protected virtual void ComputeSize()
{
var longest = XAxis.GetLongestLabel();
AxisLabelPaint.Typeface = XAxis.Typeface;
AxisLabelPaint.TextSize = XAxis.TextSize;
var labelSize = AxisLabelPaint.Measure(longest);
float labelWidth = labelSize.Width;
float labelHeight = AxisLabelPaint.MeasureHeight("Q");
var labelRotatedSize = ChartUtil.GetSizeOfRotatedRectangleByDegrees(
labelWidth,
labelHeight,
XAxis.LabelRotationAngle);
XAxis.LabelWidth = (int)Math.Round(labelWidth);
XAxis.LabelHeight = (int)Math.Round(labelHeight);
XAxis.LabelRotatedWidth = (int)MathF.Round(labelRotatedSize.Width);
XAxis.LabelRotatedHeight = (int)MathF.Round(labelRotatedSize.Height);
}
public static void DrawXAxisValue(SKCanvas c, string text, float x, float y, SKPaint paint, SKPoint anchor, float angleDegrees)
{
float drawOffsetX = 0.0f;
float drawOffsetY = 0.0f;
SKRect bounds = SKRect.Empty;
float lineHeight = paint.GetFontMetrics(out SKFontMetrics fontMatrics);
paint.MeasureText(text, ref bounds);
// Android sometimes has pre-padding
drawOffsetX -= bounds.Left;
// Android does not snap the bounds to line boundaries,
// and draws from bottom to top.
// And we want to normalize it.
drawOffsetY += -fontMatrics.Ascent;
// To have a consistent point of reference, we always draw left-aligned
var originalTextAlign = paint.TextAlign;
paint.TextAlign = SKTextAlign.Left;
if (angleDegrees != 0.0f)
{
// Move the text drawing rect in a way that it always rotates around its center
drawOffsetX -= bounds.Width * 0.5f;
drawOffsetY -= lineHeight * 0.5f;
float translateX = x;
float translateY = y;
// Move the "outer" rect relative to the anchor, assuming its centered
if (anchor.X != 0.5f || anchor.Y != 0.5f)
{
var rotatedSize = ChartUtil.GetSizeOfRotatedRectangleByDegrees(
bounds.Width,
lineHeight,
angleDegrees);
translateX -= rotatedSize.Width * (anchor.X - 0.5f);
translateY -= rotatedSize.Height * (anchor.Y - 0.5f);
}
c.Save();
c.Translate(translateX, translateY);
c.RotateDegrees(angleDegrees);
c.DrawText(text, drawOffsetX, drawOffsetY, paint);
c.Restore();
}
else
{
if (anchor.X != 0.0f || anchor.Y != 0.0f)
{
drawOffsetX -= bounds.Width * anchor.X;
drawOffsetY -= lineHeight * anchor.Y;
}
drawOffsetX += x;
drawOffsetY += y;
c.DrawText(text, drawOffsetX, drawOffsetY, paint);
}
paint.TextAlign = originalTextAlign;
}