问题描述
我已经尝试让它工作一段时间了,但我似乎无法弄清楚,并且数小时的谷歌搜索尚未显示任何有用的结果.
I've been trying to get this to work for awhile now, but I can't seem to figure it out, and hours of Googling has yet to reveal any useful results.
我有一个 RGBA 顺序的 32 位像素数组,我想从它们创建一个与设备无关的位图,并使用 SetClipboardData(CF_DIBV5, dib)
或类似方法将其放置在剪贴板上(理想情况下,我想保留 alpha 通道).注册自定义剪贴板类型不是一种选择,因为将其放在剪贴板上的目的是为了将其粘贴到另一个程序中.如果我不必手动将我的像素数据转换为其他格式(例如平面 BGRA),则可以获得奖励积分.
I have an array of 32-bit pixels in RGBA order, and I want to create a device-independent bitmap from them and place it on the clipboard using SetClipboardData(CF_DIBV5, dib)
or similar (ideally, I want to preserve the alpha channel). Registering a custom clipboard type is not an option, since the point of putting it on the clipboard is so that it can be pasted into another program. Bonus points if I don't have to manually convert my pixel data into some other format (such as planar BGRA).
我当前的代码是这样的(都在一个 set_clipboard_img 函数中):
My current code goes like this (it's all within a set_clipboard_img function):
if(!OpenClipboard(hwnd)) return;
BITMAPV5HEADER* info = (BITMAPV5HEADER*) GlobalAlloc(GMEM_MOVEABLE, sizeof(BITMAPV5HEADER));
info->bV5Size = sizeof(BITMAPV5HEADER);
info->bV5Width = img_width;
info->bV5Height = -img_height;
info->bV5Planes = 1; // The docs say this is the only valid value here.
info->bV5BitCount = 32;
info->bV5Compression = BI_BITFIELDS;
info->bV5SizeImage = img_width * img_height * 4;
info->bV5RedMask = 0xff000000;
info->bV5GreenMask = 0x00ff0000;
info->bV5BlueMask = 0x0000ff00;
info->bV5AlphaMask = 0x000000ff;
unsigned char* buf;
// One of the sources I found said that I can pass a BITMAPV5HEADER in place of the BITMAPINFO, hence the first reinterpret_cast.
HBITMAP dib = CreateDIBSection(NULL, reinterpret_cast<BITMAPINFO*>(info), DIB_RGB_COLORS, reinterpret_cast<void**>(&buf), NULL, 0);
if(dib == NULL) {
CloseClipboard();
return;
}
// img_pixels_ptr is a unsigned char* to the pixels in non-planar RGBA format
std::copy_n(img_pixels_ptr, info->bV5SizeImage, buf);
EmptyClipboard();
auto result = SetClipboardData(CF_DIBV5, dib);
if(result == NULL) {
char str[256];
str[255] = 0;
FormatMessageA(FORMAT_MESSAGE_FROM_SYSTEM, NULL, GetLastError(), 0, str, 255, NULL);
std::cerr << "Error setting clipboard: " << str << std::endl;
// Here I get "handle not valid". I have no idea _why_ it's not valid, though.
}
CloseClipboard();
最终,我还需要能够反转该过程(从剪贴板中获取潜在透明的位图),但一次只做一件事.
Ultimately, I'll also need to be able to reverse the process (getting a potentially-transparent bitmap off the clipboard), but one thing at a time.
推荐答案
您不能将 HBITMAP
传递给 SetClipboardData()
.它需要来自 GlobalAlloc()
的 HGLOBAL
代替.这就是 SetClipboardData()
因 ERROR_INVALID_HANDLE
错误而失败的原因.
You cannot pass an HBITMAP
to SetClipboardData()
. It requires an HGLOBAL
from GlobalAlloc()
instead. That is why SetClipboardData()
is failing with an ERROR_INVALID_HANDLE
error.
您需要将您的 BITMAPV5HEADER
和像素数据直接放入分配的 HGLOBAL
并按原样放入剪贴板,忘记使用 CreateDIBSection()
:
You need to put your BITMAPV5HEADER
and pixel data directly into the allocated HGLOBAL
and put it as-is onto the clipboard, forget using CreateDIBSection()
at all:
CF_DIBV5
17
包含 BITMAPV5HEADER 结构的内存对象,后跟位图颜色空间信息和位图位.
尝试更像这样的事情:
void printErr(const char *msg)
{
char str[256] = {0};
FormatMessageA(FORMAT_MESSAGE_FROM_SYSTEM, NULL, GetLastError(), 0, str, 255, NULL);
std::cerr << msg << ": " << str << std::endl;
}
...
DWORD size_pixels = img_width * img_height * 4;
HGLOBAL hMem = GlobalAlloc(GHND, sizeof(BITMAPV5HEADER) + size_pixels);
if (!hMem)
{
printErr("Error allocating memory for bitmap data");
return;
}
BITMAPV5HEADER* hdr = (BITMAPV5HEADER*) GlobalLock(hMem);
if (!hdr)
{
printErr("Error accessing memory for bitmap data");
GlobalFree(hMem);
return;
}
hdr->bV5Size = sizeof(BITMAPV5HEADER);
hdr->bV5Width = img_width;
hdr->bV5Height = -img_height;
hdr->bV5Planes = 1;
hdr->bV5BitCount = 32;
hdr->bV5Compression = BI_BITFIELDS;
hdr->bV5SizeImage = size_pixels;
hdr->bV5RedMask = 0xff000000;
hdr->bV5GreenMask = 0x00ff0000;
hdr->bV5BlueMask = 0x0000ff00;
hdr->bV5AlphaMask = 0x000000ff;
// img_pixels_ptr is a unsigned char* to the pixels in non-planar RGBA format
CopyMemory(hdr+1, img_pixels_ptr, size_pixels);
GlobalUnlock(hMem);
if (!OpenClipboard(hwnd))
{
printErr("Error opening clipboard");
}
else
{
if (!EmptyClipboard())
printErr("Error emptying clipboard");
else if (!SetClipboardData(CF_DIBV5, hMem))
printErr("Error setting bitmap on clipboard");
else
hMem = NULL; // clipboard now owns the memory
CloseClipboard();
}
if (hMem)
GlobalFree(hMem);
这篇关于如何仅使用直接 WinAPI 将独立于设备的位图放入 Windows 剪贴板?(没有 MFC 或其他包装器)的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持!