TextExtents MeasureTextExtents(ref TextBlock block, TextQuality quality)
{
// TODO: Parse layout options:
var format = block.Font.Italic ? measure_string_format : measure_string_format_tight;
//StringFormat format = measure_string_format_tight;
if (block.Direction == TextDirection.Vertical)
{
format.FormatFlags |= StringFormatFlags.DirectionVertical;
}
else
{
format.FormatFlags &= ~StringFormatFlags.DirectionVertical;
}
if (block.Direction == TextDirection.RightToLeft)
{
format.FormatFlags |= StringFormatFlags.DirectionRightToLeft;
}
else
{
format.FormatFlags &= ~StringFormatFlags.DirectionRightToLeft;
}
if (block.Alignment == TextAlignment.Near)
{
format.Alignment = StringAlignment.Near;
}
else if (block.Alignment == TextAlignment.Center)
{
format.Alignment = StringAlignment.Center;
}
else
{
format.Alignment = StringAlignment.Far;
}
TextExtents extents = text_extents_pool.Acquire();
RectangleF rect = block.Bounds;
// Work around Mono/GDI+ bug, which causes incorrect
// text wraping when block.Bounds == SizeF.Empty.
if (block.Bounds.Size == SizeF.Empty)
{
rect.Size = MaximumGraphicsClipSize;
}
SetTextRenderingOptions(graphics, block.Font, quality);
IntPtr native_graphics = GdiPlus.GetNativeGraphics(graphics);
IntPtr native_font = GdiPlus.GetNativeFont(block.Font);
IntPtr native_string_format = GdiPlus.GetNativeStringFormat(format);
float max_width = 0, max_height = 0;
// It seems that the mere presence of \n and \r characters
// is enough for Mono to botch the layout (even if these
// characters are not processed.) We'll need to find a
// different way to perform layout on Mono, probably
// through Pango.
// TODO: This workaround allocates memory.
//if (Configuration.RunningOnMono)
{
string[] lines = block.Text.Replace("\r", String.Empty).Split('\n');
foreach (string s in lines)
{
float width, height;
extents.AddRange(MeasureGlyphExtents(
ref block, s,
native_graphics, native_font, native_string_format,
ref rect, out width, out height));
if ((block.Direction & TextDirection.Vertical) == 0)
{
rect.Y += block.Font.Height;
}
else
{
rect.X += block.Font.Height;
}
if (width > max_width)
{
max_width = width;
}
if (height > max_height)
{
max_height = height;
}
}
}
if (extents.Count > 0)
{
extents.BoundingBox = new RectangleF(extents[0].X, extents[0].Y, max_width, max_height);
}
else
{
extents.BoundingBox = RectangleF.Empty;
}
return(extents);
}
