将图像转换为16位彩色图像 [英] Convert an image to a 16bit color image

问题描述

我正在寻找一种方法来优化图像，方法是将其颜色从32位转换为16位，而不是仅仅调整其大小.所以这就是我正在做的:

I'm looking for a way to optimize my images by converting its color from 32bit to 16bit rather than just solely resize it. So this is what I'm doing:

- (UIImage *)optimizeImage:(UIImage *)image
{
    float newWidth = image.size.width;
    float newHeight = image.size.height;

    CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
    CGContextRef context = CGBitmapContextCreate(NULL, newWidth, newHeight, 5, newWidth * 4,
                                                 colorSpace, kCGImageAlphaNone | kCGBitmapByteOrder32Big);
    CGColorSpaceRelease(colorSpace);

    CGInterpolationQuality quality = kCGInterpolationHigh;
    CGContextSetInterpolationQuality(context, quality);

    CGImageRef srcImage = CGImageRetain(image.CGImage);

    CGContextDrawImage(context, CGRectMake(0, 0, newWidth, newHeight),
                       srcImage);
    CGImageRelease(srcImage);
    CGImageRef dst = CGBitmapContextCreateImage(context);
    CGContextRelease(context);

    UIImage *result = [UIImage imageWithCGImage:dst];
    CGImageRelease(dst);

    UIGraphicsEndImageContext();

    return result;
}

这段代码的问题是，当我运行它时，我得到了这个错误:

The issue with this piece of code is that when I run it, I get this very error:

CGBitmapContextCreate:不支持的参数组合:5个整数 位/分量； 16位/像素； 3分量色彩空间； kCGImageAlphaNone; 10392字节/行.

CGBitmapContextCreate: unsupported parameter combination: 5 integer bits/component; 16 bits/pixel; 3-component color space; kCGImageAlphaNone; 10392 bytes/row.

所以我的问题是:CGBitmapContextCreate支持的组合是什么?在这种情况下，我应该为bitmapInfo参数选择什么?请提出建议.

So my question is: what is the supported combination for CGBitmapContextCreate? What should I select for the bitmapInfo parameter in this situation? Please suggest.

推荐答案

所以我在

So I've found my answer in Mac Developer Library. There's a table for the supported pixel formats and this is what I'm looking for:

RGB-16 bpp，5 bpc，kCGImageAlphaNoneSkipFirst

RGB - 16 bpp, 5 bpc, kCGImageAlphaNoneSkipFirst

因此，我已经更改了bitmapInfo，并且上下文的创建就很好了.希望这对某人有用.

So I've changed my bitmapInfo and the context's created just fine. Hopefully this is useful for someone.

这篇关于将图像转换为16位彩色图像的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！