public void DrawText(
Graphics graphics,
Bitmap backing,
Point position,
Color foreColor,
Color backColor)
{
COLORREF foreColorRef = new COLORREF(foreColor);
int width = backing.Width;
int height = backing.Height;
Rectangle bounds = new Rectangle(0, 0, width, height);
Rectangle margin = new Rectangle(-height, 0, width + 2 * height, height);
Debug.Assert(service.offscreenStrip != null);
Debug.Assert(service.offscreenStrip.Width == width);
Debug.Assert(service.offscreenStrip.Height == height);
using (GDIBrush backBrush = new GDIBrush(backColor))
{
GDI.FillRect(service.hdcOffscreenStrip, ref bounds, backBrush);
}
ProcessText(
position,
delegate (
int iItem,
Point where,
int endX,
ref SCRIPT_ITEM item,
ref ItemInfo itemExtra,
Font font)
{
if (!graphics.IsVisible(new Rectangle(where.X - height, 0, endX - where.X + 2 * height, height)))
{
return true;
}
int fontCacheIndex = service.FontCacheIndex(font);
GDI.SetTextColor(service.hdcOffscreenStrip, foreColorRef);
GDI.SetBkMode(service.hdcOffscreenStrip, GDI.TRANSPARENT);
GDI.SelectObject(service.hdcOffscreenStrip, service.fontToHFont[font]);
int hr = ScriptTextOut(
service.hdcOffscreenStrip,
ref service.caches[fontCacheIndex].cache,
where.X,
where.Y,
(ScriptTextOutOptions)0,
IntPtr.Zero/*cliprect*/,
ref item.a,
IntPtr.Zero/*reserved*/,
0/*reserved*/,
itemExtra.glyphs,
itemExtra.cGlyphs,
itemExtra.iAdvances,
null/*piJustify*/,
itemExtra.goffsets);
if (hr < 0)
{
Marshal.ThrowExceptionForHR(hr);
}
return true;
});
using (GDIRegion gdiRgnClip = new GDIRegion(graphics.Clip.GetHrgn(graphics)))
{
using (GraphicsHDC gdiHdcOffscreen = new GraphicsHDC(graphics))
{
// Graphics/GDI+ doesn't pass clip region through so we have to reset it explicitly
GDI.SelectClipRgn(gdiHdcOffscreen, gdiRgnClip);
GDI.BitBlt(
gdiHdcOffscreen,
0,
0,
width,
height,
service.hdcOffscreenStrip,
0,
0,
GDI.SRCCOPY);
}
}
}
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);
}