gdiplus 从字符串构造图像

发布于 2024-07-15 02:57:07 字数 260 浏览 5 评论 0原文

我正在使用 MySQL++ API 从 MySQL 数据库中提取图像。我得到的图像为 mysqlpp::sql_mediumblob ，它是字符串的表示形式。现在我想使用 GDI+ 旋转一些图片，但我不知道如何使用这个构造函数：

Image::Image(IStream*,BOOL) - Creates an Image object based on a stream.

使用保存在 blob 中的图像。提前致谢。

原文

I am extracting images from a MySQL database using the MySQL++ API. I get the images as mysqlpp::sql_mediumblob which is representation of string. Now I want to rotate some pictures using GDI+, but I am not sure how to use this constructor:

Image::Image(IStream*,BOOL) - Creates an Image object based on a stream.

with the image that is kept in the blob.
Thanks in advance.

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习ぎ惯性依靠 2024-07-22 02:57:07

如此处所述： http://msdn.microsoft.com /en-us/library/aa378980(VS.85).aspx

HGLOBAL hMem = ::GlobalAlloc(GMEM_MOVEABLE,iSize);
if (!hMem)
    AfxThrowMemoryException();
LPVOID pImage = ::GlobalLock(hMem);
... // Fill memory pointed by pImage, reading it from MySQL
::GlobalUnlock(hMem);

// Convert internal data if there is any
CComPtr<IStream> spStream;
HRESULT hr = ::CreateStreamOnHGlobal(hMem,FALSE,&spStream);

然后将 spStream 传递给 Gdiplus::Image 构造函数。

As noted here: http://msdn.microsoft.com/en-us/library/aa378980(VS.85).aspx

HGLOBAL hMem = ::GlobalAlloc(GMEM_MOVEABLE,iSize);
if (!hMem)
    AfxThrowMemoryException();
LPVOID pImage = ::GlobalLock(hMem);
... // Fill memory pointed by pImage, reading it from MySQL
::GlobalUnlock(hMem);

// Convert internal data if there is any
CComPtr<IStream> spStream;
HRESULT hr = ::CreateStreamOnHGlobal(hMem,FALSE,&spStream);

Then pass spStream to the Gdiplus::Image constructor.

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