C# Signature:
[DllImport("gdi32.dll")]
static extern int GetRegionData(IntPtr hRgn, uint dwCount,
IntpTR lpRgnData);
User-Defined Types:
None.
Notes:
None.
Tips & Tricks:
Please add some!
Sample Code:
// First get the size in bytes of the region data for the
using System;
using System.Runtime.InteropServices;
unsafe RECT[] RectsFromRegion(IntPtr hRgn)
{
RECT [] rects = null;
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.
RGNDATAHEADER * header = (RGNDATAHEADER)bytes;
if (header->iType == RDH_RECTANGLES)
{
rects = new RECT[header->nCount];
int rectOffset = header->cbSizeOfStruct;
for (int i=0; i<header->nCount; i++)
{
rects[i] = *((RECT *)((byte *)bytes+rectOffset+(Marshal.SizeOf(typeof(RECT)) *i)));
}
}
}
// Return the rectangles
return rects;
}
Alternative Managed API:
Do you know one? Please contribute it!
