1v1/MSYOUPAI/3rd/NIMChat/NIMDemo/Category/UIImage+NTES.m

//
//  UIImage+NTESm
//  NIM
//
//  Created by chris on 15/7/13.
//  Copyright (c) 2015年 Netease. All rights reserved.
//

#import "UIImage+NTES.h"
#import "NTESDevice.h"

#define ChartletBundle              @"NIMDemoChartlet.bundle"
#define EmojiCatalog                @"default"
#define ChartletChartletCatalogContentPath @"content"
#define ChartletChartletCatalogIconPath    @"icon"
#define ChartletChartletCatalogIconsSuffixNormal    @"normal"
#define ChartletChartletCatalogIconsSuffixHighLight @"highlighted"

@implementation UIImage (NTES)
+ (UIImage *)fetchImage:(NSString *)imageNameOrPath{
    UIImage *image = [UIImage imageNamed:imageNameOrPath];
    if (!image) {
        image = [UIImage imageWithContentsOfFile:imageNameOrPath];
    }
    return image;
}


+ (UIImage *)fetchChartlet:(NSString *)imageName chartletId:(NSString *)chartletId{
    if ([chartletId isEqualToString:EmojiCatalog]) {
        return [UIImage imageNamed:imageName];
    }
    NSString *bundlePath = [[NSBundle mainBundle] pathForResource:ChartletBundle ofType:nil];

    NSString *subDirectory = [NSString stringWithFormat:@"/%@/%@",chartletId,ChartletChartletCatalogContentPath];
    //先拿2倍图
    NSString *doubleImage  = [imageName stringByAppendingString:@"@2x"];
    NSString *tribleImage  = [imageName stringByAppendingString:@"@3x"];
    NSString *sourcePath   = [bundlePath stringByAppendingPathComponent:subDirectory];
    NSString *path = nil;
    
    NSArray *array = [NSBundle pathsForResourcesOfType:nil inDirectory:sourcePath];
    NSString *fileExt = [[array.firstObject lastPathComponent] pathExtension];
    if ([UIScreen mainScreen].scale == 3.0) {
        path = [NSBundle pathForResource:tribleImage ofType:fileExt inDirectory:sourcePath];
    }
    path = path ? path : [NSBundle pathForResource:doubleImage ofType:fileExt inDirectory:sourcePath]; //取二倍图
    path = path ? path : [NSBundle pathForResource:imageName ofType:fileExt inDirectory:sourcePath]; //实在没了就去取一倍图
    return [UIImage imageWithContentsOfFile:path];
}

- (UIImage *)imageForAvatarUpload
{
    CGFloat pixels = [[NTESDevice currentDevice] suggestImagePixels];
    UIImage * image = [self imageForUpload:pixels];
    return [image fixOrientation];
}


#pragma mark - Private

- (UIImage *)imageForUpload: (CGFloat)suggestPixels
{
    const CGFloat kMaxPixels = 4000000;
    const CGFloat kMaxRatio  = 3;
    
    CGFloat width = self.size.width;
    CGFloat height= self.size.height;
    
    //对于超过建议像素，且长宽比超过max ratio的图做特殊处理
    if (width * height > suggestPixels &&
        (width / height > kMaxRatio || height / width > kMaxRatio))
    {
        return [self scaleWithMaxPixels:kMaxPixels];
    }
    else
    {
        return [self scaleWithMaxPixels:suggestPixels];
    }
}

- (UIImage *)scaleWithMaxPixels: (CGFloat)maxPixels
{
    CGFloat width = self.size.width;
    CGFloat height= self.size.height;
    if (width * height < maxPixels || maxPixels == 0)
    {
        return self;
    }
    CGFloat ratio = sqrt(width * height / maxPixels);
    if (fabs(ratio - 1) <= 0.01)
    {
        return self;
    }
    CGFloat newSizeWidth = width / ratio;
    CGFloat newSizeHeight= height/ ratio;
    return [self scaleToSize:CGSizeMake(newSizeWidth, newSizeHeight)];
}

