1問題思考
2020的是被疫情覆蓋的一年,在國(guó)內(nèi)疫情得到控制之后,全國(guó)在4.4日舉行了疫情哀悼紀(jì)念,而互聯(lián)網(wǎng)的產(chǎn)物在那天也做出了很多默契的配合,比如說很多網(wǎng)站暫停運(yùn)營(yíng)一天,很多app網(wǎng)頁的UI變成了黑白模式,那天我刷了一整天的手機(jī)看到的畫面全是黑白的,第二天又調(diào)整為正常了.作為一個(gè)iOS開發(fā),我思考如何才能更好的達(dá)到這種黑白與彩色之前的切換,想了以下幾種思路:
1.iOS內(nèi)置黑白開關(guān)-
2.動(dòng)態(tài)配置,文字顏色和圖片在當(dāng)天通過服務(wù)端下發(fā),修改成黑白色,這需要比較大的工作量 3.UIColor相關(guān)方法捕獲,圖片濾鏡
通過查詢資料,未找到方式1相關(guān)的api,iOS設(shè)備自身有個(gè)功能叫顏色反轉(zhuǎn),有興趣的可以去打開該功能看看,我在想這其實(shí)和實(shí)現(xiàn)黑白模式的原理是一樣的,但是蘋果未開放相關(guān)api
方式2看起來可行,我覺得一些app等在那天就是采用了這樣的方式來實(shí)現(xiàn)的黑白化,因?yàn)閍pp里的內(nèi)容不是說有的都改成了黑白,只有部分圖片或者頁面改成了黑白模式,但是工作量有點(diǎn)太大了,而且不夠靈活
方式3我認(rèn)為是比較可靠可行的,于是我按照方式3的思路實(shí)現(xiàn)了UIColor及圖片的黑白化
2功能實(shí)現(xiàn)
首先貼上一張沒有開啟黑白化的page原圖,可以看到圖片,color都是正常的
2.1UIColor黑白化
UIColor方法捕捉
#import "UIColor+Common.h"
#import <YLT_BaseLib/NSObject+YLT_Extension.h>
#import <Aspects.h>
//是否黑白化,1表示開啟
#define monochromatic 1
@implementation UIColor (Common)
+ (void)load {
//關(guān)鍵方法交換
[UIColor ylt_swizzleClassMethod:@selector(gl_colorWithRed:green:blue:alpha:) withMethod:@selector(colorWithRed:green:blue:alpha:)];
[UIColor ylt_swizzleClassMethod:@selector(gl_blackColor) withMethod:@selector(blackColor)];
[UIColor ylt_swizzleClassMethod:@selector(gl_darkGrayColor) withMethod:@selector(darkGrayColor)];
[UIColor ylt_swizzleClassMethod:@selector(gl_lightGrayColor) withMethod:@selector(lightGrayColor)];
[UIColor ylt_swizzleClassMethod:@selector(gl_whiteColor) withMethod:@selector(whiteColor)];
[UIColor ylt_swizzleClassMethod:@selector(gl_grayColor) withMethod:@selector(grayColor)];
[UIColor ylt_swizzleClassMethod:@selector(gl_redColor) withMethod:@selector(redColor)];
[UIColor ylt_swizzleClassMethod:@selector(gl_greenColor) withMethod:@selector(greenColor)];
[UIColor ylt_swizzleClassMethod:@selector(gl_blueColor) withMethod:@selector(blueColor)];
[UIColor ylt_swizzleClassMethod:@selector(gl_cyanColor) withMethod:@selector(cyanColor)];
[UIColor ylt_swizzleClassMethod:@selector(gl_yellowColor) withMethod:@selector(yellowColor)];
[UIColor ylt_swizzleClassMethod:@selector(gl_magentaColor) withMethod:@selector(magentaColor)];
[UIColor ylt_swizzleClassMethod:@selector(gl_orangeColor) withMethod:@selector(orangeColor)];
[UIColor ylt_swizzleClassMethod:@selector(gl_purpleColor) withMethod:@selector(purpleColor)];
[UIColor ylt_swizzleClassMethod:@selector(gl_brownColor) withMethod:@selector(brownColor)];
[UIColor ylt_swizzleClassMethod:@selector(gl_colorWithWhite:alpha:) withMethod:@selector(colorWithWhite:alpha:)];
Class cls = NSClassFromString(@"UIDynamicSystemColor");
[cls ylt_swizzleInstanceMethod:NSSelectorFromString(@"initWithName:colorsByThemeKey:") withMethod:@selector(gl_initWithName:colorsByThemeKey:)];
}
- (id)gl_initWithName:(id)name colorsByThemeKey:(id)key {
// NSLog(@"name=%@ key =%@ ",name,key);
if (monochromatic == 1) {
if ([name isEqualToString:@"systemBlueColor"]) {
