public unsafe NativeTextLayout CreateTextLayout(ref NativeParagraphStyle paragraphStyle,
ref NativeTextStyle textStyle,
ReadOnlySpan <char> text,
float maxWidth,
float maxHeight)
{
// This is to avoid a null-pointer which is rejected by DirectWrite, even though length 0
// is acceptable
if (text.IsEmpty)
{
text = EmptyText;
}
fixed(char *textPtr = text)
{
if (!DrawingEngine_CreateTextLayout(
_native,
ref paragraphStyle,
ref textStyle,
textPtr,
text.Length,
maxWidth,
maxHeight,
out var textLayoutNative,
out var error
))
{
throw new InvalidOperationException("Failed to create TextLayout: " + error);
}
return(new NativeTextLayout(textLayoutNative));
}
}
public void SetStyle(int start, int length, NativeTextStyleProperty properties, ref NativeTextStyle style)
{
if (!TextLayout_SetStyle(NativePointer, (uint)start, (uint)length, properties, ref style, out var error))
{
throw new InvalidOperationException("Couldn't set text style: " + error);
}
}
private static extern bool TextLayout_SetStyle(IntPtr textLayout,
uint start,
uint length,
NativeTextStyleProperty properties,
ref NativeTextStyle style,
[MarshalAs(UnmanagedType.LPWStr)]
out string error
);
private static extern unsafe bool DrawingEngine_CreateTextLayout(
IntPtr drawingEngine,
[In]
ref NativeParagraphStyle paragraphStyle,
[In]
ref NativeTextStyle textStyle,
char *text,
int textLength,
float maxWidth,
float maxHeight,
out IntPtr textLayout,
[MarshalAs(UnmanagedType.LPWStr)]
out string error
);
