/// <summary>
/// When a GDI instruction with a brush parameter is called, there can be a lot we have to do to emulate the brush. The aim is to return a
/// style that represents the brush.
/// <para>
/// Solid brush is very easy.
/// </para>
/// <para>
/// Linear grad brush: we ignore the blend curve and the transformation (and therefore the rotation parameter if any)
/// Hatch brush:
/// </para>
/// <para>
/// Other types of brushes are too hard to emulate and are rendered pink.
/// </para>
/// </summary>
/// <param name="br"></param>
/// <returns></returns>
private SvgStyle HandleBrush(Brush br)
{
if (br.GetType() == typeof(SolidBrush))
{
return new SvgStyle((SolidBrush)br);
}
if (br.GetType() == typeof(LinearGradientBrush))
{
LinearGradientBrush grbr = (LinearGradientBrush)br;
RectangleF rc = grbr.Rectangle;
SvgLinearGradient grad = new SvgLinearGradient(rc.Left, rc.Top, rc.Right, rc.Bottom);
switch(grbr.WrapMode)
{
//I have not been able to test Clamp because using a clamped gradient appears to crash the process
//under XP (?!?!)
case WrapMode.Clamp:
grad.SpreadMethod = "pad"; grad.GradientUnits = "objectBoundingBox"; break;
case WrapMode.Tile:
grad.SpreadMethod = "repeat"; grad.GradientUnits = "userSpaceOnUse"; break;
default:
grad.SpreadMethod = "reflect"; grad.GradientUnits = "userSpaceOnUse"; break;
}
ColorBlend cb = null;
//GDI dll tends to crash when you try and access some members of gradient brushes that haven't been specified.
try
{
cb = grbr.InterpolationColors;
}
catch(Exception){}
if(cb != null)
{
for(int i = 0; i < grbr.InterpolationColors.Colors.Length; ++i)
{
grad.AddChild(new SvgStopElement(grbr.InterpolationColors.Positions[i], grbr.InterpolationColors.Colors[i]));
}
}
else
{
grad.AddChild(new SvgStopElement("0%", grbr.LinearColors[0]));
grad.AddChild(new SvgStopElement("100%", grbr.LinearColors[1]));
}
grad.Id += "_LinearGradientBrush";
_defs.AddChild(grad);
SvgStyle s = new SvgStyle();
s.Set("fill", new SvgUriReference(grad));
return s;
}
if (br.GetType() == typeof(HatchBrush))
{
HatchBrush habr = (HatchBrush)br;
SvgPatternElement patty = new SvgPatternElement(0,0,8,8, new SvgNumList("4 4 12 12"));
patty.Style.Set("shape-rendering", "crispEdges");
patty.Style.Set("stroke-linecap", "butt");
SvgRectElement rc = new SvgRectElement(0,0,8,8);
rc.Style.Set("fill", new SvgColor(habr.BackgroundColor));
patty.AddChild(rc);
AddHatchBrushDetails(patty, new SvgColor(habr.ForegroundColor), habr.HatchStyle);
patty.Id += "_HatchBrush";
patty.PatternUnits = "userSpaceOnUse";
patty.PatternContentUnits = "userSpaceOnUse";
_defs.AddChild(patty);
SvgStyle s = new SvgStyle();
s.Set("fill", new SvgUriReference(patty));
return s;
}
//most types of brush we can't emulate, but luckily they are quite unusual
return new SvgStyle(new SolidBrush(Color.Salmon));
}
