public static uint SelectFont(GDIContext hdc, System.Drawing.Font font)
{
GDI32.SelectObject(hdc, font.ToHfont());
uint size = GDI32.GetOutlineTextMetrics(hdc, 0, IntPtr.Zero);
if (size != uint.MaxValue)
{
UnmanagedMemory otm = new UnmanagedMemory((int)size);
uint err = GDI32.GetOutlineTextMetrics(hdc, size, otm.MemoryPointer);
uint otmEMSquare = (uint)Marshal.ReadInt32(otm, 92);
otm.Dispose();
LOGFONT log = new LOGFONT();
font.ToLogFont(log);
log.lfHeight = -(int)otmEMSquare;
font = System.Drawing.Font.FromLogFont(log);
GDI32.SelectObject(hdc, font.ToHfont());
}
return size;
}
public RectangleI[] GetRectangles()
{
// If the region is empty, return a single empty rectangle
if (IsEmpty)
{
return new RectangleI[1];
}
// 1. Call GetRgnData with null to get size
uint dataLengthNeeded = GDI32.GetRegionData(DangerousGetHandle(), 0, IntPtr.Zero);
// 2. allocate some memory to hold the data
UnmanagedMemory uMem = new UnmanagedMemory((int)dataLengthNeeded);
IntPtr memoryPtr = uMem.MemoryPointer;
UnmanagedPointer structPtr = new UnmanagedPointer(memoryPtr);
// 3. call again passing in memory
uint bytesFilled = GDI32.GetRegionData(DangerousGetHandle(), dataLengthNeeded, structPtr);
// If the return value is 0, then the call failed.
if (0 == bytesFilled)
return null;
// 4. convert memory to data structures
// First get the RGNDATAHEADER
RGNDATAHEADER dataHeader;
dataHeader = (RGNDATAHEADER)Marshal.PtrToStructure(structPtr, typeof(RGNDATAHEADER));
// dataHeader.dwSize - tells us how big the header is, and thus how many bytes to skip to get
// to the rectangle information
// dataHeader.nRgnSize - tells us how many bytes are needed for the rectangle information
// dataHeader.nCount - tells us how many rectangles there are
structPtr = structPtr + dataHeader.dwSize;
// The nRgnSize / nCount will tell us how many bytes per rectangle structure
// and therefore how much to advance the pointer as we turn the buffer
// into a set of rectangles using PtrToStructure.
int structIncrement = (int)(dataHeader.nRgnSize / dataHeader.nCount);
// Create a list to add the rectangles to. This is simply convenient.
RectangleI[] rects = new RectangleI[dataHeader.nCount];
// Loop through creating as many rectangles as indicated by the dataheader nCount field
for (int i = 0; i < dataHeader.nCount; i++)
{
RECT rect = (RECT)Marshal.PtrToStructure(structPtr, typeof(RECT));
rects[i].x1 = rect.X;
rects[i].y1 = rect.Y;
rects[i].x2 = rect.X + rect.Width;
rects[i].y2 = rect.Y + rect.Height;
rects[i].Normalize();
structPtr = structPtr + structIncrement;
}
// 5. free memory
uMem.Dispose();
return rects;
}
public static bool IsTrueType(GDIContext hdc, System.Drawing.Font font)
{
GDI32.SelectObject(hdc, font.ToHfont());
UnmanagedMemory tmPtr = new UnmanagedMemory(Marshal.SizeOf(typeof(TEXTMETRIC)));
uint err = GDI32.GetTextMetrics(hdc, tmPtr.MemoryPointer);
TEXTMETRIC tm = (TEXTMETRIC)Marshal.PtrToStructure(tmPtr.MemoryPointer, typeof(TEXTMETRIC));
tmPtr.Dispose();
return (tm.tmPitchAndFamily & 4) != 0;
}
