blocks|key|2208328|text|基本上，使用CreateDibSection(...)。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|2208329|最小示例用法如下：|2208330|#include+<windows.h>

LRESULT+CALLBACK+WndProc(HWND+hWnd,+UINT+message,+WPARAM+wParam,+LPARAM+lParam);

int+WINAPI+WinMain(HINSTANCE+hInstance,+HINSTANCE+hPrevInstance,+LPSTR+lpCmdLine,+int+nCmdShow)
{

++++MSG+msg+=+{+0+};
++++WNDCLASS+wc+=+{+0+};
++++wc.lpfnWndProc+=+WndProc;
++++wc.hInstance+=+hInstance;
++++wc.hbrBackground+=+(HBRUSH)(COLOR_BACKGROUND);
++++wc.lpszClassName+=+L"createdibsection_example";
++++if+(!RegisterClass(&wc))
++++++++return+1;

++++if+(!CreateWindow(wc.lpszClassName,
++++++++L"createdibsection+example",
++++++++WS_OVERLAPPEDWINDOW+%7C+WS_VISIBLE,
++++++++0,+0,+640,+480,+0,+0,+hInstance,+NULL))
++++++++return+2;

++++while+(GetMessage(&msg,+NULL,+0,+0)+>+0)
++++++++DispatchMessage(&msg);

++++return+0;
}

HBITMAP+CreateBitmapAndFillPtrToItsData(unsigned+char**+ptr_data,+int+wd,+int+hgt)
{
++++HDC+hdcScreen+=+GetDC(NULL);

++++BITMAPINFO+bmi;
++++memset(&bmi,+0,+sizeof(BITMAPINFO));
++++bmi.bmiHeader.biSize+=+sizeof(BITMAPINFOHEADER);
++++bmi.bmiHeader.biWidth+=+wd;
++++bmi.bmiHeader.biHeight+=+-hgt;+//+top-down
++++bmi.bmiHeader.biPlanes+=+1;
++++bmi.bmiHeader.biBitCount+=+32;
++++bmi.bmiHeader.biCompression+=+BI_RGB;

++++auto+bmp+=+CreateDIBSection(hdcScreen,+&bmi,+DIB_RGB_COLORS,+(void**)+ptr_data,+NULL,+NULL);

++++ReleaseDC(NULL,+hdcScreen);
++++return+bmp;
}

void+CopyInPixelData(unsigned+char*+ptr_data,+int+wd,+int+hgt)
{
++++//+this+is+just+an+example+for+tutorial+purposes+...+generate+a+red+circle
++++//+in+a+white+field+...+real+code+would+load+from+a+file,+etc.

++++int+c_x+=+wd+/+2;
++++int+c_y+=+hgt+/+2;
++++int+radius+=+c_x;
++++int+i+=+0;
++++for+(int+y+=+0;+y+<+hgt;+y%2B%2B)+{
++++++++for+(int+x+=+0;+x+<+wd;+x%2B%2B)+{
++++++++++++if+((x-c_x)*(x-c_x)+%2B+(y-c_y)*(y-c_y)+<=+radius*radius)+{
++++++++++++++++ptr_data[i%2B%2B]+=+0;
++++++++++++++++ptr_data[i%2B%2B]+=+0;
++++++++++++++++ptr_data[i%2B%2B]+=+255;
++++++++++++++++ptr_data[i%2B%2B]+=+0;
++++++++++++}+else+{
++++++++++++++++ptr_data[i%2B%2B]+=+255;
++++++++++++++++ptr_data[i%2B%2B]+=+255;
++++++++++++++++ptr_data[i%2B%2B]+=+255;
++++++++++++++++ptr_data[i%2B%2B]+=+0;
++++++++++++}
++++++++}
++++}
}

HBITMAP+CreateBitmapFromPixelDataExample(int+wd,+int+hgt)
{
++++//+create+a+bitmap+such+that+we+get+a+pointer+to+where+its+data+is+stored
++++unsigned+char*+ptr_data;
++++auto+bitmap+=+CreateBitmapAndFillPtrToItsData(+&ptr_data,+wd,+hgt+);

++++//+fill+in+some+pixel+data...
++++CopyInPixelData(+ptr_data,+wd,+hgt+);

