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前言
- 创建渐变色背景
- 用代码修改图片颜色
- 图片转颜色
- 根据RGBHex获取UIColor
- 效果
I 创建渐变色背景图片
1.1 核心代码
typedef NS_ENUM(NSUInteger, GradientType) {
GradientTypeTopToBottom = 0,//从上到小
GradientTypeLeftToRight = 1,//从左到右
GradientTypeUpleftToLowright = 2,//左上到右下
GradientTypeUprightToLowleft = 3,//右上到左下
};
@interface UIImage (Extension)
+ (UIImage*)getMaingradientColorImage4Risk_Merchant{
CGSize size = CGSizeMake(SCREENW, SCREEN_HEIGHT);
//
UIColor *topleftColor = rgba(255, 54, 87, 1);
UIColor *bottomrightColor = rgba(248, 248, 248, 1);
UIImage *bgImg = [UIImage gradientColorImageFromColors:@[topleftColor,bottomrightColor] gradientType:GradientTypeTopToBottom imgSize:size];
return bgImg;
}
+ (instancetype)gradientColorImageFromColors:(NSArray*)colors gradientType:(GradientType)gradientType imgSize:(CGSize)imgSize {
NSMutableArray *ar = [NSMutableArray array];
for(UIColor *c in colors) {
[ar addObject:(id)c.CGColor];
}
UIGraphicsBeginImageContextWithOptions(imgSize, YES, 1);
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSaveGState(context);
CGColorSpaceRef colorSpace = CGColorGetColorSpace([[colors lastObject] CGColor]);
CGGradientRef gradient = CGGradientCreateWithColors(colorSpace, (CFArrayRef)ar, NULL);
CGPoint start;
CGPoint end;
switch (gradientType) {
case GradientTypeTopToBottom:
start = CGPointMake(0.0, 0.0);
end = CGPointMake(0.0, imgSize.height);
break;
case GradientTypeLeftToRight:
start = CGPointMake(0.0, 0.0);
end = CGPointMake(imgSize.width, 0.0);
break;
case GradientTypeUpleftToLowright:
start = CGPointMake(0.0, 0.0);
end = CGPointMake(imgSize.width, imgSize.height);
break;
case GradientTypeUprightToLowleft:
start = CGPointMake(imgSize.width, 0.0);
end = CGPointMake(0.0, imgSize.height);
break;
default:
break;
}
CGContextDrawLinearGradient(context, gradient, start, end, kCGGradientDrawsBeforeStartLocation | kCGGradientDrawsAfterEndLocation);
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
CGGradientRelease(gradient);
CGContextRestoreGState(context);
CGColorSpaceRelease(colorSpace);
UIGraphicsEndImageContext();
return image;
}
1.2 使用方法
- 推荐自定义V，并在init方法设置背景颜色，同时打开drawRect方法
- (void)drawRect:(CGRect)rect {//性能差 drawRect 不可以注释，否则容易出现无法覆盖整个视图的情况
}
- (instancetype)init
{
self = [super init];
if (self) {
UIImage *bgImg = [UIImage getMaingradientColorImage4Risk_Merchant];
UIColor *tmpColor = [UIColor colorWithPatternImage:bgImg];
[self setBackgroundColor:tmpColor];
}
return self;
}
如果在init创建视图对象再设置背景颜色的时候，容易出现颜色无法覆盖整个视图的情况
II 用代码修改图片颜色
修改箭头颜色为白色
UIImage *icon_right = [UIImage imageNamed:@"icon_right"];
icon_right = [icon_right imageWithRenderingMode:(UIImageRenderingModeAlwaysTemplate)];
tmp.image =icon_right;
tmp.tintColor = UIColor.whiteColor;
