/// <summary>
/// Creates a WindowsFont from the font selected in the supplied dc.
/// </summary>
public static WindowsFont FromHdc(IntPtr hdc)
{
IntPtr hFont = Gdi32.GetCurrentObject(hdc, Gdi32.ObjectType.OBJ_FONT);
// don't call DeleteObject on handle from GetCurrentObject, it is the one selected in the hdc.
return(FromHfont(hFont));
}
// Due to a problem with calling DeleteObject() on currently selected GDI objects,
// we now track the initial set of objects when a DeviceContext is created. Then,
// we also track which objects are currently selected in the DeviceContext. When
// a currently selected object is disposed, it is first replaced in the DC and then
// deleted.
private void CacheInitialState()
{
_hCurrentPen = _hInitialPen = Gdi32.GetCurrentObject(new HandleRef(this, _hDC), Gdi32.ObjectType.OBJ_PEN);
_hCurrentBrush = _hInitialBrush = Gdi32.GetCurrentObject(new HandleRef(this, _hDC), Gdi32.ObjectType.OBJ_BRUSH);
_hCurrentBmp = _hInitialBmp = Gdi32.GetCurrentObject(new HandleRef(this, _hDC), Gdi32.ObjectType.OBJ_BITMAP);
_hCurrentFont = _hInitialFont = Gdi32.GetCurrentObject(new HandleRef(this, _hDC), Gdi32.ObjectType.OBJ_FONT);
}
// Not all state is handled yet. Backfilling in as we write specific tests. Of special note is that we don't
// have tracking for Save/RestoreDC yet.
/// <summary>
/// Initialize the current state of <paramref name="hdc"/>.
/// </summary>
public DeviceContextState(Gdi32.HDC hdc)
{
MapMode = Gdi32.GetMapMode(hdc);
BackColor = Gdi32.GetBkColor(hdc);
TextColor = Gdi32.GetTextColor(hdc);
Rop2Mode = Gdi32.GetROP2(hdc);
TextAlign = Gdi32.GetTextAlign(hdc);
BackgroundMode = Gdi32.GetBkMode(hdc);
Point point = default;
Gdi32.GetBrushOrgEx(hdc, ref point);
BrushOrigin = point;
var hfont = Gdi32.GetCurrentObject(hdc, Gdi32.OBJ.FONT);
Gdi32.GetObjectW(hfont, out User32.LOGFONTW logfont);
SelectedFont = logfont;
var hpen = Gdi32.GetCurrentObject(hdc, Gdi32.OBJ.PEN);
Gdi32.GetObjectW(hpen, out Gdi32.LOGPEN logpen);
SelectedPen = logpen;
var hbrush = Gdi32.GetCurrentObject(hdc, Gdi32.OBJ.BRUSH);
Gdi32.GetObjectW(hbrush, out Gdi32.LOGBRUSH logbrush);
SelectedBrush = logbrush;
}
// Due to a problem with calling DeleteObject() on currently selected GDI objects,
// we now track the initial set of objects when a DeviceContext is created. Then,
// we also track which objects are currently selected in the DeviceContext. When
// a currently selected object is disposed, it is first replaced in the DC and then
// deleted.
private void CacheInitialState()
{
Debug.Assert(_hDC != IntPtr.Zero, "Cannot get initial state without a valid HDC");
_hCurrentPen = _hInitialPen = Gdi32.GetCurrentObject(new HandleRef(this, _hDC), Gdi32.ObjectType.OBJ_PEN);
_hCurrentBrush = _hInitialBrush = Gdi32.GetCurrentObject(new HandleRef(this, _hDC), Gdi32.ObjectType.OBJ_BRUSH);
_hCurrentBmp = _hInitialBmp = Gdi32.GetCurrentObject(new HandleRef(this, _hDC), Gdi32.ObjectType.OBJ_BITMAP);
_hCurrentFont = _hInitialFont = Gdi32.GetCurrentObject(new HandleRef(this, _hDC), Gdi32.ObjectType.OBJ_FONT);
}
public static FontCache.Scope GetHFONT(Font?font, Gdi32.QUALITY quality, Gdi32.HDC hdc)
{
if (font != null)
{
return(GetHFONT(font, quality));
}
// Font is null, build off of the specified HDC's current font.
Gdi32.HFONT hfont = (Gdi32.HFONT)Gdi32.GetCurrentObject(hdc, Gdi32.OBJ.FONT);
return(new FontCache.Scope(hfont));
}
internal void DisposeFont(bool disposing)
{
if (disposing)
{
DeviceContexts.RemoveDeviceContext(this);
}
if (selectedFont != null && selectedFont.Hfont != IntPtr.Zero)
{
IntPtr hCurrentFont = Gdi32.GetCurrentObject(new HandleRef(this, hDC), Gdi32.ObjectType.OBJ_FONT);
if (hCurrentFont == selectedFont.Hfont)
{
// select initial font back in
Gdi32.SelectObject(new HandleRef(this, Hdc), hInitialFont);
hCurrentFont = hInitialFont;
}
selectedFont.Dispose(disposing);
selectedFont = null;
}
}