public override void ScrollViewportVerticallyByLines(VSTE.ScrollDirection direction, int count)
{
if (count < 0)
{
throw new ArgumentOutOfRangeException(nameof(count));
}
if (direction == VSTE.ScrollDirection.Up)
{
double pixels = 0;
var line = hexView.HexViewLines.FirstVisibleLine;
for (int i = 0; i < count; i++)
{
if (i == 0)
{
if (line.VisibilityState == VSTF.VisibilityState.PartiallyVisible)
{
pixels += hexView.ViewportTop - line.Top;
}
if (line.BufferStart > hexView.BufferLines.BufferStart)
{
line = hexView.GetHexViewLineContainingBufferPosition(line.BufferStart - 1);
pixels += line.Height;
}
}
else
{
if (line.VisibilityState == VSTF.VisibilityState.Unattached)
{
// Height is only fully initialized once it's been shown on the screen
// (its LineTransform property is used to calculate Height)
var lineStart = line.BufferStart;
hexView.DisplayHexLineContainingBufferPosition(lineStart, 0, VSTE.ViewRelativePosition.Top);
line = hexView.GetHexViewLineContainingBufferPosition(lineStart);
Debug.Assert(line.VisibilityState != VSTF.VisibilityState.Unattached);
pixels = 0;
}
else
{
pixels += line.Height;
}
}
if (line.BufferStart <= hexView.BufferLines.BufferStart)
{
break;
}
line = hexView.GetHexViewLineContainingBufferPosition(line.BufferStart - 1);
}
if (pixels != 0)
{
ScrollViewportVerticallyByPixels(pixels);
}
}
else
{
Debug.Assert(direction == VSTE.ScrollDirection.Down);
double pixels = 0;
var line = hexView.HexViewLines.FirstVisibleLine;
for (int i = 0; i < count; i++)
{
if (line.IsLastDocumentLine())
{
break;
}
if (i == 0)
{
if (line.VisibilityState == VSTF.VisibilityState.FullyVisible)
{
pixels += line.Height;
}
else
{
pixels += line.Bottom - hexView.ViewportTop;
line = hexView.GetHexViewLineContainingBufferPosition(line.BufferEnd);
pixels += line.Height;
}
}
else
{
if (line.VisibilityState == VSTF.VisibilityState.Unattached)
{
// Height is only fully initialized once it's been shown on the screen
// (its LineTransform property is used to calculate Height)
var lineStart = line.BufferStart;
hexView.DisplayHexLineContainingBufferPosition(lineStart, 0, VSTE.ViewRelativePosition.Top);
line = hexView.GetHexViewLineContainingBufferPosition(lineStart);
Debug.Assert(line.VisibilityState != VSTF.VisibilityState.Unattached);
pixels = 0;
}
else
{
pixels += line.Height;
}
}
if (line.IsLastDocumentLine())
{
break;
}
line = hexView.GetHexViewLineContainingBufferPosition(line.BufferEnd);
}
if (pixels != 0)
{
ScrollViewportVerticallyByPixels(-pixels);
}
}
}