III 其他知识点
3.1 根据图片获取UIColor
图片转颜色
UIColor *tmpColor = [UIColor colorWithPatternImage:[UIImage imageNamed:@"img_wode_topbg_ios_bottom"]];
3.2 根据RGB获取UIColor
colorWithRGBHex 头文件
#import <UIKit/UIKit.h>
NS_ASSUME_NONNULL_BEGIN
#undef RGBCOLOR
#define RGBCOLOR(r,g,b) [UIColor colorWithRed:r/255.0 green:g/255.0 blue:b/255.0 alpha:1]
#undef RGBACOLOR
#define RGBACOLOR(r,g,b,a) [UIColor colorWithRed:r/255.0 green:g/255.0 blue:b/255.0 alpha:a]
#undef HEX_RGB
#define HEX_RGB(V) [UIColor colorWithRGBHex:V]
#define kWhiteColor RGBCOLOR(255.0, 255.0, 255.0)
#define kBlackColor RGBCOLOR(0, 0, 0)
#define kBlueColor RGBCOLOR(0, 0, 255)
#define kRedColor RGBCOLOR(255, 0, 0)
#define kGreenColor RGBCOLOR(0, 255, 0)
#define kGrayColor RGBCOLOR(128, 128, 128)
#define kCyanColor RGBCOLOR(0, 255, 255)
#define kYellowColor RGBCOLOR(255, 255, 0)
#define kPinkColor RGBCOLOR(255, 0, 255)
@interface UIColor (KNColor)
+ (UIColor *)colorWithRGBHex:(UInt32)hex;
+ (UIColor *)colorWithHexString:(NSString *)stringToConvert;
+ (UIColor *)colorWithCssName:(NSString *)cssColorName;
+ (UIColor *)bgColor_nav;
+ (UIColor *)bgColor_view;
+ (UIColor *)bgColor_cell;
+ (UIColor *)textColor_dark;
+ (UIColor *)textColor_light;
@end
NS_ASSUME_NONNULL_END
实现文件
//
// UIColor+KNColor.m
// DetectorTypeRectangle
//
// Created by mac on 2021/5/31.
// Copyright © 2021 https://kunnan.blog.csdn.net/ . All rights reserved.
//
#import "UIColor+KNColor.h"
@implementation UIColor (KNColor)
+ (UIColor *)colorWithRGBHex:(UInt32)hex
{
int r = (hex >> 16) & 0xFF;
int g = (hex >> 8) & 0xFF;
int b = (hex) & 0xFF;
return [UIColor colorWithRed:r / 255.0f
green:g / 255.0f
blue:b / 255.0f
alpha:1.0f];
}
+ (UIColor *)colorWithHexString:(NSString *)stringToConvert
{
NSScanner *scanner = [NSScanner scannerWithString:stringToConvert];
unsigned hexNum;
if (![scanner scanHexInt:&hexNum]) return nil;
return [UIColor colorWithRGBHex:hexNum];
}
static const char *colorNameDB = ","
"aliceblue#f0f8ff,antiquewhite#faebd7,aqua#00ffff,aquamarine#7fffd4,azure#f0ffff,"
"beige#f5f5dc,bisque#ffe4c4,black#000000,blanchedalmond#ffebcd,blue#0000ff,"
"blueviolet#8a2be2,brown#a52a2a,burlywood#deb887,cadetblue#5f9ea0,chartreuse#7fff00,"
"chocolate#d2691e,coral#ff7f50,cornflowerblue#6495ed,cornsilk#fff8dc,crimson#dc143c,"
"cyan#00ffff,darkblue#00008b,darkcyan#008b8b,darkgoldenrod#b8860b,darkgray#a9a9a9,"
"darkgreen#006400,darkgrey#a9a9a9,darkkhaki#bdb76b,darkmagenta#8b008b,"
"darkolivegreen#556b2f,darkorange#ff8c00,darkorchid#9932cc,darkred#8b0000,"
"darksalmon#e9967a,darkseagreen#8fbc8f,darkslateblue#483d8b,darkslategray#2f4f4f,"
"darkslategrey#2f4f4f,darkturquoise#00ced1,darkviolet#9400d3,deeppink#ff1493,"
"deepskyblue#00bfff,dimgray#696969,dimgrey#696969,dodgerblue#1e90ff,"
