从原始RGBA数据创建UIImage [英] Creating UIImage from raw RGBA data

问题描述

我一直在尝试将数组RGBA数据（int字节）转换为UIImage。我的代码如下所示：

I have been trying to convert an array RGBA data (int bytes) into a UIImage. My code looks like as follows:

/*height and width are integers denoting the dimensions of the image*/
unsigned char *rawData = malloc(width*height*4);

for (int i=0; i<width*height; ++i) 
{
    rawData[4*i] = <red_val>;
    rawData[4*i+1] = <green_val>;
    rawData[4*i+2] = <blue_val>;
    rawData[4*i+3] = 255;
}


/*I Have the correct values displayed
    - ensuring the rawData is well populated*/

NSLog(@"(%i,%i,%i,%f)",rawData[0],rawData[1],rawData[2],rawData[3]/255.0f);
NSLog(@"(%i,%i,%i,%f)",rawData[4],rawData[5],rawData[6],rawData[7]/255.0f);
NSLog(@"(%i,%i,%i,%f)",rawData[8],rawData[9],rawData[10],rawData[11]/255.0f);



CGDataProviderRef provider = CGDataProviderCreateWithData(NULL, 
                                                          rawData, 
                                                          width*height*4, 
                                                          NULL);

int bitsPerComponent = 8;
int bitsPerPixel = 32;
int bytesPerRow = 4*width;
CGColorSpaceRef colorSpaceRef = CGColorSpaceCreateDeviceRGB();
CGBitmapInfo bitmapInfo = kCGBitmapByteOrderDefault;
CGColorRenderingIntent renderingIntent = kCGRenderingIntentDefault;
CGImageRef imageRef = CGImageCreate(width,
                                    height,
                                    8,
                                    32,
                                    4*width,colorSpaceRef,
                                    bitmapInfo,
                                    provider,NULL,NO,renderingIntent);
/*I get the current dimensions displayed here */
NSLog(@"width=%i, height: %i", CGImageGetWidth(imageRef),
      CGImageGetHeight(imageRef) );
UIImage *newImage = [UIImage imageWithCGImage:imageRef];
/*This is where the problem lies. 
  The width, height displayed are of completely different dimensions
  viz. the width is always zero and the height is a very huge number */

NSLog(@"resultImg width:%i, height:%i",
          newImage.size.width,newImage.size.height);


return newImage;

我收到的输出图像是宽度为0的图像，高度为1080950784（假设我的初始高度）宽度分别为240和240）。我一直试图解决这个问题，并检查了许多相关的论坛，例如（链接文字）关于如何去做它却收效甚微。

The output image that I receive is an image of width 0, and height 1080950784 (assuming my initil height and width were 240 and 240). I have been trying to get this sorted out and have checked many related forums e.g. (link text) on how to go about it but with little success.

推荐答案

事实证明，这个问题是我们俩都忽略的一个非常愚蠢的错误。 UIImage维度存储为浮点数，而不是整数。 ：D

It turns out the problem is a pretty silly mistake that both of us overlooked. UIImage dimensions are stored as floats, not integers. :D

尝试

NSLog(@"resultImg width:%f, height:%f",
          newImage.size.width,newImage.size.height);

相反。图像尺寸已正确传输。

Instead. The image size has been transferred correctly.

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