protected override DrawingVisual RenderCore(RenderParameters renderParams)
{
if (drawingVisual == null)
{
drawingVisual = new DrawingVisual();
}
if (null == currentScript)
{
return(drawingVisual); // No active script yet!
}
System.Windows.Point linePosition = new System.Windows.Point(
Configurations.CanvasMarginLeft, 0);
ITextEditorCore textCore = textEditorCanvas.TextEditorCore;
ITextBuffer textBuffer = currentScript.GetTextBuffer();
numberOfLines = textBuffer.GetLineCount();
int lastVisibleLine = renderParams.firstVisibleLine + renderParams.maxVisibleLines;
if (lastVisibleLine >= numberOfLines)
{
lastVisibleLine = numberOfLines - 1;
}
// Retrieve the DrawingContext from the DrawingVisual.
DrawingContext context = drawingVisual.RenderOpen();
int maxColumns = textEditorCanvas.MaxVisibelColumns + 1;
double hiddenWidth = textEditorCanvas.FirstVisibleColumn * Configurations.FormatFontWidth;
CharPosition converter = this.currentScript.CreateCharPosition();
Typeface font = new Typeface(Configurations.FontFace);
for (int lineIndex = renderParams.firstVisibleLine; lineIndex <= lastVisibleLine; lineIndex++)
{
// A constant starting point on left edge.
linePosition.X = Configurations.CanvasMarginLeft;
int startColumn = converter.VisualToCharOffset(lineIndex, textEditorCanvas.FirstVisibleColumn);
string lineContent = textBuffer.GetLineContent(lineIndex);
int lineLength = (lineContent != null ? lineContent.Length : 0);
if (lineLength <= startColumn)
{
linePosition.Y += Configurations.FontDisplayHeight;
continue;
}
if (startColumn > 0)
{
string hiddenText = lineContent.Substring(0, startColumn);
hiddenText = hiddenText.Replace("\t", Configurations.TabSpaces);
// Accounting for the part that is hidden beyond the left of canvas.
double hiddenTextWidth = hiddenText.Length * Configurations.FormatFontWidth;
linePosition.X = linePosition.X + hiddenTextWidth - hiddenWidth;
}
int endColumn = startColumn + maxColumns;
endColumn = ((endColumn >= lineLength) ? lineLength - 1 : endColumn);
for (int charIndex = startColumn; charIndex <= endColumn; charIndex++)
{
CodeFragment fragment = null;
int fragmentWidth = textCore.GetFragment(
charIndex, lineIndex, out fragment);
// We may be showing partial fragment now.
if (null != fragment)
{
fragmentWidth -= (charIndex - fragment.ColStart);
}
int offsetToNextChar = fragmentWidth - 1;
if ((charIndex + fragmentWidth) > (lineLength - 1))
{
fragmentWidth = (lineLength - 1) - charIndex;
offsetToNextChar = fragmentWidth - 1;
}
// Initialize the text store.
string textContent = string.Empty;
textContent = lineContent.Substring(charIndex,
((fragmentWidth == 0) ? 1 : fragmentWidth));
// Replace all TAB characters with actual spaces.
textContent = textContent.Replace("\t", Configurations.TabSpaces);
CodeFragment.Type fragmentType = CodeFragment.Type.None;
if (null != fragment)
{
fragmentType = fragment.CodeType;
}
Color textColor = CodeFragment.GetFragmentColor(fragmentType);
if ((textBuffer.ParsePending == true) && (fragmentType == CodeFragment.Type.None))
{
textColor = Colors.Black;
}
FormattedText formattedText = new FormattedText(
textContent,
CultureInfo.GetCultureInfo("en-us"),
FlowDirection.LeftToRight,
font,
Configurations.FontHeight,
new SolidColorBrush(textColor));
// Draw the formatted text into the drawing context.
context.DrawText(formattedText, linePosition);
if (lineContent[charIndex] == '\n')
{
break;
}
else
{
linePosition.X += formattedText.WidthIncludingTrailingWhitespace;
}
if (fragmentWidth > 0)
{
charIndex += offsetToNextChar;
}
}
// Update the line position coordinate for the displayed line.
linePosition.Y += Configurations.FontDisplayHeight;
}
// Persist the drawn text content.
context.Close();
return(drawingVisual);
}