"firebrick#b22222,floralwhite#fffaf0,forestgreen#228b22,fuchsia#ff00ff,"
"gainsboro#dcdcdc,ghostwhite#f8f8ff,gold#ffd700,goldenrod#daa520,gray#808080,"
"green#008000,greenyellow#adff2f,grey#808080,honeydew#f0fff0,hotpink#ff69b4,"
"indianred#cd5c5c,indigo#4b0082,ivory#fffff0,khaki#f0e68c,lavender#e6e6fa,"
"lavenderblush#fff0f5,lawngreen#7cfc00,lemonchiffon#fffacd,lightblue#add8e6,"
"lightcoral#f08080,lightcyan#e0ffff,lightgoldenrodyellow#fafad2,lightgray#d3d3d3,"
"lightgreen#90ee90,lightgrey#d3d3d3,lightpink#ffb6c1,lightsalmon#ffa07a,"
"lightseagreen#20b2aa,lightskyblue#87cefa,lightslategray#778899,"
"lightslategrey#778899,lightsteelblue#b0c4de,lightyellow#ffffe0,lime#00ff00,"
"limegreen#32cd32,linen#faf0e6,magenta#ff00ff,maroon#800000,mediumaquamarine#66cdaa,"
"mediumblue#0000cd,mediumorchid#ba55d3,mediumpurple#9370db,mediumseagreen#3cb371,"
"mediumslateblue#7b68ee,mediumspringgreen#00fa9a,mediumturquoise#48d1cc,"
"mediumvioletred#c71585,midnightblue#191970,mintcream#f5fffa,mistyrose#ffe4e1,"
"moccasin#ffe4b5,navajowhite#ffdead,navy#000080,oldlace#fdf5e6,olive#808000,"
"olivedrab#6b8e23,orange#ffa500,orangered#ff4500,orchid#da70d6,palegoldenrod#eee8aa,"
"palegreen#98fb98,paleturquoise#afeeee,palevioletred#db7093,papayawhip#ffefd5,"
"peachpuff#ffdab9,peru#cd853f,pink#ffc0cb,plum#dda0dd,powderblue#b0e0e6,"
"purple#800080,red#ff0000,rosybrown#bc8f8f,royalblue#4169e1,saddlebrown#8b4513,"
"salmon#fa8072,sandybrown#f4a460,seagreen#2e8b57,seashell#fff5ee,sienna#a0522d,"
"silver#c0c0c0,skyblue#87ceeb,slateblue#6a5acd,slategray#708090,slategrey#708090,"
"snow#fffafa,springgreen#00ff7f,steelblue#4682b4,tan#d2b48c,teal#008080,"
"thistle#d8bfd8,tomato#ff6347,turquoise#40e0d0,violet#ee82ee,wheat#f5deb3,"
"white#ffffff,whitesmoke#f5f5f5,yellow#ffff00,yellowgreen#9acd32";
+ (UIColor *)colorWithCssName:(NSString *)cssColorName
{
UIColor *result = nil;
// Compile the string we'll use to search against the database
// We search for ",<colorname>#" to avoid false matches
const char *searchString = [[NSString stringWithFormat:@",%@#", cssColorName] UTF8String];
// Search for the color name
const char *found = strstr(colorNameDB, searchString);
// If found, step past the search string and grab the hex representation
if (found) {
const char *after = found + strlen(searchString);
int hex;
if (sscanf(after, "%x", &hex) == 1) {
result = [self colorWithRGBHex:hex];
}
}
return result;
}
+ (UIColor *)bgColor_nav
{
return RGBCOLOR(235, 235, 235);
}
+ (UIColor *)bgColor_view
{
return RGBCOLOR(235, 235, 235);
}
+ (UIColor *)bgColor_cell
{
return RGBCOLOR(255, 255, 255);
}
+ (UIColor *)textColor_dark
{
return RGBCOLOR(0x44, 0x44, 0x44);
}
+ (UIColor *)textColor_light
{
return RGBCOLOR(0x88, 0x88, 0x88);
}
@end
