Objective-C：将浮点数组显示为图像
在 Cocoa 应用程序中，我想在 NSImageView 中显示二维浮点数组。为了使代码尽可能简单，首先将数据从 float 转换为 NSData：
// dataArray: an Nx by Ny array of floats
NSMutableData *nsdata = [NSMutableData dataWithCapacity:0];
long numPixels = Nx*Ny;
for (int i = 0; i < numPixels; i++) {
[nsdata appendBytes:&dataArray[i] length:sizeof(float)];
}
现在尝试显示数据（显示留空）：
[theNSImageView setImage:[[NSImage alloc] initWithData:nsdata]];
这是正确的方法吗？首先需要CGContext吗？我希望用 NSData 来完成这个任务。
我已经注意到早期的堆栈帖子： 32位数据，接近但相反，几乎有效，但没有 NSData，此处为彩色图像数据，但在这些工作上获得变化的运气并不好。感谢您的任何建议。
In a Cocoa App I would like to display a 2d array of floats in an NSImageView. To make the code as simple as possible, start off by converting the data from float to NSData:
// dataArray: an Nx by Ny array of floats
NSMutableData *nsdata = [NSMutableData dataWithCapacity:0];
long numPixels = Nx*Ny;
for (int i = 0; i < numPixels; i++) {
[nsdata appendBytes:&dataArray[i] length:sizeof(float)];
}
and now try to display the data (the display is left blank):
[theNSImageView setImage:[[NSImage alloc] initWithData:nsdata]];
Is this the correct approach? Is a CGContext needed first? I was hoping to accomplish this with NSData.
I have noted the earlier Stack posts: 32 bit data, close but in reverse, almost worked but no NSData, color image data here, but not much luck getting variations on these working. Thanks for any suggestions.
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您可以使用
NSBitmapImageRep逐个构建NSImage。有趣的是，它的初始化程序之一拥有 Cocoa 中最长的方法名称：
至少有详细记录。一旦你通过在
planes中提供浮点数组来构建它，你就可以将NSImage放入你的视图中：或者，稍微干净
一点有一个初始化程序，它只使用
NSData容器：尽管这取决于您的
bitmapData包含正确的位图格式之一。You can use an
NSBitmapImageRepto build up anNSImagefloat-by-float.Interestingly, one of its initialisers has the longest method name in all of Cocoa:
It's well documented at least. Once you've built it up by supplying float arrays in
planesyou can then get theNSImageto put in your view:Or, slightly cleaner
There is an initialiser which just uses an
NSDatacontainer:although that depends on your
bitmapDatacontaining one of the correct bitmap formats.好的，开始工作了。我之前曾尝试过 NSBitmapImageRep （感谢 Tim），但我缺少的部分是将浮点数据正确转换为字节数组。 NSData 不会这样做并返回 nil。因此，解决方案并不需要逐个浮点地构建 NSImage。事实上，我们可以类似地构建一个 bitmapContext（使用 CGBitmapContextCreate（上面 HotLicks 提到的）），并且一旦浮点数据被正确表示，它也可以工作。
Ok got it to work. I had tried the NSBitmapImageRep before (thanks Tim) but the part I was missing was in properly converting my floating point data to a byte array. NSData doesn't do that and returns nil. So the solution was not so much in needing to build up an NSImage float-by-float. In fact, one can similarly build up a bitmapContext (using CGBitmapContextCreate (mentioned by HotLicks above)) and that works too, once the floating point data has been represented properly.