// [UIColor systemBlueColor];
return [UIColor blueColor];
}
}
return [self gl_initWithName:name colorsByThemeKey:key];
}
+ (UIColor *)gl_colorWithRed:(CGFloat)red green:(CGFloat)green blue:(CGFloat)blue alpha:(CGFloat)alpha {
//如果是單色模式(黑白模式),則平均r攻冷、g喘沿、b值
if (monochromatic == 1) {
//r,g,b權(quán)重調(diào)整,防止出現(xiàn),1 0 0 涡戳、0 1 0,0 0 1同樣的結(jié)果
//0.2126，0.7152冶共，0.0722 這三個(gè)是根據(jù)人眼對(duì)r,g,b三個(gè)顏色面感的強(qiáng)弱算出來的
CGFloat brightness = (red * 0.2126 + 0.7152 * green + 0.0722 * blue);
// CGFloat brightness = (red + green + blue) / 3.f;
return [self gl_colorWithRed:brightness green:brightness blue:brightness alpha:alpha];
}
return [self gl_colorWithRed:red green:green blue:blue alpha:alpha];
}
+ (UIColor *)gl_colorWithWhite:(CGFloat)white alpha:(CGFloat)alpha {
return [self colorWithRed:white green:white blue:white alpha:1];
}
+ (UIColor *)gl_blackColor {
return [self colorWithWhite:0 alpha:1];
}
+ (UIColor *)gl_darkGrayColor {
return [self colorWithWhite:0.333 alpha:1];
}
+ (UIColor *)gl_lightGrayColor {
return [self colorWithWhite:0.667 alpha:1];
}
+ (UIColor *)gl_whiteColor {
return [self colorWithWhite:1 alpha:1];
}
+ (UIColor *)gl_grayColor {
return [self colorWithWhite:0.5 alpha:1];
}
+ (UIColor *)gl_redColor {
return [self colorWithRed:1 green:0 blue:0 alpha:1];
}
+ (UIColor *)gl_greenColor {
return [self colorWithRed:0 green:1 blue:0 alpha:1];
}
+ (UIColor *)gl_blueColor {
return [self colorWithRed:0 green:0 blue:1 alpha:1];
}
+ (UIColor *)gl_cyanColor {
return [self colorWithRed:0 green:1 blue:1 alpha:1];
}
+ (UIColor *)gl_yellowColor {
return [self colorWithRed:1 green:1 blue:0 alpha:1];
}
+ (UIColor *)gl_magentaColor {
return [self colorWithRed:1 green:0 blue:1 alpha:1];
}
+ (UIColor *)gl_orangeColor {
return [self colorWithRed:1 green:0.5 blue:0 alpha:1];
}
+ (UIColor *)gl_purpleColor {
return [self colorWithRed:0.5 green:0 blue:0.5 alpha:1];
}
+ (UIColor *)gl_brownColor {
return [self colorWithRed:0.6 green:0.4 blue:0.2 alpha:1];
}
@end
我們注意以下這3處的顏色變化
-
顏色1導(dǎo)航欄的返回文字顏色的Class類型是屬于UIDynamicSystemColor,其也屬于UIColor的子類
image.png
捕獲該類的實(shí)力方法initWithName:colorsByThemeKey:
[cls ylt_swizzleInstanceMethod:NSSelectorFromString(@"initWithName:colorsByThemeKey:") withMethod:@selector(gl_initWithName:colorsByThemeKey:)];
- (id)gl_initWithName:(id)name colorsByThemeKey:(id)key {
NSLog(@"name=%@ key =%@ ",name,key);
if (monochromatic == 1) {
if ([name isEqualToString:@"systemBlueColor"]) {
// [UIColor systemBlueColor];
return [UIColor blueColor];
}
}
return [self gl_initWithName:name colorsByThemeKey:key];
}
在該方法中我們可以捕獲到系統(tǒng)預(yù)設(shè)的systemColor,如果想知道到底有哪些systemColor,可以通過[UIColor systemBlueColor];點(diǎn)擊前往分類@interface UIColor (UIColorSystemColors)中,這里系統(tǒng)提供了許多預(yù)設(shè)的systemColor,這些方法與initWithName:colorsByThemeKey:中的name一致,所以我們攔截了所有的systemBlueColor方法,直接采用BlueColor返回,而BlueColor我們?cè)谇懊嬉沧鲞^了攔截處理,這樣就達(dá)到了統(tǒng)一處理,如果還有其他name類型的systemColor,可以采取同樣的處理方式,或者我們可以將需要捕獲的systemColor的name通過服務(wù)端下發(fā),同時(shí)下發(fā)對(duì)應(yīng)的r、g责球、b滤馍、a值,然后調(diào)用[UIColor colorWithRed:r green:g blue:b alpha:a]這樣更加靈活
