Question

我需要将int []转换为byte []指针。以上是必需的，以便能够像素一样逐像素地填充WriteableBitmap的条目：

//previewBuffer1 is of type byte[]
WriteableBitmap wb1 = new WriteableBitmap(nVidWidth, nVidHeight);
int k=0;
// wb1.Pixels is of type int[] by default
byte* data = (byte*) wb1.Pixels;  // ****THIS DOESN'T WORK. THROWS ERROR. HOW CAN I ACCOMPLISH THIS***
for (int i=0; i<nVidHeight; i++){
    for (int j=0; j<nVidWidth; j++){
        byte grayscaleval = previewBuffer1[k];
        data [4*k] = grayscaleval ;
        data [4*k + 1] = grayscaleval ;
        data [4*k + 2] = grayscaleval ;
        k++;
    }
}

如何为wb1.Pixels获取int []类型的字节*指针？

Answer 1

听起来您希望将数组中的每个int视为字节序列 - BitConverter.GetBytes怎么样？

byte[] bytes = BitConverter.GetBytes(intValue);

如果要避免数组复制等，请使用允许指针的unsafe（您需要勾选项目属性中的“允许不安全代码”复选框）：

unsafe static void UnsafeConvert(int value)
{
    byte* bytes = (byte*)&value;
    byte first = bytes[0];
    ...
}

Answer 2

我对你的循环感到困惑，因为我觉得它有一些问题......但看起来你正试图剥离RGBA数据的alpha分量。为什么不这样做：

假设你有： 1.一个字节[]你想存储没有Alpha组件的RGB数据 2.一个RGB []数据的int []来源

int offset=0; // offset into the 'dest' array of bytes

for (...) // loop through your source array of ints 
{
    // get this current int value as rgba_val
    int rgba_val = (whatever your RGBA source is..is it wb1.Pixels?)

    dest[offset] = (rgba_val & 0xff) >> 24;
    dest[offset+1] = (rgba_val & 0x00ff) >> 16;
    dest[offset+2] = (rgba_val & 0x0000ff) >> 8;
}

Answer 3

使用它将int数组转换为bytes array

WriteableBitmap wb1 = new WriteableBitmap(100, 100);
int[] pixels = wb1.Pixels;
byte[] data = new byte[pixels.Length];
for (int i= 0; i < pixels.Length;i ++)
{
    data[i] = (byte)pixels[i];
}

Answer 4

我想以下内容对我有用：

//previewBuffer1 is of type byte[]
WriteableBitmap wb1 = new WriteableBitmap(nVidWidth, nVidHeight);
int k=0;
// wb1.Pixels is of type int[] by default
//byte* data = (byte*) wb1.Pixels;  // ****NOT REQUIRED ANYMORE***
for (int i=0; i<nVidHeight; i++){
    for (int j=0; j<nVidWidth; j++){
        int grayscaleval = (int) previewBuffer1[k];
        wb1.Pixels[k] = ((grayscaleval) | (grayscaleval<<8) | (grayscaleval<<16) | (0xFF<<24)); // 0xFF is for alpha blending value

        k++;
    }
}

Atleast逻辑上似乎很好。然而要尝试一下。

在C＃中将int []转换为byte []类型指针

4 个答案: