在Objective-C++ Cocoa中将RGB数据转换为位图
在Objective-C++ Cocoa中将RGB数据转换为位图
提问于 2009-10-16 18:30:05
我有一个缓冲区的RGB无符号字符，我想转换成一个位图文件，谁知道如何转换？
我的RGB浮点数的格式如下
R (0,0)，G(0,0)，B(0,0)，R (0,1)，G(0,1)，B(0,1)，R (0,2)，G(0,2)，B(0,2) .....
每个数据单元的值范围从0到255。有没有人知道我该怎么做这个转换？
回答 2
Stack Overflow用户
回答已采纳
发布于 2009-10-17 09:25:14
您可以使用CGBitmapContextCreate从原始数据创建位图上下文。然后，您可以从位图上下文创建CGImageRef并保存它。不幸的是，CGBitmapContextCreate对数据的格式有点挑剔。它不支持24位RGB数据。开头的循环将rgb数据转换为rgba，末尾的alpha值为零。你必须包含并链接到ApplicationServices框架。
char* rgba = (char*)malloc(width*height*4);
for(int i=0; i < width*height; ++i) {
rgba[4*i] = myBuffer[3*i];
rgba[4*i+1] = myBuffer[3*i+1];
rgba[4*i+2] = myBuffer[3*i+2];
rgba[4*i+3] = 0;
}
CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
CGContextRef bitmapContext = CGBitmapContextCreate(
rgba,
width,
height,
8, // bitsPerComponent
4*width, // bytesPerRow
colorSpace,
kCGImageAlphaNoneSkipLast);
CFRelease(colorSpace);
CGImageRef cgImage = CGBitmapContextCreateImage(bitmapContext);
CFURLRef url = CFURLCreateWithFileSystemPath(kCFAllocatorDefault, CFSTR("image.png"), kCFURLPOSIXPathStyle, false);
CFStringRef type = kUTTypePNG; // or kUTTypeBMP if you like
CGImageDestinationRef dest = CGImageDestinationCreateWithURL(url, type, 1, 0);
CGImageDestinationAddImage(dest, cgImage, 0);
CFRelease(cgImage);
CFRelease(bitmapContext);
CGImageDestinationFinalize(dest);
free(rgba);Stack Overflow用户
发布于 2009-11-06 00:36:26
借用nschmidt的代码来生成一个熟悉的、如果有人红眼的图像：
int width = 11;
int height = 8;
Byte r[8][11]={
{000,000,255,000,000,000,000,000,255,000,000},
{000,000,000,255,000,000,000,255,000,000,000},
{000,000,255,255,255,255,255,255,255,000,000},
{000,255,255,255,255,255,255,255,255,255,000},
{255,255,255,255,255,255,255,255,255,255,255},
{255,000,255,255,255,255,255,255,255,000,255},
{255,000,255,000,000,000,000,000,255,000,255},
{000,000,000,255,255,000,255,255,000,000,000}};
Byte g[8][11]={
{000,000,255,000,000,000,000,000,255,000,000},
{000,000,000,255,000,000,000,255,000,000,000},
{000,000,255,255,255,255,255,255,255,000,000},
{000,255,255,000,255,255,255,000,255,255,000},
{255,255,255,255,255,255,255,255,255,255,255},
{255,000,255,255,255,255,255,255,255,000,255},
{255,000,255,000,000,000,000,000,255,000,255},
{000,000,000,255,255,000,255,255,000,000,000}};
Byte b[8][11]={
{000,000,255,000,000,000,000,000,255,000,000},
{000,000,000,255,000,000,000,255,000,000,000},
{000,000,255,255,255,255,255,255,255,000,000},
{000,255,255,000,255,255,255,000,255,255,000},
{255,255,255,255,255,255,255,255,255,255,255},
{255,000,255,255,255,255,255,255,255,000,255},
{255,000,255,000,000,000,000,000,255,000,255},
{000,000,000,255,255,000,255,255,000,000,000}};
char* rgba = (char*)malloc(width*height*4);
int offset=0;
for(int i=0; i < height; ++i)
{
for (int j=0; j < width; j++)
{
rgba[4*offset] = r[i][j];
rgba[4*offset+1] = g[i][j];
rgba[4*offset+2] = b[i][j];
rgba[4*offset+3] = 0;
offset ++;
}
}
CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
CGContextRef bitmapContext = CGBitmapContextCreate(
rgba,
width,
height,
8, // bitsPerComponent
4*width, // bytesPerRow
colorSpace,
kCGImageAlphaNoneSkipLast);
CFRelease(colorSpace);
CGImageRef cgImage = CGBitmapContextCreateImage(bitmapContext);
free(rgba);
UIImage *newUIImage = [UIImage imageWithCGImage:cgImage];
UIImageView *iv = [[UIImageView alloc] initWithFrame:CGRectMake(10, 10, 11,8)];
[iv setImage:newUIImage];然后，使用addSubview:iv命令将图像显示在视图中，当然，还必须执行[releases]命令来保持房间的整洁。
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/1579631
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