另外 有人指出該hook方法在xcode 11.6會(huì)造成crash，我在升級(jí)后也嘗試了果然這樣配乓，可能系統(tǒng)對(duì)于gl_initWithName:colorsByThemeKey:有比較特殊的處理仿滔，通過捕獲UIDynamicSystemColor其屬性（結(jié)果沒有）和方法，暫時(shí)沒有排查到原因犹芹，所以放棄hook 該私有方法崎页，我們可以hook [UIColor systemBlueColor]方法，來替換系統(tǒng)的藍(lán)色羽莺，比如默認(rèn)的導(dǎo)航欄返回按鈕顏色
-
顏色2 和 顏色3都是通過自己去設(shè)置的顏色,自定義顏色方法比較有限,我總結(jié)并捕獲了所有的Color類方法,即使有些第三方庫(kù)識(shí)別16進(jìn)制,但是最終調(diào)用的還是colorWithRed:(CGFloat)red green:(CGFloat)green blue:(CGFloat)blue alpha:(CGFloat)alpha,
最終我們把所有顏色的攔截都流入到了下面swizzle method方法中
+ (UIColor *)gl_colorWithRed:(CGFloat)red green:(CGFloat)green blue:(CGFloat)blue alpha:(CGFloat)alpha {
//如果是單色模式(黑白模式),則平均r实昨、g、b值
if (monochromatic == 1) {
//r,g,b權(quán)重調(diào)整,防止出現(xiàn),1 0 0 盐固、0 1 0,0 0 1同樣的結(jié)果
//0.2126荒给，0.7152，0.0722 這三個(gè)是根據(jù)人眼對(duì)r,g,b三個(gè)顏色面感的強(qiáng)弱算出來的
CGFloat brightness = (red * 0.2126 + 0.7152 * green + 0.0722 * blue);
// CGFloat brightness = (red + green + blue) / 3.f;
return [self gl_colorWithRed:brightness green:brightness blue:brightness alpha:alpha];
}
return [self gl_colorWithRed:red green:green blue:blue alpha:alpha];
}
2.2UIImage黑白化
通常情況下,我們的app里的圖片控件都會(huì)采用UIImageView,這里我只是正對(duì)UIImageView進(jìn)行了setImage的hook,如果有其他情況,需要自己處理,掌握了此黑白化的技巧,其他的處理方式也差不多
//是否黑白化,1表示開啟
#define monochromatic 1
@implementation UIImageView (Common)
+ (void)load {
[UIImageView ylt_swizzleInstanceMethod:@selector(gl_setImage:) withMethod:@selector(setImage:)];
}
- (void)gl_setImage:(UIImage *)image {
if (monochromatic == 1) {
[self gl_setImage:[self gl_grayImage:image]];
} else {
[self gl_setImage:image];
}
}
- (UIImage *)gl_grayImage:(UIImage *)image {
//濾鏡處理
//CIPhotoEffectNoir黑白
//CIPhotoEffectMono單色
NSString *filterName = @"CIPhotoEffectNoir";
CIFilter *filter = [CIFilter filterWithName:filterName];
CIImage *inputImage = [[CIImage alloc] initWithImage:image];
[filter setValue:inputImage forKey:kCIInputImageKey];
CGImageRef cgImage = [self.filterContext createCGImage:filter.outputImage fromRect:[inputImage extent]];
UIImage *resultImg = [UIImage imageWithCGImage:cgImage];
CGImageRelease(cgImage);
return resultImg;
}
- (CIContext *)filterContext {
CIContext *con = objc_getAssociatedObject(self, @selector(filterContext));
if (!con) {
con = [[CIContext alloc] initWithOptions:nil];
self.filterContext = con;
}
return con;
}
- (void)setFilterContext:(CIContext *)filterContext {
objc_setAssociatedObject(self, @selector(filterContext), filterContext, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
}
@end
圖片的黑白化,我采用的是CIFilter濾鏡實(shí)現(xiàn),我們看下黑白和單色兩種濾鏡
效果差不多,但是在圖片色彩豐富的圖片上,個(gè)人認(rèn)為Mono會(huì)比Noir效果好看點(diǎn)
至此,我們可以通過服務(wù)器來靈活配置關(guān)鍵參數(shù)monochromatic,開啟或者關(guān)閉黑白化功能,實(shí)現(xiàn)app基本全面黑白化
demo參考
