灰色主題背景

在一些哀悼日，清明節的時候app會實現一些灰色主題功能，部分app需求是tab首頁實現灰色模式就可以，但一些需求是直接整個app都變為灰色模。

普通UI界面 web頁面 xib界面 attributeText加載的htmlString頁面 attachment掛件頁面實現方式

基本的實現方式1，普通頁面用hook顏色方式2.web頁面用注入灰色js實現方式

圖片變灰

重新繪制圖片變為灰色代碼實現

//image類別- (UIImage *)getGrayImage { const int RED =1; const int GREEN =2; const int BLUE =3; UIImage *image = self; // Create image rectangle with current image width/height CGRect imageRect = CGRectMake(0,0, image.size.width* image.scale, image.size.height* image.scale); int width = imageRect.size.width; int height = imageRect.size.height; // the pixels will be painted to this array uint32_t *pixels = (uint32_t*) malloc(width * height *sizeof(uint32_t)); // clear the pixels so any transparency is preserved memset(pixels,0, width * height *sizeof(uint32_t)); CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB(); // create a context with RGBA pixels CGContextRef context = CGBitmapContextCreate(pixels, width, height,8, width *sizeof(uint32_t), colorSpace, kCGBitmapByteOrder32Little | kCGImageAlphaPremultipliedLast); // paint the bitmap to our context which will fill in the pixels array CGContextDrawImage(context,CGRectMake(0,0, width, height), [image CGImage]); for(int y = 0; y < height; y++) { for(int x = 0; x < width; x++) { uint8_t *rgbaPixel = (uint8_t*) &pixels[y * width + x]; // convert to grayscale using recommended method: http://en.wikipedia.org/wiki/Grayscale#Converting_color_to_grayscale uint32_t gray = 0.3 * rgbaPixel[RED] +0.59 * rgbaPixel[GREEN] +0.11 * rgbaPixel[BLUE]; // set the pixels to gray rgbaPixel[RED] = gray; rgbaPixel[GREEN] = gray; rgbaPixel[BLUE] = gray; } } // create a new CGImageRef from our context with the modified pixels CGImageRef imageRef = CGBitmapContextCreateImage(context); // we’re done with the context, color space, and pixels CGContextRelease(context); CGColorSpaceRelease(colorSpace); free(pixels); // make a new UIImage to return UIImage *resultUIImage = [UIImage imageWithCGImage:imageRef scale:image.scale orientation:UIImageOrientationUp]; // we’re done with image now too CGImageRelease(imageRef); return resultUIImage; }文本變灰

文本textColor變為灰色 rgb的處理有很多這里簡單提供一個

[self swizzleMethod:self orgSel:@selector(initWithRed:green:blue:alpha:) swizzSel:@selector(hdd_initWithRed:green:blue:alpha:)];+ (UIColor *)hdd_colorWithRed:(CGFloat)red green:(CGFloat)green blue:(CGFloat)blue alpha:(CGFloat)a{ CGFloat gray = red*0.299 + green*0.587 + blue*0.114; if ([CSDarkSiteManager isLocalCacheDarkSiteStatus]) { return [self hdd_colorWithRed:gray green:gray blue:gray alpha:a]; } else { return [self hdd_colorWithRed:red green:green blue:blue alpha:a]; }}

文本變灰色還牽扯到系統顏色的灰色處理，例如[UIcolor whiteColor],系統alertView彈框中的藍色按鈕顏色處理，都需要有專門的處理方法

xib圖片變灰

由于xib讀取圖片不是直接通過[UIimageView imageName:@''] 加載方式 沒辦法直接通過hook setImage直接設置xib圖片變為灰色

方法：重寫UIimageView的awakeFromNib，再去執行hook setImage的方法進行加載

webView的變灰

hook webView的初始化方法，注入js灰色

+ (void)swizzHook { static dispatch_once_t onceToken; dispatch_once(&onceToken, ^{ Method originalMethod = class_getInstanceMethod([self class], @selector(initWithFrame:configuration:)); Method swizzledMethod = class_getInstanceMethod([self class], @selector(lg_initWithFrame:configuration:)); method_exchangeImplementations(originalMethod, swizzledMethod); });}- (instancetype)lg_initWithFrame:(CGRect)frame configuration:(WKWebViewConfiguration *)configuration { Class class = NSClassFromString(@'AIRWKWebView'); if ([CSDarkSiteManager isLocalCacheDarkSiteStatus] && ![self isKindOfClass:class]) { NSString *jScript = @'var filter = ’-webkit-filter:grayscale(100%);-moz-filter:grayscale(100%); -ms-filter:grayscale(100%); -o-filter:grayscale(100%) filter:grayscale(100%);’;document.getElementsByTagName(’html’)[0].style.filter = ’grayscale(100%)’;'; // 注入 WKUserScript *wkUScript = [[WKUserScript alloc] initWithSource:jScript injectionTime:WKUserScriptInjectionTimeAtDocumentEnd forMainFrameOnly:YES]; [configuration.userContentController addUserScript:wkUScript]; WKWebView *webView = [self lg_initWithFrame:frame configuration:configuration]; return webView; } else { WKWebView *webView = [self lg_initWithFrame:frame configuration:configuration]; return webView; } }

attributeText加載htmlString變灰

attribute情況下加載html不是直接通過設置color來改變顏色的，需要通過遍歷對應的屬性進行重新顏色進行賦值

存在的問題

這樣全局修改，可能會把鍵盤的顏色也改變了需要特殊處理

系統顏色中，alertView中的藍色，不在定義的系統顏色范圍之內需要重新加載

hook系統顏色的處理

完整性

需要完整的私發信息

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