读取bmp文件的像素值 [英] read pixel value in bmp file

问题描述

我怎么能在所有像素[H * W]用C或C ++在Windows 24位读BMP图像的颜色值[更好，没有任何第三方库。我的开发-C ++ 结果
一个工作code将是非常美联社preciated，因为我从来没有在影像阅读和放大器的工作;来到谷歌搜索SO [如果你能谷歌比我好，PLZ提供了一个链接]了。

How can I read the color value of 24bit BMP images at all the pixel [h*w] in C or C++ on Windows [better without any 3rd party library]. I got Dev-C++
A working code will be really appreciated as I've never worked on Image reading & have come to SO after Googling [if you can google better than me, plz provide a link].

推荐答案

您可以试试这个：

unsigned char* readBMP(char* filename)
{
    int i;
    FILE* f = fopen(filename, "rb");
    unsigned char info[54];
    fread(info, sizeof(unsigned char), 54, f); // read the 54-byte header

    // extract image height and width from header
    int width = *(int*)&info[18];
    int height = *(int*)&info[22];

    int size = 3 * width * height;
    unsigned char* data = new unsigned char[size]; // allocate 3 bytes per pixel
    fread(data, sizeof(unsigned char), size, f); // read the rest of the data at once
    fclose(f);

    for(i = 0; i < size; i += 3)
    {
            unsigned char tmp = data[i];
            data[i] = data[i+2];
            data[i+2] = tmp;
    }

    return data;
}

现在数据应包含（R，G，B）的像素值。像素（i，j）条的颜色存储在数据[J *宽+ I] ，数据[J *宽+ I + 1] 和数据[J *宽+ I + 2] 。

Now data should contain the (R, G, B) values of the pixels. The color of pixel (i, j) is stored at data[j * width + i], data[j * width + i + 1] and data[j * width + i + 2].

在最后一部分，每一个第一和第三像素之间的交换完成，因为Windows存储颜色值（B，G，R）的三倍，而不是（R，G，B）。

In the last part, the swap between every first and third pixel is done because windows stores the color values as (B, G, R) triples, not (R, G, B).

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