internal static Bitmap RenderString(Library library, Face face, string text, Color foreColor, Color backColor)
{
var measuredChars = new List <DebugChar>();
var renderedChars = new List <DebugChar>();
float penX = 0, penY = 0;
float stringWidth = 0; // the measured width of the string
float stringHeight = 0; // the measured height of the string
float overrun = 0;
float underrun = 0;
float kern = 0;
int spacingError = 0;
bool trackingUnderrun = true;
int rightEdge = 0; // tracking rendered right side for debugging
// Bottom and top are both positive for simplicity.
// Drawing in .Net has 0,0 at the top left corner, with positive X to the right
// and positive Y downward.
// Glyph metrics have an origin typically on the left side and at baseline
// of the visual data, but can draw parts of the glyph in any quadrant, and
// even move the origin (via kerning).
float top = 0, bottom = 0;
// Measure the size of the string before rendering it. We need to do this so
// we can create the proper size of bitmap (canvas) to draw the characters on.
for (int i = 0; i < text.Length; i++)
{
#region Load character
char c = text[i];
// Look up the glyph index for this character.
uint glyphIndex = face.GetCharIndex(c);
// Load the glyph into the font's glyph slot. There is usually only one slot in the font.
face.LoadGlyph(glyphIndex, LoadFlags.Default, LoadTarget.Normal);
// Refer to the diagram entitled "Glyph Metrics" at http://www.freetype.org/freetype2/docs/tutorial/step2.html.
// There is also a glyph diagram included in this example (glyph-dims.svg).
// The metrics below are for the glyph loaded in the slot.
float gAdvanceX = (float)face.Glyph.Advance.X; // same as the advance in metrics
float gBearingX = (float)face.Glyph.Metrics.HorizontalBearingX;
//float gWidth = face.Glyph.Metrics.Width.ToSingle();
float gWidth = face.Glyph.Metrics.Width;
var rc = new DebugChar(c, gAdvanceX, gBearingX, gWidth);
#endregion
#region Underrun
// Negative bearing would cause clipping of the first character
// at the left boundary, if not accounted for.
// A positive bearing would cause empty space.
underrun += -(gBearingX);
if (stringWidth == 0)
{
stringWidth += underrun;
}
if (trackingUnderrun)
{
rc.Underrun = underrun;
}
if (trackingUnderrun && underrun <= 0)
{
underrun = 0;
trackingUnderrun = false;
}
#endregion
#region Overrun
// Accumulate overrun, which coould cause clipping at the right side of characters near
// the end of the string (typically affects fonts with slanted characters)
if (gBearingX + gWidth > 0 || gAdvanceX > 0)
{
overrun -= Math.Max(gBearingX + gWidth, gAdvanceX);
if (overrun <= 0)
{
overrun = 0;
}
}
overrun += (float)(gBearingX == 0 && gWidth == 0 ? 0 : gBearingX + gWidth - gAdvanceX);
// On the last character, apply whatever overrun we have to the overall width.
// Positive overrun prevents clipping, negative overrun prevents extra space.
if (i == text.Length - 1)
{
stringWidth += overrun;
}
rc.Overrun = overrun; // accumulating (per above)
#endregion
#region Top/Bottom
// If this character goes higher or lower than any previous character, adjust
// the overall height of the bitmap.
float glyphTop = (float)face.Glyph.Metrics.HorizontalBearingY;
float glyphBottom = (float)(face.Glyph.Metrics.Height - face.Glyph.Metrics.HorizontalBearingY);
if (glyphTop > top)
{
top = glyphTop;
}
if (glyphBottom > bottom)
{
bottom = glyphBottom;
}
#endregion
// Accumulate the distance between the origin of each character (simple width).
stringWidth += gAdvanceX;
rc.RightEdge = stringWidth;
measuredChars.Add(rc);
#region Kerning (for NEXT character)
// Calculate kern for the NEXT character (if any)
// The kern value adjusts the origin of the next character (positive or negative).
