// This idea was borrowed from Google Chrome's uniscribe handler:
// https://code.google.com/p/chromium/codesearch#chromium/src/ui/gfx/font_fallback_win.cc&q=uniscribe&sq=package:chromium&l=283&dr=CSs
// also as discussed here:
// http://stackoverflow.com/questions/16828868/how-to-automatically-choose-most-suitable-font-for-different-language
private static bool GetUniscribeFallbackFont(
Font font,
IntPtr text,
int textLength,
out GDI.LOGFONT fallbackFont)
{
fallbackFont = new GDI.LOGFONT();
// Figure out what font Uniscribe chooses for fallback by making it write to a
// metafile and then cracking it open.
using (GDIDC hdc = GDIDC.CreateCompatibleDC(IntPtr.Zero))
{
IntPtr hdcMF_ = GDI.CreateEnhMetaFile(hdc, null, IntPtr.Zero, null);
if (hdcMF_ == IntPtr.Zero)
{
Marshal.ThrowExceptionForHR(Marshal.GetHRForLastWin32Error());
}
using (GDIDC hdcMF = new GDIDC(hdcMF_))
{
using (GDIFont gdiFont = new GDIFont(font))
{
GDI.SelectObject(hdcMF, gdiFont);
IntPtr sa = IntPtr.Zero;
try
{
int hr;
hr = ScriptStringAnalyse(
hdcMF,
text,
textLength,
0, // cGlyphs
-1, // iCharSet
SSA_METAFILE | SSA_FALLBACK | SSA_GLYPHS | SSA_LINK,
0, // required width
IntPtr.Zero, // SCRIPT_CONTROL
IntPtr.Zero, // SCRIPT_STATE
null, // piDx
IntPtr.Zero, // SCRIPT_TABDEF
null, // legacy
out sa);
if (hr < 0)
{
return false;
}
hr = ScriptStringOut(
sa,
0, // iX
0, // iY
0, // ExtTextOut options
IntPtr.Zero, // rect
0, // iMinSel
0, // iMaxSel
false); // fDisabled
if (hr < 0)
{
return false;
}
}
finally
{
ScriptStringFree(ref sa);
}
IntPtr hMF = GDI.CloseEnhMetaFile(hdcMF);
if (hMF == IntPtr.Zero)
{
Marshal.ThrowExceptionForHR(Marshal.GetHRForLastWin32Error());
}
try
{
GDI.LOGFONT lf = new GDI.LOGFONT();
bool r = GDI.EnumEnhMetaFile(
IntPtr.Zero, // hdc
hMF,
delegate (
IntPtr hdc_,
IntPtr[] lpht,// capacity is nHandles
IntPtr lpmr, // ENHMETARECORD
int nHandles,
int data) // LPARAM
{
// read lpmr->iType
int iType = Marshal.ReadInt32(lpmr);
if (iType == GDI.EMR_EXTCREATEFONTINDIRECTW)
{
object cfio = Marshal.PtrToStructure(lpmr, typeof(GDI.EMREXTCREATEFONTINDIRECT));
GDI.EMREXTCREATEFONTINDIRECT cfi = (GDI.EMREXTCREATEFONTINDIRECT)cfio;
// Last one wins!
lf = cfi.elfw.elfLogFont;
}
return 1;
},
IntPtr.Zero, // LPARAM
IntPtr.Zero); // &RECT
if (!r)
{
Marshal.ThrowExceptionForHR(Marshal.GetHRForLastWin32Error());
}
if (!String.IsNullOrEmpty(lf.lfFaceName))
{
fallbackFont = lf;
return true;
}
}
finally
{
GDI.DeleteEnhMetaFile(hMF);
}
return false;
}
}
}
}
public void Reset(
Font font,
int visibleWidth)
{
ClearCaches();
if (hdcOffscreenStrip != null)
{
hdcOffscreenStrip.Dispose();
hdcOffscreenStrip = null;
}
if (offscreenStrip != null)
{
offscreenStrip.Dispose();
offscreenStrip = null;
}
this.visibleWidth = visibleWidth;
// allocation of offscreenStrip is deferred until HDC is available to make compatible with
this.font = font;
}
public void Dispose()
{
ClearCaches();
if (hdcOffscreenStrip != null)
{
hdcOffscreenStrip.Dispose();
hdcOffscreenStrip = null;
}
if (offscreenStrip != null)
{
offscreenStrip.Dispose();
offscreenStrip = null;
}
GC.SuppressFinalize(this);
}
public ITextInfo AnalyzeText(
Graphics graphics,
Font font,
int fontHeight,
string line)
{
int index;
if ((index = line.IndexOfAny(new char[] { '\r', '\n' })) >= 0)
{
Debug.Assert(false);
throw new ArgumentException();
}
if (offscreenStrip == null)
{
using (GraphicsHDC hdc = new GraphicsHDC(graphics))
{
offscreenStrip = new GDIBitmap(visibleWidth, fontHeight, hdc);
}
Debug.Assert(hdcOffscreenStrip == null);
hdcOffscreenStrip = GDIDC.Create(offscreenStrip);
}
using (Pin<string> pinLine = new Pin<string>(line))
{
return TextItems.AnalyzeText(
this,
hdcOffscreenStrip,
pinLine.AddrOfPinnedObject(),
new FontRunInfo[] { new FontRunInfo(line.Length, font, fontHeight) });
}
}
public GDIOffscreenBitmap(Graphics graphicsCompatibleWith, int width, int height)
{
if ((width <= 0) || (height <= 0))
{
Debug.Assert(false);
throw new ArgumentException();
}
// Create GDI objects for offscreen. Must be created through GDI because Uniscribe/DirectWrite do not
// like objects created by GDI+ and will draw with very poor quality on them.
using (GraphicsHDC hDC = new GraphicsHDC(graphicsCompatibleWith))
{
this.hDC = GDIDC.CreateCompatibleDC(hDC);
hBitmap = new GDIBitmap(width, height, PixelFormat.Format32bppArgb);
GDI.SelectObject(this.hDC, hBitmap);
}
graphics = Graphics.FromHdc(hDC);
}
public static GDIDC Create(GDIBitmap bitmap)
{
IntPtr hdc = GDI.CreateCompatibleDC(IntPtr.Zero);
if (hdc == IntPtr.Zero)
{
Marshal.ThrowExceptionForHR(Marshal.GetHRForLastWin32Error());
}
GDIDC gdidc = new GDIDC(hdc);
GDI.SelectObject(hdc, bitmap);
return gdidc;
}
