArray firstObject]; //將第一張圖作為背景放置 CGRect firstMergeRect = firstMergeImage.mergeRect; firstMergeRect.origin = CGPointZero; firstMergeImage.mergeRect = firstMergeRect; UIGraphicsBeginImageContextWithOptions(firstMergeImage.mergeRect.size, NO, 0.0); for (ImageHelperMergeImage *mergeImage in imageArray) { [mergeImage.image drawInRect:mergeImage.mergeRect]; } UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext(); UIGraphicsEndImageContext(); return newImage; }
定義了一個合並圖像的對象ImageHelperMergeImage,有一個UIImage屬性存儲圖像,和CGRect屬性儲存合並的位置。
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2016.09.23更新
之前的全屏截圖方法,受限於狀態欄無法獲取,導致截圖無狀態欄。
后來,打印了一下UIApplication的全部私有變量和方法,找到一個名為“_statusBar”的私有變量,類型名為UIStatusBar。
猜測為UIView的子類,使用getSnapshotWithView:方法,得到了一個(375,20)的黑條,將方法中代碼:
UIGraphicsBeginImageContextWithOptions(view.bounds.size, YES, 0.0);
第二個參數修改為NO,得到了想要的狀態欄截圖:
代碼如下:
+ (UIImage *)getFullScreenSnapshotWithStatusBar { // [StringHelper printAllPrivateVariablesAndMethodsWithClassName:@"UIApplication"]; UIApplication *app = [UIApplication sharedApplication]; //私有變量得到狀態欄 UIView *statusBar = [app valueForKeyPath:@"statusBar"]; UIImage *statusBarImage = [self getSnapshotWithView:statusBar]; UIImage *bgImage = [self getFullScreenSnapshotWithoutStatusBar]; ImageHelperMergeImage *mergeImage1 = [ImageHelperMergeImage getImageHelperMergeImageWithImage:bgImage]; ImageHelperMergeImage *mergeImage2 = [ImageHelperMergeImage getImageHelperMergeImageWithImage:statusBarImage]; UIImage *newImage = [self getImageMergedWithOriginalImageArray:@[mergeImage1, mergeImage2]]; return newImage; }
base項目已更新:git@github.com:ALongWay/base.git