//内缩放，一条变等于最长边，另外一条小于等于最长边
- (UIImage *)scaleToSize:(CGSize)newSize
{
    CGFloat width = self.size.width;
    CGFloat height= self.size.height;
    CGFloat newSizeWidth = newSize.width;
    CGFloat newSizeHeight= newSize.height;
    if (width <= newSizeWidth &&
        height <= newSizeHeight)
    {
        return self;
    }
    
    if (width == 0 || height == 0 || newSizeHeight == 0 || newSizeWidth == 0)
    {
        return nil;
    }
    CGSize size;
    if (width / height > newSizeWidth / newSizeHeight)
    {
        size = CGSizeMake(newSizeWidth, newSizeWidth * height / width);
    }
    else
    {
        size = CGSizeMake(newSizeHeight * width / height, newSizeHeight);
    }
    return [self drawImageWithSize:size];
}

- (UIImage *)drawImageWithSize: (CGSize)size
{
    CGSize drawSize = CGSizeMake(floor(size.width), floor(size.height));
    // 传入的View.frame.size是0的话，直接返回nil，防止 UIGraphicsBeginImageContext() 传入0，导致崩溃
    if (CGSizeEqualToSize(size, CGSizeZero)) {
        return nil;
    }
    UIGraphicsBeginImageContext(drawSize);
    
    [self drawInRect:CGRectMake(0, 0, drawSize.width, drawSize.height)];
    UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return newImage;
}

- (UIImage *)fixOrientation
{
    
    // No-op if the orientation is already correct
    if (self.imageOrientation == UIImageOrientationUp)
        return self;
    
    // We need to calculate the proper transformation to make the image upright.
    // We do it in 2 steps: Rotate if Left/Right/Down, and then flip if Mirrored.
    CGAffineTransform transform = CGAffineTransformIdentity;
    
    switch (self.imageOrientation) {
        case UIImageOrientationDown:
        case UIImageOrientationDownMirrored:
            transform = CGAffineTransformTranslate(transform, self.size.width, self.size.height);
            transform = CGAffineTransformRotate(transform, M_PI);
            break;
            
        case UIImageOrientationLeft:
        case UIImageOrientationLeftMirrored:
            transform = CGAffineTransformTranslate(transform, self.size.width, 0);
            transform = CGAffineTransformRotate(transform, M_PI_2);
            break;
            
        case UIImageOrientationRight:
        case UIImageOrientationRightMirrored:
            transform = CGAffineTransformTranslate(transform, 0, self.size.height);
            transform = CGAffineTransformRotate(transform, -M_PI_2);
            break;
        default:
            break;
    }
    
    switch (self.imageOrientation) {
        case UIImageOrientationUpMirrored:
        case UIImageOrientationDownMirrored:
            transform = CGAffineTransformTranslate(transform, self.size.width, 0);
            transform = CGAffineTransformScale(transform, -1, 1);
            break;
            
        case UIImageOrientationLeftMirrored:
        case UIImageOrientationRightMirrored:
            transform = CGAffineTransformTranslate(transform, self.size.height, 0);
            transform = CGAffineTransformScale(transform, -1, 1);
            break;
        default:
            break;
    }
    
    // Now we draw the underlying CGImage into a new context, applying the transform
    // calculated above.
    CGContextRef ctx = CGBitmapContextCreate(NULL, self.size.width, self.size.height,
                                             CGImageGetBitsPerComponent(self.CGImage), 0,
                                             CGImageGetColorSpace(self.CGImage),
                                             CGImageGetBitmapInfo(self.CGImage));
    CGContextConcatCTM(ctx, transform);
    switch (self.imageOrientation) {
        case UIImageOrientationLeft:
        case UIImageOrientationLeftMirrored:
        case UIImageOrientationRight:
        case UIImageOrientationRightMirrored:
            // Grr...
            CGContextDrawImage(ctx, CGRectMake(0,0,self.size.height,self.size.width), self.CGImage);
            break;
            
        default:
            CGContextDrawImage(ctx, CGRectMake(0,0,self.size.width,self.size.height), self.CGImage);
            break;
    }
    
    // And now we just create a new UIImage from the drawing context
    CGImageRef cgimg = CGBitmapContextCreateImage(ctx);
    UIImage *img = [UIImage imageWithCGImage:cgimg];
    CGContextRelease(ctx);
    CGImageRelease(cgimg);
    return img;
}

@end