[英]Build a QImage from a buffer
How I can build a QImage from a buffer for example?例如,我如何从缓冲区构建 QImage?
In this case I'm using a buffer of 3x3 with vale from 0 (black) to 255 (white).在这种情况下,我使用 3x3 的缓冲区,其值从 0(黑色)到 255(白色)。
0 255 0 0 255 0
255 0 255 255 0 255
0 255 0 0 255 0
and it is store into a unsigned char buffer[9] = {0, 255, 0, 255, 0, 255, 0, 255, 0};
并将其存储到unsigned char buffer[9] = {0, 255, 0, 255, 0, 255, 0, 255, 0};
At the moment I'm trying this but doesn't work:目前我正在尝试这个但不起作用:
QImage image{buffer, 3, 3, QImage::Format_Grayscale8};
The constructor you're using...您正在使用的构造函数...
QImage(uchar *data, int width, int height, QImage::Format format, QImageCleanupFunction cleanupFunction = nullptr, void *cleanupInfo = nullptr)
has the caveat...有警告...
data must be 32-bit aligned, and each scanline of data in the image must also be 32-bit aligned数据必须是32位对齐的,并且图像中数据的每条扫描线也必须是32位对齐的
Hence the QImage
implementation expects the number of bytes in each scanline to be a multiple of 4 -- a condition not satisfied by your data buffer.因此, QImage
实现期望每个扫描线中的字节数是 4 的倍数——数据缓冲区不满足这个条件。 Instead make use of the constructor that allows you to specify the bytes-per-scanline explicitly...而是使用允许您显式指定每扫描线字节数的构造函数...
QImage(uchar *data, int width, int height, int bytesPerLine, QImage::Format format, QImageCleanupFunction cleanupFunction = nullptr, void *cleanupInfo = nullptr)
So your code becomes...所以你的代码变成......
unsigned char buffer[9] = {0, 255, 0, 255, 0, 255, 0, 255, 0};
QImage image{buffer, 3, 3, 3, QImage::Format_Grayscale8};
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