Type a page name and press Enter. You'll jump to the page if it exists, or you can create it if it doesn't.
To create a page in a module other than gdi32, prefix the name with the module name and a period.
static extern int GetRegionData(IntPtr hRgn, uint dwCount, IntPtr lpRgnData);
This is an 'unsafe' call, and thus should be led by the [SuppressUnmanagedCodeSecurity()] attribute.
Tips & Tricks:
Please add some!
// this should be defined somewhere in a class
const int RDH_RECTANGLES = 1;
unsafe RECT RectsFromRegion(IntPtr hRgn)
RECT  rects = null;
// First we call GetRegionData() with a null buffer.
// The return from this call should be the size of buffer
// we need to allocate in order to receive the data.
int dataSize = GetRegionData(hRgn, 0, IntPtr.Zero);
if (dataSize != 0)
IntPtr bytes = IntPtr.Zero;
// Allocate as much space as the GetRegionData call
// said was needed
bytes = Marshal.AllocCoTaskMem(dataSize);
// Now, make the call again to actually get the data
int retValue = GetRegionData(hRgn, dataSize, bytes);
// From here on out, we have the data in a buffer, and we
// just need to convert it into a form that is more useful
// Since pointers are used, this whole routine is 'unsafe'
// It's a small sacrifice to make in order to get this to work.
// [RBS] Added missing second pointer identifier
RGNDATAHEADER * header = (RGNDATAHEADER*)bytes;
if (header->iType == RDH_RECTANGLES)
rects = new RECT[header->nCount];
// The rectangle data follows the header, so we offset the specified
// header size and start reading rectangles.
int rectOffset = header->dwSize;
for (int i=0; i < header->nCount; i++)
// simple assignment from the buffer to our array of rectangles
// will give us what we want.
rects[i] = *((RECT *)((byte *)bytes+rectOffset+(Marshal.SizeOf(typeof(RECT)) *i)));
// Return the rectangles
Alternative Managed API:
Do you know one? Please contribute it!
The GetRegionData API
5/30/2008 8:32:45 AM - -22.214.171.124
TODO - a short description
3/16/2007 2:19:39 PM - -126.96.36.199
Please edit this page!
Do you have...
helpful tips or sample code to share for using this API in managed code?
corrections to the existing content?
variations of the signature you want to share?
additional languages you want to include?
Select "Edit This Page" on the right hand toolbar and edit it! Or add new pages containing supporting types needed for this API (structures, delegates, and more).