// Gets the bounds of each character in a line of text.
// The line is processed in blocks of 32 characters (GdiPlus.MaxMeasurableCharacterRanges).
IEnumerable <RectangleF> GetCharExtents(string text, int height, int line_start, int line_length,
RectangleF layoutRect, IntPtr native_graphics, IntPtr native_font, IntPtr native_string_format)
{
RectangleF rect = new RectangleF();
int line_end = line_start + line_length;
while (line_start < line_end)
{
//if (text[line_start] == '\n' || text[line_start] == '\r')
//{
// line_start++;
// continue;
//}
int num_characters = (line_end - line_start) > GdiPlus.MaxMeasurableCharacterRanges ?
GdiPlus.MaxMeasurableCharacterRanges :
line_end - line_start;
int status = 0;
for (int i = 0; i < num_characters; i++)
{
characterRanges[i] = new CharacterRange(line_start + i, 1);
IntPtr region;
status = GdiPlus.CreateRegion(out region);
regions[i] = region;
Debug.Assert(status == 0, String.Format("GDI+ error: {0}", status));
}
status = GdiPlus.SetStringFormatMeasurableCharacterRanges(native_string_format, num_characters, characterRanges);
Debug.Assert(status == 0, String.Format("GDI+ error: {0}", status));
status = GdiPlus.MeasureCharacterRanges(native_graphics, text, text.Length,
native_font, ref layoutRect, native_string_format, num_characters, regions);
Debug.Assert(status == 0, String.Format("GDI+ error: {0}", status));
for (int i = 0; i < num_characters; i++)
{
GdiPlus.GetRegionBounds(regions[i], native_graphics, ref rect);
Debug.Assert(status == 0, String.Format("GDI+ error: {0}", status));
GdiPlus.DeleteRegion(regions[i]);
Debug.Assert(status == 0, String.Format("GDI+ error: {0}", status));
rect.Y += height;
yield return(rect);
}
line_start += num_characters;
}
}
// Gets the bounds of each character in a line of text.
// Each line is processed in blocks of 32 characters (GdiPlus.MaxMeasurableCharacterRanges).
IEnumerable <RectangleF> MeasureGlyphExtents(
ref TextBlock block, string text,
IntPtr native_graphics, IntPtr native_font, IntPtr native_string_format,
ref RectangleF layoutRect, out float max_width, out float max_height)
{
measured_glyphs.Clear();
max_width = layoutRect.Left;
max_height = layoutRect.Top;
float last_line_width = 0, last_line_height = 0;
int current = 0;
while (current < text.Length)
{
int num_characters = (text.Length - current) > GdiPlus.MaxMeasurableCharacterRanges ?
GdiPlus.MaxMeasurableCharacterRanges :
text.Length - current;
int status = 0;
// Prepare the character ranges and region structs for the measurement.
for (int i = 0; i < num_characters; i++)
{
if (text[current + i] == '\n' || text[current + i] == '\r')
{
throw new NotSupportedException();
}
characterRanges[i] = new CharacterRange(current + i, 1);
IntPtr region;
status = GdiPlus.CreateRegion(out region);
regions[i] = region;
Debug.Assert(status == 0, String.Format("GDI+ error: {0}", status));
}
status = GdiPlus.SetStringFormatMeasurableCharacterRanges(native_string_format, num_characters, characterRanges);
Debug.Assert(status == 0, String.Format("GDI+ error: {0}", status));
status = GdiPlus.MeasureCharacterRanges(native_graphics, text, text.Length,
native_font, ref layoutRect, native_string_format, num_characters, regions);
Debug.Assert(status == 0, String.Format("GDI+ error: {0}", status));
// Read back the results of the measurement.
for (int i = 0; i < num_characters; i++)
{
RectangleF rect = new RectangleF();
GdiPlus.GetRegionBounds(regions[i], native_graphics, ref rect);
Debug.Assert(status == 0, String.Format("GDI+ error: {0}", status));
GdiPlus.DeleteRegion(regions[i]);
Debug.Assert(status == 0, String.Format("GDI+ error: {0}", status));
if (rect.Bottom > max_height)
{
max_height = rect.Bottom;
}
if (rect.Right > max_width)
{
max_width = rect.Right;
}
if (rect.X > last_line_width)
{
last_line_width = rect.X;
}
if (rect.Y > last_line_height)
{
last_line_height = rect.Y;
}
measured_glyphs.Add(rect);
}
current += num_characters;
}
// Make sure the current height is updated, if the the current line has wrapped due to word-wraping.
// Otherwise, the next line will overlap with the current one.
if (measured_glyphs.Count > 1)
{
if ((block.Direction & TextDirection.Vertical) == 0)
{
if (layoutRect.Y < last_line_height)
{
layoutRect.Y = last_line_height;
}
}
else
{
if (layoutRect.X < last_line_width)
{
layoutRect.X = last_line_width;
}
}
}
// Mono's GDI+ implementation suffers from an issue where the specified layoutRect is not taken into
// account. We will try to improve the situation by moving text to the correct location on this
// error condition. This will not help word wrapping, but it is better than nothing.
// TODO: Mono 2.8 is supposed to ship with a Pango-based GDI+ text renderer, which should not
// suffer from this bug. Verify that this is the case and remove the hack.
if (Configuration.RunningOnMono && (layoutRect.X != 0 || layoutRect.Y != 0) && measured_glyphs.Count > 0)
{
for (int i = 0; i < measured_glyphs.Count; i++)
{
RectangleF rect = measured_glyphs[i];
rect.X += layoutRect.X;
rect.Y += layoutRect.Y;
measured_glyphs[i] = rect;
}
}
return(measured_glyphs);
}