++++return+bitmap;
}

LRESULT+CALLBACK+WndProc(HWND+hWnd,+UINT+message,+WPARAM+wParam,+LPARAM+lParam)
{
++++static+HBITMAP+bitmap;

++++switch+(message)
++++{
++++case+WM_CREATE:+{
++++++++bitmap+=+CreateBitmapFromPixelDataExample(85,+85);
++++}+break;

++++case+WM_CLOSE:
++++++++PostQuitMessage(0);
++++++++break;

++++case+WM_PAINT:+{
++++++++RECT+r;
++++++++GetClientRect(hWnd,+&r);

++++++++auto+hdc_bitmap+=+CreateCompatibleDC(NULL);
++++++++auto+hbm_old+=+(HBITMAP)SelectObject(hdc_bitmap,+bitmap);

++++++++PAINTSTRUCT+ps;
++++++++auto+hdc+=+BeginPaint(hWnd,+&ps);
++++++++//+clear+bkgd
++++++++FillRect(hdc,+&r,+(HBRUSH)GetStockObject(WHITE_BRUSH));
++++++++//+paint+in+the+bitmap+we+generated+from+pixel+data...
++++++++BitBlt(hdc,+10,+10,+85,+85,+hdc_bitmap,+0,+0,+SRCCOPY);
++++++++EndPaint(hWnd,+&ps);

++++++++SelectObject(hdc_bitmap,+hbm_old);
++++++++DeleteDC(hdc_bitmap);

++++}+break;

++++default:
++++++++return+DefWindowProc(hWnd,+message,+wParam,+lParam);
++++}
++++return+0;
}|code-block|syntax|javascript|2208331|entityMap|0|LINK|mutability|MUTABLE|url|https://docs.microsoft.com/en-us/windows/win32/api/wingdi/nf-wingdi-createdibsection^0|6|L|0|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@$A|T|B|U|1|V]]|C|$]]|$1|D|3|E|5|6|7|W|8|@]|9|@]|C|$]]|$1|F|3|G|5|H|7|X|8|@]|9|@]|C|$I|J]]|$1|K|3|-4|5|6|7|Y|8|@]|9|@]|C|$]]]|L|$M|$5|N|O|P|C|$Q|R]]]]

Basically, use <a href="https://docs.microsoft.com/en-us/windows/win32/api/wingdi/nf-wingdi-createdibsection" rel="nofollow noreferrer">CreateDibSection(...)</a>.

Minimal example usage below:

<pre><code>#include &lt;windows.h&gt;

LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam);

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow)
{

 MSG msg = { 0 };
 WNDCLASS wc = { 0 };
 wc.lpfnWndProc = WndProc;
 wc.hInstance = hInstance;
 wc.hbrBackground = (HBRUSH)(COLOR_BACKGROUND);
 wc.lpszClassName = L"createdibsection_example";
 if (!RegisterClass(&amp;wc))
 return 1;

 if (!CreateWindow(wc.lpszClassName,
 L"createdibsection example",
 WS_OVERLAPPEDWINDOW | WS_VISIBLE,
 0, 0, 640, 480, 0, 0, hInstance, NULL))
 return 2;

 while (GetMessage(&amp;msg, NULL, 0, 0) &gt; 0)
 DispatchMessage(&amp;msg);

 return 0;
}

HBITMAP CreateBitmapAndFillPtrToItsData(unsigned char** ptr_data, int wd, int hgt)
{
 HDC hdcScreen = GetDC(NULL);

 BITMAPINFO bmi;
 memset(&amp;bmi, 0, sizeof(BITMAPINFO));
 bmi.bmiHeader.biSize = sizeof(BITMAPINFOHEADER);
 bmi.bmiHeader.biWidth = wd;
 bmi.bmiHeader.biHeight = -hgt; // top-down
 bmi.bmiHeader.biPlanes = 1;
 bmi.bmiHeader.biBitCount = 32;
 bmi.bmiHeader.biCompression = BI_RGB;

 auto bmp = CreateDIBSection(hdcScreen, &amp;bmi, DIB_RGB_COLORS, (void**) ptr_data, NULL, NULL);

