在 C++ 中获取像素颜色

发布于 2024-10-15 02:21:29 字数 382 浏览 1 评论 0原文

我想获取屏幕上不同 x、y 坐标处像素的 RGB 值。我将如何在 C++ 中解决这个问题？

我正在尝试创建自己的高斯模糊效果。

这将在 Windows 7 中进行。

编辑

需要包含哪些库才能运行？

我要做什么：

#include <iostream>

using namespace std ;

int main(){

    HDC dc = GetDC(NULL);
    COLORREF color = GetPixel(dc, 0, 0);
    ReleaseDC(NULL, dc);

    cout << color; 

}

原文

I would like to get the RGB values of a pixel at different x, y coordinates on the screen.
How would I go about this in C++?

I'm trying to create my own gaussian blur effect.

This would be in Windows 7.

Edit

What libraries need to be included for this to run?

What I have going:

#include <iostream>

using namespace std ;

int main(){

    HDC dc = GetDC(NULL);
    COLORREF color = GetPixel(dc, 0, 0);
    ReleaseDC(NULL, dc);

    cout << color; 

}

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狂之美人 2024-10-22 02:21:30

您可以在 NULL 窗口上使用 GetDC 来获取整个屏幕的设备上下文，然后可以调用 GetPixel：

HDC dc = GetDC(NULL);
COLORREF color = GetPixel(dc, x, y);
ReleaseDC(NULL, dc);

当然，在执行所有像素读取以提高效率时，您只想获取和释放设备上下文一次。

You can use GetDC on the NULL window to get a device context for the whole screen, and can follow that up with a call to GetPixel:

HDC dc = GetDC(NULL);
COLORREF color = GetPixel(dc, x, y);
ReleaseDC(NULL, dc);

Of course, you'd want to only acquire and release the device context once while doing all the pixel-reading for efficiency.

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辞旧 2024-10-22 02:21:30

正如上一篇文章中提到的，您需要 GetPixel来自 Win32 API 的函数。

GetPixel 位于 gdi32.dll 内部，因此如果您有正确的环境设置，您应该能够包含 windows.h（其中包括 wingdi.h），并且您应该是黄金。

如果出于某种原因您有一个最小的环境设置，您也可以直接在 gdi32.dll 上使用 LoadLibrary。

GetPixel 的第一个参数是设备上下文的句柄，可以通过调用 GetDC 函数（也可以通过获得）来检索该句柄。

从 dll 加载 GetPixel 并打印出当前光标位置处的像素颜色的基本示例如下。

#include<windows.h>
#include<stdio.h>

typedef WINAPI COLORREF (*GETPIXEL)(HDC, int, int);

int main(int argc, char** argv)
{

    HINSTANCE _hGDI = LoadLibrary("gdi32.dll");
    if(_hGDI)
    {
        while(true) {
            GETPIXEL pGetPixel = (GETPIXEL)GetProcAddress(_hGDI, "GetPixel");
            HDC _hdc = GetDC(NULL);
            if(_hdc)
            {
                POINT _cursor;
                GetCursorPos(&_cursor);
                COLORREF _color = (*pGetPixel) (_hdc, _cursor.x, _cursor.y);
                int _red = GetRValue(_color);
                int _green = GetGValue(_color);
                int _blue = GetBValue(_color);

                printf("Red: 0x%02x\n", _red);
                printf("Green: 0x%02x\n", _green);
                printf("Blue: 0x%02x\n", _blue);
            }
            FreeLibrary(_hGDI);
        }
    }
    return 0;
}

As mentioned in a previous post, you want the GetPixel function from the Win32 API.

GetPixel sits inside gdi32.dll, so if you have a proper environment setup, you should be able to include windows.h (which includes wingdi.h) and you should be golden.

If you have a minimal environment setup for whatever reason, you could also use LoadLibrary on gdi32.dll directly.

The first parameter to GetPixel is a handle to the device context, which can be retrieved by calling the GetDC function(which is also available via <windows.h>).

A basic example that loads GetPixel from the dll and prints out the color of the pixel at your current cursor position is as follows.

#include<windows.h>
#include<stdio.h>

typedef WINAPI COLORREF (*GETPIXEL)(HDC, int, int);

int main(int argc, char** argv)
{

    HINSTANCE _hGDI = LoadLibrary("gdi32.dll");
    if(_hGDI)
    {
        while(true) {
            GETPIXEL pGetPixel = (GETPIXEL)GetProcAddress(_hGDI, "GetPixel");
            HDC _hdc = GetDC(NULL);
            if(_hdc)
            {
                POINT _cursor;
                GetCursorPos(&_cursor);
                COLORREF _color = (*pGetPixel) (_hdc, _cursor.x, _cursor.y);
                int _red = GetRValue(_color);
                int _green = GetGValue(_color);
                int _blue = GetBValue(_color);

                printf("Red: 0x%02x\n", _red);
                printf("Green: 0x%02x\n", _green);
                printf("Blue: 0x%02x\n", _blue);
            }
            FreeLibrary(_hGDI);
        }
    }
    return 0;
}

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