if (face.HasKerning && i < text.Length - 1)
{
char cNext = text[i + 1];
kern = (float)face.GetKerning(glyphIndex, face.GetCharIndex(cNext), KerningMode.Default).X;
// sanity check for some fonts that have kern way out of whack
if (kern > gAdvanceX * 5 || kern < -(gAdvanceX * 5))
{
kern = 0;
}
rc.Kern = kern;
stringWidth += kern;
}
#endregion
}
stringHeight = top + bottom;
// If any dimension is 0, we can't create a bitmap
if (stringWidth == 0 || stringHeight == 0)
{
return(null);
}
// Create a new bitmap that fits the string.
Bitmap bmp = new Bitmap((int)Math.Ceiling(stringWidth), (int)Math.Ceiling(stringHeight));
trackingUnderrun = true;
underrun = 0;
overrun = 0;
stringWidth = 0;
using (var g = Graphics.FromImage(bmp))
{
#region Set up graphics
// HighQuality and GammaCorrected both specify gamma correction be applied (2.2 in sRGB)
// https://msdn.microsoft.com/en-us/library/windows/desktop/ms534094(v=vs.85).aspx
g.CompositingQuality = CompositingQuality.HighQuality;
// HighQuality and AntiAlias both specify antialiasing
g.SmoothingMode = SmoothingMode.HighQuality;
// If a background color is specified, blend over it.
g.CompositingMode = CompositingMode.SourceOver;
g.Clear(backColor);
#endregion
// Draw the string into the bitmap.
// A lot of this is a repeat of the measuring steps, but this time we have
// an actual bitmap to work with (both canvas and bitmaps in the glyph slot).
for (int i = 0; i < text.Length; i++)
{
#region Load character
char c = text[i];
// Same as when we were measuring, except RenderGlyph() causes the glyph data
// to be converted to a bitmap.
uint glyphIndex = face.GetCharIndex(c);
face.LoadGlyph(glyphIndex, LoadFlags.Default, LoadTarget.Normal);
face.Glyph.RenderGlyph(RenderMode.Normal);
FTBitmap ftbmp = face.Glyph.Bitmap;
float gAdvanceX = (float)face.Glyph.Advance.X;
float gBearingX = (float)face.Glyph.Metrics.HorizontalBearingX;
float gWidth = (float)face.Glyph.Metrics.Width;
var rc = new DebugChar(c, gAdvanceX, gBearingX, gWidth);
#endregion
#region Underrun
// Underrun
underrun += -(gBearingX);
if (penX == 0)
{
penX += underrun;
}
if (trackingUnderrun)
{
rc.Underrun = underrun;
}
if (trackingUnderrun && underrun <= 0)
{
underrun = 0;
trackingUnderrun = false;
}
#endregion
#region Draw glyph
// Whitespace characters sometimes have a bitmap of zero size, but a non-zero advance.
// We can't draw a 0-size bitmap, but the pen position will still get advanced (below).
if ((ftbmp.Width > 0 && ftbmp.Rows > 0))
{
// Get a bitmap that .Net can draw (GDI+ in this case).
Bitmap cBmp = ftbmp.ToGdipBitmap(foreColor);
rc.Width = cBmp.Width;
rc.BearingX = face.Glyph.BitmapLeft;
int x = (int)Math.Round(penX + face.Glyph.BitmapLeft);
int y = (int)Math.Round(penY + top - (float)face.Glyph.Metrics.HorizontalBearingY);
//Not using g.DrawImage because some characters come out blurry/clipped. (Is this still true?)
