/// <summary>
/// Draws a layout with a given style to the render context.
/// </summary>
/// <param name="displayContext">The display context.</param>
/// <param name="renderContext">The render context.</param>
/// <param name="region">The region for the various elements.</param>
/// <param name="style">The style used for borders and padding.</param>
public static void DrawLayout(
IDisplayContext displayContext,
IRenderContext renderContext,
Rectangle region,
BlockStyle style)
{
// If we don't have a style, then don't do anything.
if (style == null)
{
return;
}
// Get the style for the line number.
Spacing margins = style.GetMargins();
Borders borders = style.GetBorders();
double marginLeftX = margins.Left + borders.Left.LineWidth;
double marginRightX = margins.Right + borders.Right.LineWidth;
// Get the context and save settings because we use anti-aliasing
// to get a sharper line.
Context cairoContext = renderContext.CairoContext;
Antialias oldAntialias = cairoContext.Antialias;
try
{
// Draw the background color.
Color?backgroundColor = style.GetBackgroundColor();
if (backgroundColor.HasValue)
{
var cairoArea = new Rectangle(
region.X + marginLeftX,
region.Y,
region.Width - marginLeftX - marginRightX,
region.Height);
cairoContext.Color = backgroundColor.Value;
cairoContext.Rectangle(cairoArea);
cairoContext.Fill();
}
// Figure out the width for rendering the horizontal borders so
// they line up a little bit nicer. We adjust for half the border
// width because Cairo draws in the middle and we have to shift by
// half that to get the side to line up with the end of the
// horizontal.
double topMarginY = region.Y + margins.Top;
double bottomMarginY = region.Y + region.Height - margins.Bottom;
double leftMarginX = region.X + margins.Left + (borders.Left.LineWidth / 2);
double rightMarginX = leftMarginX + region.Width - margins.Width;
// Draw the border lines.
cairoContext.Antialias = Antialias.None;
if (borders.Top.LineWidth > 0)
{
// Set up the line width and colors.
cairoContext.LineWidth = borders.Top.LineWidth;
cairoContext.Color = borders.Top.Color;
cairoContext.MoveTo(leftMarginX, topMarginY);
cairoContext.LineTo(rightMarginX, topMarginY);
cairoContext.Stroke();
}
if (borders.Bottom.LineWidth > 0)
{
cairoContext.LineWidth = borders.Bottom.LineWidth;
cairoContext.Color = borders.Bottom.Color;
cairoContext.MoveTo(leftMarginX, bottomMarginY);
cairoContext.LineTo(rightMarginX, bottomMarginY);
cairoContext.Stroke();
}
if (borders.Left.LineWidth > 0)
{
cairoContext.LineWidth = borders.Left.LineWidth;
cairoContext.Color = borders.Left.Color;
cairoContext.MoveTo(region.X + marginLeftX, topMarginY);
cairoContext.LineTo(region.X + marginLeftX, bottomMarginY);
cairoContext.Stroke();
}
if (borders.Right.LineWidth > 0)
{
cairoContext.LineWidth = borders.Right.LineWidth;
cairoContext.Color = borders.Right.Color;
cairoContext.MoveTo(region.X + region.Width - margins.Right, topMarginY);
cairoContext.LineTo(region.X + region.Width - margins.Right, bottomMarginY);
cairoContext.Stroke();
}
}
finally
{
// Restore the context.
cairoContext.Antialias = oldAntialias;
}
}