 ReleaseDC(NULL, hdcScreen);
 return bmp;
}

void CopyInPixelData(unsigned char* ptr_data, int wd, int hgt)
{
 // this is just an example for tutorial purposes ... generate a red circle
 // in a white field ... real code would load from a file, etc.

 int c_x = wd / 2;
 int c_y = hgt / 2;
 int radius = c_x;
 int i = 0;
 for (int y = 0; y &lt; hgt; y++) {
 for (int x = 0; x &lt; wd; x++) {
 if ((x-c_x)*(x-c_x) + (y-c_y)*(y-c_y) &lt;= radius*radius) {
 ptr_data[i++] = 0;
 ptr_data[i++] = 0;
 ptr_data[i++] = 255;
 ptr_data[i++] = 0;
 } else {
 ptr_data[i++] = 255;
 ptr_data[i++] = 255;
 ptr_data[i++] = 255;
 ptr_data[i++] = 0;
 }
 }
 }
}

HBITMAP CreateBitmapFromPixelDataExample(int wd, int hgt)
{
 // create a bitmap such that we get a pointer to where its data is stored
 unsigned char* ptr_data;
 auto bitmap = CreateBitmapAndFillPtrToItsData( &amp;ptr_data, wd, hgt );

 // fill in some pixel data...
 CopyInPixelData( ptr_data, wd, hgt );

 return bitmap;
}

LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
 static HBITMAP bitmap;

 switch (message)
 {
 case WM_CREATE: {
 bitmap = CreateBitmapFromPixelDataExample(85, 85);
 } break;

 case WM_CLOSE:
 PostQuitMessage(0);
 break;

 case WM_PAINT: {
 RECT r;
 GetClientRect(hWnd, &amp;r);

 auto hdc_bitmap = CreateCompatibleDC(NULL);
 auto hbm_old = (HBITMAP)SelectObject(hdc_bitmap, bitmap);

 PAINTSTRUCT ps;
 auto hdc = BeginPaint(hWnd, &amp;ps);
 // clear bkgd
 FillRect(hdc, &amp;r, (HBRUSH)GetStockObject(WHITE_BRUSH));
 // paint in the bitmap we generated from pixel data...
 BitBlt(hdc, 10, 10, 85, 85, hdc_bitmap, 0, 0, SRCCOPY);
 EndPaint(hWnd, &amp;ps);

 SelectObject(hdc_bitmap, hbm_old);
 DeleteDC(hdc_bitmap);

 } break;

 default:
 return DefWindowProc(hWnd, message, wParam, lParam);
 }
 return 0;
}
</code></pre>

I'm reading image data in as a multidimensional array of RGB data, and want to draw it on the form at a location in WM_PAINT

I know how to read a whole bitmap from file and paint it at a location:

<pre><code> case WM_PAINT:
 PAINTSTRUCT ps;
 HDC hdc;
 BITMAP bitmap;
 HDC hdcMem;
 HGDIOBJ oldBitmap;

 hdc = BeginPaint(hwnd, &amp;ps);

 hdcMem = CreateCompatibleDC(hdc);
 oldBitmap = SelectObject(hdcMem, hBitmap);

 GetObject(hBitmap, sizeof(bitmap), &amp;bitmap);
 BitBlt(hdc, 0, 0, bitmap.bmWidth, bitmap.bmHeight, hdcMem, 0, 0, SRCCOPY);

 SelectObject(hdcMem, oldBitmap);
 DeleteDC(hdcMem);

 EndPaint(hwnd, &amp;ps);
 break;
</code></pre>

But not how to pain specific pixel data as a bitmap on the form. I've looked for literal days.

Any help appreciated.

C++ Paint rectangle on form given array of pixel data

我将图像数据作为RGB数据的多维数组读入，并希望将其绘制到表单上WM_PAINT中的某个位置。我知道如何从文件中读取整个位图并将其绘制到某个位置：    case WM_PAINT:        PAINTSTRUCT     ps;        HDC             hdc;        BITMAP...

问C++在给定像素数据数组的窗体上绘制矩形
EN

社区

活动

资源

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问C++在给定像素数据数组的窗体上绘制矩形EN

社区

活动

资源

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问C++在给定像素数据数组的窗体上绘制矩形
EN