g.DrawImageUnscaled(cBmp, x, y);
rc.Overrun = face.Glyph.BitmapLeft + cBmp.Width - gAdvanceX;
// Check if we are aligned properly on the right edge (for debugging)
rightEdge = Math.Max(rightEdge, x + cBmp.Width);
spacingError = bmp.Width - rightEdge;
}
else
{
rightEdge = (int)(penX + gAdvanceX);
spacingError = bmp.Width - rightEdge;
}
#endregion
#region Overrun
if (gBearingX + gWidth > 0 || gAdvanceX > 0)
{
overrun -= Math.Max(gBearingX + gWidth, gAdvanceX);
if (overrun <= 0)
{
overrun = 0;
}
}
overrun += (float)(gBearingX == 0 && gWidth == 0 ? 0 : gBearingX + gWidth - gAdvanceX);
if (i == text.Length - 1)
{
penX += overrun;
}
rc.Overrun = overrun;
#endregion
// Advance pen positions for drawing the next character.
penX += (float)face.Glyph.Advance.X; // same as Metrics.HorizontalAdvance?
penY += (float)face.Glyph.Advance.Y;
rc.RightEdge = penX;
spacingError = bmp.Width - (int)Math.Round(rc.RightEdge);
renderedChars.Add(rc);
#region Kerning (for NEXT character)
// Adjust for kerning between this character and the next.
if (face.HasKerning && i < text.Length - 1)
{
char cNext = text[i + 1];
kern = (float)face.GetKerning(glyphIndex, face.GetCharIndex(cNext), KerningMode.Default).X;
if (kern > gAdvanceX * 5 || kern < -(gAdvanceX * 5))
{
kern = 0;
}
rc.Kern = kern;
penX += (float)kern;
}
#endregion
}
}
bool printedHeader = false;
if (spacingError != 0)
{
for (int i = 0; i < renderedChars.Count; i++)
{
//if (measuredChars[i].RightEdge != renderedChars[i].RightEdge)
//{
if (!printedHeader)
{
DebugChar.PrintHeader();
}
printedHeader = true;
Debug.Print(measuredChars[i].ToString());
Debug.Print(renderedChars[i].ToString());
//}
}
string msg = string.Format("Right edge: {0,3} ({1}) {2}",
spacingError,
spacingError == 0 ? "perfect" : spacingError > 0 ? "space " : "clipped",
face.FamilyName);
System.Diagnostics.Debug.Print(msg);
//throw new ApplicationException(msg);
}
return(bmp);
}
internal static Bitmap RenderString(Library library, Face face, string text, Color foreColor, Color backColor)
{
var measuredChars = new List<DebugChar>();
var renderedChars = new List<DebugChar>();
float penX = 0, penY = 0;
float stringWidth = 0; // the measured width of the string
float stringHeight = 0; // the measured height of the string
float overrun = 0;
float underrun = 0;
float kern = 0;
int spacingError = 0;
bool trackingUnderrun = true;
int rightEdge = 0; // tracking rendered right side for debugging
// Bottom and top are both positive for simplicity.
// Drawing in .Net has 0,0 at the top left corner, with positive X to the right
// and positive Y downward.
// Glyph metrics have an origin typically on the left side and at baseline
// of the visual data, but can draw parts of the glyph in any quadrant, and
// even move the origin (via kerning).
float top = 0, bottom = 0;
// Measure the size of the string before rendering it. We need to do this so
// we can create the proper size of bitmap (canvas) to draw the characters on.
for (int i = 0; i < text.Length; i++)
{
#region Load character
char c = text[i];
// Look up the glyph index for this character.
uint glyphIndex = face.GetCharIndex(c);
// Load the glyph into the font's glyph slot. There is usually only one slot in the font.
face.LoadGlyph(glyphIndex, LoadFlags.Default, LoadTarget.Normal);
// Refer to the diagram entitled "Glyph Metrics" at http://www.freetype.org/freetype2/docs/tutorial/step2.html.
// There is also a glyph diagram included in this example (glyph-dims.svg).
// The metrics below are for the glyph loaded in the slot.
float gAdvanceX = (float)face.Glyph.Advance.X; // same as the advance in metrics
float gBearingX = (float)face.Glyph.Metrics.HorizontalBearingX;
float gWidth = face.Glyph.Metrics.Width.ToSingle();
var rc = new DebugChar(c, gAdvanceX, gBearingX, gWidth);
#endregion
#region Underrun
// Negative bearing would cause clipping of the first character
// at the left boundary, if not accounted for.
