internal unsafe static void DrawLine(this Gdi32.HDC hdc, Gdi32.HPEN pen, int x1, int y1, int x2, int y2)
{
using var ropScope = new Gdi32.SetRop2Scope(hdc, Gdi32.R2.COPYPEN);
using var bkScope = new Gdi32.SetBkModeScope(hdc, Gdi32.BKMODE.TRANSPARENT);
using var selection = new Gdi32.SelectObjectScope(hdc, pen);
Point oldPoint = new Point();
Gdi32.MoveToEx(hdc, x1, y1, &oldPoint);
Gdi32.LineTo(hdc, x2, y2);
Gdi32.MoveToEx(hdc, oldPoint.X, oldPoint.Y, &oldPoint);
}
/// <summary>
/// Draws the text in the given bounds, using the given Font, foreColor and backColor, and according to the specified
/// TextFormatFlags flags.
///
/// If font is null, the font currently selected in the hdc is used.
///
/// If foreColor and/or backColor are Color.Empty, the hdc current text and/or background color are used.
/// </summary>
public static void DrawText(
this Gdi32.HDC hdc,
ReadOnlySpan <char> text,
FontCache.Scope font,
Rectangle bounds,
Color foreColor,
User32.DT flags,
Color backColor = default,
TextPaddingOptions padding = default)
{
if (text.IsEmpty || foreColor == Color.Transparent)
{
return;
}
ValidateFlags(flags);
// DrawText requires default text alignment.
using var alignment = new Gdi32.SetTextAlignmentScope(hdc, default);
// Color empty means use the one currently selected in the dc.
using var textColor = foreColor.IsEmpty ? default : new Gdi32.SetTextColorScope(hdc, foreColor);
using var fontSelection = new Gdi32.SelectObjectScope(hdc, (Gdi32.HFONT)font);
Gdi32.BKMODE newBackGroundMode = (backColor.IsEmpty || backColor == Color.Transparent) ?
Gdi32.BKMODE.TRANSPARENT :
Gdi32.BKMODE.OPAQUE;
using var backgroundMode = new Gdi32.SetBkModeScope(hdc, newBackGroundMode);
using var backgroundColor = newBackGroundMode != Gdi32.BKMODE.TRANSPARENT
? new Gdi32.SetBackgroundColorScope(hdc, backColor)
: default;
User32.DRAWTEXTPARAMS dtparams = GetTextMargins(font, padding);
bounds = AdjustForVerticalAlignment(hdc, text, bounds, flags, ref dtparams);
// Adjust unbounded rect to avoid overflow since Rectangle ctr does not do param validation.
if (bounds.Width == TextRenderer.MaxSize.Width)
{
bounds.Width -= bounds.X;
}
if (bounds.Height == TextRenderer.MaxSize.Height)
{
bounds.Height -= bounds.Y;
}
RECT rect = bounds;
User32.DrawTextExW(hdc, text, ref rect, flags, ref dtparams);
}
/// <summary>
/// Draws lines with the <paramref name="hpen"/> using points defined in <paramref name="lines"/>.
/// </summary>
/// <param name="lines">
/// MUST be a mulitple of 4. Each group of 4 represents x1, y1, x2, y2.
/// </param>
internal unsafe static void DrawLines(this Gdi32.HDC hdc, Gdi32.HPEN hpen, ReadOnlySpan <int> lines)
{
Debug.Assert((lines.Length % 4) == 0);
using var ropScope = new Gdi32.SetRop2Scope(hdc, Gdi32.R2.COPYPEN);
using var bkScope = new Gdi32.SetBkModeScope(hdc, Gdi32.BKMODE.TRANSPARENT);
using var selection = new Gdi32.SelectObjectScope(hdc, hpen);
Point oldPoint = new Point();
for (int i = 0; i < lines.Length; i += 4)
{
Gdi32.MoveToEx(hdc, lines[i], lines[i + 1], &oldPoint);
Gdi32.LineTo(hdc, lines[i + 2], lines[i + 3]);
Gdi32.MoveToEx(hdc, oldPoint.X, oldPoint.Y, null);
}
}
