GetContrastingColor
(
GraphDrawingContext oGraphDrawingContext,
Byte btAlpha,
Boolean bUseMaximumContrast
)
{
Debug.Assert(oGraphDrawingContext != null);
AssertValid();
return(WpfGraphicsUtil.SetWpfColorAlpha(
WpfGraphicsUtil.GetContrastingColor(
oGraphDrawingContext.BackColor,
bUseMaximumContrast), btAlpha));
}
DrawLabelBackground
(
DrawingContext oDrawingContext,
GraphDrawingContext oGraphDrawingContext,
FormattedText oFormattedText,
Color oFormattedTextColor,
Byte btBackgroundAlpha,
Point oTextOrigin
)
{
Debug.Assert(oDrawingContext != null);
Debug.Assert(oGraphDrawingContext != null);
Debug.Assert(oFormattedText != null);
AssertValid();
if (oFormattedText.Width == 0 || oFormattedText.Height == 0)
{
return;
}
// Note: Don't make the background any more opaque than the text, which
// might be translucent itself.
Color oBackgroundColor = WpfGraphicsUtil.SetWpfColorAlpha(
oGraphDrawingContext.BackColor,
Math.Min(btBackgroundAlpha, oFormattedTextColor.A));
SolidColorBrush oBackgroundBrush = CreateFrozenSolidColorBrush(
oBackgroundColor);
Rect oBackgroundRectangle = WpfGraphicsUtil.GetFormattedTextBounds(
oFormattedText, oTextOrigin);
// Draw a rounded rectangle with a small amount of padding.
const Int32 Padding = 1;
const Int32 Radius = 2;
oBackgroundRectangle.Inflate(Padding, Padding);
oDrawingContext.DrawRoundedRectangle(oBackgroundBrush, null,
oBackgroundRectangle, Radius, Radius);
}
DrawLabel
(
DrawingContext oDrawingContext,
GraphDrawingContext oGraphDrawingContext,
Point oEdgeEndpoint1,
Point oEdgeEndpoint2,
String sLabel,
Color oColor
)
{
Debug.Assert(oDrawingContext != null);
Debug.Assert(oGraphDrawingContext != null);
Debug.Assert(sLabel != null);
AssertValid();
if (sLabel.Length == 0)
{
return;
}
sLabel = TruncateLabel(sLabel);
if (oEdgeEndpoint2.X < oEdgeEndpoint1.X)
{
// Don't let text be drawn upside-down.
Point oTemp = oEdgeEndpoint2;
oEdgeEndpoint2 = oEdgeEndpoint1;
oEdgeEndpoint1 = oTemp;
}
Double dEdgeAngleDegrees = MathUtil.RadiansToDegrees(
WpfGraphicsUtil.GetAngleBetweenPoints(
oEdgeEndpoint1, oEdgeEndpoint2));
Double dEdgeLength = WpfGraphicsUtil.GetDistanceBetweenPoints(
oEdgeEndpoint1, oEdgeEndpoint2);
// To avoid trigonometric calculations, use a RotateTransform to make
// the edge look as if it is horizontal, with oEdgeEndpoint2 to the
// right of oEdgeEndpoint1.
RotateTransform oRotateTransform = new RotateTransform(
dEdgeAngleDegrees, oEdgeEndpoint1.X, oEdgeEndpoint1.Y);
oEdgeEndpoint2 = oRotateTransform.Transform(oEdgeEndpoint2);
oRotateTransform.Angle = -dEdgeAngleDegrees;
oDrawingContext.PushTransform(oRotateTransform);
FormattedText oFormattedText = CreateFormattedText(sLabel, oColor);
oFormattedText.Trimming = TextTrimming.CharacterEllipsis;
if (sLabel.IndexOf('\n') == -1)
{
// Unless the label includes line breaks, don't allow the
// FormattedText class to break the text into multiple lines.
oFormattedText.MaxLineCount = 1;
}
Double dTextWidth = oFormattedText.Width;
// The ends of the label text are between one and two "buffer units"
// from the ends of the edge. The buffer unit is the width of an
// arbitrary character.
Double dBufferUnit = CreateFormattedText("i", oColor).Width;
Double dEdgeLengthMinusBuffers = dEdgeLength - 2 * dBufferUnit;
if (dEdgeLengthMinusBuffers <= 0)
{
return;
}
// Determine where to draw the label text, and where to draw a
// translucent rectangle behind the text. The translucent rectangle
// serves to obscure, but not completely hide, the underlying edge.
Point oLabelOrigin = oEdgeEndpoint1;
Rect oTranslucentRectangle;
if (dTextWidth > dEdgeLengthMinusBuffers)
{
// The label text should start one buffer unit from the first
// endpoint, and terminate with ellipses approximately one buffer
// length from the second endpoint.
oLabelOrigin.Offset(dBufferUnit, 0);
oFormattedText.MaxTextWidth = dEdgeLengthMinusBuffers;
// The translucent rectangle should be the same width as the text.
oTranslucentRectangle = new Rect(oLabelOrigin,
new Size(dEdgeLengthMinusBuffers, oFormattedText.Height));
}
else
{
// The label should be centered along the edge's length.
oLabelOrigin.Offset(dEdgeLength / 2.0, 0);
oFormattedText.TextAlignment = TextAlignment.Center;
// The translucent rectangle should extend between zero and one
// buffer units beyond the ends of the text. This provides a
// margin between the text and the unobscured edge, if there is
// enough space.
oTranslucentRectangle = new Rect(oLabelOrigin,
new Size(
Math.Min(dTextWidth + 2 * dBufferUnit,
dEdgeLengthMinusBuffers),
oFormattedText.Height)
);
oTranslucentRectangle.Offset(
-oTranslucentRectangle.Width / 2.0, 0);
}
// The text and rectangle should be vertically centered on the edge.
oDrawingContext.PushTransform(
new TranslateTransform(0, -oFormattedText.Height / 2.0));
// Draw the translucent rectangle, then the text.
//
// Note: Don't make the rectangle any more opaque than the edge, which
// might be translucent itself.
oDrawingContext.DrawRectangle(GetBrush(
WpfGraphicsUtil.SetWpfColorAlpha(oGraphDrawingContext.BackColor,
Math.Min(LabelBackgroundAlpha, oColor.A))
),
null, oTranslucentRectangle);
oDrawingContext.DrawText(oFormattedText, oLabelOrigin);
oDrawingContext.Pop();
oDrawingContext.Pop();
}