// A positive bearing would cause empty space.
underrun += -(gBearingX);
if (stringWidth == 0)
stringWidth += underrun;
if (trackingUnderrun)
rc.Underrun = underrun;
if (trackingUnderrun && underrun <= 0)
{
underrun = 0;
trackingUnderrun = false;
}
#endregion
#region Overrun
// Accumulate overrun, which coould cause clipping at the right side of characters near
// the end of the string (typically affects fonts with slanted characters)
if (gBearingX + gWidth > 0 || gAdvanceX > 0)
{
overrun -= Math.Max(gBearingX + gWidth, gAdvanceX);
if (overrun <= 0) overrun = 0;
}
overrun += (float)(gBearingX == 0 && gWidth == 0 ? 0 : gBearingX + gWidth - gAdvanceX);
// On the last character, apply whatever overrun we have to the overall width.
// Positive overrun prevents clipping, negative overrun prevents extra space.
if (i == text.Length - 1)
stringWidth += overrun;
rc.Overrun = overrun; // accumulating (per above)
#endregion
#region Top/Bottom
// If this character goes higher or lower than any previous character, adjust
// the overall height of the bitmap.
float glyphTop = (float)face.Glyph.Metrics.HorizontalBearingY;
float glyphBottom = (float)(face.Glyph.Metrics.Height - face.Glyph.Metrics.HorizontalBearingY);
if (glyphTop > top)
top = glyphTop;
if (glyphBottom > bottom)
bottom = glyphBottom;
#endregion
// Accumulate the distance between the origin of each character (simple width).
stringWidth += gAdvanceX;
rc.RightEdge = stringWidth;
measuredChars.Add(rc);
#region Kerning (for NEXT character)
// Calculate kern for the NEXT character (if any)
// The kern value adjusts the origin of the next character (positive or negative).
if (face.HasKerning && i < text.Length - 1)
{
char cNext = text[i + 1];
kern = (float)face.GetKerning(glyphIndex, face.GetCharIndex(cNext), KerningMode.Default).X;
// sanity check for some fonts that have kern way out of whack
if (kern > gAdvanceX * 5 || kern < -(gAdvanceX * 5))
kern = 0;
rc.Kern = kern;
stringWidth += kern;
}
#endregion
}
stringHeight = top + bottom;
// If any dimension is 0, we can't create a bitmap
if (stringWidth == 0 || stringHeight == 0)
return null;
// Create a new bitmap that fits the string.
Bitmap bmp = new Bitmap((int)Math.Ceiling(stringWidth), (int)Math.Ceiling(stringHeight));
trackingUnderrun = true;
underrun = 0;
overrun = 0;
stringWidth = 0;
using (var g = Graphics.FromImage(bmp))
{
#region Set up graphics
// HighQuality and GammaCorrected both specify gamma correction be applied (2.2 in sRGB)
// https://msdn.microsoft.com/en-us/library/windows/desktop/ms534094(v=vs.85).aspx
g.CompositingQuality = CompositingQuality.HighQuality;
// HighQuality and AntiAlias both specify antialiasing
g.SmoothingMode = SmoothingMode.HighQuality;
// If a background color is specified, blend over it.
g.CompositingMode = CompositingMode.SourceOver;
g.Clear(backColor);
#endregion
// Draw the string into the bitmap.
// A lot of this is a repeat of the measuring steps, but this time we have
// an actual bitmap to work with (both canvas and bitmaps in the glyph slot).
for (int i = 0; i < text.Length; i++)
{
#region Load character
char c = text[i];
// Same as when we were measuring, except RenderGlyph() causes the glyph data
// to be converted to a bitmap.
uint glyphIndex = face.GetCharIndex(c);
face.LoadGlyph(glyphIndex, LoadFlags.Default, LoadTarget.Normal);
face.Glyph.RenderGlyph(RenderMode.Normal);
FTBitmap ftbmp = face.Glyph.Bitmap;
float gAdvanceX = (float)face.Glyph.Advance.X;
float gBearingX = (float)face.Glyph.Metrics.HorizontalBearingX;
float gWidth = (float)face.Glyph.Metrics.Width;
var rc = new DebugChar(c, gAdvanceX, gBearingX, gWidth);
#endregion
#region Underrun
// Underrun
underrun += -(gBearingX);
if (penX == 0)
penX += underrun;
if (trackingUnderrun)
rc.Underrun = underrun;
if (trackingUnderrun && underrun <= 0)
{
underrun = 0;
trackingUnderrun = false;
}
#endregion
#region Draw glyph
// Whitespace characters sometimes have a bitmap of zero size, but a non-zero advance.
// We can't draw a 0-size bitmap, but the pen position will still get advanced (below).
if ((ftbmp.Width > 0 && ftbmp.Rows > 0))
{
// Get a bitmap that .Net can draw (GDI+ in this case).
Bitmap cBmp = ftbmp.ToGdipBitmap(foreColor);
rc.Width = cBmp.Width;
rc.BearingX = face.Glyph.BitmapLeft;
int x = (int)Math.Round(penX + face.Glyph.BitmapLeft);
int y = (int)Math.Round(penY + top - (float)face.Glyph.Metrics.HorizontalBearingY);
//Not using g.DrawImage because some characters come out blurry/clipped. (Is this still true?)
g.DrawImageUnscaled(cBmp, x, y);
rc.Overrun = face.Glyph.BitmapLeft + cBmp.Width - gAdvanceX;
// Check if we are aligned properly on the right edge (for debugging)
rightEdge = Math.Max(rightEdge, x + cBmp.Width);
spacingError = bmp.Width - rightEdge;
}
else
{
rightEdge = (int)(penX + gAdvanceX);
spacingError = bmp.Width - rightEdge;
}
#endregion
#region Overrun
if (gBearingX + gWidth > 0 || gAdvanceX > 0)
{
overrun -= Math.Max(gBearingX + gWidth, gAdvanceX);
if (overrun <= 0) overrun = 0;
}
overrun += (float)(gBearingX == 0 && gWidth == 0 ? 0 : gBearingX + gWidth - gAdvanceX);
if (i == text.Length - 1) penX += overrun;
rc.Overrun = overrun;
#endregion
// Advance pen positions for drawing the next character.
penX += (float)face.Glyph.Advance.X; // same as Metrics.HorizontalAdvance?
penY += (float)face.Glyph.Advance.Y;
rc.RightEdge = penX;
spacingError = bmp.Width - (int)Math.Round(rc.RightEdge);
renderedChars.Add(rc);
#region Kerning (for NEXT character)
// Adjust for kerning between this character and the next.
if (face.HasKerning && i < text.Length - 1)
{
char cNext = text[i + 1];
kern = (float)face.GetKerning(glyphIndex, face.GetCharIndex(cNext), KerningMode.Default).X;
if (kern > gAdvanceX * 5 || kern < -(gAdvanceX * 5))
kern = 0;
rc.Kern = kern;
penX += (float)kern;
}
#endregion
}
}
bool printedHeader = false;
if (spacingError != 0)
{
for (int i = 0; i < renderedChars.Count; i++)
{
//if (measuredChars[i].RightEdge != renderedChars[i].RightEdge)
//{
if (!printedHeader)
DebugChar.PrintHeader();
printedHeader = true;
Debug.Print(measuredChars[i].ToString());
Debug.Print(renderedChars[i].ToString());
//}
}
string msg = string.Format("Right edge: {0,3} ({1}) {2}",
spacingError,
spacingError == 0 ? "perfect" : spacingError > 0 ? "space " : "clipped",
face.FamilyName);
System.Diagnostics.Debug.Print(msg);
//throw new ApplicationException(msg);
}
return bmp;
}